广西弄拉几种适生药材叶片对岩溶环境的生态适应

The Ecological Adaptation of Several Medicinal Materials to the Karst Environment in Guangxi Nongla

目的:探讨植物微形态结构与岩溶生态环境的关系。方法:利用光学显微镜对常规石蜡切片法处理的生长于广西弄拉适生药材忍冬(Lonicera Japonica Thunb)、华南忍冬(Lonicera confuse)、瓜子金(Polygala japonica Houtt)、黄花草(Solidago decurrens Lour)的解剖结构进行了观察,并利用扫描电镜技术对四种灌木叶片表皮形态进行研究。结果:(1)忍冬、华南忍冬、黄花草下表皮均分布浓密的表皮毛,忍冬上表面中脉有少量表皮毛,黄花草上表皮分布有稀疏的星状表皮毛,忍冬、华南忍冬和黄花草的气孔位于下表皮毛间隙,这种结构可反射阳光和阻止水分蒸发,从而适应强光和水分不足的环境;(2)瓜子金叶片为肉质叶,上下表面均有气孔分布,并出现明显的下陷。气孔主要分布在叶片表面凹陷处,这种局部微环境有利于水分的保持;(3)四种植物叶片表面均出现表皮细胞外壁加厚或角质化,这种结构有利于减少水分蒸腾。结论:几种植物叶片结构特征是其长期在岩溶区干旱环境条件下形成的适应性变化,适应方式有一定的趋同。

Objective： To explore the relationships between the micromorphological structure of several medicinal materials and their ecological adaptability. Methods： The anatomical characters of Lonicera Japonica Thunb, Lonicera confuse, Polygala japonica Houtt and Solidago decurrens Lour treated by paraffin method were observed with optical microscope, and the anatomical structures were observed by the scanning electron microscope. Results： （ 1 ） Dense epidermal hairs covered on the upper epidermis of Lonicera Japonica Thunb, Lonicera confuse and Solidago decurrens Lour. A few epidermal hairs distributed on the costa of Lonicera Japonica Thunb. The upper epidermis of Solidago decurrens Lour were covered with sparse stellate hairs. The stomas distributed on the upper epidermis hairs of Lonicera Japonica Thunb, Lonicera confuse and Solidago decurrens Lour, which could reflect the sunlight and decrease the transpiration to adapt the highlight and drought environment; （2） The leaf blades of Polygala japonica Houtt were fleshy, and the sunk stomas distributed on both the sunk place of the upper epidermis and lower epidermis, which help to water conservation. （3） The outside cell wall of upper epidermis cells in the leaf blades of the four plants all thickened or keratinized, which were helpful to decrease water transpiration. Conclusions The structure characteristics of leaf blade of the four plants resulted from their adaptation to Karst drought environment and the acclimatization tended to similarity.