中国看麦娘属植物叶表皮微形态研究

Micromorphology of leaf epidermis of Alopecurus in China

关键词:  看麦娘属, 叶下表皮, 叶鞘, 微形态,

Key words:   Alopecurus, abaxial leaf epidermis, leaf sheath, micromorphology, taxonomy

摘要:

看麦娘属是禾本科早熟禾亚科的重要类群,中国分布有8种。该研究采用光学显微镜和电子扫描电镜,对中国看麦娘属7种植物的叶下表皮(含叶鞘下表皮)微形态特征进行观察并探讨其分类学意义。结果表明:(1)看麦娘属叶鞘下表皮长细胞的形状呈长筒状或短筒状,深波状弯曲的细胞壁,脉间短细胞密布,单生或对生,形状多为新月形或椭圆形,脉区硅细胞为椭圆形,平行形或低圆屋顶形的气孔器,看麦娘属叶鞘下表皮特征高度一致,分类价值不大。(2)看麦娘属植物叶下表皮和叶鞘下表皮的显微结构存在很大不同,看麦娘属植物叶下表皮长细胞多为长筒状或短筒状或长菱形,平周壁平直或不明显弯曲,脉间区短细胞分布或无,脉区刺毛密布,脉间区有或无刺细胞的分布,平行形的气孔器,脉区分布的硅细胞多为长方形边缘呈波状弯曲。看麦娘属植物叶下表皮的不同主要体现在脉间区长细胞的形状及平周壁的弯曲与否,脉间区短细胞出现或无,脉间区刺细胞的分布数量以及气孔器的列数。7种植物的叶表皮微形态的分类检索表据此列出。依据叶表皮微形态划分的组与根据外部特征划分的组并不完全一致。但是,由于该文仅研究了7种,叶表皮微形态对于看麦娘属的分类意义还需要更深入的研究。

Abstract:

Alopecurus was a common and widespread genus of Poaceae subfamily Pooideae. It was common across temperate and cold regions of the north hemisphere, South America. Alopecurus is a genus of eight species distributed in China. They are Alopecurus aequalis, A. japonicus, A. arundinaceus, A. brachystachyus, A. myosuroides, A. longiaristatus, A. longiaristatus, and A. pratensis. A few, particularly Alopecurus aequalis and A. japonicus, were considered weeds, other species were used as fine grasses for animals. It is of great significance to infer systematic relationships among species of Alopecurus. But there are few studies about the leaf morphology of Alopecurus. The micromorphology of leaf abaxial epidermis(including leaf sheath)was observed under light microscope and scanning electron microscope for seven species of Alopecurus occurring in China. The results were as follows:(1)The leaf sheath epidermis of Alopecurus were characterized by long-tubular or short-tubular cells with markedly sinuousness cell walls, elliptic or crescentic short cells distributed solitary or in pairs, elliptic silica bodies, parallel-sided or low dome-shaped subsidiary cells. The morphology of leaf sheath epidermis was highly consistent. The evidences of leaf sheath epidermis made no sense to distinguish species of Alopecurus. There was nearly no significant differences exited at species level.(2)Leaf epidermis structure and leaf epidermis sheath structure were significantly different. The leaf abaxial epidermis of Alopecurus was characterized by long-tubular or short-tubular or rhombic long cells with straight or undulating walls, presence or absence of short cells in intercostal zone, presence of prickles in costal, presence or absence of prickles in intercostal zone, parallel-sided subsidiary cells, horizontally elongated crenate silica-cell in costal zone. Some epidermal features varied in the shape and wall thickness of long cells, presence or absence of short cells, the numbers of prickles in intercostal zones, the rows of stomata. These diversities could provide the evidences for classification of species. A key of the species of the genus Alopecurus on the basis of the leaf morphology was present in the paper. In addition, the type of division on the basis of leaf epidermis morphology was not entirely consistent with sections identified based on external morphology. But due to limited species of the research, the leaf epidermal micromorphology for the significance of Alopecurus's classification still needs further research.