含水量与温度对球孢白僵菌孢子粉贮存寿命的影响及模拟分析

将含水量 1 12 %、4 73%、7 2 3%、9 84 %及 14 11%的球孢白僵菌BeauveriabassianaSG870 2分生孢子粉在4℃和 2 5℃下黑暗贮存 18个月 ,定期检测活孢率 ,以确定孢子粉的贮存寿命。结果显示 ,各温度处理中含水量显著(P <0 0 5 )影响孢子贮存期间的活孢率。在 4℃下 ,含水量为 1 12 %～ 9 84 %处理的活孢率在头 16个月均稳定在91%以上 ,且相互间差异不显著 ;次高含水量处理的活孢率在第 18个月才显著低于其它较低含水量处理 ;高含水量处理的活孢率则从第 6个月起显著低于其余较低含水量处理 ,第 12个月时降至 2 4 2 %。而在 2 5℃下 ,第 3和第 6个月的活孢率在不同含水量处理间均呈极显著差异 (P <0 0 1) ,即随含水量升高而显著下降 ,次高含水量处理在第6个月的活孢率仅剩 17 6 %。贮存期间活孢率对贮存时间和孢子粉含水量的依赖关系很符合改进的存活衰变模型(r2 >0 85 )。根据拟合的模型预测 ,在 4℃下贮存 ,若保证活孢率 90 % ,12 %含水量的孢子粉可贮存 7 3个月 ,10 %为 11 2个月 ,9%为 14 9个月 ,8%为 2 1 0个月 ,7%为 33 0个月 ,6 %达 6 5 5个月 ,故孢子粉冷贮的含水量应控制在8%以下。若在 2 5℃下贮存并保证活孢率 80 % ,含水量 10 %的孢子粉仅可贮存 1 7个月 ,8%为 2 3个月 ,6 %为 3 0个

Impact of water content and temperature on the shelf-life of Beauveria bassiana conidia stored in dark

Batches of Beauveria bassiana SG8702 conidia as powder with water content (Cw) of 1.12, 4.73, 7.23, 9.84 and 14.11% were stored in dark at 4 and 25 degrees C during an 18-mon period and monitored at 15-day intervals for viability in order to determine their shelf-lives under controlled conditions. The Cw was found significantly affecting the viability at each temperature. Stored at 4 degrees C, conidial viability always fluctuated above 91% during the first 16 months among the Cw treatments of 1.12%-9.84% with no significant difference from one to another until at the end of 18 months, when the 9.84% Cw treatment had a significantly lower viability than other treatments with lower Cw. The viability in the high Cw treatment (14.11%) was significantly smaller than those in the Cw treatments of 1.12%-9.84% from month 6 onwards and dropped to only 24.2% at the end of 12 months. Stored at 25 degrees C, however, the viabilities differed significantly among the Cw treatments of 1.12%-9.84% on months 3 and 6, respectively, with a remaining viability of only 17.6% in the 9.84% treatment at the end of 6 months. The observed viabilities (Vc) depending on the (Cw) over the time of storage (Ts, months) at each temperature were well fitted to a modified survival model with the coefficients of determination exceeding 0.85. When a viability of 90% was expected on a basis of the fitted model, the shelf-life of B. bassiana conidia stored at 4 degrees C was estimated as 7.3 months at Cw = 12%, 11.2 at Cw = 10%, 14.9 at Cw = 9%, 21.0 at Cw = 8%, 33.0 at Cw = 7%, and 65.5 at Cw = 6%, respectively. Thus, the Cw for long-term storage at 4 degrees C could be controlled at < or = 8%. In contrast, for an expected viability of 80% at 25 degrees C, the shelf-life was estimated as only 1.7 months at Cw = 10%, 2.3 at Cw = 8%, 3.0 at Cw = 6%, and 3.8 at Cw = 4%. Obviously, an expected 3-month shelf-life required Cw < or = 5%.