The Physiological and Biochemical Responses of Non-heading Chinese Cabbage after Infected by Downy Mildew
In order to investigate the physiological and biochemical changes of non-heading Chinese cabbage af-ter infected by downy mildew,highly resistant material 605 and susceptible material 250 were used as experimen-tal materials.The physiological and biochemical responses of non-heading Chinese cabbage under disease stress at 0,24,48,72,120 h after inoculation in three leaves stage were studied.The results showed that activity of SOD in-creased,decreased and increased again,while activities of POD and CAT increased first and significantly de-creased at 48 h after inoculation.The content of MDA and soluble sugar both showed two peaks under the stress of the pathogen,which appeared at 24 and 72 h respectively.The chlorophyll content reached the highest 48 h after inoculation,and gradually decreased with the extension of inoculation time.Pn and Gs of the two materials showed a decreasing trend under disease stress.Ci reached the lowest value at 48 h,increased rapidly after 72 h,and then decreased slowly after 72 h.Pn had little change before 72 h,and then increased sharply,while Tr showed an in-creasing trend.The results showed that POD changed significantly at 48 h,CAT changed significantly at 24 h,MDA and soluble sugar content changed significantly at 72 h.All these indexes could be used as physiological in-dexes to evaluate resistance to downy mildew.After downy mildew infection,transpiration rate of the leaves was increased,then moisture content loss of the leaves was rapid,and stomatal conductance was poor,which affected stomatal transport of carbon dioxide and net photosynthetic rate was decreased.
Non-heading Chinese cabbageDowny mildewPhotosynthetic parametersPhysiological indicators
NETL
NSTL
万方数据
