麻疯树叶浸提液对万寿菊幼苗氮代谢的影响

目的]揭示麻疯树对林下植物的化感生理机制。方法]研究麻疯树叶浸提液对万寿菊幼苗叶片的叶绿素总量、蛋白质、硝态氮、铵态氮及与氮代谢相关的酶的影响。结果]与对照相比,麻疯树叶浸提液加入土壤后,明显抑制了万寿菊总叶绿素含量。同时,叶浸提液也减少了叶片中总氮、蛋白质和硝态氮含量,但增加了铵态氮的含量,而且这种效应随着叶浸提液浓度的增加而增加。另外,麻疯树叶浸提液在较低浓度时,硝酸还原酶(NR)和谷氨酸合成酶(GS)活性没有显著变化,但在较高浓度时,NR和GS酶活性明显降低。谷氨酸脱氢酶(GDH)活性随着叶浸提液浓度增加而增加。结论]麻疯树能释放化感物质进入土壤,通过干扰氮代谢的生理活动,抑制植物的生长。

Allelopathic Effects of Jatropha curcas L.Leaf Leachates on Nitrogen Metabolism in Seedlings of Tagetes erecta L.

Objective] To understand on allelopathic effects of Jatropha curcas.Method]The allelopathic effects of J.curcas leaf leachates on photosynthetic pigments,concentration of nitrate(NO-3),ammonium(NH+4),soluble proteins and enzymes nitrate reductase(NR),glutamine synthase(GS) and glutamate dehydrogenase(GDH)] activities in leaves of T.erecta.seedlings were studied.Result] The application of J.curcas leaf leachates in the soil significantly inhibited total chlorophyll content compared to the contrast.Meanwhile,the leaf leachates significantly decreased the total nitrogen,soluble protein and nitrate content in the leaves of T.erecta.seedlings,and yet increased the ammonium.The effects increased with increasing concentrations of leaf leachates.In addition,NR,GS and GDH were not affected by the leachates at lower concentrations,but at higher concentration,both NR and GS activities were reduced while GDH activities were increased.Conclusion] J.curcas released the phytotoxic compounds into soil,which were inhibitory to certain test species by interfering with nitrogen metabolism.