绒白乳菇发酵液提取物对杨树叶枯病菌保护酶活性、丙二醛含量及电导率的影响

Effects of extraction from Lactarius vellereus fermenting liquor on the activity of protective enzymes,content of MDA and conductivity ratio in Alternaria alternata(Fr.) Keissler.

为了探明绒白乳菇发酵液提取物对杨树叶枯病菌生长的抑制机理,研究了该提取物对杨树叶枯病菌保护酶活性的影响,并探讨了保护酶活性、丙二醛(MDA)含量、电导率与呼吸强度变化的相互关系.结果表明,提取物处理过的菌体中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)活性前期均呈上升趋势,前二者均在8 h时达到最高,而后者是在10 h时达到最高;随着处理时间的增加,3种酶活性下降迅速,48 h时降至最低,而POD活性已降至为零,3种酶对提取物均较敏感.结果还表明,MDA含量在8 h时最高,为对照的9.2倍,48 h时降到最低,但始终比对照的含量高,表明膜脂过氧化严重,膜系统结构被破坏,导致电解质渗漏,电导率及呼吸强度最终均呈现下降的变化趋势.这些均反映出3种酶、MDA含量、电导率与呼吸强度在提取物处理下变化的一致性.提取物打破了保护酶系统原有的平衡状态,导致自由基清除系统出现障碍、MDA含量增加,严重破坏了膜系统的完整性,使叶枯病菌菌体受到损伤和破坏,这可能是绒白乳菇发酵液提取物抑制杨树叶枯病菌生长的机理之一.

In order to explore the inhibiting mechanism of Lactarius vellereus fermenting liquor extraction to the growth of Alternaria alternata（Fr.） Keissler,the influences of the extraction on the activity of protective enzymes in A.alternata were studied,also the correlations among protective enzyme activity,content of MDA,conductivity ratio and variation of respiration intensity were discussed. The results showed that,after being treated with the extraction,the activity of SOD,CAT and POD in mycelium trended increasing in prophase,both SOD and MDA reached the maximum at eight hours,while POD reached at 10 hours.Along with treated time prolonged,the activity of these three enzymes decreased rapidly in anaphase,and dropped to the minimum at 48 hours.However,the activity of POD dropped to zero.These three enzymes were sensitive to the extraction.These results also indicated that the content of MDA reached the maximum at eight hours,which was 9.2 times of the control,and decreased to the minimum at 48 hours,while it was larger than the control all the time.These indicated that the lipid was peroxidized seriously,configuration of membrane system was destroyed,and induced to the leakage of electrolyte,both conductivity ratio and respiration intensity trended decreasing ultimately.These reflected that these three enzymes,the content of MDA,conductivity ratio and respiration intensity varied correlatively after being treated with the extraction.The dynamic balance among SOD,CAT and POD was broken by the extraction,which leading to the free radical clear system undergoing dysfunction,the content of MDA increased and the integrality of membrane system was damaged seriously.So the mycelium was damnified and destroyed.This is probably one of the mechanisms that the extraction inhibites the growth of A.alternata.