中文摘要：

目的筛选蕺菜属植物优异种质。方法以产自中国不同地理类群的蕺菜属植物为材料,比较其形态特性,并通过Li-6400便携式光合仪测定其光合特性,分析正常及高温（40℃）、低温（5℃）、干旱（土壤饱和持水量70%）逆境条件下的差异。结果 6个类群的形态差异主要表现在植株颜色、主茎高度、地上茎节间长和叶长及叶宽上。正常条件下,6个类群的光合速率（Pn）无显著差异,蒸腾速率（Tr）、气孔导度（Gs）和水分利用系数（WUE）在个别类群间存在显著差异;经逆境处理后,各类群Pn、Tr、Gs均出现较大幅度的下降,多个类群间的差异达到了极显著水平,但各类群的WUE均有增加且差异极显著。峨眉蕺菜（EM）和湖南怀化蕺菜（HH）居群逆境处理后,叶绿素荧光参数的变化趋势十分相似,PSII作用中心光能传递和转换效率显著降低,光能用于非光化学反应比例显著增加。结论较高纬度的江苏如皋蕺菜（RG）对低温的耐性较强,西南和中南地区居群的蕺菜对高温和低温耐性较强。各类群光合作用抗逆性与其原产地的生态气候条件关系较密切,中国西南和中南等地具有抗逆性较强的蕺菜属资源,是鱼腥草栽培抗性品种选育的良好材料。

英文摘要：

Objective To select outstanding germplasms of Houttuynia Thunb. Methods Take diffrent geographical Houttuynia Thunb. taxa as materials, to compare their morphological properties. Their differences in photosynthesis at normal temperature, heat（40 ℃）, cold（5 ℃）,and drought（70% soil water holding capacity） conditions were studied by Li-6400 Portable Photosynthesis Instrument. ResultsThe morphological differences of six taxa mainly manifested as plant color, main stem height, internode length of aerial stems, leaf length and leaf width. Pn（Photosynthetic rate） was not significantly different among the six taxa under normal conditions, and Tr（Transpiration rate）, Gs（Stomatal conductance） and WUE（Water use efficiency） differ significantly only among a few taxa. By contrast, adverse treatment could substantially decrease Pn, Tr and Gs, but increase WUE. The differences in Pn, Tr and Gs were significant only among multiple taxa, while the difference in WUE was significant among all taxa. The alteration trends of chlorophyll fluorescence parameters in EM（from Mount Emei） and HH（from Hunan Huaihua） after adverse treatments were very similar. The energy transfer efficiency and conversion efficiency of PS II were significantly decreased, and the proportion of non-photochemical reaction increased significantly. Conclusion Rugao Houttuynia cordata taxon which from high latitude has a low temperature resistance characteristics. Houttuynia taxa with strong tolerance to heat and cold are from Southwest and South-central China. The photosynthetic stress tolerance of each group was closely related to the ecoclimatic conditions of its origin. It had strong resistance to drought in Southwest China and South China, which was a good material for selection of resistant cultivars of Houttuynia cordata Thunb.