不同浓度槲皮素对盐胁迫下罗布红麻种子萌发和幼苗生长的影响OA

This study investigated the growth regulation mechanism of quercetin on seed germination and seed-ling growth of Apocynum venetum L.under salt stress,and determined its optimal application concentration.This study utilized A.venetum as the experimental material,and established eight treatments:HCKN:200 mmol·L⁻¹ NaCl salt stress;Q1+N-Q6+N:200 mmol·L-1 NaCl+50,100,150,200,250,300 μmol·L-1 quercetin).The study systematically measured seed germination traits(germination rate,germination vigor,germination index),seedling growth indicators(plant height,root growth parameters,biomass,leaf growth parameters),photosynthetic physiological traits(photosynthetic pigment content,chlorophyll fluorescence parameters),and stress resistance physiological indicators(antioxidant enzyme activity,malondialdehyde con-tent,proline content).The alleviation effects were comprehensively evaluated using the membership function method.The results indicated that salt stress had a minor effect on the germination rate of A.venetum seeds but significantly reduced germination vigor and germination index.It severely inhibited the growth of A.vene-tum seedlings and impaired photosynthetic system function,characterized by significantly decreasing photosyn-thetic pigment content and PSⅡ photochemical efficiency,along with increasing accumulation of malondialde-hyde,a lipid peroxidation product.The salt stress-alleviating effect of quercetin exhibited a pronounced concen-tration-dependent response:Low quercetin concentrations(Q1+N,Q2+N)provided limited alleviation,while high concentrations(Q5+N,Q6+N)failed to effectively improve growth and even inhibited A.venetum seed-ling development.Compared to other quercetin concentration treatments,the 150 μmol·L⁻¹ quercetin(Q3+N)treatment showed the best salt stress alleviation effect.Compared to the salt-stressed control(HCKN),it increased seed germination potential and germination index by 2.1％and 3.5％,respectively.Seedling height increased by 97.2％,total chlorophyll content and carotenoid content increased by 17.1％and34.9％respec-tively,proline content increased by 20.6％,and malondialdehyde content decreased by 22.8％(P<0.05).Concurrently,it significantly improved root morphology and chlorophyll fluorescence parameters,bringing seed-ling growth and physiological characteristics closer to the normal control level.Quercetin enhances salt toler-ance in A.venetum seedlings by synergistically promoting photosynthetic pigment synthesis,strengthening anti-oxidant system function,regulating osmotic balance,and optimizing root structure,thereby effectively mitigat-ing salt stress damage.This study identifies the optimal concentration and key physiological mechanisms by which quercetin regulates A.venetum's salt tolerance,providing crucial technical guidance for large-scale culti-vation and ecological restoration of A.venetum in saline-alkali soils.