Analele ştiinţifice ale Universităţii Al. I. Cuza Iaşi Tomul LIV, fasc. 2, s.ii a. Biologie vegetală, 2008 VEGETATIVE ANATOMY OF TWO GALIUM L. SPECIES (RUBIACEAE) ANCA HEMCINSCHI *, RAMONA GALEŞ **, C. TOMA ** Abstract. The structure of two medicinal Galium species (G. album Mill. and G. verum L.) was studied to determine the range of variation in certain histo-anatomical characters of the vegetative organs. The study revealed several interesting anatomical data that have not previously been reported in these species, e.g. the structure of the rhizome, the presence of the trichomes on the adaxial face of G. verum foliar limb. Key words: anatomy, vegetative organs, Galium Introduction Following-up our histo-anatomical investigations on Rubiaceae genre and species [22], the present study compares the anatomical structure of two perennial species belonging to Galium genus: Galium album Mill. (syn. G. mollugo L. ssp. erectum (Huds./Briq.) and G. verum L. The two species are considered medicinal plants [13], [19] and are distinguished from each other by several morpho-anatomical characters, e.g. the colour of the flowers, the presence, the frequency and the length of the trichomes. Among the 37 Galium species from the Romanian flora, G. album and G. verum are common in the entire country, from the durmast to the subalpine belt [4], [12]. The existing literature on the structure of the representative members of Rubiaceae family is quite abundant in results from studies dedicated exclusively to them [14], [15], [17], [18], [21] or from the synthesis treatises on anatomy of Dicotyledons [9] or Angiosperms, in generally [10]. Some authors investigate the medicinal Galium species [1], [2], [6], [8], others analyze several aspects regarding the foliar venation [5], the infraspecific variability [7], the stomata ontogeny [11], the stipules structure [16], the number of stomata in different ecological conditions [20], [3]. Material and methods The research material is represented by two species of Galium genus: G. album Mill. and G. verum L. from the Romanian flora. The material was fixed and preserved in 70% ethylic alcohol. Cross-sections of the rhizome, aerial stem and leaf were performed using a manual microtome, coloured with iodine-green and ruthenium-red and embedded in glicero-gelatine. The superficial sections through the foliar limb were coloured with iodine-green. The obtained * Pharmacy AncaFarm, Botosani, Romania ** Al. I. Cuza University, Faculty of Biology, Carol I Bd., no. 20A, 700506, Iasi, Romania 30
permanent slides were analyzed on a Novex (Holland) microscope and photographed at the same microscope with a digital photo camera. Results and discussions The aerial stem The contour of the transverse section through the aerial stem is quadratic rhomboid, with rounded ribs, less prominent towards the basis of the organ. In G. verum, the epidermis presents unicellular trichomes, with very thick walls, whose frequency decreases towards the upper and the lower level of the stem. In the four ribs there are cordons of tangential collenchyma and the cortex ends with a Casparyan endodermis on the entire stem length. In G. verum, between the stem ribs, the outer cortical layer is collenchymatous. The stellum presents secondary structure, the conducting tissues being of annual type. The xylem ring is thicker than the phloem one, comprising numerous libriform fibres with very thick and intensive lignified walls. The rhizome The outline of the transverse section through the rhizome is circular. In both analyzed species, the rhizome presents secondary structure, resulted only from the cambium activity (in G. album) or from the activity of both lateral meristems (in G. verum). In the latest case, the phellogen is differentiated from the Casparyan endodermis; the epidermis and the cortex are exfoliated. In G. album, the cortex is relatively thin (5-6 layers); this histological feature is unusual for a subterranean stem. In the thickness of the cortical parenchyma, crystalliferous cells with crystal sand and raphides are often present. The stele is very thick and comprises: 1) a thinner (in G. album) or a thicker (in G. verum) phloem ring, some of the collenchymatous parenchyma cells containing crystal sand and 2) a single very thick (in G. album) or three (in G. verum) xylem rings, whose thickness increases from the pith to the secondary phloem. The secondary xylem consists of much libriform, in which the vessels are irregularly disposed. Only in G. verum, there are islands of xylem cellulosic parenchyma, some cells containing crystal sand. The pith is thin, parenchymatous-cellulosic of meatic type, with very big cells in G. verum, many of them containing crystal or raphides (in G. album). The leaf The sessile leaves are hipostomatic, with stomata of paracytic type. The epidermis (in front view) presents cells of irregular outline, their lateral walls being moderately (in G. verum) or mighty (in G. album) wavy. In cross-section, the cells are isodiametric, being much bigger in the upper epidermis. 31
At epidermis level there are unicellular, short trichomes with very thick wall, more numerous on the abaxial face. Our observations, in concordance with the anterior published papers [22], quash the data from Flora of Romania [12], according to which the adaxial face of G. verum leaves is glabrous. The foliar limb has bifacial heterofacial structure, the mesophyll being differentiated in one (in G. album) or two (in G. verum) layers of palisade tissue and 4-5 layers of lacunous tissue; in the thickness of the latest, cells with crystal sand may be observed. In both species studied, the outer wall of the epidemic cells is thicker than the others and covered by a thin cuticle. On the margins of the foliar limb, all the walls of the epidermic cells are thick; a collenchymatous hypodermis is present. The median and lateral vascular bundles are surrounded by parenchymatous theca with isodiametric cells containing slightly chloroplasts. Conclusions The structure layout is similar in both analyzed Galium species. The structural differences between the two Galium species are quantitative, reffering to the frequency, dimensions and localization of the trichomes, the frecquency of the crystalliferous cells, the lignification degree of the pith, the number and thickness of the secondary xylem rings, the sclerification degree of the libriform fibres, the number of the palisade cells layers, the amplitude of the undulations of the lateral walls of foliar epidemic cells. REFERENCES 1. BORYSOV M. I., 1965- Étude de la structure anatomique de Galium ruthenicum Willd., Farm. Zh. Ukrajin. R. S. R., 39, 5: 59-63 2. BUTTLER K. P., BRESINSKY A., 1966 Beitrag zur Zitologie von Galium ser. silvatica. Ber. bayer. bot. Gesellsch Erforsch. heim. Flora, 39: 25-28 3. CHERMEZON, H., 1910- Recherches anatomiques sur les plantes littorales, Ann. des Sci. nat., Bot., sér. 9.,12: 117-313 4. CIOCÂRLAN V., 2000- Flora ilustrată a României. Pteridophyta et Spermatophyta. Ed. Ceres., Bucureşti 5. DARWIN S. P., 1980- Leaf venation and the classification of certain Rubiaceae. ICSEB-II 2 ed Internat. Congr. Syst. and Ecol. Biol., Vancouver (Canada), Jully 17-24, 1980, Abstracts, 176 6. FISCHER F., 1937- Beiträge zur Pharmakognosie der Plataginalen and Rubialen. Anatomie des Laubblattes. Thèsis. Basel 7. HENDRICH R., 1977- Bemerkungen zur Variabilität von Cruciata glabra (syn. Galium vernum). Preslia, 49: 193-201 8. KOHLMÜNZER S., 1964- Recherches botaniques et chimiques sur l espèce collective Galium molugo L. en considérant les caryotypes croissant en Pologne. II. Recherches anatomiques. Dissert. Pharm., Pologne, 16, 3:381-392 9. METCALFE C. R., CHALK L., 1972- Anatomy of the Dicotyledons. 2. Clarendon Press, Oxford 32
10. NAPP-ZINN, KL., 1973, 1974 - Anatomie des Blattes. II. Angiospermen, In Handbuch der Pflanzenanatomie, Bd.VIII, A 1-2, Gebrüder Borntraeger, Berlin, Stuttgart 11. PANT D. D., BHARATI M., 1965- Ontogeny of stomata in some Rubiaceae. Phytomorphology (Indic), 15, 3: 300-310 12. PAUCĂ A., NYÁRÁDY E. I., 1961- Rubiaceae. In Flora R. P. Române, 8: 524-589, Ed. Acad. Române, Bucureşti 13. PERROT E., PARIS R., 1971- Les plantes médicinales. 1., Édit. Presses Universitaires des France, Paris 14. ROBBRECHT E. (ed.), 1994 - Advances in Rubiaceae macrosystematics. Opera Botanica Belgica, Bruxelles, vol. 6 15. ROBBRECHT E., PUFF C., SMET E. (eds.), 1996- Second international Rubiaceae Conference. Proceedings 16. RUTISHAUSER R., 1984- Blattquirle, stipeln und Kollateren bei den Rubieae (Rubiaceae) in Vergleich mit andern Angiospermen. Beitr. z. Biol. Pflanz., 59, 3:375-424 17. SAINT-JUST S., 1904- Recherches anatomiques sur l appareil végétatif aérien des Rubiacée. Thèse, Paris 18. SOLEREDER H., 1893- Ein Beitrag zur anatomischen Charakteristik und zur Systematik der Rubiaceen. Bull. Herb. Boissier, 1: 167-199 19. STĂNESCU U. şi colab., 2004 Plante medicinale de la A la Z, monografie ale produselor de interes terapeutic, 1, Ed. Gh. T. Popa, UMF Iaşi 20. TOKARZ H. T., SULMA T., BUJEWICZ M., 1969- The number of leaf stomata in Asperula odorata L. plants derived from ecologically different forest communities and from garden cultivation. Acta biol. med. Soc. Sci. Gedau, 14: 443-466 21. TOLLE H., 1913- Beiträge zur vergleichenden Anatomie der Rubiaceen. Thesis, Göttingen 22. TOMA C., GOSTIN I., 2000- Anatomical structure of some Rubiaceae species. An. şt. Univ. Al. I. Cuza, Iaşi, ser. II a (Biol. veget.) 46: 1-10 The explanation of figures: Plate I. Galium album L. Fig. 1, 2. Cross-sections through the rhizome (x200). Fig. 3 (x40), 4(x200). Cross-section through the upper third of the aerial stem. Fig. 5, 6. Cross-sections through the middle third of the aerial stem (x200). Plate II. Galium album L. Fig. 1. Cross-section through the lower of the aerial stem. (x200). Fig. 2, 3. Cross-sections through the foliar limb (x200). Fig. 4, 5. Superficial sections through the folair limb (x200): 4. lower epidermis; 5. upper epidermis. Plate III. Galium verum L. Fig. 1, 2. Cross-sections through the rhizome (x100). Fig. 3 (x40), 4(x200). Cross-section through the upper third of the aerial stem. Fig. 5. Cross-sections through the middle third of the aerial stem (x200). Fig. 6. Cross-section through the lower of the aerial stem (x200). Planşa IV. Galium verum L. Fig. 1(x40), 2-4 (x200). Cross-sections through the foliar limb Fig. 5. Superficial sections through the folair limb: lower epidermis (x200). 33
ANCA HEMCINSKI et al. PLATE I 1 2 3 4 5 6 34
ANCA HEMCINSKI et al. PLATE II 1 2 3 4 5 35
ANCA HEMCINSKI et al. PLATE III 2 1 4 3 6 5 36
ANCA HEMCINSKI et al. PLATE IV 1 2 3 Analele ştiinţifice ale Universităţii Al. I. Cuza Iaşi Tomul LIV, fasc. 2, s.ii a. Biologie vegetală, 2008 4 5 37