百部科植物叶表皮特征及其分类学意义

Characters of the leaf epidermis of Stemonaceae and their taxonomical significance

利用光学显微镜和扫描电子显微镜,对百部科4属30种植物的叶表皮微形态特征进行了观察研究。结果显示,叶表皮细胞形状仅有无规则形和多边形2种,垂周壁式样有深波状、浅波状和平直-弓形3种;表皮角质层纹饰微形态多样化,绝大多数物种的叶片表面不具有毛被,仅少数植物叶片表面具单细胞毛;气孔器主要分布在下表皮,仅Stemona prostrata I.R.H.Telford、S.cochinchinensis Gagnep、S.rupestris Inthachub、S.pierrei Gagnep和S.involuta Inthachub 5个种上下表皮均有气孔器;气孔形状均为椭圆形,而气孔器类型均为无规则型。百部科叶表皮微形态特征在属间有一定差异,但在属内各种间没有明确规律,表明该类群应该是一个自然的单系类群。由于百部科植物采样困难,在缺乏系统进化树数据的情况下,这些微形态特征可为探讨百部科不同种类的分类学、生物地理及其生态适应性提供部分新证据。

The micromorphology of the leaf epidermal surfaces of 30 Stemonaceae species from four genera were observed using light microscopy and scanning electron microscopy. Results showed that both the adaxial and abaxial epidermal cells were polygonal or irregular in shape,with undulate,straight,or arched anticlinal walls. The leaf epidermal characteristics of most species were amphistomatic, though some were hypostomatic or hyperstomatic. The micromorphology of the epidermal cuticle sculpture ornamentation was diversified. Most species had no hairs covering the leaf surface,though some species had unicellular hairs on both the upper and under epidermis. The stomatal apparatus was mainly distributed on the under epidermis of the leaves, except for Stemona prostrata I. R. H. Telford, S.cochinchinensis Gagnep, S. rupestris Inthachub, S. pierrei Gagnep, and S. involuta Inthachub,which had stomatal apparatus on both the upper and under epidermis. Thestomata type was anomocytic in all observed species and the stoma were oval in shape.Definite evolution regularity was found in the micromorphological characteristics of the epidermis of the leaves of Stemonaceae among genera,but no clear regularity was detected within genus,implying that the family might be a natural monophyletic group. Considering the difficulty of sampling,and in the absence of a phylogenetic tree,these micromorphological characteristics may provide new evidence for the taxonomy,biogeography,and ecological adaptability of Stemonaceae.