国产白茅属Imperata Cyrillo(禾本科)部分生物学特性的研究

Major Biological Characters of Imperata Cyrillo (Poaceae) from China

通过扫描电子显微镜和X 射线能谱分析技术、冰冻切片制片技术、蒽酮定糖法、Lowry氏基本测蛋白法、高效液相色谱技术等方法或技术对国产白茅属植物白茅Imperatacylindrica(Linn.)Beauv.、丝茅I.koenigii(Retz.)Beauv.、黄穗茅I.flavidaKeng的部分形态解剖学、生物化学及生态学特征进行了研究.结果表明:(1)白茅、丝茅、黄穗茅的叶均具有典型的禾本科黍型叶的形态解剖特征.(2)白茅、丝茅、黄穗茅叶表皮微形态特征较为一致.根据硅质乳突和泡状细胞的分布和特征,可将本属叶表皮分成三种类型,但此区分分类意义及环境指示意义均不大.(3)丝茅地下茎在形态解剖学特征上是其根和茎之间的过渡类型.(4)黄穗茅春夏季节地下茎含糖量和叶片含蛋白量均高于丝茅,其作为饲料的可开发性较之丝茅为强.(5)黄穗茅和丝茅叶片黄酮类化合物的成分相似,各化合物的含量也大致相当.其中的杨梅黄酮/杨梅树皮素迄今为止还未在除本属以外的禾本科植物中发现.(6)丝茅对土壤酸碱度的适应范围较广,作为极贫瘠土壤的改良植物和江、海堤固堤植物等具一定价值.

Though the genus Imperata Cyrillo of the family Poaceae (Gramineae) from China has a long history to be used as an important forage grass and traditional Chinese herbal medicine, its biological characters have not been well known yet except for some basic ones. In the present paper, three Imperata species from China, i.e., I. cylindrica (Linn.) Beauv., I. koenigii (Retz.) Beauv. (= I. cylindrica var. major (Nees) Hubb. ex Hubb. et Vaughan), and I. flavida Keng have been studied and their major morphological, anatomical, biochemical, and ecological characters are described. Samples used in this study include herbarium and fresh leaves of the three species, roots of I. koenigii, subterraneous stems (rhizomes) of I. koenigii and I. flavida, and earth samples from different types of soils on which plants of I. koenigii grow naturally. Methods and/or techniques employed in this study are scanning electron microscopy (SEM), energy dispersive Xray, frozensection manufacturing, anthronechromometry, Lowry's method, and high performance liquid chromatography (HPLC) respectively. In addition to the major biological characters documented in the present paper, the following conclusions can be drawn: (1) Leaf anatomical characters of these three species are all of Panicoid type of the family Poaceae. (2) The micromorphological characters from leaf epidermis of the three species are nearly identical. Based on the distribution and characteristics of the siliceous papillae and bulliform cells, three types of leaf epidermis of these species are recognized. However, such differentiation has little taxonomical significance, and its value as an environmental indicator is still unknown. (3) The subterraneous stem is intermediate anatomically between the root and the stem of the genus Imperata. (4) During spring and summer both the saccharide contents in the subterraneous stems and protein contents in the leaves of I. flavida are higher than those of I. koenigii, which suggests that I. flavida (an endemic species in China) might be a better forage grass than I. koenigii. (5) Both I. koenigii and I. flavida contain myricetin (flavonoids), which is not known by far in any other taxon of the family Poaceae. The chemical compositions of the leaf flavonoids and their contents in I. flavida are somewhat similar to those of I. koenigii, a plant which has been used as a traditional Chinese herbal medicine since ancient times. (6) I. koenigii has a broad tolerance to adapt both acid and alkaline soil, and thus could be used as a pioneer grass in areas with unfavorable soil conditions.