不同钾钠比的查氏培养基对大丽轮枝菌生物学性状及致病力的影响

研究了大丽轮枝菌(Verticillium dahliae)在不同钾钠比(K~+/Na~+)的查氏培养基中生长的生物学特性及致病力的变化。结果表明,菌株在0K~+/Na~+≤5.248的固体培养基上生长呈近M型,在K~+/Na~+5.248的固体培养基上生长呈近W型。与常规查氏培养基(CK,K~+/Na~+为1.312)相比,菌株在0K~+/Na~+5.248区间的固体培养基上,生长速率明显上升;在K~+/Na~+5.248的固体培养基上,生长速率无显著性差异;在K~+/Na~+为5.248的固体培养基上,菌核型菌株的微菌核产量最大;但在无K~+条件下同样有微菌核的产生,说明K~+对微菌核的产生有一定影响,在适中情况下会增加菌株微菌核的产量,但非必要产生因素。K~+浓度会影响到菌株的致病力,当K~+/Na~+≤2.624时,随着K~+浓度的上升,菌株的致病力有所增强,当K~+浓度过高,K~+/Na~+达到26.24时,菌株的致病力反而减弱。在K~+浓度不变时,Na~+浓度与病原菌的致病力初步呈正相关,Na~+浓度升高,钾钠比下降,病原菌的致病力增强;反之亦然。

The Influence of Different Ratios of K+/Na+ in Czapek's Medium to Biological Characters and Virulence of Verticcilium dahilae

The biological characteristic and virulence of Verticcilium dahilae strains were observed and recorded of strains on Czapek's solid medium with different ratio of K+/Na+.The results showed that the growth rates of strains were signifcantly different when the ratio of K+/Na+ were less than or equal to 5.248,however,there were no signifcant differences when the ratio of K+/Na+ were greater than 5.248.The growth curves appeared M-form when the ratio of K+/Na+ less than or equal to 5.248,and appeared W-form when the ratio of K+/Na+ greater than 5.248.The yield of microsclerotia(MS) was biggest while the ratio of K+/Na+ was less equal to 5.248,but microsclerotia aslo exsited in the solid meddium which lacking of potassium.It showed that potassium affected the formation of microsclerotia,it would obviously improve the yield of microsclerotia in the appropriate content,but it was not necessarily produce factors.K+ concentration would affect the pathogenicity of strains,when the ratio of K+/Na+ were less than or equal to 2.624,by increasing K+ concentration;the pathogenicity of strains were enhanced.When the ratio of K+/Na+ was equal to 26.24,K+ concentration was very high,the pathogenicity of strain was weakened.In the case of the same K+ concentration,the virulence of strains had positive correlation with Na+ concentration.Increasing the concentration of Na+,the ratio of K+/Na+ was decreased,and the pathogenicity of strains was increased and vice versa.