CONTRIBUTIONS REGARDING THE LEAF HISTO-ANATOMY OF SOME PELARGONIUM SPECIES

Size: px

Start display at page:

Download "CONTRIBUTIONS REGARDING THE LEAF HISTO-ANATOMY OF SOME PELARGONIUM SPECIES"

Buddy Holmes
5 years ago
Views:

1 Rev. Med. Chir. Soc. Med. Nat., Iaşi 2013 vol. 117, no. 3 PHARMACY ORIGINAL PAPERS CONTRIBUTIONS REGARDING THE LEAF HISTO-ANATOMY OF SOME PELARGONIUM SPECIES Cristina Elena Iancu, Oana Cioanca, Cornelia Mircea, Monica Hăncianu University of Medicine and Pharmacy Grigore T. Popa -Iaşi Faculty of Pharmacy Department of Pharmacognosy CONTRIBUTIONS REGARDING THE LEAF HISTO-ANATOMY OF SOME PELARGO- NIUM SPECIES (Abstract): L. genra (Fam. Geraniaceae) includes over 250 species, most of it native to southern Africa. Nowadays, four perennial species are cultivated in Romania as ornamental plants. Our aim was to establish the main characteristics and differences that occur between,,, and. All in all, the quantitative differences (regarding the leaf-stalk, blade and trichomes) have a taxonomical value for all five species included in the research. Materials and methods: The plant material was represented by fresh leaves harvested from 5 species of : (L.) Aiton, H.E. Moore, (Andrz.) Willd.,. (anthesis phase) and preserved in ethanol 70%. Using a dissecting microscope, sections were made through leaf blade surface and cross sections of/ for leaf stalk and blade. Results: The common characteristics of the leaf is the palmatilobate blade with long petiole. Although many studies regarded glandular trichomes from leaves, most of the leaf structures are still unknown. The most important for the quality and quantity of essential oil extracted from sp. are trichoms. Keywords: PELARGONIUM SPECIES, ANATOMY, MEDICINAL PLANTS, DECORATIVE PLANTS. genre represents a large number of species that were brought to Europe from southern Africa. Species of have long been cultivated due to their attractive scents and bright colors (1). At the beginning the most common were the species with red flowers. Ever since, their popularity increased slowly along with the horticultural enhancement until The abundant foliage form and color were especially valued. Starting with 1870 horticultural improvement of pelargonium reaches the highest peak (a larger variety of colors, flowers, forms and a longer flowering season). Nowadays, the majority of pelargonium species stand out through vigorous plants, with variated colors (red, scarlet, white, pink, purple etc.), fragrant, simple, double and sometimes very large flowers (2). It is among the top 20 aromatic plants that are particularly rich in essential oils; therefore most of the chemical studies were concentrated on this fraction. Our study goal was to establish the existent hysto-anatomical differences between five species of considering that, such variations will be notable 812

2 Contributions regarding the leaf histo-anatomy of some pelargonium species in the chemical composition of the volatile oil. Therefore, the emphases of this paper especially regarded the structure, place and density of the glandular trichomes. The present research is part of a larger study, the chemical analysis and biological potential of the essential oil will be included in a following paper. MATERIAL AND METHODS 1. Plant material. The plant material was represented by fresh leaves harvested from 5 species of : (L.) Aiton, H.E. Moore, (Andrz.) Willd.,. (anthesis phase) and preserved in ethanol 70%. The plants were cultivated in the greenhouse of the Botanical Gardens in Iaşi. 2. Preparation of the microscopic sections. Using a dissecting microscope, sections were made through leaf blade surface and cross sections of/ for leaf stalk and blade. The microscopic preparations were colored with iodine green and ruthenium red and then, analyzed with NOVEX (Holland) photonic microscope. The photographies were taken with Olympus photo camera. RESULTS AND DISCUSSION Petiole. Cross sections did not show significant discrepancies between the basis and the top of the leaf blade. It was noted that the number of conducting fascicles was higher at the basis than for the rest of the leaf. Thus, in accordance with other researchers (3,5) we analyzed sections from the middle of the leaves. The cross section had a circular shape excepting Radens and with semicircular-elyptic shape and the plane adaxial surface, whereas the second species has the thickest leaf stalk (4). Epidermis consisted of isodiametric cells with external and internal wall of cells slightly thicker than the lateral ones; the external wall was couvered by a thin cuticle. External collenchymatous parenchyma was typically lacunar, hypodermic cell layer was much smaller and tangentially collenchymatised. The number of cell layers in the anatomical area ranges from 4 to 6 and only the external parenchyma of is thicker (8-9 layers), many cells containing a single or a few crystals of calcium oxalate. In the epidermis of the 5 species included in the study glandular and surface trichomes were found; their number, thickness and dimensions variates from one species to another (tab.i, fig.1-5). Sclerenchyma ring bylayer is thicker (three rows) near the vascular bundle; the polygonal cells present thickend walls that are lignified. presented sclerenchyma (2-4 rows), with fibres that have thick and lignified walls and very large cells, whereas the structure of sclerenchyma was still primary with weak lignified walls. Lacunar parenchyma was uncolored with bigger cells than those of the external layer, especially in the median part of the petiole. It was noted that the cells from sample contained 1-2 oxalate druses similar to external parenchyma (5). The vascular bundles bear both xylem and phloem vessels next to the sclerenchymatic fibers. For all five species, the vascular fascicles are in great number and various dimensions alternately, the biggest of them representing central isles in the parenchyma. On the external layer phloem consisted of sieve elements, companion cells and few 813

Cristina Elena Iancu et al. large parenchyma cells, whereas the xylem (the vessels disorderly dispersed with parenchyma cells) was situated inside the bundle.

Species TABLE I Structural differences in petiole epidermis Surface trichomes Glandular trichomes Number Characteristics Number Characteristics Dense - uni/bicellular Sparce -short: - long -one basal

3 Cristina Elena Iancu et al. large parenchyma cells, whereas the xylem (the vessels disorderly dispersed with parenchyma cells) was situated inside the bundle. Internal layer of xylem had a group of small polygonal cells with moderately thickened walls (tab. II). Species TABLE I Structural differences in petiole epidermis Surface trichomes Glandular trichomes Number Characteristics Number Characteristics Dense - uni/bicellular Sparce -short: - long -one basal cell -basal (2-3 short cells overlapping) -unicellular gland Sparce Very dense Abundant Very dense - long, thin şi thick - multicellular bunt tipped - short - unicellular - long bicellular; thick - uni/bicellular; rarely with 3 cells - variable dimensions - unicellular - variable dimensions -pointed tip Dense -short: basal (2-4 cells) -long: basal (3-4 sharp point cells) -globular or pear-shaped gland Dense -short: basal (2-4 cells); globular gland Dense Very dense -short -medium: basal (3-4 cells) -large globular gland - short: basal (3-4 cells) - pear-shaped gland Fig.1. petiol Fig.2. petiol 814

Contributions regarding the leaf histo-anatomy of some pelargonium species Fig.3. petiol Fig.4.

petiol TABLE II Structural differences of vascular bundles for all samples Fascicle number 10 11 10 8 19-21 Fascicle type

thick 6 thin 4 large (abundant xylem) 4 small 4 large 4 small 11-13 very small (only phloem) 1 large 1 large 1 large

4 Contributions regarding the leaf histo-anatomy of some pelargonium species Fig.3. petiol Fig.4. petiol Species Characteristics Fig.5. petiol TABLE II Structural differences of vascular bundles for all samples Fascicle number Fascicle type Central vassel 4 thick 6 thin 1-2 xylem vassels large, thick 5 large 6 small 14 at the basis of petiole 1 large 1 small 4 thick 6 thin 4 large (abundant xylem) 4 small 4 large 4 small very small (only phloem) 1 large 1 large 1 large surounded by 2-3 smaller Sclerenchyma cells absent absent absent peripheric peripheric In the surface view of the lamina we noticed the upper epidermis had cells with irregular outline and slightly waved sidewalls, whereas the lower epidermis had 815

5 Cristina Elena Iancu et al. very sinuated walls. In cross section, the leaf blade looked like a ribbon and the midveins were thinly ( ) and extremly ( ) prominent on the abaxial surface. All the veins contained one liberoligneous bundle surrounded by a sheath of polygonal cells, smaller than those from the lacunar tissue. One of the specific characteristics of was the presence of 3 opposite fascicles (one large and two small) with xylem elements face to face. The epidermis has small isodiametric cells with internal and external walls thicker than the lateral ones and the external wall is covered by a very thin cuticle. The epidermis of all selected species presented stomata and trichomes (surface and glandular) (6) (tab. III). TABLE III Stomata and trichomes in sp. Species Stomata Surface hairs Glandular trichomes * amphistomatic amphistomatic hypostomatic hypostomatic hypostomatic -dense and long -abundant, long and very long -abundant, long and very long -abundant, long and very long -dense and long -abundant on the abaxial surface and on the midvein and thin - bicellular basal - short: bicellular basal - long: tricellular basal - short: bicellular basal -medium: tricellular basal - long: tricellular basal - short: uni/bicellular basal -medium: tricellular basal - short: bicellular basal -medium: tricellular basal - long: tricellular basal * variated dimensions and number on the surface unit, with a basal cell, pluricellular basal and one globular-shaped gland The mesophyll had a unistratified palisade and a bistratified lacunar tissue (7). The main differences that were noted between the five samples of pelargonium consisted in: height of the palisade, number of the layers in the lacunar tissue, abundance and layout of calcium oxalated druses (tab. IV). 816

Contributions regarding the leaf histo-anatomy of some pelargonium species TABLE IV Mesophyll

slightly elongated cells, the size decreases towards the abaxial epidermis -along the mesophyll

rounded cells -sparce only in lacunar tissue -short -3-4 layers, small, elongated - only in palisade

reveal the most important characteristics of the lamina from the five samples included in the study:

6 Contributions regarding the leaf histo-anatomy of some pelargonium species TABLE IV Mesophyll characteristics in species Species Palisade Lacunar tissue Druses -short and wide -4-5 layers, slightly elongated cells, the size decreases towards the abaxial epidermis -along the mesophyll -short -5 layers, slightly elongated cells -only in lacunar tissue -high and long -3-4 s layers, rounded cells -sparce only in lacunar tissue -short -3-4 layers, small, elongated - only in palisade cells tissue -high layers, elongated cells - only in palisade tissue The following images reveal the most important characteristics of the lamina from the five samples included in the study: (fig. 6-7), (fig. 8), (fig. 9), (fig. 10) and (fig. 11). Fig. 6. lamina Fig. 7. lamina detail Fig. 8. lamina Fig. 9. lamina 817

Cristina Elena Iancu et al. Fig. 10. lamina CONCLUSIONS As we expected, most of the notable differences between the samples were mainly quantitative and have a great taxonomic value.

lamina and have abundant and long hairs. On the other hand,,, have the longest trichoms on the petiole.

7 Cristina Elena Iancu et al. Fig. 10. lamina CONCLUSIONS As we expected, most of the notable differences between the samples were mainly quantitative and have a great taxonomic value. Since the most important for the quality and quantity of essential oil extracted from sp. are trichoms, the results showed that has a small number of hairs, whereas Fig. 11. lamina and have abundant and long hairs. On the other hand,,, have the longest trichoms on the petiole. Such differences are to be expected to influence more or less the chemical composition of the plants metabolites. Therefore, our future research is going to establish if there are such correlations. REFERENCES 1. Carolin R.C. The genus L Her. ex. Ait. in Australia. Proc. Linn. Soc. N.S. Wales 1961; 86: Ciocârlan V. Flora ilustrată a României. Pteridophyta et Spermatophyta. Edit. Ceres, Bucureşti Neubauer H.F. Über den Bau der Blattstiele von. Österr. Bot. Ztg. 1972; 120: Gostin I., Toma C., Damian M. Histo-anatomical data regarding the aerial vegetative organs in some species and varieties of L. An.şt.Univ. Al.I. Cuza Iaşi, s. II a (Biol.veget.) 2000; 46: Schmitz K.L. Untersuchungen zur funktionellen Anatomie des Leitgewebesystems im Blatt von. Planta 1970; 92: Korn R.W. Arrangement of stomata on the leaves of and Sedum stahlii. Ann. Bot. 1972; 36: Legault A. Recherches anatomiques sur l appareil végétatif des Geraniacées. C.R. Acad. Sci. Paris. 818

Irina Berciu *, Constantin Toma Department of Biology, Al. I. Cuza University, Iasi

HISTO-ANATOMICAL ASPECTS OF VEGETATIVE ORGANS OF THYMUS DACICUS BORB. AND THYMUS GLABBRESCENS WILLD. Irina Berciu *, Constantin Toma Department of Biology, Al. I. Cuza University, Iasi * Correspondence: