高温胁迫对香菇菌丝生长及其抗哈茨木霉能力的影响

Effect of Heat Stress on Lentinula edodes Mycelial Growth Recovery and Resistance to Trichoderma harzianum

拈抗和接种试验表明，胁迫温度及其处理时间共同影响香菇（Lentinula edodes）菌丝生长及其抵抗哈茨木霉（Trichoderma harzianum）侵染的能力，3个供试菌株Q7、L607和Y2对高温胁迫的耐受能力不同，37～42℃短时间胁迫处理对菌丝生长及其抗哈茨木霉能力没有明显影响。Q7在37℃处理24h或39℃处理18h和24h，Y2在39℃处理24h和48h，菌丝体转移至PDA中正常温度（25℃）均能继续生长，但已失去了抵抗哈茨木霉侵染的能力。但L607在39℃处理不超过30h时，保持了对哈茨木霉的抗病力。高温胁迫处理时间过度延长可导致香菇菌丝死亡。栽培试验表明，25℃室内培养的香菇菌棒没有发生腐烂病，而在缺乏控温条件的栽培棚内，菌棒腐烂率达到76％。温度测定表明，当秋栽香菇制袋时间提前至7月中旬时，7月下旬至8月上旬栽培棚内菌丝体受到了40-43℃高温胁迫。本研究表明，高温胁迫引起香菇菌丝抵抗哈茨木霉能力下降，甚至死亡，最终导致香菇菌棒腐烂病发生。

Three L. edodes strains （QT, L607 and Y2） exhibited different responses to heat stress although mycelial growth recovery at 25 ℃ and resistance to Trichoderma harzianum （determined by antagonistic tests） were not obviously affected when exposure to heat stress （37-42 ℃ ） was temporary（6 h）. However, when subjected to prolonged exposure, both stress temperature and time of exposure jointly affected the subsequent mycelial growth under non-stress temperatures and resistance to T. harzianum. Thus, when Q7 mycelium was exposed to 37 ℃ for 24 h and to 39 ℃ for 18 h or 24 h, and Y2 mycelium to 39 ℃ for 24 h or 36 h, both grew normally when subsequently incubated at 25 ℃. However, resistance to T. harzianum had been lost. Conversely, mycelium of strain L607 exposed to 39 ℃ for up to 36 h was unable to grow normally at 25 ℃ but remained resistant to the pathogen. Mycelia of all three L. edodes strains became non-viable when exposed to higher temperatures for prolonged periods. Cultivation experiments revealed that log rot （rotting and loss of shape due to impaired mycelial viability）did not occur when L. edodes mycelia in the logs were incubated at 25℃ but increased up to 76% when the inoculated logs were placed in cultivation sheds lacking proper temperature control. Tests revealed that L. edodes mycelia in the cultivation sheds encountered temperatures of 40 - 43℃ from late July to early August, which decreased resistance to Trichodema species and loss of viability, ultimately resulting in log rot.