ptft pldr

CHAPTER.2
R,EVIEW OF LITERATIJR.O
code sh* dviroMdl! bel@ r[.y @ ua!|e to Dov. or
chorp th€n habiral. A@!di!g to . prej.ctio4 trcBrd icld of l[ mjor .griculiEl
cFp pldts k rEd@d de to €xposlr! !o dv* 6vi!1m@ts (B!j et al., 1999, Btty
^j
e, dl, 2000). Dtuugh slr6s is oft of th. main orwmdial fa.l6 ihat
"fre.l
podudion
(Bny
u/.,
2008)
becau.
al,
2000i
M6iva!)ro,t
{orldrid€ asricdnnal
a
weler is the most inpondt f&toi for plot grcqll| ed d€v€lopmcnt. Pl&tr idy
PbDts barc ro
lbe
add
€xpdi€M drcudt undd condition! tuch 3 low rainfall, hid salinily h $il or high
t@FEtw in the smudinss (Zh!, 2002). Dreu8lt c.ss saia deficit in Plets
*h'ch nltinrt€ly
6dts
in a
dc.rle
r.Lrirc wat r mnlent
in
pbdrs sufrd d6ic.ali@ (tado,2010).
ofliss
to a
How6, wld Equi@tut v&i6
I@l *b€t
nom cop to
os s@ dmusbr siBs fo. a c€rrab cop
$te@, a dlt sF[ of nG f@ ! ek Dy mr crl5,c droue]t foruelher Np.
Np- A few &)E *irbout dinfdl
Goe6Uy, dmught
is.
ptft
i5
2.1
pldr erewtb
E(et
De
lo
@ndilion
DAy
b qtich svrilobL
s@ly.f..r.d (Os@i.,
of drcughr
soil
ooi$'e
i5 r.du.€d ro a poirt
ar, !9E7).
ltiar
oBidenbL chdse
in lh.
wrld climt€ ed Bitfal Pan€d caed
by
.gssive
firl bmine dd global Bmilg (Coy.l, 2004; Kim ed Byua 2009), ih.1o1al did ea
of th€ world is ilclgidg spidly. ftis E@nt dobd chtugc in cljlale and incEding
utq ehonlge e Lading to huge Gootnio 10$6 in creP Fduciion ieludi4 tbd of
qlsr
(zhu,2002i Wmg e/ al., 2003i Hong-Bo ./ at, 2005; Enc..t al,201A) Moft
ebbol @
(tujar.o,2001: Ashsf, 2010).
rh6
50%
oG ihitd
of
in
u.l* wh..l cutirttron is afic.t d by dtuughl slrcss
I! b$ is vdy dc%ilting 3 eh€41is a slrple food rot
of6. wrld popialion,
mi{id climL (Alonymou, 2000). of lh. btal ?9.6 nilion h.
of the coury, only 9dlo 6eiB nor iha 508 m 6i! !q eM. M()mEr, thh
Binfall i5 Fediccd to cd@ turther i. tutur Kopt!., dl, 2004r Hone-Bo er 4l,
oily
2006b; Kin ard BtlA 2009). Mor d& 70 % of thc 6i!&I i! P*istar M
dwirc lhe @!s! Eortbs of I!., July ed Augun. Allho[gh $pdddd ini8alio.
by 6d Mlcr t .Eilablc foi Me ad., howr, it is mt Gooud ro frilfill th. reds or
P*&ia! ba d eid
ro
crops. This l€ads ro low !@nomic
yi.ld ofdiftcdr cop6 including wh.d,
Atve4 .fl..a, of dNlgbt rtra o! crcp lmwtb dd prod!.livily
h ha b.a qidcly sMicd thr. hcobnn ellility, chloophyll pigndtr oilotic
adjuhqt, wr.r r.l.lioEr rnd @t phordynrh.tic ot ofpl@rs gmeing undd dmughr
condinc @ badly.tr€cted sNiDs r dccr.e h sowt! sld icld (B!se ad Tud,
19?6; B@j@i! dd Niclsrl 20{6; PEb. s, al, 2009). Drought str.$ l*ds to difreht
2.2.
det$olic cheg€s in plet tissB (A.hrif.nd O'L.dy.
Deniml@ ./ 41. 2010).
Ih*
my b. ir
f@
1996;
Lwlor ard Cotuiq 2002i
h srivity of c.d!i!
dchlolit s 6d crzym6, ladirg 10 inLibi|d e[ dp.nsion ard r.duc.d gN*lh (AbEf
., 4r, 1995) or diltub@s in ga qch|.€! (Cohjc, 1994; NalE sd L.wlor, 2005) &d
Fodudio! of hmtul @1ir oxygen sF.i.s (P.lra. er al, 2002) whjch afeci plmt
nebholisn in diflqut wys dd cNse celhl& dmage (Rddy er 4t, 2004; Mal@j&
md Tuicja, 2005). In sho4 dnD8hi sr6! c.Es ch&ees in trny all pbess vitat for
gro*th md &v.lopDclt ofplets (Ctsv6
dr
the
of vuiarion
a,, 2003; Farwq r, al., 2010).
Dblght .ffects plsc ar all ere*tl slsg$ of rh.n ff. cyclc (Atmrd .r dl, 2oo9),
holffi, 61ain $.g.s skh a g@iDtioa sNdlbg establishmor dd llowring e€ ih!
non diticd pcnods (Arhftf dd Md4oo4 1990; Betoii .r 4a l999illti.s et a1.,20021
KhtrE€zh.d €r al, 2010). Ihe .dv!e .llel3 of dsuelt on s6d g@inrlio! ed
s..dling srcw$
YN[i2Mi
hrr! ben tboblgbly i!v61isrr!d
t,!]ii'&
et
in
!@y cbp 3pei6 (s.desbie
rd
al..2lt]9\. In r rccar stlldy, osoric arss in miz. sis fi@rty
dcEaed gemiroion pdafaee, ldgth of ndicsl ed plMul. dong wirh bionss
affiulalion of lecdlinss (Klayahezhad €r al, 2010). Hoycv.r, when $bFd€d b
dewlt rl bLr sLg6
moddating both ceu
n6,.i!
plrd delrlop|M! pL.ts &tidy GF%m ilcn g@,rb by
divisior ed .ell dpuion (Sknycz &d ri?e, 2Ol0) in order ro
of
.xdpl., Kla .r dt (200t) Fporrcd lha,r pl&t b.ishr, leaf @
ed st m dbseld of rnaie pler d..@ed signjfic&rty ufttcr dbughr 3tres. The
d6liE iD pler lEigh of s@OoE bls b@r .tEibded Mirly io r<turi@ ir c.tt
cdegcn.nr (Mdiv@tu sr ar, 200?a) dd @n nMbd (Ski.ycz et at.,2OtO\. Th.
dcci.{s. i! ell flrDbq k eirh6 du. b Foldgcd duatiu of c.I divis'd d ndsc{t
division de, Ii M Eported &!r rtrollghl atr€r.d lhe q to S phae tr.rsirior in
AEbidoFis dd 3!dow (cdlid &<l Tldiqr l9r; stirye ?, al, 20t 0).
@ll tugor. For
FBh rnd dry bioll4 of pldrs sufails ton elt . srr33 i, cGidehlly d.d*.d
(ArhEf aod O'l.ary, 196). Ewn a stighr dare in sGr @nr.n! m, lod to
idibition of phat gbert (Taiz &d zci8d, 2006). Ku$t! .r 4l (2005) Fpon d !
consi&nble
d.ficit
d.cl!* i!
dera!6 srcirt
fr€sh
widt
of
Fdt nil.r $bjetcd
to dtoudt slr6s. war.r
i.sfictins c.U dp€sion GDa, l9E5) l@dilg 10 i.duc.d
b,oms productior (ahraf ard Matn@d, 1990). rn maize, tlroughi srE$ led to
subsLdrrl iDp.imenr io
34% ar
by
biofri, s..muljrtio4
gain 6llin8 stas. ed
2 | % at
maiuiry
rbe
E<tetion
(Kmd
er
E
lTyo ai
si[ing i.gc,
at, 2003).
DnuCl-rclstcd Edudion of pbd gF*t! ed ietd ii @uscd bv
photosyrlh$is. PhorosyDrh*is @nrefts ligbl dFey inro
cbcDicat
dcc6c
tug)|
in
&d
syiiL6i2.s ory.nic cdpo@d! fo! pLtrB (tawlor, I995aj Triz ed z.igd, 2ooo.
Ir G
cxtr.tuly $Biriv. to.lrowbl srr.s be€!I. v.ala is cfuid for rhc nbctionirg of rhis
r[1)l* 0rwlor, 195.} Phorosyrthcab pdiriv.ly @fttatls with ptdt productiviv
(Cifford ed Evs, l98ti tj*tor, 1995.). A <Lctle h pbororlrbGis
dE 10 dreughr
stEs my b. sfuiburql b srombt
clore whi.h i.d|6 $ohatat condErarcc rcomic.
2000) Ladias to a d.qo!. ia rlEpir.tio. ald u}tarc of
CO, (Cohic, 194: t99:
Molnd !/ dt, 2002; PooFIi
€r
ul,
20t 0).
Plorotrindb tuy d$ d.c@ d@ to @-nooarat f&1ol' (Ftcxs.r ol, 2004),
wlt D
rctltrc wrer contol <trcps bclow ?Oyq rh. rcd@{o! in phorosynrheis is g.n Elly
loMtomid
atuibut d io
.ffdt (Kd*r,
rubis .nzr@ &c@s urd.r Ml€r
l9E7; Ennrfli .nd Eel, 2005). ntc
eliviry of
dcficn (Anin e, 41, 2009; DmiFvsta er 4a,
*tlich cdu6 ncl pborosynthBis. Mosi of thc Gvide@ d dsudr,indk€d
chdg.r ind,eG th.t rhc dour 6d &nviv of dbi$o @ftol photosyndaic ..rbor
2010)
Cq sinit.tio! ol! (lhorosrlrhetic 6te) of b.e
pldrs d.cEed dtuiGuy undd dreuchi (ZLtev dd Yordtuv, 2004). Lswtor (1995b)
Eport d r 16 i! photcynileti. !4rivity udo dsugh d@ to rhc d€crtas ir i.Grirl
Cq pc$w od lca in lbility of d€sophyU c.lls to photoslhthesize. Ir is pid.ly
Binilalion
(Reddy .r ai., 2004). Na
sc
eporI.d tb,l rct photoaynt!.tic
G,
of diflq€ni
199; Yousf
er
mp
dl,
(PJ, ranspinriotr E& (E) ald nomLt oDdElsee
sliccics d6rcr6ed uDdd drcudt slr.ss
20r 0;
Ali dd Ash.af,
201
ondilioN (Pekovic a al,
I). G.|mJy declin€
iI ss .xchag. (p-
E, g,)
,oliliEly @relat\* silh rhe inten$ity of deuehi shcs (Cimi@ et at., t992).
Ho@d, rhe cffer of dreushr @ ditr.Mr pb +oci6 vdi6. soBhm @utd
photosynth*ize ar a Frc up to 25% oflAim@ ai s leafwar€r poretrtial of -t .2 Mta, At
lhc @c !o&.ri.l, om lave silr.d lrd stow<l D pboroByntheis (BadL .r at,
1973). Me$@m6t of photoslnthesis hs b.m rcported u!.nrt in seniu plmis for
doughl6istsrc. b6ae it E0ers rhc ovlBtl bchlvid ofa pt&r sbj.crcd to wt r
dL$cn (S.bpi& aad plmhon, 1984; F.hina ed plmhoa 1994).
Chlobphyll pign.nts
dd "b'
e
pbe
ro
&. viiat
io hwest
dchrdnrio!
3rs
(2001) thc cblorcphyll conient of plmt
et at., t990.
lidl
(F.&oq
for photoslhthBi!. Both chlobphylt ..a,,
dr
dl., 2009)_
d.q€66 ttraslic.lly
R.ttuW et al.2005t Adjr .r zt,
,'@di4 b Chd6 ., a/.
under drcuejr srcss
2009). This
drc
i,
(Kwd.
cl oopnyu
conlent l.ads to disryeizarion of rhyLkoid
l)@blecs (L!dj.l e/ dl, 2000) th4by,
Gsult.g in l()M!e1ptoidynlh.iic 6la C 6pny[ |actinpl6nr g6e6ly de|las
or r soDe c€g rcmiB bchaScd ude drcu€h sr6s dcFndins on lh. duration ed
s.qity of dreudt (Kr?yo&isir ., dl, 1995; A{g ard KilrrM, 1995). for exmplq
d@ueht
stB cssld !
substaitrl
de.ile
in cht@phyU a cblorcphyll b md iolal
chlobphyll @nt. i! sudflo$E pl&t (Mdivat|m s, zr, 200?a). wttE6, a{B md
Kirkbd
ob6d.d tu cfl6t oD 6c cnbbphyll @ror! of sulnowq Dl6ir
subjot d to dDught stes nay b. d@ io nild drcught, On rh€ orhd had, Arhrf &tl
(1996)
K'rin (l9l) EF Ld s ilcr. !. in c[ooPhyU i! 3om. cltlim of bb.t 8m lnilc
dc.rtls in olh6, 'nEy cofftl|d.d tld lbi. ditrawc ban@ diffqal cultild ott
d@ to wiiio! in @yG iMlv.d i! t tytlh6i! of cblorePiyll af.cli!8 dtouSit
rolcrldcc .blity of tbc g.ootypca, TL chlotlllyn conLnts of dt@ght l.siriet
g.ooryF of sta!.dl e.,4 ew hiSba @DF !d lo {E .aitill SpnoDF utrds
d$lgbr st* (Pntdi &d T&pi 199, 193). SiDiltly,lh. cbldqhyll6ntds of
rlsiltot culiils of b.d!y tadcd ro b. hi8!d ttd lhd of &ouglt s.orilit
o|g (Rdg-Hu r, 4r, 2()6l Stly rra .bility E fould to b. .!.sid.d *il!
in'tllrd icld lDd trBpindon cfrcict y udcr d$uSht fBi i! sorghim (BotEll .r
al20O0i H.Bt!4.r.l,2mD.nd *h.d (B.abclt.nd Pt'n!co, l9E).
dNogbr
sLr od.or, laf e.Lr &d oloolic Po!.oti.b G lb. orin cobloFls of
plst $ld GLlioo! (Anjun,, ar., 201l). tt f*.Lr Potalid !!d oootic Po!6tirl of
Erir. (^li!!d A$!.f,20lD et .r (Adjci ed K*b!', l9E0) rnd tbnow (Ad!d
R.brivc
ed O'L.{y,
2007).
1996)
Cdrivc
wilh
.p.ei6 Fdu.d sisific&tly 'Edcr douSbl 3t* (Rodti .r ar'
bishd ndrctio! in lofooolic poi6li.l e coi.id.r.d Gid.lt to
Fqo5.d thd l..f sbc (dlnotic) Polalirl n vbc u$d a
drought tlrin m. clcclio! dicriod (Sojt!.r dr., l9El i Crtr.r &d Prll.r3oi' | 9E5) Soil
v!r.. poEltilt d.ct!.sd undd wlt r dcfcn cotdilids, 30 plrd! b&t to tlducc 6cir
douglt 3lF$.
I !$ ba
ltd Eridrh nlsor. ni. k elidrcd ttlmogh
tlE e@ul.tio6 of . vei.g of iloalnic &d oa.nic otaotkt ittcludiig @bFliblc
$ld6 nl.h s fmli& ed dyci!. ttLilc GL.!d it llfar.d lo.3 ocnolic ldjuslt!.dt
Gl!g, l9?9i Kcyvla 2010). Piolin i! lb non 3tudicd conpdiblc $lul! strch i5
lrDotud ro ircra. npidly uda ddgh (Anju ., ar., 201 l). fttu oldoic ldiNE cnt
6 *lil! lowrils of clll o6doic por.did urd.. dreugh h.lF i! pl&t gmelb &d
osrolic poiaiid in ddd to rb€orb e/sa
dcvdopn@l by prolidirg
Bid!@
Pd.!tli, 199) by DdDat,lN of Ei
@ducbF (DoMlo!,
PGl.ti!.
vd6 6
(Ddit!$16 ., ,r.,
cot
&ficit (Ludlow rdd Mubow' 1990;
plolotvltblic nL !!d hiSh 3tod.lal
to srd.r
l98ili OUF! dd BclowiE, l9E4
of k f tieaE i! dvc$.lv !ft.td bv dsahl s!3e
Ali .rd A!h6f. 201 l). RtldiE $rt6 cdiat of wll hvdlrlxl
nvq
2010:
tissB
is
!$ally
b.t@
E5'95o,6 (P!rdo, 2010)
cclls loF thcn nlgor
sdq
Lav6 declees. D!.
ro
dreu8ht
wd.
Bnich
wi6
Guftr, l98O w[.n
ia
difcMr sp.ci6 Pbnt
th€ Elatirc
lds of *at r. .eU nenb@6 dIy
ster 6nidr of
up, bc.ome
poios md
be thcn pbla fiDctioaiDg (L.vit! l9E0). It h obs..v.d thrl rhe s!6i6 ldap.td to dry
dvionlrMl! minllin bigha RWC dp.r.d to th. ollcrs. A@tding ro m. studi.s,
$drM suff.6 s smrllq d4rce in RWC p.t uil ch48e ir l4f w1c. Fot€nd.l {M
@don dd miz *ha subjd.d ro &o!dI stB (Actm dd Kri& 1977i kvitt,
l9E0). In a d6r s:rudy Yocf .r ar e0l0) EFn d thc cf€rs of urd rtEs @ *r&r
r.latio6 oftvo Tuisie alfdfr (n&dic4g rdt'rd) populltios ftom did ard mi{id
E8ioB. Tn y foud $ar wlGr deficil signi6@0y rcdE d rbc Fldiv. v.r.r @!tdt of
both populrtioa tuiftd, how6, rh. d..@ *!l lolq in t!. dreudl lol.rdt
populatior Maintcme of hid RwC ud€r linitcd waier b @Nidded a $islant
neheisn 1o drougbl s1!.6s ,trd is lw.sLld 3 a *l@lion qit don for drou€h
rolctle @ayd, 1980; Marin .r 41, l9E9; Riichic .r 41, l99q Gdt dd K.yomio,
t992).
A@rdi'g ro Foyr &d N6ror (2000), dreuebt sr* €lB d inb,tse h lidr
eptlring dd ib utilizalio. duing phol$yntlBir. Tht .xca a.r$/ is hmtul for
II b.c6w of o@rcducdon of the rcaction @nr€ (D.mj4 Adms ad
Adm, 199), Pbor.syst o ll (PS tr) !.iiviry is doM-Fgulsr.d Bultle in chag6 ir
qwtm icld, Excs clccrton Lir.g. @cN (ccen d 41, 1994; Asbhf,2009)
lodins ro disipation of fre iadicals of tdked oxygctr in the cl o.oplNrs (Sminof,
1993). IR t!! Fdtqb e ..--o"ry cdlcd s '!*d!e oxygcn !p.ci6, (ROS) or
'4tirc oxrs@ !p6i€s' (AOS). Th.s ROS inludc sin8l.r oxygen, erFrcxid. sion
phoios'slen
ndi.al, hydrcxy Fdicals, alkoxy n<l,cals
e, dr, 2010)- Th.
knoM
inj'ry caut d by
6 oxidatiE str*
ard is
@
and
rhe
hydrcgo Fbxid€ (Ashrd 2009; Csrelli
Ros
sh .! hydrc8@ Foride (rrrot is
of thc Mjor
drn S.lo
pt
nr.xp6ed
to
stEs
6 drclghl (Tartoua 2010). Mous od Abdel-Aziz (2008) Eponcd e incE6e in
HrO, @Loi in tuize uldq drclght strs. Horwd, thcy obs€d lha1th. uowr of
t!O2 Prrdrc.d in <lioughr rot@t cdrivG *6 ls onF&d ro thc drougbr eNidv€
such
oDB.
Sinild clulB wr€ Eloned
by H. a
at (20t l)
in
what.
12
@ .le piodald in pblts gDsirg dd€. ,orn l coqtrtioB Oone
2001), then Fodu.iiod is pDmor€d udd sa€s @ndiliois. Drought st€s es6 e
i!.!!e ir pDdEdoa of @.tivc oxtt@ speics (IrFire, l99t; Ashnf ed F@tad,
2007) stich !q@ly ttamage ihc lipid contat of menbrc teading b th€n
damage
ard di$4rio! (Mirdq,2002; A!hsl20o9). MDA (hatoldilkt tyd.) b.i4 !
bypr.ducl
ofihh m@btu dao.8c r.!.rion 0ipid p@nddion) @ b. N.d d ! n .sW ro de$
rhc mout of rhngc o!*.t ro eI @bturs (ZIdg er dr, 2007.,
Ftoog et ol.,
Although ROS
20t0).
Ardond,ni!
e
prcduc.d
i!
r+oc.
ro rh. ROS (A!bd,2009) ar v&ioB
e[
t@rioB
ir
wh@vd Erc1ive oxyg€n spe'.s e podeed. Ihe @io ROS swnsins
drjoxidats e tuFtonde disutas (SOB), a fdity of berattczloB ,!icb
trE
c{tartz€ rh. dilDutarioa of slperoxid. adical lo HrO, (Bowlq e/ at
, t'{r'l
200t; AsbEf,2009). SuFuidc disiie. @4D. Equis corpd (cu),
oalgh*
(Mn)
a
@f&ros.
wws .t
al.,
zinc (ZD) or
fte
crrod@ic i$fom equic oprE, rhe
Ejtocho!&ial o@ Equic brng&€$ qhile tle dra.ellule one rcquir.s Crrzn
(Diplelq l9a; M{Uud t99O). SOD,ciiviiy c& te dcrmined
on th€ b€lis of
inlibilion o{ a }€Uop @mpoud niDbl@ ctraaliu. cata.l.g (CAT3)
ud
F@xi&€ (POD9 fou'd itr Frcxis@6 @ h@c pbreid l|!r cslllr% th. mov,l of
H1O, by 64v.nidg ir ini! m1f (Asd4 1992; Dipt6t, 1994j
Wilhrcw e, ot , r!{/1j.
p@xi&*
Thd e svcrd fo@ of
CsldM cxisr in &c ba! iefo@: CATI.
cAI2, ed CAT3 (Will€tds
€r
st,
199?).
othd dzrraric elioxideis, !$Ibai!
Fmxidd (ApD, Stulattion Edera& (cR)
dd &ly&@rbare rcdrctas (DHAR) e invotv.d ir tbc s.ornatcglllrrion
(Aod!, I94). Asolb.r. p.rexidrs @ pe*d i! cbrorcpllst jroiA
cycte
rhyLkoi&.
microbodi*, crlosl, pcmxieDes
ed
niiochontrti& Tt€y lcrrliz€ thc e$aprng HrO,
duiag pbotosynth6is lad pholoEspialioL Atrhough cdre ed
ApX both Edw
HlO, !o E o, rlE affniry of ApX for rLO, is doE rh@ thai of
@tatdc (SDirnof ed
vhcld, 2000). Ia addition ro rh.* crrrbaric iondats, rhft
,
c
art
i!
@n_
dzyn lic otioxidots slh a $colbic aci4 .amLmid!, 0.@dds, lo@pltuk rld
glulathione (N@lor ed Foyd, 1998; schdd.t at,2002; Ashnf,2009). All lh*
tuytudc dd rcn- .MF.tic drioxidel3 prctccr pldts aSrinst oxiddiv€ dahage
ca@d by ln. ROS (Niki cr 4t, 1994). ft. erivity of sdond,nt3 g*r.lly isltls
udcr !tr6s @ndilioE (lrrrine et al-, try4iP$ttd et dl..2!A0} ftc .l.vat!d Lv.l ed
hieh &tivit of &doxiddB povid.3 6id!M to plrlts assDll sts (Ca!@ ., dL,
2001). For cxmple, MoBs dd AbdelAziz (2008) obsflctl a subslgntial imte in
lhe &rivitiq of SOD, POD 6d CAT in dia pLtrts subjer.d b dbuglt ct .d qiilt
rEG eoly€thyl.ne glycol). How.r, a &w rcMchc6 biv. Eponld a &cEde ii ilE
&rivity of $m etioxidat Glzynd uda {ress. Fo. .}Mpl€, Hong-Bo .r ul (2005)
epdr.d a d66e in N6bic &id h miz. lnd eh.!t pldtr subj..ted lo *al€r d.ncn.
'Iris nly b. du.
10
th.
Mbic
&id bciag ucd
up by
ih. APX
wtte
c Mtidly
r.quiFd by Pld$ for ptoF
gro{! dd Mintena@. Dcfici@y of €v.i t si.elc lutri€nt mv l.!d 10 d.ith of pldt
Ma.oiut iats ruh
s
N, P, K
MircEl Nti.nl upt*e fiom
$v.rtly aff4ied
by d&wht
!d
eit
Ca
aDd thc rcsFclive lran
3li6 vtic!
lcdion wirhi! pbtis
is
lads to imP.itunl in phtrlgoleth (Taiz Dd
z€isd, 2006). Ac@ding to Powe. (1990), dtought Fsults in r€du@d oxvgen $Pplv to
lhe @q lna.by, lihiting .ulrie upLle ltd llspinlid W.l4 lnd nindal t9ltlc bv
DldE se clos.ly rclatcd besute *al€t it Mdsary for lhe ratuleation of nutri€nis inlo
&d wirhin thc Dldt, nE av&labilily &d wtd.e of .ulri4ts g4nllv de.Ms undd
wald d.ficit d@ to subst nti.l
de.rt4
in
trnspintio!
rarc .nd
inp.ircd a.tivc
odpoa
Poslr, 1990) TlF plant @t svstqi noduLt s iisclf uda drcuglt
qhich Nl'idt
@nditioE by loBilg its p.deabiliry ald ardvit (Alab, 194) dft to
uprake is nutilaLd, A ddlirc b sil moistG hs h€cn rpdlcd io be posiliv€lv
(lrv'r!
1980;
assid..l *ith
Pota$i@
dqle
G) pq.nl
in flow of
withi! pLnrs pl!,s
poLdlial of ilE ens by aclivating
.ls
Ntrids
edyG
nom
eil
mt (Mis
e ibpdblt oL
.ttd Tvlq' 2000)
t sulllid
in the
of
o$bric
ll
ldlPindon A@ding b enlin
involved in
ceulalG sloMtsl oFniig, pboidtnlh.sis ald
teports, a declede in Kr
io
spinlion
and
uptlic ws ob$lved ud.r dreugh slres
photosvnlh6is
(Baquc
t'
al 2C46)
'
A d€cr.se in
CalciM
K' lwel
of {h.at Dldis is
hmftl
for Pl6ts
d
may
c.w
stomatd
't
kale!vit l nuti.rt i! plrli deittolis ltpLy3.6E lrelcilPL 90*l!
&d c.U dit6'on (Taiz anl zei8d, 2006) c.[ cl@s.don 6 sfered bv Ct7' ion
6rentr.tion. C.lciM is ds iovolv.d in cotollirg @[ 6db6n Fdcibili9
(giFhi, 2004). B€ins t onPone of ll6btag, it @ntdbuca to iI!. 64n&lD@ of
fieir structe ud tunctid by L.eping lipids &d preteis bonded toe.th€r' Mo@v.r,
.
sig!i6@t relc in aiiioxid&t .Mvnc sigMl
ta$ddio! (Hitrhi. 200a. As!fl.l ?t.1.. 2005) A rcdkton i! Ca" densaLion
Mder wrer sir.s hs b€r Epon d in *'trtl plsts (Khe .t al. t994; Ashdf tr 4r'
CAr' bcirg a s.cond
t|r.sgger, pl.ys
1998).
NitroSd is an
Mlirl
@npoMt of adim &i&.nd lu.leic &ids rl
w[ s I@v
s.!w!v inlibits plmt
gbstb. Siish ed Ush! @003) FFll.d a d6.d i! pldt N 6nr'nt undcr *dd strd'
Oihq cs€dh.B rcPoncd siDil& tsulis .3rli€r (T&gunig et at' 198?) Pho'3Phoru'
otls bio-nol..d* iFluding €izvnc& Nitrosen
dcfciencv
motnd mjor cl€odl involvc<t in ptdt grc*th aId aSdation, is ltso afrctcd bv
lt
drclght sitts. lttosphoN b.irg a pst of AT? Plary3 a k'v ole in elular Espiatid
(Iaiz ed Ztig€r, 2006) Dcficidcv or P
a pln of Ncl.ic eidr e.l t@v 64fet
dirtttt@@ in o.t lolis of pblts Phosph@u u/ake h$ ben
g.lently Fpon d ro decr* und.t wt{ d.nc $F!s in d'lTftnl Pld( sFcies
qtcd (Khtt t' 41, 199) dd FpFr
including Mize (Pffia.b4d6 4 d, 190)
c.es ! s@
's
ff@.l,1985)
beaw
Vcgdrdrc gowrh ed treld u!d.t d.oleht f.@lly h't ! redivc dlthrioq
gnin vield uda
incFr!.d vegctrtive gro*'th uder good noistut€ condiions suppsss
b ! @nPld ttit bdle ofh'ils ihc @bbiraion of
(Hutd, 1976) Gain
dreusltr
vield
yi'ld tcgddless of th€
s.v€sl pldl gre*tl @bFn d' W.ld 3t!.s t!d@s @p
$8961 $at
gre*lh stas. !t $'hi.h ii o@utr (J€M! ad Mogds'l! 1984) some s1udi6
dtrcsis (Austia 1987;
higb tilldiig crpocity @v b. h.ffrci.l if dtought sLtu and
15
Im€s and
Qwiq
pbotoctnrblte
l9E7). Ibis
Bdd
i!
My
be
du. io th€
€nobiliztior
of .lr@dv
emdat
d
the stqD ro th. d.v.loping gnjn (A98.!wal
dd Sin!!,
1984)
rcirht ud* drcudt ste$
@nditions
(Gqt,
which nay @niributc up to 22% of edin
Howa, HBd (1971) st 16 dal a br8h dldilg ability tuy be & u9ut d
luuy in dry !16 bcew it i5 q6&tu1 ofsoil noistur, $dich my bc n cd.d lal€r on
i! noe critical slagca of d@lopE .L Po6t-dnesis drcughr stt!33 M Gport d lo b.
hdtul to sFin yi.ld ofb..lct tgddl* of lh. sr*s ld.l 4pli.d. satuj lrd WdtsaL
(2000) epon€d tEt mdimm d.c@ ii yield @culcd std crcps we'e €xpoed io
drcusht sEes ar tu nowitrg $49.. Drou€trt s.s inP.iB floE produdion ad tawr
gnis e prcduc€d (Anjm e, al, 20ll). Reduction in elah nllnb€r pd sPike udd
1995).
beaue s.cd sel D qnc.t is ensitirc io wrld str€s al or IF lo
Dorrd d.iosis (Saini .!d AspDdl, 1981; l9E2). A@ding lo Fatooq et dl. \2009) wn r
d.ncit subquntiaily r.du@s idd thirs by dktutbins Llf gs dchsge psm.tca etich
trds
drcueh also
mt only dkturbs rhc ph@n|@ of phlo@ lo{dine atd
Niniht
t!!61@tro4 bul ale
@ftlltion betw@ photosynilrcsis dd
yield ws ob3d€d ir whotlldh udq dreudt (&ul, 1974). Accoding lo Nicol4 end
Tu@ (1993), lal photosyntlGis datlls ryidly afie! rndcis itr s in 6P3
distupts th. dty datrq pdidoninS, A signi6@t
subjecr€d to
low
dou8lft. DE to this, pldtr hiv. io
g6in pldu.tion. 'Irtu, dreush sEes
phrsiologicd modificltioB ir dl pler
tly
els
on veg€htiv. r€€ryca leadiog
d.lcidioN.ll4ts on.oF
10
rbrcu8h
oryd d€ntudlv l.rding b dea..d sdin vicld
(c@hdd cl dl. 2002r Dolarabadid .t al., 2010).
rbqa 8tuwrh dd i6 Pblblo5f
23.1G$vlh rld bloDN
&dindion is a v.ry critical ph* of qh.!t lif. cyclc s it is thc @3i .ftcitd
23 Efrat of dtu!8nl o!
bv
douelt (Davidsotr 4d Chav.lia, l9s7; Jajmi, 2009) Th. exftmal osodc poi€nlisl of
$il b.ilg highd th& lbtt ofth. !€d pF6ts n AoF inbibins wl.r O,luillcAbldor
€, aI,2002)
$
s..d
sm it
hoisnE ltlss€d
lcading to poof or no gemimtiotr al atl. Poor
@p
6itN wb6 th. sedlinss e
nor
eil
faes ibP.jr.d
uLr.b$!lioo
e€mimtio./sdling erotrth Mv le'd
PloFlv 6t!btish.<l
Th.EIor, siies lolcrde.t gcmi@lron dd $e{Iing st g.
to
(SolaDi dr 21,2006)
is inPottalr for lhc
wival
of
*n !t plan (Adjci ed KirUE!
sdlilg
imbib'lioA Smimtion rnd
sh.s. Lald on,
drough
stslnd
Btrile th.r
!d.dt
Iljldi
ge
l9E0). Ashnf
ed Nrqli O95) ob@.d lh,r
Croslh in she.t
wF
sev€ely
(2009) @ndwt.d s similu snldy on 7
foud ild
thc
of si$vc oes
!fr4t
wt
r
d by <LouSltt
$t€al g.dot'?€s wd.r
8ltDtvpe B 78%,
360r. Tttc snrdy tlso dealcd thsl gmidiion
gEmiddonp.Md.€F
re
ed s*dlilg grosdt d..@s.d wid
inci4i4
oftold!
int€srty of dreught
d*loFndt ud6 dDugh! grev.i! d4@ de to de.1!e ir
photosynthetic ni. dd @ll divisio! (Isuji .l 4r, 2003) Water d.ficit str€$ caucd
Ai I.t4 stag6 of pl.rt
signifi@i rdkrion b sh@t lelgth ofwh.ll (Arhnfer dl, 1996) Bhln ald Ra (2C$5)
GFnld
thal
&di& i!
ord.xpNio!
dd
due 10 low
hciSh
dt
bc a{libuted io
tlductio!
i, ell dld$mcnt
tusor ulder d!ou8!t Sill]re tr el, (193) g@ 5
$,ltdt 8etutt?6 in @ltsting soil
moisG &d
dry E,|!er @mulati@. viucgs ?t
ul
found th8t dtouglt str.ss @used
@00l) slso studicd
dffi
loqlr
lb. pllt m of biomrs
ecmdalion in dltlm whcli SdoR!6. 'ftcy foud lhat dty wight rq plad EdE.d
by 42 % t q dtuught ondili6. Mey oth€r studies Epoit lhat wat€r d€fi.it
$&lr!ti,lly Eds.d dry biotrN of rieal (A$4f 4 al, 199; SiDgb .nd Usha, 2003)
Iltis r.dElion h bioltB ofsi.ll i. de io Edued *l phobsv n sis (Bhan ad Re'
2005).
d..i€es dsidmbly uader both d.ought dd hal stles
(Shd ald Pruls.4 2003). A .Lc1!e in Elativ. *ter @nt@t undd drcueld c.'M
dosw of slo@i! wnich in lM rdlB ner Pboiottlthcric Ele (R.ddy e, al, 2004;
Nct pholoslath$is of wir.5r
Aljm.t dr,20tl). H n fid d dl (198) sfidi.d ihe.ftci ofdsud on sFilg s'lcai
culti@ ard foud lhat nct CO, simiLlrior 6t t snd stomral @ndei.nc'
$bt ld,lly ilducld dE io dtoughr stB. Th.v @@hdd thll d dlv d@{* in
phoiosrathlris
w
dE to hid stonatal Fsiet ne whil. contidEd wltq d€fcit l.d to
rtduction in m€sophyu netlholism wlich d.crcased phoiosvndsis Ac.ording
10 Steven
d.
s€lation
?t al.
0990), hiSltd
*tdl
tEt pholo6Fth6is
cddon fd &ought tsistan4.
I
ud6
d.olght
mv b. u!.d
ba b..n obw€d thit dou€hl
Giso
goot?.s or
*t !r
G6t
[ave @dpendrcly bighd
aod
ftt phobsrrtl6is (O@i 6d Otui,
ycyomto, 199). ILe nsultr of Ritchi.
er
zt (190) aDd Manin
s, al.
sho{ ihat ihe bioch.hical facloB @ntolling intenal CO, Bsinilarion.pptu
1983;
(194)
10 b€ l€ss
6istd1 vdi.li* th& iD sl|eplibl. on6. A nuba of
studja EFn aistee of wilbili9 i! @phylls for pholostrthAis ir EpoM to
drolght fi* (Joh@E ., aa, 1987; CaJldguy .d Ma*nr4 | 992; S.wda ald Sugai,
afecl€d by str€ss in dsught
194).
Allen
sd
On, (2001) rcDorled thal tltought
st
$s
adv€Ety.lLds photosynih6h by
.leEon Ftulporr chlin ed inhibiting $e
M.junda €r 41, (l99l) 3ndi€d lh. a.livity of Rubis ozrn
closing stonai4 disturbing the thyl.loid
c&bod ied@tion cyclc.
R$is m dpidy lc! lading ro a
d.ce* ia n t photortath.sis. It ir widcly FIDnd in liidtw rhrt th€ min @.slonaial caBe for dc.re or iihibitior of pholosynth.sis k thc reduction or los of
unda dmughl
sl!*
&d found
lt
t ilE etivity of
of @bon cycl€ .nzymcs; ihc hosr imporral o@ b.in8 dbulos t,t
bisphcphlte wboxybs./oxys@ (t wlor !d CoDic,2o0Z R.ddy .t .t.,2W, Mt
el a|'2ln{j Anin.t d!..2Cn9;84@.t d-,2010)activ'1i.s
2.3J Ctlorcpbyu
o.tdl!
CNorcphyll pigm.nis &d thcn
a@iat
d proteia
(Iaiz md z€i8q, 2005)- chlorcphyll bcing
posilire Elaliochip
doughr
e itporla
lads
b d4@
20ll). Hdcq plats with higha chloophyll
nF deudl-induc€d d@r.e
o4E E!'dly wh6 inlensily
mmpondt ofchloepldts hs a
of deughr
in
Er
phot6ylrhcsis (Anjm €r al.,
cont€nls would show
b.t&r
Fi. of
in th€ toial chlorophyll €ort nr of wh€ar
sh* ill.ffi (krrys, 2010). fte .lecM* in
st s rat6 pl@ du 10 ils phoio{ndrdoa ald
udd eEta d€fcil
decFdri@ ( njM ., ar, 20ll). Majdmd!
cblomlhyn @D&nt
fodd in chlor@lst nmblms
*ith mtpholosy !.si!. Los of cblorcD[yll @r.nis of *tEr uldd
stt* (M6hi, 20ll)
photosynihsis.
e
ar 091) sMi.d rhe a.tiviis of
chloophylla* &d p.oxidse uder drcu8hl slrlss ed fould that thc degnddioD ral€ of
chlorcphyu
wa flstcr $m iE synth6h.
€r
Lat€r on Mihiilovic er
al
(1997) also
obwcd
t3
s
inw.5. in
d$u8h1.
lLe cblobphyla.
&rivit
in thc
lec
of *dqr Dl4ts srbjcLd !o
Thi! slFs ihrn dsu€h 3a6s dcsF<Ls lhe chlobphyl @nlcnl of
plea|5.
Howvcr, dsughr Gistart g@tyFs of whcr! n.rntain ihcir chlorcphyll conLntt undd
drousht shc$ (Pdtod .nd Tdppi, I993).
vdiou fo@s iavolv.d i! sil-pldt{d)06ph.rc @ntinlm ed lpLtc .nd los of
wld @lllituic rb. uG. lElatioN. wlra soil elrd po&ltitl deq.3s, Pldt olmonc
Thc
(ehnc)
Ftcldd ad h
ru lafwra pot nii.l tl$ dq:|!e
(Bl'rd, 19?4i Aslnfdr 4i
,
sEs lelds to ! s6ttl d.c@
in lcaf osiriotic od w.r.r Fte id of ditrqtot ehcd g@oi}!6 qtilc higl* trdd
dcficii l@ds to sv@ Fdutim in sLr Fl.t on pMct s (K!@a-chop6 &d S.loL,
l92i MdE ./
da, 2002).
ExFs@
io
dld tEid
dcficn
ar, 0994) EFrt d vaiation h l€al Dl€l dd osnoiic Po&ntial in
difr.Eot wh.at g.notlT.s $bj4t d to drought. Lvitt (1980) qpLjned th.t l.tf water
Flnli.l b. !s.d 4 a elfttid qicrion to sEd gdoBFs ag.itst drcugnt !tr$
2007). A3h6f e,
!ot@li.l of sndt uldq &ou8trl b loeqtd dE lo higtr @uulrdon or
conpdjbt. elul6 i! th. c€ll by Oe pbenon.M crU.d ocmiic djullD.nl (Asbnf &d
F@b4 2007). nre tuin (Moiie or obFliblc solu16 4 tot l elubL .!ge, Pslie,
Thc osmlic
slyc'ft bctaire &d inorg&ic ioc swh s K' (RobiMn od Jor6, l98q Sakamoto ed
MMi4 2002i Sabados ed s.vow, 2009; Silva er 31., 2010). Thes @nplliblc solut s
help in Minlainug tle tugor potential of@lb. lt is ePoded t r whe.t Pl&tr rlalively
lowr dmuLtion of th€e coftDltibL slutes dda drcudt (Navvar ed
Walis, 2O0l), [ow.r &cuul lid of prclift hB b.€! Flornd 6 ihc fist EspoN or
*h.d pbnis rubjcr.d to Mrd defcn (Aljun ., a/., 20ll) Hong-Do dt al (2006b)
.x@iEd $c !!Ao@ of ter wnel SdtF 10 $il sl!. d€6cit in ! Poi qF.ind!
Thcy Fponql tb!. K* ed poliE @cdtltion incB.d @der dtuoebt sss.
show a
of laf
th!u. (Anjm er 44,2011).nd is adwly aifcctd in $tted uder dreugh (Saird er
,1,. 1998), llet Mler r€l6iio6 e impoirnt foi th. a.tivlrion of the mlioxiddl dcf6@
P\etltiv.
mLt
sysren undd
@nl€!t (RvC) is co$id.tld
dtoudr sEes (Mencod ,/ 41,
$ n.6sN
of
pldt wld
l95i Kh,@ {hop6
and
stdtus
scloi.' 2007).
TIF RWC of *t|err plels wsi dorlscd by 43 %
(Siddique a
dl. 2001).
Mliit n&e
ofh'gh Rwc
(tm
ud*
88 10 a5 %) @dd dmughr
wt
r js
@Bid€d as a
E$siei hcchdis agaisr deught s.ss (St @., dt, t99o) be€@ n is obsry.d
$rt &olghr Gi!|.d c' ivs of*tEt minrlined bighs Ft.tire h&. @nldr i! lof
iises @dpaEd lo lle su@pribte oc (tuhrzf dd K.lD4 1990; Et Hafid ?r 4t, 198).
Lo$
ofell
whicb
e's
tiDited
tugor dE to low RWC u.del dDuglt srrss @ulis in e uto dehydr.rion
lN of idcgri9 ild mi-p..@Uc Ere of ttmbtu6 tedi4lo ih.ir
ruphft dd btaldoM (Tlipaiht 2000). A 3ignfi@t
d.c@
in CMS (@lt
tI@btue
stabilily) of wh€at under dbughr stres ha b.e! rcpotud (KhM-ChoDF dnl Setor..
2007; M@v6i 20lt). IhcFfoG, @
dabiliy Eflets a
odb,e
s
lh'siotogicd
indiqtor of dmught Gitsmc of a enlin pLnr g@type (Lvin, 1980; Btm &d
Eb€M& t98l; Prrchedn ald ShiD|rtr 198?; psna.hedn ? | at., t992 "ftbat\y,
Hidd rh. e[ b@ttrd slabiliry Edc. dewhl !!s, th. higha wodd b. thc
dto!8ht Eiste@. CMS of wbet hs ben exploir.d !s ! srss lor@ indiqlor
(Ashraf?r 4t, 1992; saim €/ dl, 2005).
2000).
23J M.ttbou McrioB
Photored.ution
ofo
in rh. chloroptajrs unda drcugh conditios lezle to pmdurion
&d
ecuulation ofihe Eerivc oxygen sFcie& supetuxid€ ard H?O2 (Robin$n od Bbc.,
2000). 'ftc lhyh&oid neEbE6 ofdloioplr,rs @npdliDg &e @aion @rB pSI
&d
e
ir\. Mjd sir6 of FodEiion of ROS (It3ctive oxygd spei6). .nris
Pncnonoon of chdges in pholo6yst€D eliviti6 LadinS b prcduciion of H:O, by
PSn
pholoEdultion of oxyg€r
E&iiotr
E
( $d4 199). TL
of.l*lron
di6@ved by Mehl{, l!@forc, ir is crlcd the M€hld
doM,Egutalion of PSII ous.s a
eft
Bttiitr
on
l[c hr.
!r..s*d l6v6 todins to fEc ,atticnl prcduclion. nse ie
Edicals or r.acriv. oxygd spei* e prcdo.ed i! cNodpt cts,
FDnm6 lrd
diioclon&ia of pl&t e s (A$n4 2009). siE 0E RoS bave e cxft,up.ircd
flow id drcught
.l@tro4 thcir configuaiion is not stablc. Thcy i€nd !o m.ke th€m*lv6 sLbt by
@ting wirh othd @leutcs ad !rod@in8 hoF fE n<rj.{b. h rhis wy, a cbain of
@IioB is
initiat
d (Min|6,
2002). Hydrsen
Frcndc is pbdued film lh.
disur.lion of su!.rcnd.
lh. m€sptyu
or
Ptotonqintioo
@lls (Foy.t, 2001).
(N.w
Hrq h.i!s
e
.r aL, 2010) &d
is
!..@'nal€d in
itrhibitor of Cdvin cvclq is a v€ry
&d @ b. lcth.i for plmts (tunf, 2009) Ros ddtrp ldlv aI
nj.@mlaules (Apcl at'd Hin,2004) and w@ly distutb nctabolic rcadio6 of @lls
ddgeos
ROS
(AshFf, 2oO9}
Fotein
ft.y .ae svft
dd ligid! (Aeda, 1999;
Seloh (200?) r€poned
subjecled
b dnudl
.
Mitder, 2002; Jhonsn 3r ul . 2003) Kh'lm-chopd
siSnitiol
th. Hrq edent in wheal pL g
in qh.at pLnts also incltes ud{ dtoudt
ndbrssc!
ed udulalion
dd
incl€ale in
stess. MDA @nlcnt
str€s du€ io oxidltivc damg. of
ROS produdioD
oxi.lalivc drnag. lo biolosical nol€cules! DNA,
(Hong-Bo €r 41, 2005)-
is conEollcd by th. .ffici€nt etioxidart sysren
of
pldrs Gnlm-clopa dd ScloL, 2007) @mFiring of lhc en2:ttatic md rcn'
€nzyn'ric diioxid4rs. I! a<lditio! i! soD, PoD &d cAT, AlA (.slbic @id), GsH
(Glutahi@) dd aPx is . pdr of thc rs6d. glulrlhioe cycl. (Mold, 2001). They
pDvide
pbl.ctid
agaiNl ccUulu ald
$b-ellubr dd!9. by
d\etoxirying
ln. Ros.
sldi6 FDo.Ld @he!d 3ltB tolctu* doc b ovs Fodrclioo of SOD &d
cAT in thc sirdt chlobplsrs (Foy.r,2002; LuD., ai.,20Ot). Drcuslt 6indt
g@t!€ ofeiar showd hish.! a.tiviti6 of SOD, !OD, CAT 4d APX ud€r dsught
Sderal
(B (Kb@4hop6.nd selote,2004.'I!e
a.4@ularior of &Or 6 [ighd in dmuSh sitirc g@tyFs of l!.d showing dEt
rb€ ROS sdvcnging systcm of lhcs plor3 w Elariv.ly inefrcidti padiculdly tb€
CAT and AIX €nzr@ etivity w lowd in thcF plots. H@s-Bo .t ,1. (2005)
srr6s @o9aEd io lbar of rh.
s4irirc
obsen€d lb€ p€rfomdcc of i.n wh..t
foud thal
lhe drcusht rcsislad grcup
SmtnB ud.r drourh srcs ll mt@tion ed
dhibilld hid aclivitiA ofPOD.
SOD, CAT md in
tum low€r MDA conlert. Thir sho\rs that lhe m.mbm. damas€ due to lipid
ws lowd. Anong ihe
nonaztmtic mtioxiddts, .$$ic &id b v.ry impone!. wil[ rhe help of d@$aL
Fmnd!* (APX) enzlm., a@ibic eid play! 6 min p6.t ir odondlrl defde stsld
of plads (Ioyd ud Ha$i6o!, 1994; Noctor.nd rotq, 1998; Smimoff rnd vheld,
Frexidsrior of wh4t plant! with €fiicient
eiioxidel
syst m
2000).
23.5
Ii
tu
Gni.
rloded thai APX
i@s6
in wh.al pldts subjec&d to dreugh str.ss
Yield
onPoMc in
wh.aI (kluaf, l99s). ROS hN. ,n td\&r cfect or a vdi.tv of biolosical
@rcnolcul6 lcltlins lo s@ cdus dtn gc, bhibition in pholostnth€is tnd
hd. r.dsrion in yteld. Kld !r a/. (1990) nudi.d th€ apo@ ofnirc $lst cultivd
&Id rpoi.d thai gttu yield of all vh€a1cultiv.6 de.rsed utd{ droudt condirioG'
Drelgit st!c! *pciauy th.
|mitlt
drelgh Edu4 vi.ld
eid
lid
yicld
e
$bj@t d ro [igh l@ls of deught
stEs (Keyvsq 2010). Sire 80 v. yicld of*leat b dsivd &om photGrrth'sk du g
mlurilioq thus dc.i*c in photosynihdi! educcs ield (shth dd Paulen, 2003) ll
vlt !r ynl(t Edues $b6l&ti!Iy
ha bc.n rcpott
drcught
n6
d lh!,t
ptatu
Laf pho$tnthBis d &lh.si!
(AusM
d.cEs
o'r&'dlv b wlar
a al lg82l Dougbl d EpmdstiE sge caM
udc
abonion ol
kmcls du. to d.ctte in supplv of cebobvd!.tcs (Saini ald w€stgai', 2000) Nicols
ad Tulq (193) tlcsi@rLd *bst pLdi usins h.g!di@ cblorate ar lb€ gtain fining
Thev
e,se lo inhibit phoGynthesis odd esd deuglt tol'lee of lh' 9@00T6
$g8d.d
rhat drcught
ioL6
stFlt Sdot!6
@uld
b' el'cled bv llis
ndhod
a
si4 tnd
iedEli@ in pholxlntb6's .t 8nh 6uing ttlge ld b $b'st"tial los in eoin
liercl widlt of drcurt ssitiE gs9p6. Th. &-r'!s in phdros,trh6is Lads 10
disorbe@ h othct bioohmicd od Phvsiolosictl Prccssd a!
i! rloulh dd y,cld ofthc wlFlc ddt (cbiid!4 20{3)'
wll
lelding lo
d6c0s
Dblsil toldnce oehinilDt to oD. wtrh dtuorll rlla
goeib' Gtulic potdiial
Dtuuehi lalinadon is . mdbilation of.htneEs in linrcis'
dd anboxith.r defeue! ol Planrs (Dw ?r 4r' 200?' Mosdv pluts 6dopt t\o eenedl
i!'
sEai.giq drcugltt avoidd@ dd &ou8hl tot'@@ rtouglt lvoid'ne is
2.4
ph.@n@! by whicn pblte miltai!
hiSh
sal4 poi'ltisl
i'
th'ir lqve ud'r
'Lou$t
su'h d
chegcs
moDholoeical
$rcueh
&hi.v'd
colditioN (Blm, 1988). h is usuallv
Nl
dtrc.d sloD,ral @d@ta!e, rd@lion i! laf I.!, dqelopEdt of dEdsile
sy$.ms ard
imEa* in Mlshool t lio (Kuftl|m,
1980i
l'vitl'
1980) Drcu€ltl
22
tol.|r@ is rlE ability ofapla to @intrjn md.l net holic tmrioning ad alld
wter pot riiafs (Dw et aL,20o7), DF sbiliry to roL@c dreug)rr 8tr.$ @y b.
obwd in dl plaaq howd, ils cxi.ni v&is tom sFci6 to speies dd d€t
b.tw@ cultivs of lhe tu€ sIei.s (Hong-Bo er al-, 2006; Yildiz-A}tss er al., 2009).
DrcuCt tol@ of a phlt depcn& oD t!. gorilh srage 6 wll a dudj@ rnd sdity
of tbe &oughr 3aB (D.niffL!
nchdis
againn
.t
al.,
2@, I,l^ns hrE .volvld rol@@
stns dvircl'|mis offcn.r th.
cosl of ih.ir
Frfollrrc.
e vcry @npl€x. Edly rslons.s help plmts swive
for e@ tinc whilc drcught tol@ nebois @ ldg tdn pbtc.liv€ MU6 ro
Plel rspoNs io
egulde pler
droughl
sr.s
frsrjoE @dd dtuu8lr srs (Pirh.N
er
4I, 2001). Pl&Is Espond !o
*Era d.ficir @nditioa l!reD8h a wi.ty of Doipbologicd srd physiologic5l
b4h&is includins Eol6uld t3ponlcs or chaled i! e.!. dpEsion. A gEdl d€.I
of infodli@ on how plart! rcsFld to drcugh ar tlE mol@uld, physiological,
@tomi€l ad nophological lcrcl h3! ben gath€rcd in thc past il@u8! exrBivc
m@! on drcudt rolefue n@hois of plotr (Hutst tld .r ,r, 2004. ft.
..rt ooleulA Fspotg i! pl&ts &d h.tp
lh6 adjusl th.m*lv.s @qdingly (P.rdo .r ul, 2010)- nE ditr nqphologicil and
ovire'milal
cucs Eiggq phtsiologi.d
phrsiologic.l drcudt
211.1
MorpbololL.l
tol€tue
nabdis
ir
Dlmts
e:
n*nnis@
y6 ago, rhey
ble b6 copirs siil dress corditis Cftoc, l99D by adlpdng ! vuicty of
Ev( si@ ih. pl.nt6 lcn wa&r ard colo.iad rh. lard euad 400 millioi
borphologicd adapLtioG to @ntilE
dsushr dvoid.ne
hd Slut4l
!d.pr{io6
(2004) rcponed a
lh.ir
Sres1h
ad swivsl, On of th. wly
in pLais b clEnsc in oovsboot nrio
Edw.d
shoot
(Tmd,
1979).
Liu
lrd mt gtuv1! ude. drcudt howvd,
the
m1 sn*,lh ws l.s df*&4 Avi@ er al. 099?) obsed ihal lcSrbes lilc alfalfa slorc
C ard N llld.i in Mts sticl [.lp ir cgros{t of plrlt! an r dcfoliatior u d
drouSht
by
sli6s, Alothd nDdm.ntal pldt nlrF.tion
-eh""is
is
gowing dc.Fr @rs
in@io8 Mt ttickns ad ldsrb willl in@ine drcudr in odd b
avsiLbl€
wGr &d ituE.ie
absoDtion
cfi.i.ncy (Hur4
1976i
Weg
e,
expbn
4i, 2003). Si@
d.fcil looi gosrh bccom.s mE
dt6siv. u!dc. sreh @ditio6 (Bolq, 196) $ lhal plalt Lp t!@ *d.r .!d bilMls
Gob ihc loM l.'6 of.oil,
th€ uppcr laycrs
of
eil uurlly dry f$t l)I.Lr
walo
hr!.long qLciv. @ts *dich r.!.h lI€ qald
taue e tt y @6 dFd.ne ft8aiv. qitd pot ials. Sl|ch pldts e cdlcd w&r
sFrdel' (S.lisbury &d Ro$, 2007). T!.y ltid drcught ed lmfici.ndy s the
lvoilabL soil wter. The D6.rt @hderale escale dreoSltt by rDainiry domdn dll
So@ pldr3
sh a alfalfa rdd pd4
*Bt4 bc@n i svlilable dd thd cmpLt th.i! lif€ cycL in the short sl posible tim
(P.rdo., al,2010). D6ic..li@ lol@t plslts @ I@Er Eom b.lot 10./. RII/C
(Ona.t et a1.,20cot
vi..
et al., 2004). Succuldl
pldts
sucb .3
@li dd othd CAM
(crNd@e r'fid Meilbolis) pleis clos. th€ir stoo.ta duing the day &d @ wate.
sarm b...N tbey 6 st@ wcr ir tleir lbick s@d.rl tissB. sore s!ei6 6
sil.h AoD CAM ro Cr *l*n *d.r b4.lB avalablc (Sdbbury md Ps, 2007)
Vdd sv$ ed wtlr sD.ndes d€ ef.ftd io d "D€sicdtiotr postponeB'(Taiz dd
28i86,2005).
PBdion of elt r los fiob the swf... of da!. i5 .tlotbd drought lsid,G
i4heisn in pldis- TtFy 6nnol w!l.r loss thrdgh trdsPiFtior by ddc6ing ldf
dpsion sd leEf .m udd dreught @ndilioq th€Eby s.ving ihcrelva tun
dcbydr.ri@ (Ricl'dr, 1983i MdeliE .r c/., l98i Liu ttrd St_utzel 2@2i ttlel et al ,
200?). R.dlction in ldf a8 i! .ddilio! io pEv@ling *d.r los fton plsl surf@ de
helps pler in mainlaining hisk! !.t photdynthcsis udcl .lroucrtl Gao9p€s havine
sGls l6vd show high.r L.f *l photoeyrihdsis pd uit led .M (Condo! ed
tuchads, | 993) *nicn @y bc de io sntlla ell siz. It n g.n nilv oberv.d thar pLnt
vilh smdl.r c.tls tuy b. @mprativ.ly dmudl iolcet conp.Ed
@lls b€cause srniller
elh ce mai
to
lho$ h.ving ldgq
.ffici.dily (Gupta ed Bdkowila
@ly 6Po@ of plants to derghl slrss
ain tugor morc
d$ e
by \riic.h th.y @ ninihir tt qF€ut of ldd lo dir*l sudrgbr (Lehcr, 1995)
thftby lvoidins dcsi@tion. Inc6e in @idcdis ihictnds (Ashtm ald Bqlt!, 1994),
198?).
Culing
ad wiltirg
of
lav6
is
thick$ ad $a,iy cuiicl€, hiiry lav.s @hling.r, 1980), sunko slomata (Ta'? dd Zeig4'
l.lf.bFisio! ed xylm d.nsly (P!!sioE4 1983; scl lnd Holb@lq 2006) e
ale aFn d to b. plet drcughl adrltire Bpo66. fte t:aits my be ruipua|d to
improvc .ltought tolc@ of crcp pl&ts,
2000,
2.41 Pbrtiolo?iol
Dahrbd
Uidnsilrdine of ihc biochdjcd ed physioloSrcat
spou*
e inporir
Eicri6
for
dr
dqelolc
ph)siological rcspoE.s
ofrldt
of
sf*bl.r.
of pLlts to .lroudt stres
(Reddr et
.gainn dsudrt @ bn.ny d6crib.d
at.,20{,4).W&
a followingl
$our.l .16!E dd pr.d!.tid ot r.B
An inde6. in lesf-.i vapou pFsff difrd.rce is im.diately *Ecd
2.4e1
which Epidly closc lhen stomr[
(Asfu,
dd
ai.,2000). CiDrd @lk of
lN
trrgor whjch
@t
be
l€d!
10
sloMtal
ABA (Ab$isic aid)
siodt
d(xN
d.F d&t
.ow b..n cxi€sively studied thlr
a
if @ts dill
or
by
pldt lav6
have sutrrcicnt ahilablc
lo<{&d in
th€.!id.djr
of larcs,
(T.,2 dd zciger, 2006). This $omiAl
wtd
qidly
cloM
ABA-'ld@dddl (YokoL., al,2006).It h6
@r-to.lcd sigEl is Muc.d by tlrouShr which is
trdpnand stre. \r4!cn loil *!rd is dcplet d ad roots sr'n drying,
thc sign l is !6si!.d to tbc ldv6 *tich dpidly doe lhcir 3toDrra Thjs chcnic.l
sign l G knoM Io b. ihe hodo@'ABA' (Reddy ./ al, 2004). S@id er ar 099?)
Elon d . dilet FLtion ben€n a!6ci3ic &id aDd don r.l @.d!.lae, ABA is
syDt'6i4d & rdo tom xanihophyls edd drcu€lt stEss ed plays a main pdd i! the
dtuught rol@ drpoN of pl&rs (Shilozki lnd Y@gtrchi-Shin@Ii, 1999)
0Nugt rcgulalid of stornd ondElmc. (wilki$n dd Dwi6, 2004 Sch&htne
ed Goods.r,2008). Stoller at (2000) repod.d rhal & incrcae in xyld sp-A3A ed
Laf ABA po6itirely coftld.d eilh a Edlxliotr in sroo!$l @ndEr!re. Lry siomlrl
@nducld@ or hid stomatal Esist tre has ba Fpott d a o drol'd adaptitr
pal2ftt . (Alla er 4t, l9?O b€aw it d.cFir€s th. dt of tr6pi6tion.It is eponed
$at dought Bislant g@ltF hlE loe bospirarion nr! @np.r.d to rle su..ptible
0!6 (Blm, 1982). In@ed pDduclion of ABA udq drought slrc$ incMes stomatal
Esislae to pw6t stc.los ed rcgah Nso. (Himn ad Wd8hl l9R). The goc
.trcodi4 lbccisc atdchyde oxids& w foed to b. cxprcscd i! s!8d c€lls of
ErdaLd by
the
ItaI@ lc!6 (Koiwi .. ar', 200a) AEA e@uhl6 in lb.
o.soDhyl s $@ ar plrlt b dlt]drdd (I!iz .td ZiB.r, 2006). HiC ABA utdd
&.rgh ha Dccn r.Eo.Ld to @id.i! bid t r Phoiottilt€i3 by t!&.ing laf 3izc &d
luDb.t of 3t@.16 p.r lc|t (Qlttic (l9l) ABA i! .l& t!9od.d to Fgnbl. lh.
dpBioo of tclttl drcugh idu.cd oRN !.!dFoait (Kin8.rdl,192).
d(t{/dllr'L.d
'lratrMrs
.dlllhat
TBior didde i! plrnt! ulda ddght tt t
2,all Ot.odc
ttry iDlonor ro csry ost norDtl
n talolis rId SroelL PLlts Dd .i! nrip. u!d.r &orth d.s |bol{l lh FqB
of oootic ldjudn rt (Blu r, ar., 1983i McC\, ed Hanlo4 1990; ltolnb.rg &d
Bulow, 1998). fti! tu & dqlivc o.ctoi3D of dl Pltlt3.g.i8t dtorgh ir* (Molte
b
.!d A!b.f, 20lD Phbtt .rnthaiz. aqt
u@ul& vsiour @DFtiblc elutc.; lbiro ai& $d .! Foli!., 3uga3, polv.DiB
.!d ldrhry ononium coDPoud! ruh l' g!4iE bdri!. ctc i! tlsPoos lo (!u$l
., ai., 2oo2i MrLjD .!d Tuqi.,
2005i Ali
$.h !5 K', Ni' !d Cr tlolg trith $cio!., $gu rlcohol3
.ttd digeaddid- @ .bo iEltd.d lnoog lh. @o!.liblc $lutB (I@E! ., ar,
d..r
SsEd imrgrnic
iods
ft.y @ .l$ cdlcd oooliq, odoltlB d oooDroLcnds, t{4i.h PLY o
idporlllt Fl. i! in!i!. iriig lusor by is!.!iig *dd tpt l(., ptor.ciii€ cdb bv
MtiE8 ROS (f.hod6 rld &db4 l99l; l(.utit.!il Bbl! 2003i TlDm., at,
2003; Pi.h.ro .r dr., 2005) dd ntbiliri!8 Mklo€ s s[ 3 ullitri'n g Flt i!
@forD.liotr @d.r dlo||th tn3i n orStDic elu.t c!.dtl, cb.ticdly lcur.l.!d
2003).
codp.libl. si6 cclubr
FEB (Y@r ., ol, l9t2) 'Dty &cuduld. lo high l!v.b
cllomp|s! .!d clrdol @d.r dftugh clodilioB (R.ddy d ar, 2C'@. r}cv d! mi'
toric crto d mbr ccto'jio6 (Alodo ., 4r., 2ml). Tb.n cdc.ddi@ cs Ercb up
to 200 DM i! Dhn! c.l| (Rlod6 rld ser$, 1994). Hosq, ib.d.6l of lh.i!
in
r.cedrtid vdi6 b.tw
(Pbh.to.r dr,
2005).
rp.ci..
tL 5e 3p.ci.3
n . !.ldtid qil4i@
!d b.aH diftal cddla
Oootic.dj!tu@t i! rlFi.d
lo bc ulcd
of
fd (bouglt |! i.l@ (i/o4rD, l9E4). A lin!| EbtiodhiP bauetn ocboli. ldjusto€o!
ud d.hydrdid *s! ioldrG b! b.t! tu@d (Irllow ,l 41, l9E3) h.ca!s. it
udt .ia nlsor (Mor.A |98a).rd hisl Rwc (noE.d LudLo*, 1986)
26
2,4.2.2J
Pblift
Preli!.
is hdsic€Iy
ldj\dmnt
s ditu
&id llodE d ir pl.ni.' 6nd pllts ! oajor ble
d ! @patbl. elute !id6
incE4d to a gsr
dt
2001; MoDt-Guadly
rool&1,2007j
nt
e?
dreleir
stBl l!
udd Mr.r d.ficit @ndirioc
in
osodc
'n
@l|@t!lion
dpidlt
n6y pla
sp@ics
(L@h.r,
d,2001: Choudh.ry., at,2005; Kavisr aI,2005; Ashr.f ed
M.niraM
er dr..2008;
Anju r/ dl.20ll). Prolift al$
@1s
a
a
stistlB aid crl'M &tiviti6 of ccnlin
.nzy@s. b dditior io its olc in Motic r.tjNtle (Ashnf ud F@lad ?007), polile
noledd cbr!€mrc to For..t
eis a
d
siFaring nol.cul.
pmr.in
i! ceuLling
mito.hon<tial rcactioN, ellpolif€ration
dd
h ne€$aty for Mov€ry nom stEs (Sabodc od Savow,
2009). Pblie is @nsidcEd ! poi.nlid pldt netalolitc wiih prctectir nDdiotu
(sabados ad savoN, 2009). It !.rs d!l a ioxidr (P€ddy dr a./.,2004) by EdEing
th. ,l.nigiig ellels of silSLl oxyCd rd hydrlryl radi..is on phorosys&d n (Ali. lad
r.n
expl€sion whjch
bufiB ellulai r.dox po&rr,al ed nriDiB pholciilibilion of thc
thyhkoid ndbme of chlooplasis by fte ndicd qwnching sd d.c@i!8 ROS
ptodu.tion (AslEf ed Foola4 2007). HorS .r dr e000) obldld rhar preli@ iDctEs.d
sv.nging of ROS prodt*.d by oxiddirc sir6s. Pblic biosl n6is ii a.tivdd wnib
Moh&ry
(197}
Ir
ils dcgtuLtion is i@tivat d udd sr!$ conditi@ (Morer-cu.dry e, a1., 200D_
Sabddos dd Savoe, (2009) argu€ ihil pr.lin€ bidyrhesis rarhq tha prelioe iielf
my be invotved i! stEs adaptaliliry,
2.1-2rl Cly.irc b.a.i!.
clyci'. b€l!i@ (GB) i! a N-n€rbyl
(Rlrcd6
ed Hmon,
sutEtirut d dlTivarirc of
th.
ditu
@id gtycin
o@ntdion in plalts comiddably ircE46 uder
droqhr ard sarility stE$ (N.Ltuu et al'200l.1tata.t al-,200),Iokot^ et zl., m06,
Muivllll@ ., dl, 2008) .!d h.lF lotct ell l)mbd6, Folcis dd .r4rd by
1993). Irs
wt . baltue ben'M eI &d dvimmal. It is e .lcldcally rcun l
ed Eadily disolv* in wt q th.cby 4ily inlqading wiih both hydrcphilic
mainbining
nol.cul.
ed Muhr4 2002). It is sFihBiad
tom cholin€ witb tbc h.lp ofe d4!e choliE ooF oxys@ (lsbitad d, al., 1995).
ard hydbrhobic .lonaiN of pDreiN (Srkdoro
Il
is foud in hiSh coicdtalioN in rh. chlNpLst
adjutrd!
n
d$
hclp,
2.423 Andorid.ll
T[c ird&tid of
ir
st
liliz.tion of
PSII
ed in ldditio! to o6@ric
uldq ondatiE
'lr.$
(Pala€eorsiou
ed
ryrL6
oi.lt iE s!6
itr plots u!d.. s?I.r
(Plddy €r al., 2000i Mr!o, 2002). HiSh
pmductior uDdq oxidadv. Blr.s is
l*l
hladoa
of
d.fcit b$
ROS
bccD
(@riv.
w[
r€lond
oxygc! spd4)
ard toxic to pleis (Arada, l99q
BoMi
.r dl, 2001). They d.mlge cell tlmbtucs rad cas prcteb oxidllon. nrdfoE,
cfficidt ddondrnt d€ftns srstm (c.npririig d4tudc
eiioxi.lanrs) is ..iivaLd in pl4rs
i!
fts4ons. lo oxiddirc
ed
&
mndzyn tic
dGs (Rlddy
cr al., 2004;
tunrl I*1.
Patori er 4t, (2000) Epollld th.t drcurh sr.$ qws e increlse in bbl foli&
eliond@ir of lqvd. A@.dj!s to Mm (200?) . seq@ of ddb 1!les plee in
pldls edd wt r .!.ficit sires. Fi$t tb. .nhft.d lrodeti@ of ROS lrd tb€D th€
Ashnf, 2009). Tluough lbb syst@ pb!t!
cxpBio!
of g€i.s ilvolEd
ir prodsri@
sliqid, i ed ha|cc drolgb. rol@
Anju .r 4r (201l)
Tbc
ro
tep tho.
ROS ar a
of etioxidets l€ding
b !.bid€d
Epon! lbll rh. &osdt
dlioxiddr c!p&ity, Th@
dzyEric.
h@g.
be.@
td.fue abilit
of ih.
10
highd lelds of
.6ci.d elivily of
of plerr d.p€lds or th.n
e tlo SrorF of &rioxidlrts i! pldtsi 64ra1ic and !o&
@ir a4D.ric otionddE @ sou PoD, cAT,
GR &d
Alx
(Reddy
Itu mnarlrric pldt erididlntr @ clNifcd fili!.r ilro $o sreqs;
Ashc &id lit s€v.!sa, dd th. pistMtt tuch 6 c@t rcft|s, taveoF ed
.r ai., 2004).
dth@rdiG (Conklin,
and
2001;
MmeBosh ed Alege,
2002;
Trbsi .t aL,2002i Apel
Hi4 2004; AshFl, 2009).
28
2.4.3
Moleubr r6potrr.l
Mey biochdic.l ard @l.cdd adlpr.iios se .xprss.d in pldts 3ubj4&d ro wtcr
dcficit (R.ddy.r dr, 2004). Dbugh r€poBivc |Mbatis d th. mlQula rnd 8.n.
@npLx and blvc mr ben nnlv wd.'sldd tet (aq 2002i
qpe.icd to b.
Chaitlrva er ot. 2003i Chav6 ?t al., 2003) A .ubd of gdes e
bvolved in adapt lion of plants against dreudt lness. Tlt v cd@d. ptor€iN 6shr.d
.xprsid l{.l e try
Mtd cha@l piotcils ecb s aquporiN
(M.ggio ard Joly, I95). Dehldris dd ddicelid sts pdt iB p.oduc.d bv sts
Esporuivc gd6 e th. n6i @mon nd4uls adlltltios pluts apG3 whcn
subj@t tl to drcught etrE s (cuhn& &d Bohtcn, 2000; Tai €/ dl ' 2000; zhu. 2002)
Prot ins sh s d.hydriB (drcusht indu.d Fotetu) e v.ry impoiant ir c.uult
with
F.Eb|e t@sFn $.h
!s AT?ts6 ttrd
ttmblle pmi6lio! nd stalilizatio of c.rt in a4t6 uda droughl sts (Cloe'
l97i SchwE./ dl,200|; Chowy et d,2cf1iLisg.t a|,2003:''l.iz a ztigd,
2006).
2.5 lupbvirs drc{tla ,oLtuc i! phntt hv .togdou
or8di. .boiciL/Phll gn& regoLton
!r.
of
il.rguic
'!d
or$d. $hG! eDh 6 bNiNlidt6, salicvlic &id,
tduloF, Slycine b.tsin , Pmline ed agDic &id hav€ ben Fporred ro inFove
drou8lrt tol@c. i! nMy plmt sFci€s $ch s whea! n!i4' blrl€v, sunllow.r and oka
.!c. (It lf dd BiIglM, 193; Att€.4 l996i s@ear.a.r 4l' 2000i sif{A.1 al '20oli
Af-H.timi ord s.rrd.. 20oli Khd .r al., 2006; Ali et al., 2m8; Dola^belrfu' .I at.,
doscloc solutd @v be
zOtO: Aaditu et ot.,2orr', Ni dd Ashr.f, 20l l) ft*
n. .rog@
alpli.Elion of
tqtrlmvs€d prining (WeeD a at 2006;
Bashirld.b ed Hajrch@b"d|€ai), $ a folid spav (gusi! €r al 200E;
Dolat lodid ., aL 2010; Khlu ., ai. 2ol0) d lhDush rh. @t D.diM (siten er al.
2OOl), All Eod6 of apPlicdi6 hae b@ fould etr*liv. i! @ut@tilg th. drce
eftels of stes, howaet .pplicaiion duoud ih. rcoling m.diu hd been foud
rlativcly norc efectirc (Atb& sr al., 2009) du. to continuou supplv of $hte b.ins
applhd io Dl&re
s
a
prc.$wins sating
2.5.I Alcorbi. .cld
vi,roi!
C
(L*cotic
vitdin
@id) is a ubiquitiou tuoledc in
eutlr}!l6. It
is
. sDdl *.1d-
3!ga. It ws fi6i islat d by Szed- Gyorgyi in 1928, Hc c{I.d
i! t.'@iic &id. It M llld @!.d a$lbic &id by Harcrtb ald Sat- Gy6q/i ir
1932. It is fouod abudddy in all @ll compo&nls leh !s.po!la!ts, chlorcpl0sts,
cltosol, va@l€, nn@hold.ia dd D6nffi OinC@ ., al, 198). Gffilr laf
solubL
like C6
@lls @nLin 2.5
nM Mrbic @id; howvd ils @'c€nt6don
cbl@plsti (Smi@tr, 2000). Sonc
dics
on
'nay
reach
ovd
20
DM in
bi6ydhe& dd nD.rid of @rbic
eid hw. bd publish.d $l'ich ddcdbe thc @nplelc bi6rath.li. paihwy of @rbic
eid (Soimtred wtcdq,2000).Ino.di.t p6uer of @rb,c tuid is Lsal.ct\tm-
l+la.bn€, *trich is fom.d froD DSluse6P via Dbarnos l-P .nd
A$orbic &id pbys
e
import&t Fl€
ir
'My
c.llular
CDP-D-
Foes6- ft involvq
in c.ll
divisid ald ell s"ll .xFEim (PicMlccni ud Fotq, 2003) lh6lby rcguldi4
grc*dr dd .t vclopbent of plels. Apopladic s@rbale is . ofetor for Pblyl
acliv.l6 hy&oxy FotG glycoFoicin iquitld for eU divisi@.nd
expdsion (Snimotr, 1996). FEUmoE, Asrbic aoid lcts s a @substa& of Fd
diortgc@ rhi.h has s rcL i! !o$ tultktiotd @difieliotr of ell *![ prc&iN
hrdtuxyle
which
(Anigoli,194).
Asrbic &id h.i4 a lo$qful &lioxid&r sbg6 .!d c@Eols tbe @m.!t!ti@ of
Irlor in pldts (s.im a al, 1998) with lhe hclp of 4 enzyme a@date
Frcxid!&(APX). 'ftis .nzye tmlfd .L.toB fi@ Mritr. to ll1q OvdbSd
peoxidc) Fodrc'ng dehydoMrbltc dd st t s podu.ls (Rlvel! 2000).
A$.!!ot
+ Hydogcn
pdxidc
C6ll.O6 +
Asrbll. hs .
-
Dchyd$a*o6d.
Hrq + Cdl5oi
+
2It
+
wds
O
turge of APX iso@ztt6 thd calallu the r.ducdon of Hro! to E
o
ed MDth 'moN<l€hydro46rbd.' (Asada 199). Thce APX dzld6 w dcoliale
d a substa& rnd oxidi4 n b d.bdMs.o$aL lhrcush tc H.Iiwll-A$da p.tlMv
l0
via Dorcd.hy&odcdbai!.
@ion @c6 in
'fte
dehydroascoftalc is
thc viciriry of PSI. In thb
diBdy scav.ng.d (Forq od N@lor,
rhd r€duld ba.k to N!.orbale. Ilris
wy,
ROS
(@1i!e oxyg.n sFci6) d€
2000).
h[m
6a b€! l@M siF ili dievay s . vilsui!. Ir5 duny
|ptrl. b co6i&Fd r o6pu!$ry pan of hllD di€t fd preF h6lth Mid.I|a@
(Noctor and Foy.i, l99E; MulFBo*h 3!d Alg@,2003) b.cr& I camr b.
stdhdizcd in th. hl)lM body ad hE b be t!}d Aotu en€tuI $!Ms.
Its
inpod!@ for
A@ding
!0
BtH.
(2006),
e.bic
&id (A&{)
@nrent in
vaiou pler!
is
e
@tler:
ArA (i! n!/r009)
l
l0
6
Malgo
20
7
Spi@h
30
t0
46
l0
53
l0
80
*te!t s€.dlings, !$6i. @id cdrdr is uslslly foud b.i@ 2.6
io 3 b8/100 8 wl$b n b 15.3 DE/100 I in !d8!m Its ddlr.tion incia56 wirh
gdell (M.ion ., al, 2010). Aeording to ToIlKi .r ar. (200D r*ds of too
ft is Epon d thlt in
gtmospcm &d &giorFms
only
a
linlc
moDt
e
godally d.void of th. r.duc.d eorb!i., @nrajnjng
of dehydrDs@6.&. Howd€r, or imbibitioo of
wt
r 6co$ic a.id
ldel sldtt inct,sing npidly {ith Semiiltion of sed prcb6bly duc to r..tirztior of its
sFth6is od6 !o coF wilh lh. brmtul ROS. 'ft. stnlhBis and etivity of ihe APX
'n
crzyE .swi.r.d
wilh
erbic &id .l$ gnduly
$.ns i@€rin8
ei}
sedli.g
31
ofl*orbi. |cid .€|iul rbiod. rtE i! pltult
Rol. of Mrbic acid (@rb.te ion) in d.lioErirg oxidliilc stF$ ir plarts sreM
urdd adv.sc dviloffndts ba beer rcpon.d by FvEnl rs.Nh.u (Gillhm fld
Dodge, r98?; Pstod sd Trippi, 1992i Bsisak ?r al., 1994i KbN et oL,2006t Atdt et
4t, 2009). Aelbic eid b.'!g & .liioxidrat (MigEl d, ,r, 2006) $ld di.d
dogmuslt io plsl! SroM ir salirjty or drcuglt slrs, pdl&ls PreLiE and liPidr
t,52 RoL
rs'i.d on.htiE dmlgc G@bBi ., dl, 2000; shdala dd N.tfu, 200 | ) by &1i'8
6 a substni. for $.orbdle pddd.le which s.3vdges Hrq. M.nconi €, al (1995)
foud ihat prep.r tunclioning of ricoft6i./8lutlthione clde Mintained Ros ai ile
cod.ol lev€l in {hcd pletr subjwt
is
str*
to sltcr d.ftcit ExogFno$ sPPlic.lio!
oferbic
pboLstnthdic Pigi.dls a.d gto*rn of plds Ed.t
(Khs\ 2006: AsiD .t a1,20(4i Dolatu,iia .t al ,2010)- Astbic &id
&id inprcB roEl
dsughr
d
l4f de,
ale rpon€d b rynth6i2! prelile which
s.t 6 6 osoFsnlator udcr st6s (Sind
et d|..2001).
lr!8 aso, Xrist@yyr and Mluty (1979) Epon d $at .$lbic eid imned thc i.ld of
de frp $bjet d tt st r d.ficit Ads $d Kiilhe (1996) gt * lutAoM s€edling3
in
.uttiat $luion @Linirs loly.lbyLnc
Epon d th't dog.nouly lpplied
!$$ic
8ly@l (PEG) to ind@
osotic
$6r It
v
&id i.hrbiLd nenbrane donage @!s.d bv
Sind ., ar (2001) s:tudi.d ihc ctrd of alcorbic eid otr
cd/.
pl&b subjed.d ro
-ft.y aid.d a$lbic lqd b $. $il !t ih. nL of l-7ng/kg a
fou.d llat M$ic &id bad u ilsailg .fr@1 o! RrvC, ct ooDhvll @tenG.
Dhotosrrtieti. 6& ed poline &cedition in thc plants $bjei.d to drougln irss
dtuught slr6s in soil.
&d N.unan (2001) ercw lonaro plots b hydrcponic culfut€ and added salt
INaCD 10 the nuticnt ncdiM io indkc sdt srEs ir oft sel dnd PEC it th€ n'tri.nt
m.diu ro ind@ osotic sEs ir ooibd et 'Ilcv obscd rhtt addition of Mibic
Shalala
&id (0.5 bM) lo lh. nutrie ncdia iftelcd 3..dlitg swi\El.d A!.b siSht d wll
r.s ttcccs.d MDA conLnts, This pDv.d thc lbility of Mbic eil to rcd@ oxid.tit
doEage
udd
drcught ond
sI
str6s,
32
gniu i! 0.6 DM eqlic &id elurion Fior 10 ewing
h saline sh$cd soil sli obw.d by Al.H.lini dd Hd!d! (200t). I ws foud rhai
wheal rldls grcM iom sEds pdbcd eiih sorbic eid solution slDwd hicld
@Ido$, sl@t ud $luble s!g& @lrcar @mp{!d to th. M-tr.aild ons und.r slt
slrs. Kbe.7 al (2006) stdi€d lb. .f@1 of.xog.noB alpli@lion of Mrnic eid or
$ttat sdli!$ subj6r.d io NaCl stB in hydtuFdc culrft. Th.y lppticd 0, 50 dd
100 lptn Mrbi. &id a a folid sp6y which ircMed ct[obphyll "." colcoB of rh€
steal plads. Anin ,r al. (2009) foud thrt eo$ic eid in@d frcah ed d.y wi8ltl,
l.dan4 polilc @nten( &d d@s.d lipid p@lidltid od ion lcabSe in ok6 plsrs
subjdtcd to waicr d.ficit 1!.i. 6ult3 &d @lid Eports BeLd rhlr scooic &id ir a
powin edqiddt (Anigoni ed Dc Tullio, (2002) elich oijidarbly allwidB
Itre etrer or 6 h sdkins *beat
onddiv. da@gc eu.d
Ath& e,
al
by {irought
stB,
(2009) rcpoded th€ etrdr of
pldis. They g.w rwo cullilgts,
eorhic &id in implovitrs sdl tol€me of
dd MH-97 (a modent€ly
slt tol@i) i! s.liniz.d bydroFnic cdtE .rd appli€d @.bic &id at lnc ra& of too
eg/L in Mling b.dju, s a foli& stny &d.F+ewirg s..d tr6tn nr As.bic &id
BtEat
dndE
d
S-24 (a
golvth, gls qcheg. ch&a.r.ri$i6,
aliviti.s of
SOD, POD
etins Eedim wa th!
sludied th€ etrcct of
dd
stl
tol€@1)
Idf a$rbic
CAT. Th.y concludcd th.l appli@rion of
Mrbic &id
on
FdEilg
rt
MDA
Miz. pl&rs udd drcudr strls,
orcrt
in
taE.
etioxidat
eo$ic &id
mosr etrdtive modc ofapptication. Dolarabadjan
@rbic &id 6 a folilr A6y ed fould th.r il irco*d
CAT, tLdt6y,
tuid @r.nt dd
d dl.
.r al
i2OO9a)
They dpplied
tLe &rivirics of SOD,
Dotarabrdie
in
mD dd
(2009b)
rt$
a$ftic lcid sp6y ro @ob plet! $bjelcd to s.tr srr.$. Th.y apon€d th.t th.
applation of eorbic &id Edeed MDA co!&nt by cfl4riv.ty couraa.tiog thc
adveae effect of oxidalive sires. Anf! e, ar @009) ,Mied lor8hw udo salin€ stress.
Awbic eid w6 .ppli.d G a $6ti!s/pF-$wing s€d haon nr .lon. d @nbincd
*i$ folid a?plicllion- Then 6dts dqld rbd aglbic eid !.lp.d pls s minr.in
llen laf ult! stlehr .d ami.ation urdd sfs @ndiric,
rpplied
33
Hassan€in er
al
(2009) rcpon€d that
,9
io
eid
aPplied
4
a
prc-sowing
ed rratudt
.nd folid sp6y to mize pla s under ltlitr€ strcs enhoc.d gto*th palntrlers,
ilr@.d th. IAA, c.4r. chlorcphyll piemcnt! .!d d..@ed ABA ld.l. SOD dd PoD
incar.d, SiEi|fly Dolab!.di.n and Joucebai,
(2009) stutlicd th. .fr@t of aslbic &id or @@on b@ greh urdd sll sEss tlEv
add€d aMlbic sid (0,25, 50 .d l0o PPD) 10 Holgled3 nurri.nl elltio! u$d ir
saline culie. A!@ibic &id inc@s.d thc chloDphyll pigndB aad Educed ABA
&lirity ders.d
tt l
vrhilc
of cAT
conienl of Dlsrs.
folE applidtion of .elbic eid (50'
l0O, 150 bg/L) d c@ ptdls $bjeLd !0.!rcugln s[s ar th. vcg.tni* &d
EpDdudiw stg.3. BiotN &d gnh yi.ld of @m pb s sr v.setative ad
Dolalabadis .r
zl
(2010) @nducted a $udy on
GFodudirc phs6 wG obw€d. Irlcy itPodld that Mbic acid imrca$d E6h dd
dry v€ight of lten &d l.af s wll s grajn w.ighr pe planls lt was foud thal 150 mgll
of
dorii. eid s
E
ddig r!i[moc,
tBh
aod dry
sighr5
folid spny ws tlF iost cff4dve in dlarcing gnin vield ofthe
100
Ds& of 8oftic eid solulion
al lbc rcgEt
B.frdtivc
in
iftMing n@
tir *tilc 50 68/L at dE ltprbdrclivc allgc
Khn 4 a/. @0lO) lrplicd a$rbr eid I0. 50. 100 ds,4-) 4 t pcowing sed !E tuor
in A/drica md obs.ded ihe Crosil of sc..liigs Eon pdn d e€ds undq ell str€s.
They eponcd thal a$$ic @id dl6c€d gre\tfi, in@d shooi/ root ftsh wigln &d
ctdorephyll
cont
s
of satt st!€ss€d plaotr. Thcy foud lhat 100 mgr- asao6ic &'d
w!
Lkl in @lioElirg tlE adEts. €fcts of s.lt str.s Kl'lil d al
(20i0) alpliql difrdl l@ls of !5.orbic eid (q 100, 150, 200 PPo) $ . folid anv 10
dNught slts.d bsil (o.tD@ ,6t/dn) alv.gcilrile ard loMing stage ltouehi
th. non ctrctivc
sienifi@tly d.cas.d
a
ed
th€
so*th
chloophvn
pl4t! howv4, aswhc &id
'tcMs.d
of plet! ft.v foud 100 ed 150 pPm ofscorbic
of
b @naits, RWC and Sros,lh
ldel. R6!nrly, Anin ed Hajmh@mdt.@i (201 I ) have
obwed tF .ffdt of ae|bic &id on oba pl4i5 groM in nurridt $lutior udet
osolrc sfts ildu.cd by PEG.'nEy t!9ticd sscoibic eid s a led eddng lah€nt
eid
10 b€
pdor ro
lhe mosr cff@tive
wirg. ft.y rcpod.d a sub{rntidlv ircm!.d ediMriotr m'!
sh@i lmglh
tm r,\e s€ed! prim.d wirh a$!bi. eid. Az.nirltr .t al.
(2011) sbdi€d dudu qi..l eedlilgr in sslr sEs &d EFned ibrt dog6o!,
ed biobrss of
opplicjri@ of
se.dlings
Mrbic &id
.nhdcing goslh
2.6 Breedilg crcp
PL
sil ibFoitd
@ie s s wtl
ar<l prolir. @ror trtril. dcccNing H1O! @!tor'
pldb
(O? mM) in
to iDpmy. drou8hr
cblomphyll
.s
toten!.e
tol@ ofcrep ptdts. LneEtu.
cPoris tnai dreught 1d-a@ in 6oF i! rt min f(s of ffit rserch (Matnje.nd
$icnf6$ bsvc b.cD stiivilg to ioprevc drotghr
200t de ro dininihins wLr t3olrc€s aEitrbt. to coF. D€Etoptunr of
dFldt st6s tol€m1 cullivEB cd bc &hicvcd thDugh d.ploying rEditional/mpinc.j
breding s wll a gen Miputation by Dol@old brrdirg (Drbnva et ot.,2l1r,
MU6 .r ar., 2003: Tatd. ,, ot , 2004; Alhni 2010).
Tut ja,
h
thG
pasi,
fdn6
b.itq pleB Aom
by
hrrc
the
b6
bE ding mps *irtrcur toowLdg. of ea.tics by selecring
popularior Yi.td potcnri.t ofcdlivs inprcv.d 10 a ldge cxrenl
utirg knowl€dg€ of g.ncti.s sFb
.tron
s
to c@biE dc.ihblc planl trails
th. godic Fi@iplca di*ov€Ed by Mcndcl.
![!gr
ir ditrffit g@typ6
itrto rhe sam
n.
ptdt
cNilg
bcg.4 With rlr. dir@vdy of Walson &d cricl's Dodct of DNA i! l9Jt,
g.ndic codc in 1960r Btricrior .nzyE r h 1970r dd rhe d€v.topmor of@onbimr
DNA l4hnoloey in 1980 hs nad€ posibl. lo inirod@ a dcrnabb cde froE @y
by
?J,l Convotio!.t bh.dllt .pp|@r6
Irnproving yield of croF to
e!)lw
food
s.cuity
udd
varyins
ovirom@B
for rh€
leSc \reodd population hrs b€m ftc majn concm ofplanr brccds. Duing the
Dsr
y.rF,
50
cNiderable gmaic ioprov€incnr hs
road. Birg conveotidst or
bd
taditiorEl brEeding rehniqu€s to d.vetop hiSh lelding cullivd wil|l dcsiEbtc
combhalid of !"jrs i. diff.@t dop sFciB Aslnf (2010) condlct€d e srflsive
rcview oD vdious
&oudl iolcmr cultivan4in.s prcdE.d in diff€Ml dops through
Brclding for drclghl r.sistdc. in the p6st
*"s minlv do.c
thrcugh emPirical
bEdilg by !.l4ting plstts brscd on thcir phdotlTes. TFditional brceding to
improve d$ught r€sisllt@ in vh.d !d olhd croPs l8 bcen Micd dn ainS
iom sses*d cnviromcnt (Skovnand er ol ' 2001). Selftlion for
bigh ield porcrnial udd drcughl ddilions ha lcd !o ibgovcndts in s1|n vicld
of{h€at ed barley (tuau et dl, 2002). Cenetic variatio is imporlsd for ddirabl€
eenctic rc$urces
t?it in
thc populalid. Gsetic v.ri.tiotr
wifiin sP.cis gocrallv qists, howver
if
vsiation in the poputan@ ofsotnc spdns .bB not cxist' thm wild rclalivd ce b€
.xploiled a3 a sule of vdi.rin. Widc do$in8 hB b.en dPloired lo iltlode
tom wild rclati\ts (Valko!4 2001) PlaDr gprctic 6o'@s
hav. ben cxplored for drcught Bist nt laiis ed thev hav€ been incoaoratcd
ilrouglr cft3ring and Y&i€ti.i4in6 fd &ought ttrds €nviment! hlve b€'n
sEBs Fisrant 8FD.s
d€vcloped (Quicl
"t
al. 2001; xinglai er
und.sird c.n6 @ aho h@fdEd
haits. For
ddDle-
hliaL
P
at
2006;
Tdruo
3r
al, 2010)
Howevei,
lc qDssng two p6mts !o @obim d€siFblc
has bcm d€vclop€d bv crossing
wltdt ed
ryc sP@i$
It
qualirv
i3 Eldtivelr drcught r$ist@t hoBEver; iB graio do€s trot contlin ddirable
int'tution of envircmcnl
*ith dulllplc ga.s so 8.retic inprevdd! in crop pla s for drought tole@4 ha
Si.cc, drcudt lolenncc
2.6.2
Brcdin!
by
ir
a complex t
sl
and involves
Mrld Asitt .l Seletlon
tn crop pbnts. plant bEeders rced to n.DPulate q@titaliv' tals coniloll'd by
in
nunbd of g.G, Th.s. qMliLlirt d polvgdic tlits e dfrcult to Mipultte
h.ding pbStu conPNd
hisb
dviioM€
t
th'ir ltiScnic mnN antl
Bv idddrying DNA ndtd link'd to th* l!!rrs'
to ihc M€ndclim taits d@
x g.@ irtem.iior
a
b
@ h. .4sily ruipulated ed ilcdPotlt d into conn'Eitl culiir"6 Zhao t' dl'
(2008) ba d.$tib.d thc ptoc.dw for !)dk{ dsist d slslion odAS) in brc'ding;
nsdy physiolos€l dtlysG of fF cop is studi€4 thd selation of g'rcnc @l'@
th.y
(ohr&t
vs lB@pliblc
g6aic vdiarion
Smplaln), enlblhhrcrn of
based on
Spmdic
Lclslogi6
a
s@nins cdEna, disdtion of
(DNA @kedQTL
ddvsit' fidilg
thc rsposible g€n€s
cultiw
ed fbally
uling lh.
i
omatior in lailoring deught GislrDl
thhu8b bedine or s.netic .ngirenng
vsi.tion in DNA s€qMe (5gndg. md
Ch.il|m, 2OO4). DNA odt6 h.y bG dctFt d by Non'PCR sEh 6 RFLP (Esfiction
tuglMt ldgth polbdPbis) or by PCR betc{t techniqB sth 6 SSR (SiEplc
s.qu.G EFats). In 1980s! RFLP E thc 6on @tunlv us.d teh.iq@ in pldts ed
DNA
ea*6
deret
poltsoahj$
b!s.d
d
eibals ro iddd-ry mlk6 fq tnidyinS dirttsity and @nsr.Etid of c.ndic naPs
(Gdd e| dt. l9l; Mccouch a ai., 2OO2; UU@ ed Mediih., 2000; Kotu.t.''
Pdlbq.r
2ool;
shstl tagsdts
a/..2001r. In RFLP, S.nomic DNA is @l bv rsriclro.Mtd.s inlo
of dif.Hl sift. Thce cln th.n b€ sepdted ihrcu8! el€cirophoFsir'
Radiolabeled ereb€s
@
.utodd'ognphy, The
6N ensiv. go{ic Mpr Ning
hybddi4d with restict€d DNA
toMlo (Bdalzky ard Te}sley, 1986)
RFLP
inrclB
!d niia
dd
RFLP
lhen visualiad bv
w olBrucd
(H€l@tdis., at,
1986).
Howvcr'
n<Lo!.tivity, is idbni.ltly ditrcul to u!. dd vi€lds low PolvnoipbisD.
'nF dilevdy of poltDc@ cbi! rali@ (PCR) bv M![is ad f.]@u
dobnodzed DNA
such
s [M
hcpatiris ald
in
Mltd
tecbmlogy nol oldy in cre! b&.diDg but
DNA fig.rFinting
prlhity
ale in oth.r 6clds
h fot8ic atud€, dlv dcletid
dis?utcs ci., Thc PCR is
4
@plitr
(1987)
rdid ofa
of
d*.g .g
sp@ific Egion
of
dplified Bing a slEd pdmct ltc PCRbed n thods nDv eithd ue
dbitry, sii-ebit.fy d gme sp.cific ptih6 The L.hlologis iNolving sinSlc
aftirsry pine$ N tudom uplili.d Poltmahrc DNA (BAIDi wilids tr at'
DNA thil
@
h€
w.hh md Mccl€lland, 1990) and DNA
mplificdiod 6ngdprinti4 @Ar; C@bno ADol€s., al, l9l). Ir'€e t chniqo* rc
simpl.,6y to ue ard do not irvolvc ndj@tivily eiich hd Mde th€n v€ry poprld
for mappilg .nd gd.dc dimity !tudie, RAPD ald DAF both e svnlh€tjc
oligolucl@tid€s to idgEt s!6ifi. bln u.kmm ddom sire of gmnq DAI us v€ry
shon pri!6 uu.Iy 5J ffi. ft. 6plif.d p@dats e lglitd d lolt$ler-b.ct d
poly!4rylani.le sel ad d.l-Ld by 3ilvd sLinite @ass@ ed B.trtl€y, 195) RAPD
1990),
dbitrsly pimed
PCR (AP-PCR
(RlDdoD rEplifi€d polrdoipbic DNA) i! lhc tinPlcd
rcR
bss€d
tebniq@. L Fquil.
l9l) ad involv$ short EndoE IGE
dlitiry Fil!6 to dptry rh. DNA. RAID uplficdiod 6 b. $FnLd d aeaee
lnrl
sel
quntity of DNA (Mic[clnoE ./ a1.,
(Dmiklt .r ol, l9a).
c{@l
RAPDS
@
.tomiDtnt
tur!.c dd h€letuzvlpB ildrviduds
bc difreMtiated Aom homozygos o@s R-APD cchniqws hav. b.co widelv
(Bodkova.r zt, t95; Stubd, l95i [(rtl@ r,.L,2004; Thda d 4r,2006)
HMvd, QTL adlysis ltd oappitg e t ldivcly not e slc6snn wih R-A.PD ort6
ls€d
du. to th.ir non-Eltoduciblc .nd domiml
Btun
'n!e n.tho&
!.ni{bie&y PriEd e eplfi€d A.smdt ldgi!
'nwlving
polForpbis (AILP;
vos ., al-, 195), Eic|wLlil6 tq.d'pdm.d DNA (M]_rcq
Sh,m .t al, 1995). s.lcciivc dplifidion of nicl@lellitc Poltooryhic l@i (SAM?L;
Mo4et sod vogel, 1994) @d @domly @plifi€d micmstellit€ polvnorlhis
dl, 194) .L. AILPS c b!.d on RFLP3 but slich{v d,frdt ln lhi5
te.b.iquc, rdapt 6 @ li8!t d to.!d! of Gtictior nagDGnB !d lhd uplificd with
pdn€6. Anplification EeulB e E$lv.d or .lenaturing poll€crvlvnide gel. Th'e
ML.6 !rc domiMt io Datw ard ths yid.l pd au.lic info@tiol Oth.t PCR bas'd
(RAM!; wu rr
labliques iftlude SSR (sibple s€q@c. rc!€l/dicos&[il6)' CAPS (clevcd
@pli6cd polroorp[ic equ.!B), SCAR (scqEa chleLrit d uplificd eeio$)
dd sN? Gingle nu.l6tid. polldorphirn) (VarslEv e, .r, 2006)
SSR
(mic.6d.llil6)
rincs. ubiquirou in
ou
e
2-E
neleotid. E!.alr
FF&d
otlroca o2sellfue., ar,
in
tttdd
1993) SsPs
e
up ro huldrEds
sid.lv
th. g.none on €&h chroncotu (Lin aid Lutv, 1989). Di!@letid€
of
distribnted
rp.{r
tuotifs
pL!!i twh d Bt*t (Motsste ., dl' 2002) SSRS
hde bccom rcry Fpulu beae of $cir cxrasirc g.mtu @v@sc (Ctpta and
veslney, 2004)- ftey @ higlly polFotPhic, rcpodEiblc in 6ulrs, .nd b.ing locs
s1rch
6
spdifi.,
AG/CT
arc
e mc filqMl
v.ry infom.liv. od
in
rotc.
h.ing @{oEiun in Dlu. @ dif.cnfDte lonozvgotes Aon
hehzygoGs. Th€e MkGR cd be Hdily arobdld (Shdiflou .t al ' 2003) ed ts'd in
divdsity studi4 s w.ll 4 nappirg of idPoda gen€s, Msjn soNd of gencotion of
SsR
nst6
33
whqt micGat€llires
N
John
Idcs cent oIC) Norwich LK (StcPh4son
"
41.
I98),
G€tudy (Ro<kr, l99E), wbst Ficlwt lliL oMni@ (vMC;
v6hn y ., al. 20OO) 6d u,tFd SSR club (Ni6t .t at ' 2003)
tPK (C'aleBlcbd ald
tEhrqE involve foNsd ald dc Find ro dplifv tb' t3lgtr s'qu4c
Ih6. Fib.6 @ d6'8ned fot nsrins csioN of itF Equired FqUE@ (Beka atd
SSR
H.ua 195). Ga€nlly,
Flyldvleilc
g.l
is
wd
to visralize Mplified DNA bv sSR
edtlm, howvd. asflose @ al$ be Led SSRS e considcr'd lh' nct id'd oatcrs
crcP
for D4ping stul,es (VNh!.y./ dl,2006) Thev !!vc b@ *id'lv ued in ruv
sD6id b iddti& Q'ttr dd @Btst s€ldic b46 (Mccosb et al,2@2iLjntt a!
al,2010;
2005; Z6g et a1.,2005; Tddd! et dL.2(nf; sornlin.t zl-' 2008; N'linj
'r
veg .t .1., 201 1: Li a o/., 201 I )
2.?
QILM.ppirg
Algaji (2009) defn d QTL 6!pDi!s 6 "tlE D,itd-hcilirstcd g€detic dissetion or
vsiaiion of @Fdd Ph@lyFs ilbueh spPbpdat dF ibdttl ddign md statisical
dul)s€s of segeeding mildals" It b t!. oo.r efrcidt tppm&h for sMving
*eFeltid
populalion from eencticdly ed pimtt?icsllv div€$e pdenls is ihe lEt siep fft QTL
{Dlysis Th. .bili9 !o tteid QIrl is hi8!.r in F1 or Frndivd poPdatioN 4d
poly8dic nars 3Eh
c.onbind
bDloid .&l
$
dmughl
loto"M
D.aeloPf,€nt of a tb!Ppi!8 or
inbr<t lircs, howvcr, oth€i nsPping Populalis such
lar
isos@ic
lic
2.?J Popul.lioN lor QTL
Two @ntrdtilg
@
d backdo$, doubl'
.ls 8cd.
dPPbg
pdnG @ q!6!.d
to d.vcloP
e
rr hvbnd ehich
is
*lf'fcrtrliz€d to 8cl
i! ecMrllv N€d in sded€ mPping sM''s (Mccouch
Dd Dor8., 1995; H.tund.z .r al , 2oo2i fnsga .t 41 2o04i sofali$ €l al ' 2008;
.t ai. 2Ol0) b4!s il is 6v !o d.rclop in a shon'r Fiod ot lim' MoF*r' il
e
F, pregdy.
Ite
F, popdarion
NaliN
naridiz3
the
domarioi of co{oniMr
ma*s
Thc
Gdonimt
n!*s
sSre$c
39
sI:2:!d ctb.dooin b!*6
fiat
a.!
*gFS!r.
8tug!€ $
individud is a @iqu.
s
3:l- Mljor drastdlk
.pplication
of[, poptdion
ofo dFdtnot
i3
l d6isn md
Gplicario! is not pcaible.
Bak Mr poloLlio!
2.7.1.2
Backctus populatior is dev€lop.d by @stin8 tPo contBling Pdelrts to gel e Fr which
qnich b u*d itr
is frfilF @$.d eilh @ of rbe pd.nl3 lo gd a tacrrc pregdy
mppbs (Bo@a 2001; coPl!, 2002) It
ed diedvdages.
sgcgalcs
ll
in
The only
ba.kN
jusl like th. F, lnd hd sinile advottgca
difrftnce h tlat donimt lnd ccdooindt narkes bo{t
Prc8dY.
2,7.13 DoubL brplold (DH)
liB
is
lhd
qe dd.lop.d by g.lmtirg hlPlo'd pdots fton hlploid cclls
Doublc
b4loid
(Flld
or c8s ells) followd
tt
cls@3om
doublin& Doublc btPloid
liG e
dl l@i. TLy htlc b€n u!.d fo. i.lenti66iion drd nt4'ping
of QTLS in wh.at (Qwie ./ dr,ls,4i\.@ et al ' 200q dtn veou oihd oop6
(Irip.lhy .t .1., 2000: Jing et al , 2{}04; chlouFt .t ut' 2006i KuM t' dl' 200?; Dtslii
ompt.&ly honozygoE
., al
200n. Thc ody
2.?.r.4
at
drsdwlag. of dolbL h4loid
tiN
is that
0!c1e
6{v
10
R@dbiNt bbl.d li!6 {Rlt!)
s.lf-fttliliadon oflbe F bdividuds fd nve or
moe g*nliotu. RtLs h.v. bcn usd exl.roivdv in QTLS n'pping stqdiA (HeN€ t/
'IrFy
e
d€v.loped 0mush 0|c
tFli.d
at, 20ol; Yu d/ aL, 2005i Veg ct d , 2@7i clSN a 61. 2009; Wt!! 4r 4i 20l l)
how€, R[r n €d lons tDe 1o ttevdop and sonciiM tbe PoPularios 3ho*
erllgadon disiortion (S.ns
2.t,15
N.s
Nd lt r.!i.
NIL! litc
i.
,l,
2006).
lin6 (NUi)
i$seDic lirca bde
Th.y ditrq
s/
de b.c!
presme ot !h6.ne of
tenbi.a
inbtld
(vith Fspd io a ert in
sdctic @!Pin8 (JaEkongIw al , 2004)
"
sp..ific t{g€t s.ne How€v'r, d'v'lopMt of
used for
a
liB is iiG @sMils b..tr lrc @ltatng pe
!!io e
cosscd sad
ihd
the pbgelv h
boclc$ed
s
for 6
40
will hav. th. s. gtr1ic backSroud exc.pt fo! a
si4l. sdc lo@ d loci of @e chrcno$ne, oy pollboryhs
DNA oelG tuy bc.o id.nd 6 fintcd *ithlhal p.nicule g@.
goer.tions. Si@ the NlLs
diffeE@ D
t
d.tectcd throud
mkd
A egrcgaing
populadon,
Th* p!fl.@ 6
udnEdioB
the
tclls .bour th€ allclic aianis of erch individual of ih€ *ge84io8
@ g.l
oo ihe
s.dd non
gcl
pictc
cl6topho6ir. A gatic lirlog. E
tlar
h.lp ofgcnoit?ic
Mkd
be
p
@
lner
Ming
tb€ PCR
th@ bc cdsmei.d with
It pbvid.s informdion or thc gd€ric di$dc€
b.r@r
b6is ofthet rccombb.tion fr.quocy (Kor'y dd Psny, 1996).
or disr.!@ is tak6
Fcombi@tion.
d
cM (clnri Molge). A disrare of
A ga.ric nup speifid tlE ordd of
I
each
ft. uit
cM ir cquiwt.d ro l%
es*d ed thc iner,ndk
r
KeBy &d P@oy (1996) hlE deeib€d Eioc sieFr fo. corsirudio! of gdcric n ps:
6Bdy, ph.m9ping of tb. popuLlior for rlE quaffibriv! rtri! iho wnid8 of pam6
polporyhim, eenoq?ing @h
of thc popuhdotr with th! polrroahic
'ndividual
markds, sorilg of th. allclic
of .$h irdividu.l of rh€ populstion aad flslly'
'l.rB
ddmirlliotr oford* of8.n dc Er*.B sithin rle fnlrg. gm!p.
ror
Ato $oiing rh. data of altclic $ans of.ach individud fion gel ptoto8nphs. rh€ data h
su.lly lubjet d io silri3ricil $ftwe 10 tu&e a g4ric Da! ed dctccr eILs.
g@6lly red for thi5 pupo*. Ir consEsrs a g@cric Dap of ihc
nark€a t$ted ba$d o. EcodbiMrio 6!qu€ncy. Ir us.s a nap tumtion rratdaE or
Kosbi lo tr&slate dist n@ inb cM toh l@mbiMiion Ii€qllmy. An atgorirhn is
us.d to o.dcr lei or ! Dlp b€$d m tOD (los of ihc odd!) atio. t-oD ffi is loc of
MAPMAKER/EXP i5
odds of one
'fto
hnotbBis (c.g linLge)
v€s d .lrderiv.
or
ndl h,"orlEis (m Dnk!g.}
pregm h u!.d ro dei.ci QTLS on rhe gderic Mp. Q II" C.nogaph€r
is the n$t populd $iwar.. Bsi@Iy .ll 6e sft,es id.ntify QII,s by f+sgEsation
b<rv6 lle !l|16 .r Eria lai ad rhe all.l6 ar 6€ QTL (8rem4 20ol).
a sbtistical
".alrsis
'Ite tuin
s1a&1ical
n
rhods
omposit€ iotcwd mppin&
u$d @ sinSle mlq ealtsis, inrdat mppil8 ed
singlc
D!*a ealFis
(SMA) neilod
E
IiBr inllodEld by Sd 0923) who dctect d
s€ed pigodtation in bc8. Ir iJ siDpl. .rd doe mt
th. first QTL fo. sad sia !d
cquitc 8.n ordd. h ws ANOVA app@h ed is sonetim cau.d lnd*et
rcgE$ion" at oe bi*.r l6i (SoId, 1976). The nuppils popu/.rion is gcnorr?ed wirh
oE
blrtd ed is cbsi6.d
ph.en?icdly
mqd
into
te
ald @npoDd for.
iadsticdly 3ignjftcdr, th.
Mkq
delelion mdbd is loq in
pow
QTL @y bc
h sid to
d l[.i!
ed
b€ finred
of Bolurion
stN
iadividuals
gootyrB.
Tbc popddion is
cqlli! q@rirllirc lair rrlc difctlc
b
a QTL
g@lyFs
e
is
fo. rhal i6ir. Th€ SMA
bed$ whd tuk6 @
fe fiob th. dart6. S.puG 6tnatio.
6rcu8h tht method
t5d6
g6up! brs€d
widcty sD6..d,
of QTL efer5 is nor posiblc
mi$ing st
a
Da*d
have to be
etd Eots&in (1989) itrrodE d rhc Intemt Erppi!8 (n{) ndbod. Ir is noE
.d@tag6!s rhe
rhc SMA tuihod
(Clpta
20()2).
ft.
IM appM.h ttquiB ! gdctic
ba! md podre8 a cwc dd is ba$d on joint tlquaciB of a pair of ddj&cnt @tds
ad a pubtiv. QI! flek d by ihe rwo ffi.k ts which nak s ir rusibl. ro prodM
nd.ladai 6dD,r.r of ldlrio ald cfccr of eTL ft is llE mosr Dopuls, nethod ro
detd QTrr. Elch l@tion of gmre i! co iil@d o@.1. titu s lo.dio. of purariE
QTL. LOD
th€
$oF is calcul.t
whol. gbup. LOD
d ar
@h incrdnot (lalking
sE In46
ndr comoily u.d
wa dsiglcd lo map
a 3in8le QTL
th. tr.i! *nich
aankin8
Ddk6 s
mcthodolory in eTL mlping. Howcvd.
&d do.r
dc@s i[.
conposi| i!&rv.l tutping (CIM)
B
tho fo.
ile sr.ngth ofth. d'den@ of!@s.M of a eTL
Allhough, IM is th.
a.treting
sr€p) ofrhe inr.rual
i1
cosida othd linr€d or ulinlcd eTrr
pok &d @lurion of lhis ncrhod. So,
nor
irrodwed
3
o@ of iB e(ensiod. Additionat
@-vdiar.s Edu.e onfouding etr cis of
l:eby
eTl_s (Zou
od
zag,2008). ft is lh. molt infom.tive sppr@h. Aly nmb$ of eTk @ bc mlped
adr.€ly th'ough a cue It rEdlB thc .r$'c of d.tarbg gh.st eTb M.jor
&istqck of lM ard CIM n
thods is rhlr thcy EquiF a
nddad
staiisticd
pbstu
speilly d6ign
sratisiical
d for DalpiDg QTL'
eft{a.c
using corelation
*hL
SMA mly be
@i.d
out vith
&y sinple
teclriqE.
dnlgll toLn.c. h ctup pLol!
2.t.2 R.poned QTL' lor
$c.g hs bcn n de i! n4piDg tuy agricuhElly inpondt g.m wirh
DNA b'lc6 in crep ptots. QTIr fo! th. tiliG sE! 6 osotic adjrBtlr@l ir sufoE
T@.ndoN
(ltq\. .t
al., 2oor',
r,isi .t
al., 20Oi!), wUE in ,9/oszn
2001), d€€p
$il wd.r qploFtion
41., 2004),
leaf gtoMh aod anlh6is{ilkiiS inLryal in
chl@phyll
'!"
.nd
of
$did
ooE
41.,
201r', I\obin et el" 2003)
Mt
at
et
in
bw. h.€!
rie (Coqroi* et al,200A:
etbd
(Du., ar
2007J,
2009),
Lngth (St€L dr ar, 2006) @1
ad
ell
ih,ctGs
osnotic adju$ndt in n@
Epon€d. Although QTL mappine
for drcught iolc@@ h!v. bdn @nducted in
rEpons on
tuire (W.l*$
,,
md icLd in @lton (S.m8! .t al. 2004), t*.
ir etghm @orcll a ar' 2000), floMing tim i. botLv €n e,
(Zhare er ot, 2001), ooi F@ttaiion (kicc .r 41, 2000)
88 et
., dr,
"t', oootio poldtid
beDbtue stabiliry (Triplthy .t dt. 2oo0),
(
(Ihm
in Ln!@ (Johren .r al. 2000), bot-ABA (Giulimi
laf sqlc*.M
2r.,2005), s.d yicld rld dreush su!flibility iDdq
o.*t
r.r r.4r'4
IMy
@p3;
how.r lh@ re
Z}@g .t d!-,2001. Krno6hita ,t
ul,
2002;
trftt! tr al, 2004; KllM et al ,2@'li B.tuq .l
a/., 2008; Yd Ying .' at, 2008), wl4t b rh. l4t shrdied cmP in lhb FsD4t
Babtr et
al, 2003; Robi!
2.73 QTk
dt
for druuCt
al, 2003;
tol.r.oe
ln
wb.rt
chonosm. subdtitutio! lifts &d populttroN d.riwd lion the
c@ bet*ra a hiSrt-ABA ptodwi.s *tEt cultirli Ci@ 67 ald . IoFABA ptodEins
Qwi.
., al.
1994 us.d
Chilw SpdnS wicty to dder QTrr for ABA emuLli@ trdLr drcught slrcss ABA
Gumlldon ud6 dtuugLl slBs lad! !o tionalal clore, *hich p@.nts Mtct 16
fton pL $rcugh ttll3pin id. AMrdiDg to thek rcs ts, th€ g.@ eocoding ABA
prduction h prcs.nt on the chremosm. 5A. Morge and Td (1996) u!.d @ombimr
ilbrEd lin6 ir wh.al dd EporLd ihit th. 8ft for osNgrlaliod wd l@&d o.
chsm$N ?A. Thcy u$d l[. RFLP lehliqE .nd dplov.d linhge aElFis for
.Ltection of QTL.
Th.t apodcd iit leslioi
on
lh.
short
1owlrds th. c.nnomrc &@ tbe RFLP tocu Xprtl 19.
m
of 7A
clftn@@'
13
cM
vdma rr al (2004) adoiad Ds linca dqivcd fton the cb$ of tm EwPce Wint'r
wnols for QTL sntlttit of a.g |af scsme ed sdin vield Thcv us.d AFLP
technieue
dd
detaled d
QI! fd
flag lcdf sd€edc. und€r drcugnt stre$ on
EaFd Q'Es for spft. bngt! u&t drougbt st6
onclmm$n s IA,2D,3D, 5A, 58ed?A,tunmb€tof spfteblson lA'4B'5,A'6A
&d 68, fd tml nMbq pd s?it &d l00O gnin wi8h on 2D, 5A 68 !d 78- Thev
cpoiied thst th€ chronosm.s 2D, 54' 68 ed 78 pltved e inpoisl rcle in c&ryilg
g6cs for inpond lgtumnic !!its i! *tcal.
chsEoem 28. Jisg.t ai.
(2004)
gten
QTtr for Ed@liou in dqs to hedilg, 8nl! fl dralior ed ie@sd dl. of
filliog in a rtuobimi inbtd ltred populalion udq drcodl stcst k@ ide ified bv
Knigwi et al. (2fi14) uilg SSR b,rtd Th. Eicr@tllit -fvm,a otr chremoen' 4.\
was
foud ro be s@iaLd with a i\.duction in dlF to h€.dirs; in$*sed san nUine
raG
&d low dreurli ss..ptibility itrd.x.
a popdnid of
wd wd
96 <toubled
for QTL
rraits inLritcd
ddlyst
tqloid
li6
by Dlshti €r
diffdarlv in
tod a cos b.l*a Chit@ s!fi!8
dl
'[tev
(200?).
lrfitl ed st*
suggesled
@!dilio6,
ard
SQ
I
fiat mdt agremm'c
So, QTL aldvsis is
lav
t.iis. TlFv deieted 6 QTk fof
l0OO grainwis!! | fdp.d@Llengt!,I forSllinvicldond5 forNntdof sEi$Pa
ed. n!.y d.t6t€d 3 QTLS for str* sleflibilitv hdd on chrcffiom.s 7A' 4B dd 68
dd 2 QTLS for si.!$s lol€tlM ind.x on ih. chbdose 5.4 ald 58 Diab d ar @008)
id6ti6ed 63 QIr-s for @opy t mpesne, 43 for chtorcphvll coni'n! l2 for
rd$ointion Fte, 3 for clatik mld co cnt &d 7 for osoiic adjusbndt i! a
eoDbi@t ilbrEd popul'tio! of dtu *h.5 @&. drcugli std
cfici€di in ud€stllding th. geielic.ont$l of th.s.
QTL
d.lysb h€bs pldt bltedeB to t ilot pDdwtiv€
uing
dlrtd
Q
ll,ggcc
6sisn:d $l@tion (MAS).
in MAS adds F@ision
't!c
w
i! $l*tio!
and
of DNA
of
ueftl as'iculrud c'ndvs
bdt6
liltcd
desinble
of
'onbiittion
h!v' b€n iddlift'd
pldts *ith d.sinble
gdca. QTL! for soN com@ially iFporttlt Fdits i! cop Plmrs
and qploi.d in na*d dbr.d bt! ding pDgrds (Cldvelli .' a/ 2008)
QTLS
10
Th identift'd
will Dovidc sein iofmdon n) Plst noleuld biolosists for clonins 8cn6
udalying tlcs. tr.iis ed thcn @ipuhli@ in
biot chmlosy/gmelic oSinding.
2.8
cl)ffiial cultim
thtugh
C.!dn Elrilertug
ctsicat bre.ding nethods involw ctusi.g of !6@t! Mth dsinble Lsitt Howdd, in
thsc .!Fo&l|s, pLli bc.dd ts to @Dptonisc for lhe inttodlclion of ud6idbL
traib lirlcd lo th. dcsiEd o!.s, Thc dtat iniroduction of Equircd 946 iluough Scnelic
dsindiie b e .mci. wy to ilEod@ ddiBblc ch68! (Cuhnll ed Bohn 4
somc e.neiic DdipuLtions ftr drcu*lt lol@cc have b.d und.nak{
(Csniv€lti er ai. 200E; Asbnf, 2010; Iipdm tld Buiitr, 2010) For qdple
2OO0).
inE duciid of g.@ for biosldhcsis of osnropretec-r{is (Bohn.rr and shcvelda,
E E .r dl., l99E; Mc@il .,
2010).
al,2c,r',vu',j^et dl 2005i Z}no 4
srcngcs of Elive oxyga acics (Noclot ald foyer,
induc.d ptuleic (ftomssbow, 1999i cnena et
41. 2002l'
D6laI et
g.ldic iryrelclMl for dDughl asi$Ee in Pnet ltd oD4
zl
6Dps
l98j
41,2009: Ashtaq
ad
1998)
2009)
hs
not
stt
s
Howcr,
ben vdv
$cc6sntl by 8.ndic €ngiftding, Dowht Fsisld@ in *b@t and oth€r @P plels nav
mr b. lchidcd by inlrodurim of g@.s fd a single d!it, A lrrg. gtow of gcG
@t sys16t, hid$ Flauv. w.1er
@nrdr Educ.d v,l.r los, Sood omnc adjuthe4 cll ndb|le $.bililv'
contolling a codbi@tion of tdits lik€ .xt€Nive
Mulalim
of &lioxidell in hidt anoul
inboduc€d for inprcving
Bisrse
in
6p
.ic udd
dsuSlt wuld
Ed b
be
pbtrts
.xog€lou lpPli@tod of tutio{idots inplovs
'lrought
9m
to
hrE a
d
dtioFd,nt
&id
$
pldl!
*nc4
lgdic
irclditr8
bl.t!@ of c|op
good polertial in m.lionring ihc adv@.tr cls of oxidliiv. stress on cDp Pldis but
tuind r€*eb on bi@h.Dicd lnd phtliologcsl bL of elbic &id in pldts
$bier.d to drcuslt t!!s is FquiFd. MGI of lh qo* t lon d f@us€d on salt
A! eeliq
studica €pon ihat
qdlid
tol@c€ of pldt! rbrougi dogooN applic{tion of edbic acid Motov'r in
sndi.s |tschcE sdc6lly 4pli.d d En&n d* of @tbic eid wirlour Pdor
opiniation of its nost .f€cdve doe, High conc4tr.tion of a solute mlv be bxic lo
platrt whle a loM ld.l @y b. nEfrdlivc so' th. .!sssi@t of oPtiDN ldcl of
dcorbic &id ltplicliion @ droodt stEs!.d planB should bc
died ou MoFE
to.ll lbc dpdiodltl popuLtid Mv b. 4llicd in hvdoponic
cultw by sins PEG (lolrdtyl@ 8ly@l) ii! contitst io eil cult@. L4.Nqfr et al.
(1961) rpod.d th.r rEC @old be Ecd to nodify the molic pot nlial of nuiri4l
elurio! snd ind@ drcuCt stlsr ir t.oftllLd ll|lrw Ir 1970's ald E0'3 the e of
PEG of high (4000-8000) noleulat wiCt b€ec vdy PoPub .! hiShd ool.c'nd
wigh PEG @fit Penct!& into plad lisc. Arnong th. dtoughl iodrcing olnoli€
cmFurdlj PEG i! pEf.nEd oE thc ot!.s (Irga*ff .t d' l lr Slloa 'r 4''
200?). B€ing no&ioxic to planis it is widely ed to indw dloughl 3it s (Ch4n ed
NMua I9'4; zhes ed KirklaD 1996 gaElru d/ .i , 2010). slFh,b ./ al (2010)
ls€d 5, l0 .!d 15 % IEC ir nuticnt elulion for $dy i! ii.c viiL HrEltu t' 4'
i2010) u*.t 8 ald 16 % PEC to ilduce dild and sv@ dtuuelt sLc$s 6p4!vdv for
uifom dtourh
sri6s
pollmd ltodued i! a msc of tul@uld
wistu. Thc cdibdtion cw. lle$od .€aiNr tb€ noled! wigbl ad @nc'ntialio! oI
lEG M danonstal€d by Mon v (19E9) As PEG of ditr@1 mol@uh w'i8hls hd a
dif.Flr omtic pollntial Pncd in $llni@ fm, thccf@' (!s'tml of tE optinM
syb.!! pldts. PEG
is a Dn-iolic
"d.r
Lv.l (do!8 vErying colc€ftr.tioB of PEC) for indebg dough '3tl's
osolic pot rtial is ale vcry trnportdn,
Thu, the
trt$t
crog@uslt spplicd
io
s.
how
it
projdl
w
.sftic sil
@nsidsinS the
deigncd 1o .v.lutic thc nost cflddw l€rcI of
d st6t PttDB ud.. o6mtic str4 @r'd bv PEc
dl€viates the advee .ff@ts of &ought
Funlcnot,
identifi'adon
of
ro initir&
QTb fd dm!8!t tol.ru€ in ih. pc.rt Ptoj.ct rculd prcvidc t b6is
war.b @ cloiing of g.tEs dd theii @iPulation for hjghd 'ldogclou Mbic &id