核桃叶水浸提液对棉花生长及棉花枯萎病菌的化感效应

Allelopathic effect of walnut leaf extracts on cotton and Fusarium oxysporum f.sp.vasinfectum

研究了不同浓度核桃叶水浸提液对棉花种子萌发、幼苗生长及对棉花枯萎病菌菌丝生长的化感效应。结果表明,不同浓度核桃叶水浸提液对棉花种子萌发、幼苗生长及棉花枯萎病菌菌丝生长均体现出抑制效应,且抑制作用整体随着浸提液浓度的增高而逐渐增强。浸提液对棉花种子发芽势、发芽指数的影响要大于对发芽率的影响,20 mg·m L^(–1)以上浸提液浓度处理的棉花种子发芽势与发芽指数显著(P<0.05)降低,而30 mg·m L^(–1)的浓度下对种子发芽率的抑制仍不显著。浸提液浓度大于20 mg·m L^(–1)时,棉花幼苗根的生长及根系活力开始受到强烈抑制,当浸提液浓度大于30 mg·m L^(–1)时,幼苗总叶绿素含量显著降低,导致幼苗的鲜、干重减少。同时,在高浓度浸提液胁迫下(>30 mg·m L^(–1)),还会造成棉花植株体内MDA含量急剧增高。不同浓度浸提液对棉花枯萎病菌菌丝的生长均有一定的抑制作用,40 mg·m L^(–1)浓度浸提液的抑菌率达到最高,为47.9%。

Allelopathic effect of walnut(Juglans regia L.)leaf extracts against seed germination and seedling growth of cottonas well as mycelial development of F.oxysporum f.sp.vasinfectum was investigated.It was found that the aqueous extractsfrom walnut leaves exhibited strong inhibitory effects on the growth of cotton and Vasinfectum in a concentration-dependentmanner.Seed germination rate of cotton was less affected than seed potentiality and germination index by walnut leaf extracts.Seed potentiality and germination index of cotton were decreased significantly(P<0.05)while exposed to walnut leaves extractsgreater than20mg·mL–1,but the seed germination rate was not significantly affected even under the concentration of30mg·mL–1.The roots growth and vigor of cotton seedling were severely inhibited by walnut leaf extracts greater than20mg·mL–1.Chlorophyll content in cotton seedlings significantly declined in response to walnut leaf extracts higher than30mg·mL–1,which further led to the reduction of fresh and dry weights of cotton seedlings.Meanwhile high dose(>30mg·mL–1)also caused a rapid accumulation of MDA in cotton plants.In addition,all the test concentrations of walnut leaf extracts showedsuppressive effects on the mycelial growth of F.oxysporum f.sp.Vasinfectum.The maximum antifungal rate of47.9%wasobserved when treated by40mg·mL–1of walnut leaf extract.