云南秋海棠属植物叶片横切面比较解剖研究

Anatomy on leaf cross sections of Begonia from Yunnan, China

关键词:  云南  秋海棠属  叶片解剖  生态适应性

Key words:  Yunnan  Begonia  leaf structure  ecological adaptation

摘要:

报道30种主产于云南的秋海棠属植物叶片的横切面解剖构造特征。采用常规石蜡切片法切片观察,结果表明:云南秋海棠属植物叶片薄、横切面均为异面叶、呈典型的阴叶结构,叶肉组织虽有栅栏组织和海绵组织的分化,但栅栏组织不发达,占叶肉组织的比例较小。表皮多为单表皮,极稀复表皮,表皮毛均由多细胞组成。气孔集中于下表皮,孔下室或下陷气孔特大、通气组织极发达; 角质层形状多样,呈均匀增厚、瘤状和片状突起; 叶绿体椭球形、数多、个体大,主要分布于叶肉组织,集中于栅栏组织。解剖构造特征在各分类组内呈现不完全一致性,而在相同茎的形态类型中有些较一致的特征,在不同种间解剖特征各有差别; 根状茎和直立茎类型种类的横切面组织结构表现为表皮细胞壁外的角质层薄、栅栏组织与叶肉组织厚度比例较小等弱光照、湿生等适应性较弱的特征。球茎类型的种类表现为角质层较厚、栅栏叶肉组织厚度比例较大等适应略为干燥和较强光照的特征。

Abstract:

The characters of transverse anatomic leaf structures of thirty species of Begonia L.mainly from Yunnan were studied by paraffin method for the first time. The results were as follows:The leaves of studied Begonia species possessed typical characters of shady plant leaves with thin leaves,cross section to be bifacial leaves,differentiation of the palisade tissue and spongy tissue but the palisade tissue to be not flourishing to make up less proportion of the mesophyll tissue. Most epidermis was single. The epidermal hairs composed of multiplayer cells. The stomata were distributed mainly over lower epidermis and stomatic nest was big and the ventilating tissue was utmost flourishing. The keratinous form of epidermal cell was varied(even incrassate,tubercular,lamellar,and so on). The elliptical and spherical chloroplast was distributed mainly over palisade tissue in the mesophyll tissue. The characters of the anatomic leaf constitutions of thirty species showed incomplete unanimity between sections of Begonia but showed complete unanimity among the same stem types in different species; The characters of tissue of leaf cross section were horny layer more thin,less proportion of palisade tissue to mesophlly tissue on the rhizomatous and erect stemmed Begonia,which plants adapted to a weak light and hygrophytic environment,but it was horny layer more thick,big proportion of palisade tissue to mesophlly tissue on the corm Begonia,which plants adapted to a strong light and a little xerophytic environment.