外来种加拿大蓬及其伴生种的生物生态学特性比较

目的]为制定加拿大蓬的防控措施提供理论依据。方法]通过样地调查、生物学特性分析及生理生态特性观测,对加拿大蓬及其伴生种的地上生物量分配、种子产量、生长特性、光合作用、蒸腾作用和水分利用效率等进行了比较研究。结果]加拿大蓬的单株地上生物量、叶生物量、茎生物量均在7月26日达到最大,花序生物量在8月26日达到最大;加拿大蓬的叶片净光合速率呈典型的双峰曲线,最大值出现在12：00,14：00出现光合＂午休＂现象,其伴生种刺儿菜、还阳参和车前均在12：00左右出现光合＂午休＂现象。结论]加拿大蓬具有较强的光合和迅速扩散能力。

Comparison on Biological and Ecological Characteristics of Alien Conyzacanadensis (Linn.)Cronq. and Its Accompanying Species

Objective] The study was to provide the theoretical basis for instituting preventing and controlling measures against Conyzacanadensis (Linn.)Cronq.. Method] Through sample plot investigation,biological characteristics analysis and physiological and ecological characteristics observation,the aerial biomass distributions,seed yields; growth characteristics,photosynthesis,transpirations,water utilization efficiencies of Conyzacanadensis and its accompanying species were studied comparatively. Result] The aerial biomass,leaf biomass and stem biomass of each plant of Conyzacanadensis reached their maximums on 26th Jul. and its inflorescence biomass reached its maximum on 26th Aug. The net photosynthetic rate of Conyzacanadensis leaf was shown to be typical double-peak curve,its maximum appeared at 12:00,its "midday rest" phenomenon of photosynthesis appeared at 14:00 and that of its accompanying species Cephalanoplos segetum,Crepis rigescens and Plantago asiatica all appeared around 12:00. Conclusion] Conyzacanadensis had stronger photosynthesis and fast diffusing capacity.