不同水分条件下三裂叶豚草叶解剖结构的生态适应性

三裂叶豚草（Ambrosia trifida）是世界公害杂草，于20世纪30年代传人我国后，对我国人民的生产生活和生态系统造成了严重危害。本研究以我国北方地区主要分布的入侵植物三裂叶豚草为对象，采用盆栽实验的方法及石蜡切片技术，在Zeiss Image．A，光学显微镜下研究不同土壤水分条件下三裂叶豚草叶片解剖结构的变化。结果表明：三裂叶豚草在90％土壤相对含水量处理下叶片厚度、上下表皮厚度均增加，是细胞储水量增加，细胞体积增大的结果；在50％、30％土壤相对含水量处理下三裂叶豚草叶片变薄、栅海比值增大，是典型的节约型干旱适应，同时叶肉栅栏细胞层数增加、栅栏细胞密度增大，表现出强壮型干旱适应特征；干旱胁迫程度越大，三裂叶豚草叶显微结构变化越大。不同水分条件下三裂叶豚草解剖特征总体可塑性值为0．39，具较高可塑性，其中叶片厚度、上表皮厚度、下表皮厚度、栅栏组织与海绵组织的厚度比（P／S）、栅栏细胞密度等指标较栅栏组织厚度、海绵组织厚度具有更大可塑性，表明这些因素对三裂叶豚草成功入侵有较大作用。

Ecology compatibility of leaf anatomical structure of Ambrosia trifida to different water condition

Ambrosia trifida is an invasion plant that came to China in 1930s, and caused serious hazards to the people, production, and the ecosystem .It mainly is distributed in north China. This paper studied its leaves anatomical characteristics under the different water conditions through pot experiment, paraffin section technology, and Zeiss Image. A1 optical microscope. The result demonstrates that the thickness of leaves and epidermis increased by the treatment of 90% soil relative water content, which is due to the increasing of storage capacity of cells and the cell volume; while the Aambrosia trifida leaves thinning and the palisade/spongy ratio increasing exhibit a typical saving adjustment by the treatment of 50% and 30% soil relative water content, and palisade cell layers and density increasing signifiest a strong-type of adaptive features. The greater the drought stress, the greater the variation of its leaves microstrueture. The index to anatomical characteristics of the overall plasticity is 0.39 in different water conditions, which shows high plasticity, the thick-ness of leaf, epidermis thickness, palisade/spongy ratio and density of palisade cell show more plasticity than the thickness of palisade and spongy tissue, which indicates that these factors are playing significant role in its successful invasion.