外源茉莉酸甲酯对干旱胁迫下甘蓝生理特性及BoPRX基因表达的影响OA

To investigate the alleviation effect and relguatory mechanism of methyl jasmonate(MeJA)on cabbage seed-lings under drought stress,the seedling of Qiu Tian 2 cabbage was used as experimental materials.Three treatments were established:CK(normal growth conditions),T1(15%PEG8000-induced drought stress),and T2(drought stress with 15%PEG8000 was applied after spraying with 25 μmol·L-1 MeJA).Chlorophyll content,relative electrical conductivity(REC),malondialdehyde(MDA)content,antioxidant enzyme activity,and the expression patterns of peroxidase genes(PRX)were measured at 0,3,6,12,and 24 h post-treatment.The results indicated that compared with CK,chlorophyll content in T1-treated seedlings decreased,while REC and MDA content increased.Activity of superoxide dismutase(SOD),peroxidase(POD),and catalase(CAT)(except treatment for 24 h)progressively increased over time under stress conditions.However,after T2 treatment,chlorophyll content,as well as the activity of SOD,POD,and CAT was higher than that in T1,while the REC and MDA content were reduced compared to the T1 treatment.The expression of the five BoPRX genes rapidly and were up-regulated expression in the early stages of both T1 and T2 treatments but were down-regulated expression after 12 or 24 h.Notably,except for BoPRX113,the expression level of other four BoPRX genes under T2 treatment were lower than those under T1 treatment.In conclusion,exogenous MeJA can alleviate the damage of drought stress to cabbage seedlings and enhance their drought resistance by maintaining chlorophyll content,reducing cell membrane damage,regulating the activity of antioxidant enzymes,and modulating the expression of BoPRX genes.The findings of this study provide a theoretical basis for drought-resistant cultivation of cabbage.