The Impact of Exogenous Selenium on the Physiological Characteristics of Flax under Drought Stress

WANG Wenxia; LIU Yuqi; XIA Qing; ZHI Hui; DU Jie

doi:10.15933/j.cnki.1004-3268.2025.07.006

Abstract：To investigate the methods for alleviating drought stress in flax and improving its drought resistance,the cultivar Jinya 10 was selected as the experimental material.At the budding stage,three treatments were designed:normal control(CK),drought stress following a spray of clear water(DS),and drought stress after spraying 50 g/ha Na2SeO3(SE).Foliar applications of water and selenium fertilizer were conducted,and after the drought period,various parameters were measured,including photosynthetic indices,chlorophyll fluorescence parameters,H2O2 content,malondialdehyde(MDA)level,antioxidant enzyme activities,osmotic adjustment substance content,nitrogen metabolism-related enzyme activities,yield,and yield components.The results revealed that drought stress at the budding stage significantly impaired plant growth and development,whereas selenium application notably mitigated the detrimental effects of drought on flax.The grain yield under the SE treatment was significantly higher,with an increase of 16.43%compared to the DS treatment,primarily due to a substantial rise in the number of capsules per plant and seeds per capsule.Exogenous selenium treatment substantially improved the net photosynthetic rate(Pn),stomatal conductance(Gs),and transpiration rate(Tr)in flax leaves under drought stress,while also increased chlorophyll content.Additionally,the maximum photochemical efficiency(Fv/Fm)and the actual photochemical efficiency of PSⅡ(ΦPSⅡ)were significantly enhanced.Selenium fertilizer also considerably enhanced the activities of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),nitrate reductase(NR),glutamine synthetase(GS),and glutamate dehydrogenase(GDH)under drought stress,with activity increases ranging from 11.19%to 20.57%.It also significantly reduced the non-photochemical quenching coefficient(NPQ),H2O2,and MDA content.Therefore,foliar application of 50 g/ha selenium fertilizer effectively alleviated the negative effects of drought stress during the budding stage on flax growth and yield by enhancing photosynthetic efficiency,optimizing chlorophyll fluorescence parameters,boosting the activity of antioxidant enzymes and nitrogen metabolism related enzymes,and decreasing reactive oxygen species and MDA levels.