恶疫霉有性杂交个体在土壤中的越冬存活与腐生定殖能力

Overwintering survival and saprophytic colonization on host tissue of hybrids from sexual outcrossing of Phytophthora cactorum in soil

被测的 6个杂交后代菌株的卵孢子经 12 8d越冬后 ,均有部分仍然存活 ,从土壤中回收的越冬卵孢子在实验室条件下的萌发率为 1 0 %～ 6 4 0 %。杂交后代菌株在土壤中的苹果病组织块 (大小约 10mm× 10mm× 10mm)经 4～ 5个月的越冬后进行分离 ,从灭菌土壤中 5个月后的检出率为 2 9 0 %～ 10 0 % ,在未灭菌的自然土壤中 4个月后的检出率为5 0 %～ 33 3%。供试的杂交后代菌株游动孢子在土壤中寄主组织材料上的腐生定殖能力与亲本菌株相似。上述结果表明恶疫霉有性杂交后代在土壤中有较强的存活能力和腐生定殖能力。

Portion of oospores of 6 tested hybrids of Phytophthora cactorum was found to survive after they overwintered for 128 days in soil.The germination rate of the recovered oospores was 1 0% 64 0%.Overwintering experiment with inoculated apple blocks (10 mm× 10 mm×10 mm)in sterile or natural soil was carried out.The results showed that the hybrids could be recovered at the rate of 29 0% 100% after overwintered in sterile soil for 5 months,and 5 0% 33 3% in natural soil for 4 months.The zoospores of 3 hybrids tested showed the same capability to saprophytically colonize dead host tissues in soil as their parents.All the results indicate that hybrids of Phytophthora cactorum are of strong ability to survive and colonize in saprophytism in soil.