| Abstract:This study investigates the relationship between the leaf prickles and drought tolerance in Brassica juncea.The experiment used red leaf juncea with prickles and Shaanxi winter juncea without prickles as materials.A water-controlled potting method was used to comprehensively analyze plant phenotypes,photosynthetic exchange parameters,osmotic regulating substances,chlorophyll content,antioxidant enzyme activities,chlorophyll fluorescence,and leaf stomata under varying drought stress treatments.The results showed that drought tolerance indexes differed between the two-leaf structures of oilseed rape as drought stress intensified.The degree of wilting,the relative water content,chlorophyll content,number of leaf stomata,gas exchange parameter,and chlorophyll fluorescence all decreased.The photosynthetic system of Shaanxi winter juncea was less affected than that of red leaf juncea.Malondialdehyde (MDA),proline (Pro),superoxide dismutase (SOD),peroxidase (POD) and catalase (CAT) all exhibited an increasing trend.The activities of SOD,POD and CAT of Shaanxi winter juncea were significantly higher than those in red leaf juncea,and were 1.06,1.39 and 1.38 times higher than those of the pre-stress period under drought,respectively.Correlation analysis showed a close relationship between drought resistance and leaf prickles,indicating that Shaanxi winter juncea with leaf prickles exhibited greater drought resistance than red leaf juncea without them.In conclusion,Brassica juncea responds to drought stress through various mechanisms,including plant phenotype,photosynthetic exchange parameters,osmotic regulating substances,chlorophyll content,and antioxidant enzyme activities. |
