甜瓜种质幼苗在高盐胁迫下的生长及生理响应OA

Thirteen melon germplasm resources were used as the test materials to comprehensively evaluate their salt tolerance at the seedling stage by measuring growth and physiological indicators,combined with principal component analysis(PCA)and cluster analysis,in order to provide references for salt-tolerant breeding.The results showed that salt stress significantly inhibited seedling growth,with plant height reduction ranging from 15％to 57％.Malondialdehyde(MDA)content increased,proline(Pro)content accumulated substantially,and chlorophyll content decreased.Salt-tolerant materials maintained higher activities of superoxide dismutase(SOD),peroxidase(POD),and catalase(CAT),and the activities of these three enzymes were significantly negatively correlated with MDA content.PCA extracted three principal components with a cumulative contribution rate of 86.039％.Cluster analysis classified the 13 materials into five salt-tolerance grades,among which No.8('2025-42')and No.12('Mengmi')were highly salt-tolerant,while No.4 and No.11 were highly sensitive.In conclusion,salt tolerance in melon was synergistically regulated by multiple physiological processes,with the coordinated defense capability of the antioxidant enzyme system serving as the core mechanism.