Studies On Leaf Epidermal And Anatomy Of The Genus Seriphidium From China

The genus Seriphidium, belonging to the tribe Anthemideae of Compositae, comprises more than 130 species distributed in Europe,Asia,North America and North Africa of temperate. Now,according to the Flora of China ,the genus was known about 31species,3 varieties in vol 76,No.2,which were classified into 3 sections, nam- ely, Sect.Seriphidium, Sect. Minchünensa and Sect.Juncea.They were distributed mainly in aried inland, especially in xinjiang region. Seriphidium possesses important value in economy, most species for medicinal value ,some for sand-shifting control.Studies on the genus began from Besser and Less in 1828,subsequently, scholars such as fourr, M.Krascheninnikov, P.Poljakov and Ling You-run et al.contributed to this genus,and made admirable achievements.Even so, there are still various problems needed to further research.Based on the field investigation,identification and experimental conditions,we have put emphasis mainly on some problems as follows:1.After most species of the genus seriphidium were examined and supplied on classical studies, herbarium works and field investigation, we have known the genus are about 31 species, 3 varieties in China.But whether the species S.rhodanthum distributed in the northwest of Xizang were unknown. .The genus seriphidium were distributed mainly in aried inland, especially in xinjiang region.2. The epidermal characters of 15 species leaf of Seriphidium were observed under scanning electron microscope (SEM).The results showed that the epidermal leaf had the character of obivous xerophious, distributing amounts of wax and epidermal hairs on the epidermal, and salt parts occured on wax surface. Epidermal hairs were similar with each other in this genus, the stomatal apparatus were different from each other in the combination of the shape of guard cells and wax ornamentation, which can be used in the taxonomy of Seriphidium.3. The epidermal characters of 21 species leaf of Seriphidium were observed under light microscope (LM), emphersizing on the shape of cells and types of stomata.The results showed that upper epidermics had stomata or no, but the lower epidermics all had stomata, and there were four kinds of stomata,that were anomocytic,staurocytic,anisocytic and anomotetracytic; the shape of epidermal cells were irregular or near squared, and the pattern of anticlinal walls had varities of straight,arched,sinuolate or sinuous. The combination of these mocricharacters were different among species, which can be used in taxonomy.4. The anatomy characters of 10 species leaf of Seriphidium were observed under light microscope (LM), the results showed that they have formed the character of drought plants, small ratio of the external leaf surface to its volume;its palisade tissue was developed and there were no spongy tissue;mechanical tissue were well developed.