烟草疫霉侵染后剑麻H.11648叶片细胞超微结构和防御酶活性研究

Changes in Ultrastructure and Activities of Defense-related Enzymes in Leaves of Sisal H.11648 after Phytophthora nicotianae Breda Infection

斑马纹病是剑麻的主要病害之一,本研究以剑麻斑马纹病高感品种H.11648为材料,分别在接种烟草疫霉0、24、36、48、72 h取样,用电镜观察H.11648叶片细胞超微结构变化,同时分析过氧化氢酶(CAT)、过氧化物酶(POD)、苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)、抗坏血酸过氧化物酶(APX)和超氧化物歧化酶(SOD)等防御酶活性变化情况。结果表明:H.11648在接种24 h,可见大量休止孢,叶绿体结构被破坏,植物组织开始降解,随着时间延长,附着孢出现,吸器形成,植物组织解体更严重,接种72 h,可见大量菌丝。在整个接种过程中,CAT、PAL和PPO活性显著增强,72 h达到最高,分别为501.44、25.73、1 742.67 U/(g.min)。SOD和APX活性显著下降,72 h达到最低,分别为2 888.62 U/g和841.96μmol/(g.min)。POD活性先下降72 h又上升,但均显著低于接种前POD活性。本研究从细胞学和生理水平为探讨剑麻与烟草疫霉互作关系提供了理论基础。

Zebra disease that caused by Phytophthora nicotianae Breda, is a major disease of sisal. In the present study, ultrastructural changes were examined by transmission and scanning microscopies and the activities of some defense-related enzymes（superoxide dismutase（SOD）, catalase（CAT）, peroxidase（POX）, ascorbate peroxidase（APX）, phenylalanine ammonia-lyase（PAL） and polyphenol oxidase（PPO）） were investigated in the leaves of susceptible sisal H.11648 at 0, 24, 36, 48, 72 h after they were inoculated with P. nicotianae breda. Many cysts were observed at 24 h after inoculation, and the chloroplast structure was destroyed and the plant tissue began to be degraded. With the prolongation of infection time, the appressorium appeared, haustoria formated,and plant tissue was seriously degraded. Many hypha were observed at 72 h after inoculation. The activity of CAT, PAL, PPO significantly increased during the infection process and reached the maximum value at 72 h after inoculation. The activity of CAT, PAL, PPO was 501.44, 25.73, 1 742.67 U/（g.min）, respectively. The activity of SOD and APX significantly decreased during the infection process and reached the minimum value at 72 h after inoculation. The activity of SOD and APX was 2 888.62 U/g and 841.96 μmol/（g.min）, respectively. The activity of POD showed a decline at the beginning and then increased at 72 h after inoculation, but was lower than that of POD at 0 h after inoculation. The results would provide a cytological and physiological reference for revealing the interaction between sisal and P. nicotianae Breda.