两种入侵能力不同的莲子草光合系统稳定性的比较研究

Comparison of stability of photosystem Ⅱ between two Alternanthera invasive species with different invasion ability

为揭示恶性杂草空心莲子草入侵的部分机制,并为采取防控措施降低其危害提供理论依据,比较了空心莲子草与其同属的入侵能力相对较弱的刺花莲子草对光氧化胁迫(由10μmol·L-1甲基紫精在光强100μmol·m-2·s-1条件下诱导产生)的生理响应。结果表明:在光氧化胁迫下,空心莲子草和刺花莲子草两者的叶绿素、类胡萝卜素、总酚和类黄酮含量均显著下降,叶片细胞死亡率相应升高,但空心莲子草对光氧化胁迫具有较高的忍耐性,这可能与其总酚和类黄酮含量以及DPPH·(1,1-二苯基苦基苯肼)自由基清除能力有关。这种特性可能是空心莲子草光合系统稳定性更高、入侵能力更强和危害性更大的重要因素之一。

To reveal the invasion mechanism of an alien noxious weed-Alternanthera philoxeroides and reduce or ultimately eliminate its damage,physiological responses of A.philoxeroides and A.pungens with a relatively weak invasion capacity to photooxidative stress（induced by 10 μmol·L^-1 methyl viologen at light intensity of 100 μmol·m^-2·s^-1）were investigated and compared in the present study.Under photooxidative stress,the contents of chlorophyll,carotenoids,total phenolics and flavonoids in A.philoxeroides and A.pungens significantly decreased and leaf cell death rate correspondingly increased,but the former showed a higher tolerance to photooxidative stress,which might be related to total phenolic,flavonoid and DPPH· scavenging capacity in A.philoxeroides.This could be used to explain why A.philoxeroides had more stable photosystem,greater invasion capacity and higher damage.