湿筛法和蔗糖悬浮法分离土壤中大丽轮枝菌(Verticillium dahliae)效果的比较

本文对湿筛和蔗糖悬浮两种方法在分离到大丽轮枝菌微菌核数目的稳定性及回收率(回收到大丽轮枝菌百分率)、自然病土分离效果等方面进行了比较。试验结果表明,湿筛法的稳定性好,回收率达80%;而蔗糖悬浮法的稳定性要差,回收率只有18%左右。两种方法在分离同一种自然病土时,湿筛法分离到大丽轮枝菌的数量要比蔗糖悬浮法高三倍左右,但湿筛法分离平板上杂菌显得多一些,大丽轮枝菌菌落也要小一些。而蔗糖悬浮法分离平板上大丽轮枝菌菌落要大,易于识别和计数。故在研究土壤里大丽轮枝菌动态变化与棉花黄萎病发生的关系时,综合评价宜采用湿筛法。

COMPARISON OF WET-SEIVING AND SUCROSE-FLOATATION METHODS IN SEPARATING VERTICILLIUM DAHLIAE IN SOIL

Wet-seiving and sucrose-floatation methods were compared in results stability,recovery rote and separating naturally infestious soil.The results showed that stability of wet-seiving method was the better and its recovery rate arrived at about 80%,but the recovery rate of sucrose-floata- tion was only 18% or so.Amount of MS obstained with wet-seiving method was about three times more than sucrose-floatation method.But on the separating plates with wet-seiving,there were more other fungi than sucrose-floatation,mainly white Fusarium spp.and the V.dahliae colonies were smaller.Comparatively speaking,its selectivity was not very good.On the plates with sucrose-floatation,the other fungi were few and the V.dahliae colonies large,concrete and easy to identify and count.On the whole,wet-seiving method is more effective and suitable than sucrose-floatation in studying growth and decline of V.dahliae in soil.