, Gökay ArarAnatomical investigations on Haplophyllum cappadocicum Spach
Hüsniye Kayalar*, Gökay Arar
Ege University, Faculty of Pharmacy, Department of Pharmacognosy, Bornova, İzmir- Türkiye.
ABSTRACT
Aim and objective: The aim of this work is to put forward the anatomical features of Haplophyllum cappadocicum, an endemic plant for Turkey.
Methods: Plant materials were fixed in 70 % ethyl alcohol. The anatomical studies include transverse sections of roots, stems, leaves, fruits and seeds with illustrations. The investigations were made under microscope and photographs were taken by microphotography apparatus.
Conclusion: Haplophyllum genus with potential pharmaceutical interest are worthy of investigation not only for chemical content but also anatomically. This is the first report on anatomical features of Haplophyllum cappadocicum collected from Malatya, Türkiye.
Keywords: Anatomy, Haplophyllum cappadocicum, Rutaceae.
INTRODUCTION
The Rutaceae family is represented by 153 genera and 1800 species1.This family is represented in Turkey by the genera Ruta L., Haplophyllum A. Juss., Dictamnus L., Citrus L. and Poncirus Rafin. Haplophyllum, richest in species, is one of the least known genus of Rutaceae. Turkey is an important gene center for the Haplophyllum genus with an endemism rate of 58% (19 taxa, 11 of which are endemic)2,3. The genus Haplophyllum is represented by about seventy species distributed in an area stretching from the Mediterranean to Eastern Siberia4. Members of the genus Haplophyllum are known for their use in traditional medicine5-7, as well as for containing a variety of chemical constituents of diverse structures such as lignans, quinoline alkaloids, coumarins, flavonoids and volatile compounds8-18.
The leaves of plants belonging to Haplophyllum genus are used in traditional medicine for malaria, rheumatoid arthritis and gynecological disorders. Haplophyllum species are reported to be used in the treatment of diarrhea, constipation, and skin diseases19,20,21. In addition to cardiovascular effects, Haplophyllum species are previously shown to exhibit antimalarial, antileishmanial, antioxidant anti-insecticidal, antimicrobial, anti-inflammatory activities whereas H. sahinii and H. vulcanicum were reported to possess anti-cholinesterase and anti-tyrosinase activities22,23. The phytochemical analyses, morphological and palynolo-gical studies have been previously conducted on plants from Haplophyllum genus.
In respect of anatomical characteristics, Haplophyllum species were also inve-stigated but the most important anatomical studies were restricted for species such as H. megalanthum, H. myrtifolium, H. telephioides and H. vulcanicum24-36. In previous studies, phytochemical investigations have been carried out on H. cappadocicum. Lignans and quinoline alkaloids isolated from this plant exhibit its potential activity18,37,41. Although secondary metabolites of H. cappadocicum were extensively examined, comprehensive anatomical features of this species is scarcing in the literature.
The aim of this work is to put forward the comprehensive anatomical features of H. cappadocicum which is endemic to Turkey.
MATERIALS AND METHODS
Material for H. cappadocicum was collected from Boranköy, Malatya. Voucher specimens are deposited in the Herbarium of the Ege University, Faculty of Pharmacy, Department of Pharmacognosy (1178). Plant material was identified by the authors HK and GA. A part of the plant material was fixed in 70% alcohol for anatomical studies of root, stem, leaf, fruit and seed. The investigations were made under Carl Zeiss Jena microscope and photographs were taken by Carl Zeiss Jena microphotography apparatus with 3.2x, 10x , 40x, 100x magnifications.
H. cappadocicum Spach
Stems moderately to densely crisped-pubescent, 25-50 cm. Leaves usually entire, oblanceolate to linear, rarely lanceolate-obovate, occasionally trisect or incised, long-attenuate and pseudopetiolate below. Infloresence broad and lax, the lower branches much exceeding the terminal cyme, at least the upper branches crisped-pubescent. Sepals broadly to narrowly deltoid, persistent. Petals bright yellow, oblong-elliptic, 5-6 mm. Filaments abruptly expanded and ± parallel-sided in the lower half. Young ovary segments biovulate, each with a pronounced terminal apical corniculus, densely pilose on the upper inner surface, more sparingly so below. Capsule with divergent unbonate appendages on the upper dorsal surface, remaining glands convex, the raised margins not confluent into transverse ridges. Fl. 6-7. Grassy and stony steppe, 700-1500 m4.
RESULTS AND DISCUSSION
Anatomy of Root
On the outermost side there is a single layer of exodermis made up of suberised cells. The vascular bundles constitute a collateral arrangement. The endodermis is not detected in the transverse sections (Figure 1).
Anatomy of Stem
Stem cortex, with a thin cuticle on the outer side, has xerophytic stomata. On the epidermis, thick cell walled unicellular hairs with dots on cuticle (Figure 2), assume straight or hook-like shapes. In the cortex parenchyma, schizolysigenous oil cavities are just in touch with the epidermal cells (Figure 3). The cortex parenchyma consists of starch sheath cells, schlerenchyma fibers, xylem, phloem and the pith. The pith is composed of parenchymatous cells (Figure 4).
Anatomy of leaf
The leaf is monofacial. As seen in the cross sections of leaf laminae, the outer layers of lower and upper epidermis with thickened walls, have xerophytic stomata (Figure 5). Within the mesophyll tissue, palisade parenchyma is composed of two or three rows whereas the spongy parenchyma takes a little place on the center of the mesophyll tissue. Oil cavities are just in touch with upper epidermis (Figure 6).
In the cross sections of the mid-rib region, thin-walled parenchymatous cells surround the collateral vascular bundles. Schlerenchyma fibers are detected between starch sheath cells and the phloem (Figure 7). In the surface view of the leaf, on the basis of the arrangement of four to six subsidiary cells relative to stoma, the stomata is found to be as anomocytic type. In the surface view of the epidermis, the epidermal cell walls seem to be thick and unicellular hairs assume straight or hook-like shapes (Figure 8).
Anatomy of Fruit and Seed
The exocarp with thick outer cell walls, has thin cuticle. In the tissue of the mesocarp, essential oil cavities are orientated where the neigbouring cells to these cavities are thin-walled. The tissue of the endocarp is entirely sclerenchymatous (Figure 9). Testa, the destroyed cells of nucellus, endosperm and embryo constitutes the seed. In the cross section of the seed, the epidermal cells of the testa, assuming papillae with thicker outer cell walls, have hair-like elongations and crystal-like grains which are destroyed by acidic reagents with gas relase.
The lateral and inner cell walls are thinner than the outer walls of the epidermal cells of the testa. The cell walls of the testa parenchyma are thick and seemed to be partially pressed in the mature seeds. The endosperma lying under the destroyed nucellus cells, is composed of thin walled parenchymatous cells and oil droplets as reserve substances are located within the cells (Figure 10 A and Figure 10 B). Rutaceae plants are distinguished from all other families of the order Sapindales by possessing secretory cavities containing aromatic ethereal oils scattered throughout almost all organs, a synapomorphy to the family42.
The lateral and inner cell walls are thinner than the outer walls of the epidermal cells of the testa. The cell walls of the testa parenchyma are thick and seemed to be partially pressed in the mature seeds. The endosperma lying under the destroyed nucellus cells, is composed of thin walled parenchymatous cells and oil droplets as reserve substances are located within the cells (Figure 10 A and Figure 10 B). Rutaceae plants are distinguished from all other families of the order Sapindales by possessing secretory cavities containing aromatic ethereal oils scattered throughout almost all organs, a synapomorphy to the family42.
Schizogenous sac gaps are characteristics for Rutaceae family. In contrast, in this study schizolysigenous secretory cavities were observed in cross sections of H. cappadocicum. Taxonomic and systematics studies among Haplophyllum A. Juss. and Ruta L. taxa, which are naturally occuring in Turkey, were previously investigated based on morphological, palynological, anatomical and molecular studies. The anatomical characteristics of leaf and stem parts H. cappadocicum were also described43. Interestingly, thick cell walled unicellular straight or hook like shaped hairs were not mentioned in transverse sections of H. cappadocicum. In Rutaceae, in most species stomata are confined to abaxial sides. Conversely the leaves of H. cappadocicum are amphistomatic and mesophyll is equifacial as described. Some anatomical features of Haplophyllum species were reported before. The most important studies in respect of plant anatomy are restricted for species such as H. myrtifolium, H. telephioides, H. megalanthum etc34-36.
In the present work, anatomical characteristics of H. cappadocicun did not show significant differences. The anatomy of roots, fruits and seeds of H. cappadocicum is reported for the first time whereas these findings might be useful for distinguishing and for comparison with other Haplophyllum species.
CONCLUSION
Haplophyllum genus possessing biologically active natural substances of potential pharmaceutical interest, are worthy of investigation not only for chemical content but also anatomically. To the best of our knowledge, comprehensive anatomical studies have been carried out on H. cappadocicum, an endemic plant to Iran-Turan phytogeographical region, from Boranköy-Malatya, Turkey, for the first time in this report. Unfortunately there is a lack of academic education in taxonomy and properly trained pharmaceutical botanists. Endemic medicinal plants that might be of potential economic and pharmacological importance should also be investigated not only for secondary metabolites but also for their morphological and anatomical properties.
ACKNOWLEDGEMENTS
We thank lecturer Proffessor M. Ali Önür (Ege University Faculty of Pharmacy Department of Pharmacognosy) for his guidance in preparing cross-sections and for taking photos.
CONFLICT OF INTEREST
Authors declare that there is no conflict of interest with the present work.
AUTHOR’S CONTRIBUTION
Hüsniye Kayalar, and Gökay Arar collected the plant material. Hüsniye Kayalar performed the anatomical studies and drafted the manuscript under the supervision of Gökay Arar.
REFERENCES