【摘要】 【背景】外来入侵恶性杂草——三裂叶豚草在我国迅速蔓延,并对我国经济、人民健康、生态等方面造成巨大影响。【方法】本文运用光合仪(CIRAS-1)测定豚草锈菌侵染后的三裂叶豚草叶片的光合效率、蒸腾速率、叶表面蒸汽压差、胞间CO2浓度、气孔导度等指标,以探讨豚草锈菌影响三裂叶豚草光合作用的机制。【结果】豚草锈菌侵染三裂叶豚草叶片后,对叶片水分代谢与光合代谢有明显影响,从而影响叶片有机物质的合成。豚草锈菌侵染显症1～4d后,受侵染叶片蒸腾速率与气孔导度下降,光合作用有所加强,导致胞间CO2浓度下降,进而使叶片细胞水分代谢与光合代谢加强。显症4d后,随着叶片发病程度增加(4～5级),胞间CO2浓度增加,蒸腾速率与气孔导度大幅降低,光合速率下降。【结论与意义】豚草锈菌能干扰三裂叶豚草叶片的光合生理活动。该结果可为防治三裂叶豚草提供参考。更多还原

【Abstract】 [Background]At present, the alien invasive weed—Ambrosa trifida L.is rapidly spreading in China, with grave consequences on economy, ecology, and human health. [Method]In order to study the influence of the rust (Puccinia xanthii f.sp.ambrosiae-trifidae) infection on photosynthetic characters of giant ragweed, photosynthesis rate (Pn), transpiration rate (Tr), vapor deficit at the leaf surface (Vpd), intercellular CO2 concent rations (Ci), and stomatal conductance (Gs) were measured on individuals with photosynthesis measuring system of (CIRAS-1). [Result]After infection with the rust, Pn increased, while Ci, Tr, Vpd, Gs decreased in the leaves from 1 to 4 days after the disease symptoms appeared. During this period, disease severity rised from one to three degree. From 5 to 9 days after the disease apparition, Pn, Tr, Vpd, Gs decreased, meanwhile, disease severity rised from grade four to grade five. [Conclusion and significance]We found clear evidence that P.xanthii f.sp.ambrosiae-trifidae disturbs the photosynthetic ability of ragweed leaves. This agent merits further study as a potential biological control organism of the giant ragweed.更多还原