Effects of exogenous silicon and salicylic acid on the physiological charac-teristics of melon seedlings under salt stress

ZENG Chengcheng; QIN Fang; LI Qin; LI Fangyuan; CHEN Jinping; SU Tianming; HE Tieguang; SU Lirong

doi:10.16861/j.cnki.zggc.2024.0557

Abstract：To explore the alleviating effects of exogenous silicon(Si)and salicylic acid(SA)on salt stress in melon seed-lings,medium salinized greenhouse soil was used as the experimental soil,and melon seedlings were used as experimen-tal materials.Four treatments were designed:Blank control group(CK),applied silicon treatment group(Si),applied sali-cylic acid treatment group(SA)and combined applied silicon and salicylic acid treatment group(Si+SA).The effects of different treatments on the photosynthetic characteristics,chlorophyll fluorescence parameters,and physiological charac-teristics of melon seedlings were investigated.The results showed that compared with CK,exogenous silicon and salicylic acid could significantly promote the growth of melon seedlings under salt stress,with the Si+SA treatment being the most effective.The plant height and aboveground biomass in the Si+SA treatment were significantly higher than those in CK by 28.02％and 50.13％,respectively.Compared with CK,SA and Si+SA treatments significantly increased the net photo-synthetic rate of melon seedling,with increases of 49.91％and 77.01％,respectively.The results of chlorophyll fluores-cence parameters showed that the repair effect in the Si+SA group was optimal.The activities of superoxide dismutase,peroxidase,and catalase were ranked as Si+SA＞Si＞SA＞CK,while the content of malondialdehyde showed the oppo-site trend:CK＞SA＞Si＞Si+SA.The soluble sugar content and proline content in all treatment groups were significantly higher than those in the control group,with proline content being 156.83％-189.84％higher than that in CK.The results showed that both the exogenous Si and SA could alleviate the stress caused by moderately salinized soil on melon seed-lings,and the combination of SA and Si exhibited a significant synergistic effect in improving the photosynthetic efficien-cy and resistance of melon seedling.