Physiological Response Of Perilla To Water Stress And Its Prevention And Treatment Of Brown Spot Disease

Perilla is a traditional medicinal and edible crop with a history of more than 2000 years.The domestication history of Perilla is short.Perilla varieties in different regions cannot be planted in different regions.At the same time,guizhou is a typical karst region,with poor soil water retention capacity,uneven distribution of water resources and low annual precipitation in some areas,resulting in frequent drought disasters.Therefore,it is of great significance to explore the physiological response of Perilla to water stress and to screen Perilla suitable for local planting in guizhou.At the same time,in the study of planting Perilla in guizhou,it was found that the brown spot disease was one of the important diseases that caused the reduction of Perilla production,and it had the characteristics of fast onset,strong infectivity and so on.Once Perilla is infected,it will spread rapidly in the field,causing a large number of plants to become infected,leading to leaf death,falling off,and serious production loss.Therefore,in this study,five species from guizhou province were selected for pot experiment to study their physiological changes under different drought stresses by setting different drought stresses.At the same time,the pathogen of brown spot of Perilla was isolated,purified and identified,and three bacteriostatic agents on the market were selected 70%Mancozeb,72%Metalaxyl-mancozeb and 69%Dimethomorph-Mancozeb.The main results are as follows:1.With the increase of drought intensity,plant height and diameter:different varieties decreased to different degrees compared with CK;Soluble sugar content:varieties M311 and M46 increased,varieties M99 decreased first and then increased,and M39and M84 increased first and then decreased.The soluble protein content of M311, M39 and M84 increased first and then decreased,while that of M99 and M46 increased continuously.Proline content:variety M46 showed continuous increase,and other varieties showed increase and then decrease.2.With the increase of drought stress intensity,POD enzyme activity:M39 increased,M311,M46 and M84 increased and then decreased,M99 increased and then decreased,and M39 increased.SOD activity:M311,M99,M46 and M84 all showed a trend of increasing first and then decreasing,while M39 first decreased and then increased and then decreased.MDA content:M311,M99,M46 and M84 showed a trend of increasing and then decreasing,while M39 showed a trend of decreasing and then increasing.Chlorophyll content:the content of leaf green A and chlorophyll B of the five varieties increased first and then decreased.3.As the drought continues,the net photosynthetic rate of varieties M311 and M99increased first,then decreased,and then increased.The remaining three varieties showed a trend of continuous decline.Stomatal conductance of M311 and M99 increased first and then decreased,M39 showed a trend of decreasing first and then increasing,and M46 and M84 showed a trend of decreasing.Intercellular CO₂ concentration:M311,M99 and M84 showed a trend of increasing first and then decreasing,M46 showed a trend of increasing first and then decreasing,and M39showed a trend of decreasing first and then increasing.Leaf transpiration rate:varieties M311,M99 and M84 showed a trend of decreasing and then increasing,while varieties M46 and M39 showed a trend of decreasing.4.Alternaria Nees was responsible for the pathogenic bacteria of purple Perilla.69%Dimethomorph-Mancozeb of the three agents had the best overall inhibition effect on the growth of mycelia.Its EC₅₀0 is 0.16 g/mL.The worst inhibition effect was 70%of mancozeb and 0.76 g/mL of EC₅₀.