Effects of Alternaria porri（Elliott）Cif.?Crude Toxin on Protective Enzyme Activities and Leaf Anatomical Structure of Garlic Seedlings
LI Xiao-min，CHENG Zhi-hui*，DONG Yin-xin
College of Horticulture，Northwest A&F University，Key Laboratory of Horticultural Plant Germplasm Resource Utilization in Northwest China，Ministry of Agriculture，Yangling 712100，Shaanxi，China
Abstract：The effects of Alternaria porri（Elliott）Cif.?crude toxin on the activities of SOD，POD，PAL and contents of MDA and leaf anatomical structure were studied，taking the resistant cultivar G087 and susceptible cultivar G025 of garlic（Allium sativum L.）as experiment materials．The results showed that the SOD activities of both cultivars appeared the same dynamic changing trend in 120 hours after the pathogen crude toxin treatment and reached the peak at 96 hours．But the SOD activities in resistant cultivar were higher than that in susceptible cultivar．The POD and PAL activities in the leaves of susceptible cultivar showed a trend of sustaining increase first then a slight decrease and had a peak value．However，the activities of POD and PAL in the leaves of resistant cultivar had 2 peak values，which presented at 48 hours and 96 hours for POD and 48 hours and 120 hours for PAL，respectively after pathogen crude toxin treatment．The activities of both enzymes in resistant cultivar were higher than that in the susceptible cultivar at the peak．The MDA content in the leaves of resistant cultivar was lower than that in the susceptible cultivar at the most time after pathogen crude toxin treatment．The mesophyll tissue in the leave of resistant cultivar was more compact than that in susceptible cultivar．The leaf palisade tissue and spongy tissue became more compact in both cultivars after pathogen crude toxin treatment，but the mesophyll tissue structure in the resistant cultivar became more compacter than that in susceptible cultivar．
