26 HISTO-ANATOMICAL ASPECTS OF SOME LONICERA L

Analele ştiinţifice ale Universităţii “Al. I. Cuza” Iaşi
Tomul LIII, s. II a. Biologie vegetală, 2007
HISTO-ANATOMICAL ASPECTS OF SOME LONICERA L. SPECIES

RODICA RUGINĂ , C. TOMA 
Abstract. The authors investigate the structure of 9 Lonicera L. species (L. canadensis Bartr., L. chrysantha
Turcz, L. fragrantissima Lindl. et Paxt., L. nigra L., L.x notha Zab., L. pileata Oliv., L. ruprechtiana Rgl., L.
tatarica L., L x xylosteoides Tausch.). The stem and the leaf (lamina and petiole) are analyzed, evidencing
common and distinctive characteristics which may confirm or infirm the species identity. For example, in the stem
is evidenced the epidermic cells shape and periderm structure, the type of vascular tissue, especially of xylemic
vessels, the structure of the medullary parenchyma. In the leaf, the structure of the lamina and petiole is focused on
epidermic cells shape in front face view, the mesophyll structure and the petiole contour in cross-section.
Key words: Lonicera, structural characteristics
Introduction
The Lonicera L. genus includes numerous species spread mainly over the Northern
Hemisphere in Eastern Asia, Northern America and Europe, also in Romania where four
taxa can be found in the spontaneous flora.
For those 50 taxa found in the cultivated flora of Romania [8], having peculiar
ornament value, it is difficult to establish the identity according to the morphological
characteristics of the vegetative and reproductive organs. If in the parks the taxa
identification of the species is less interesting, in the Botanical Garden this fact should not
be neglected.
As it is known, some structural characteristics may confirm or infirm the species
identity, so, in the present paper we have proposed ourselves to analyze certain taxa
cultivated in the Iassy Botanical Garden. We have continued our previous investigations [9,
10, 11, 12] referring to the woody shrubs species found in the Collections of the Iassy
Botanical Garden.
Brief Bibliographical References
The Lonicera genus is represented by about 150 [4] or 120 [2] species framed within
4 sections and 22 subsections, identified by flower, fruit and sometimes leaf morphological
characteristics.
According to our knowledge, so far there are few histo-anatomical studies about
Lonicera species (L. flava, L. peryclimenum) cited in the literature and they were carried
out only when Caprifoliaceae [5, 6] family was taken into account.
By analyzing the petiole in the taxa of Caprifoliaceae family, some authors [3, 7]
refer also to Lonicera species, but other than those which we have taken under investigation
in the present paper.
The same histo-anatomical characteristics with systematic relevance were analyzed
by us in the species Cotoneaster, Ligustrum, Spiraea and Syringa genera of the Iassy
Botanical Garden’s Collections [9, 10, 11, 12].

„Anastasie Fătu” Botanical Garden, Iaşi
Faculty of Biology, „Al. I. Cuza” University, Iaşi

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The poor existing histo-anatomical data, even the absence of Romanian or foreign
literature upon Lonicera species have motivated us to approach this subject and we have
selected some characteristics with taxonomical value.
Material and Method
The foliate shoots (annual or biannual) sampled from 9 taxa of Lonicera genus (L.
canadensis Bartr., L. chrysantha Turcz, L. fragrantissima Lindl. et Paxt., L. nigra L., L.x
notha Zab., L. pileata Oliv., L. ruprechtiana Rgl., L. tatarica L., L x xylosteoides Tausch.)
collected from the Iassy Botanical Garden have been analyzed.
The vegetal material has been processed according to the preparations methods as
described in our previous papers [9, 10, 11, 12].
Results
The stem (Plate I). The shoot is protected by an epidermis which in most of the
cases is tired by an early grown up peridermis (L. fragrantissima, L. ruprechtiana, L.
tatarica, L x xylosteoides).
The cells of the persistent epidermis are isodiametric (L. chrysantha) or tangentially
elongated (L. canadensis, L. nigra, L. x notha, L. pileata) covered by a thin (L. chrysantha,
L. pileata) or a thick (L. canadensis, L. nigra, L. x notha) cuticle; only in the last case the
cuticle penetrates between cells.
Except for the taxon L. x notha, which normally is deprived of hairs, when however
exist, they are frequently present as unicellular hairs, always short and rare or having
various lengths and frequently (L. canadensis) with thickened and cutinized walls (L.
chrysantha, L. nigra, L. pileata).
The phellogen arises in the internal pericyclic layers having an atypical suber with
cells ranged in radial rows, lengthened in the same direction or deformed.
The periderm thickness is variable:
- Thin, with 2-3 suber(s) and 1-2 phelloderm layers (L. canadensis, L. chrysantha, L.
pileata);
- Relatively thick, with 3-4 layers of suber and 1-2 layers of phelloderm (L.
fragrantissima, L. nigra);
- Thick, with 5-6 suber and (2) 3-4 of collenchymatic phelloderm layers.
The cortex, when present, is collenchymatised only in (1-2) external layers or in
whole thickness (L. x notha, L. pileata).
In the pericyclic position there is a sclerenchymatic tissue forming a thin ring (2-3
layers) with moderate thickened and unlignified (L. x notha) or lignified walls (L.
canadensis, L. chrysantha, L. nigra, L. ruprechtiana) or a discontinuous rind having cells
with strong thickened and lignified wall (L. pileata, L. tatarica, L x. xylosteoides).
The vascular tissue is of annular type, the ligneous ring being much thicker.
The phloem consists of sieve tubes, companion cells and parenchyma cells, the latter
having rare or frequent (L. nigra, L. x notha, L. xylosteoides) cells with calcium oxalate
crystals.
The xylemic vessels are narrow (L. canadensis, L. fragrantissima, L. ruprechtiana,
L. x xylosteoides) or wide (L. nigra, L. x notha, L. pileata, L. tatarica), dispersed (L.
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pileata, L. ruprechtiana, L. x xylosteoides) or arranged in short radial (L. fragrantissima, L.
nigra), oblique (L. canadensis) or transversal (L. tatarica) rows.
As a rule, these are included in a few xylemic paratracheal parenchyma and much
libriform weakly (L. canadensis, L. pileata, L. ruprechtiana) or strongly (L. fragrantissima,
L. nigra, L. x notha, L. tatarica) thickened and lignified.
The libriform has been uniformly spread except for L. nigra and the hybrid L. x
notha of which this prevails towards peripherical zone of both ligneous rings.
The medullary rays are homogenous, 1-3 (4) seriated, having the cells in radial
direction, lengthened, rich in starch and calcium oxalate crystals; the walls are thin,
cellulosic (L. chrysantha), insufficiently lignified (L. pileata) or strongly sclerified and
lignified.
The medullary parenchyma is decaying (L. chrysantha) or replaced by large,
aeriferous cavity, bordered of numerous oxalyferous cells. The perimedullary zone remains
parenchymatic and cellulosic (L. canadensis, L. chrysantha, L. nigra, L. x xylosteoides) or
is lignified (L. ruprechtiana, L. x notha, L. tatarica). Only in L. pileata, the pith is still
present with cells having slightly sclerified and lignified walls, rich in starch grains and
calcium oxalate crystals.
The leaf (Plate II-III). The lamina (Plate II). The epidermis in front face view: in
many cases, the cells of the upper epidermis are much larger, with straight, thin lateral
walls or monilliform thickened (L. chrysantha, L. canadensis, L. pileata). On the opposite
face, the cells have thin and slightly ondulated walls; here and there anomocytic stomata are
present. Their number varies from 3-4 (L. chrysantha, L. x xylosteoides) to (7) 8-10 (L.
canadensis, L. x notha, L. pileata) on surface unit, the stomatic index varying from 0.0350.050 (L. chrysantha, L. x xylosteoides) to 0.128-0.164 (L. pileata, L. tatarica).
In cross section, the midrib appears prominent on both sides, more prominent at the
lower one (L. canadensis, L. fragrantissima, L. x notha, L. pileata, L. ruprechtiana, L.
tatarica) or only at the last one (L. chrysantha, L. nigra, L. x xylosteoides).
The midrib contains only one vascular bundle of collateral open type, with small
fundamental parenchyma around, having a rich crystalliferous phloem; in a subepidermic
position there are 2-3 colenchymatic layers. Only in L. pileata there are sclerenchymatic
sheaths at both poles.
Between the lateral veins (Pl. II), the epidermic cells are heteromorphous or
heterogenous, tangentially elongated (L. canadensis, L. x notha). The external wall is
moderately thickened with a thin cuticle or very thick with a thick cuticle (L. pileata).
The lower epidermis presents long (L. chrysantha) or short (L. nigra, L. x
xylosteoides) monocellular covering hairs, having thick walls. The glandular hairs, present
only in L. chrysantha and L. nigra, have one monocellular pedicel variable in length and a
spherical, multicellular gland.
The mesophyll is differentiated in palisade and spongy tissue, meaning that the
lamina has a bifacial heterofacial (dorsiventral) structure. At the same time, the mesophyll
is formed of 4-5 (L. nigra, L. x notha), 5-6 (7) (L. chrysantha, L. canadensis, L. x notha, L.
tatarica, L. x xylosteoides) or 7-8 (L. fragrantissima, L. pileata) layers. The palisade tissue
is monolayered (L. canadensis, L. nigra, L. tatarica, L. x xylosteoides) or bilayered (L.
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chrysantha, L. fragrantissima, L. x notha, L. pileata, L. ruprechtiana), representing 30% or
50% of the lamina thickness.
The petiole (Plate III). The cross section contour may be semicircular, with plane
adaxial face (L. chrysantha, L. nigra, L. pileata) or slightly concave (L. chrysantha, L.
nigra, L. tatarica), modified by two latero-abaxial ridges (L. pileata). In two of the
investigated species (L. fragrantissima and L. ruprechtiana), the contour is slightly
elliptical in latero-lateral plane.
The epidermis presents covering or glandular monocellular hairs, similar to those
described above.
The vascular tissue forms only a single lamellary bundle, slightly curved toward the
adaxial face (L. chrysantha, L. nigra, L. tatarica).
The fundamental parenchyma is still of parenchymatic type, except for the 2-3 (4)
hypodermic layers which are collenchymatic.
Everywhere, but especially near the vascular bundle, cells with crystals of calcium
oxalate can be frequently found.
Discussions and Conclusions
The histo-anatomical investigation of the foliate shoots sampled from 9 Lonicera
taxons has evidenced common and distinctive characteristics necessary in their
identification.
Stem. In the persistent epidermis, the covering hairs, exclusively monocellular, are
frequently present and variable in length in L. canadensis, L. chrysantha, L. nigra, rarely
occur in L. pileata or are totally absent in L. x notha.
- The peridermis is thin (1), of 2-3 layers at L. canadensis, L. chrysantha, L. pileata
or thick (4) of 5-6 layers in L. x notha, L. ruprechtiana, L. tatarica, L. x xylosteoides.
- The pericycle, sclerified, lignified or nonlignified, forms a continuous ring in L.
canadensis, L. chrysantha, L. nigra, L. x notha, L. ruprechtiana or discontinuous in L.
fragrantissima, L. pileata, L. tatarica, L. x xylosteoides.
- The xylem has narrow or large secondary vessels with few paratracheal
parenchyma and are ranged in short radial rows in L. fragrantissima, L. nigra, L. x notha,
oblique at L. canadensis or transversal in L. tatarica; sometimes the vessels are dispersed in
L. pileata, L. ruprechtiana, L. x xylosteoides.
- The libriform exhibits an homogenous arrangement in both secondary woody
rings, less homogenous in L. nigra and the hybrid L. x notha, where forms a compact zone
toward the outer side of each ring.
- The medullary parenchyma, rich in crystalliferous cells and partially replaced by a
wide aeriferous cavity, remains cellulosic in L. canadensis, L. chrysantha, L. nigra, L. x
xylosteoides or it is sclerified or lignified in L. x notha, L. ruprechtiana, L. tatarica; only L.
pileata presents a wholly sclerified and lignified pith.
Leaf. As a rule, the cells of the upper epidermis, in front side view, are large, with
straight and monilliform thickened walls in L. canadensis, L. chrysantha, L. pileata.
-The stomata of anomocytic type are present only in the lower epidermis and have 34 cells on surface unit at L. chrysantha, L. x xylosteoides, or 7-10 cells in L. canadensis, L.
x notha, L. pileata.
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-The stomatal index varies from 0.035 to 0.050 in L. chrysantha, L. x xylosteoides
and from 0.128 to 0.164 in L. pileata and L. tatarica.
-The lamina, with variable (4-8) layers of various thickness, has a bifacialdorsiventral structure with monolayered palisade tissue in L. canadensis, L. nigra, L.
tatarica, L. x xylosteoides or bilayered in L. canadensis, L. fragrantissima, L. pileata, L.
ruprechtiana.
-The palisade cells are 3-4 times longer than wide, except for L. chrysantha, in
which the subpalisade layer the cells present invaginated external walls.
-The petiole has a variable contour in cross section: semicircular with plane adaxial
face in L. canadensis, L. x notha, L. x xylosteoides or slightly concave in L. chrysantha, L.
nigra, L. tatarica, modified by two latero-adaxial ridges in L. pileata or slightly elliptical in
the latero-lateral plane in L. fragrantissima and L. ruprechtiana.
The covering hairs, similar to those from the stem level are present only in L.
chrysantha, L. nigra, L. x xylosteoides; the glandular hairs, with sphaerical multicellular
glands and monocellular pedicels, are present only in L. chrysantha and L. nigra.
L. x notha, hybrid between L. ruprechtiana and L. tatarica, through some structural
characteristics (i. e. thick periderm, annular continuous pericycle, ligneous secondary
vessels ranged in short transverse rows and semicircular contour of petiole in cross section)
is more related with L. tatarica.
BIBLIOGRAPHY
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548-555
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9. TOMA C., RUGINĂ R., NICHITA L., 1982- Cercetări morfo-anatomice comparative la specii de
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Iaşi (Grăd. Bot.), 2: 313-321
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la specii de Cotoneaster Med. Anuarul Muz. şt., nat. Suceava, 5: 7-18
11. TOMA C., RUGINĂ R., BUTNARU E., 1983- Observaţii asupra structurii organelor vegetative
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1.
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Plate I- Structure of stem: A- Lonicera canadensis; C- L. fragrantissima; D- L. nigra; E- L. x notha; G- L.
ruprechtiana. A- details of epidermis and cortex; C, E, G- details of xylemic tissue; D- detail of periderm and
pericycle. 1- epidermis; 2a- trichome; 3- collenchyma; 4- parenchymatic cortex; 5- sclerenchymatic pericycle; 6cork (suber); 7- phellogene; 8- phelloderme; 10- xylemic vessels; 11- lignified parenchyma; 12- libriform; 13cellulosic parenchyma; 14- medullary parenchyma.
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Plate II- Structure of leaf: details of limb. A- Lonicera canadensis; B- L. chrysantha; C- L. fragrantissima; D- L.
nigra; E- L. x notha; F- L. pileata; G- L. ruprechtiana; H- L. tatarica; I- L. x xylosteoides. 1- epidermis (1a- upper,
1b- lower); 2- hair (2a- trichome, 2b- secretory); 15- palisadic tissue; 16- spongy tissue; 17- calcium oxalate
crystals.
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Plate III- Structure of leaf: diagrams of petiole. A- Lonicera canadensis; B- L. chrysantha; C- L. fragrantissima;
D- L. nigra; E- L. x notha; F- L. pileata; G- L. ruprechtiana; H- L. tatarica; I- L. x xylosteoides. 1- epidermis; 2hair (2a- trichome, 2b- secretory); 3- collenchyma; 9- libero-ligneous bundle; 17- calcium oxalate crystals.
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