碎米莎草穗部总生物碱化感活性和抑菌效果的研究

以种子萌发率、幼苗根长、幼苗株高和单株鲜质量以及菌落直径为指标,对碎米莎草(Cyperus iria L. )穗部总生物碱的化感活性及抑菌效果进行了初步研究.结果表明,不同质量浓度的总生物碱溶液对6种供试植物的种子萌发和幼苗生长均有不同程度的影响;质量浓度为500～4 000 mg·L~(-1)的总生物碱溶液对水稻(Oryza sativa L. )种子萌发率和幼苗的株高和单株鲜质量无显著影响(P>0.05),但4 000 mg·L~(-1)总生物碱溶液对水稻幼苗的根长有显著的抑制作用(P<0.05);总生物碱溶液对烟草(Nicotiana tabacum L. )、鳢肠Eclipta prostrata (L. ) L. ]、千金子Leptochloa chinensis (L. ) Nees]、三叶鬼针草(Bidens pilosa L. )及丁香蓼(Ludwigia prostrata Roxb. )的种子萌发和幼苗生长的抑制作用随质量浓度的提高而增强,且当质量浓度达到4 000 mg·L~(-1)时, 种子萌发率和幼苗的根长、株高和单株鲜质量均最低, 与对照差异显著(P<0.05). 碎米莎草穗部总生物碱溶液对6种供试植物病原真菌的抑菌效果有一定的差异, 但总体上随质量浓度(25～400 mg·L~(-1))的提高抑菌效果逐渐增强;当质量浓度达到400 mg·L~(-1)时,总生物碱溶液对苹果轮纹病病菌(Physalospora piricola Nose)、油菜菌核病病菌Sclerotinia sclerotiorum (Lib. ) de Bary]、水稻稻瘟病病菌Magnaporthe grisea (Hebert) Barr. ]、小麦赤霉病病菌(Fusarium graminearum Schw. )和番茄早疫病病菌(Alternaria solani Jones et Grout. )的抑菌率最高,分别达到74.05%、64.73%、43.54%、35.09%和32.56%,与对照差异显著(P<0.05);但25～400 mg·L~(-1)总生物碱溶液对杨树溃疡病病菌(Dothiorella gregaria Sacc. )无显著的抑菌作用(P>0.05).研究结果显示,碎米莎草穗部总生物碱具有被开发为稻田用生物源农药的潜力.

Study on allelopathic activity and antifungal effect of total alkaloids from Cyperus iria stachys

Using seed germination rate, seedling root length, seedling height, fresh weight per seedling and colony diameter as indexes, the allelopathic activity and antifungal effect of total alkaloids from Cyperus iria L. Stachys were primarily studied. The results show that total alkaloid solutions with different concentrations have different degree influences on seed germination and seedling growth of six tested plants. Total alkaloid solutions of 500-4 000 mg·L~(-1) have no significant inhibition to seed germination rate, seedling height and fresh weight per seedling of Oryza sativa L. (P > 0.05), but 4 000 mg·L~(-1) total alkaloid solution has a significant inhibition to root length of O. Sativa seedling (P<0.05). With concentration increasing, the inhibition of total alkaloid solutions to seed germination and seedling growth of Nicotiana tabacum L. , Eclipta prostrata (L. ) L. , Leptochloa chinensis (L. ) Nees, Bidens pilosa L. And Ludwigia prostrata Roxb. Increases gradually, and using 4 000 mg·L~(-1) total alkaloid solution for treating, seed germination rate, seedling root length, seedling height and fresh weight per seedling are all the lowest with a significant difference as compared with the control (P<0.05).The antifungal effect of total alkaloids from C. Iria stachys to six tested phytopathogenic fungi has a certain difference, but displays a gradually increasing trend with concentration rising (25-400 mg·L~(-1)) generally. With 400 mg·L~(-1) total alkaloid solution for treating, the antifungal rate to Physalospora piricola Nose, Sclerotinia sclerotiorum (Lib. )de Bary, Magnaporthe grisea (Hebert) Barr. , Fusarium graminearum Schw. And Alternaria solani Jones et Grout. Is the highest with a value of 74.05%, 64.73%, 43.54%, 35.09% and 32.56%, respectively, with a significant difference as compared with the control (P<0.05). But total alkaloid solutions of 25-400 mg·L~(-1) have no significant antifungal effect to Dothiorella gregaria Sacc. (P>0.05). It can be concluded that total alkaloids from C. Iria stachys possess the developmental potential as a biopesticide for rice field.