Abstract: This study investigated the growth regulation mechanism of quercetin on seed germination and seedling 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 content， 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. venetum seedlings and impaired photosynthetic system function， characterized by significantly decreasing photosynthetic pigment content and PSII photochemical efficiency， along with increasing accumulation of malondialdehyde， a lipid peroxidation product.The salt stress-alleviating effect of quercetin exhibited a pronounced concentration-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 seedling 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% respectively， 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 seedling growth and physiological characteristics closer to the normal control level. Quercetin enhances salt tolerance in A. venetum seedlings by synergistically promoting photosynthetic pigment synthesis， strengthening antioxidant system function， regulating osmotic balance， and optimizing root structure， thereby effectively mitigating 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 cultivation and ecological restoration of A. venetum in saline-alkali soils.

Key words: Quercetin, Apocynum venetum L., Salt stress, Seed germination, Seedling growth

摘要： 为探讨槲皮素对盐胁迫下罗布红麻（Apocynum venetum L.）种子萌发和幼苗生长的调控机制，明确其适宜施用浓度。本研究以罗布红麻为材料，设置8个处理（HCK：正常对照；HCKN：200 mmol·L^-1NaCl盐胁迫；Q₁+N~Q₆+N：200 mmol·L^-1NaCl+50，100，150，200，250，300 μmol·L^-1槲皮素），系统测定种子发芽特性（发芽率、发芽势、发芽指数）、幼苗生长指标（株高、根系生长参数、生物量、叶片生长参数）、光合生理特性（光合色素含量、叶绿素荧光参数）及抗逆生理指标（抗氧化酶活性、丙二醛含量、脯氨酸含量），并通过隶属函数法综合评价缓解效应。结果表明：盐胁迫对罗布红麻种子发芽率影响较小，但显著降低发芽势与发芽指数，并严重抑制罗布红麻幼苗生长及光合系统功能。施用槲皮素后，发现其对盐胁迫的缓解效应呈现显著浓度依赖性：低浓度槲皮素（Q₁+N，Q₂+N）缓解作用有限，高浓度槲皮素（Q₅+N，Q₆+N）则无法有效改善甚至抑制罗布红麻幼苗生长。相比于其他斛皮素浓度处理组，150 μmol·L^-1槲皮素（Q₃+N）处理缓解盐胁迫效果最佳：较盐胁迫组（HCKN），其种子发芽势和发芽指数分别提高2.1%和3.5%，幼苗株高提高97.2%，叶绿素总含量和类胡萝卜素含量分别提高17.1%和34.9%，脯氨酸含量提高20.6%，丙二醛含量降低22.8%（P<0.05），同时显著改善了根系形态与叶绿素荧光参数，其中根长、根表面积较HCKN组分别提升37.2%，51.3%；光系统Ⅱ最大光化学效率（Maximum quantum efficiency of photo-system II，Fv/Fm）、光系统Ⅱ实际光化学效率（Effective quantum yield of photosystem II，Y（II））均得到明显改善，有效缓解了光系统 Ⅱ（Photosystem II，PSII）反应中心损伤并且提高了实际光合效率，使幼苗生长及生理特性接近正常对照水平。研究表明，槲皮素可通过促进光合色素合成、增强抗氧化系统功能、调节渗透平衡及优化根系结构，协同提升罗布红麻幼苗耐盐性，有效缓解盐胁迫损伤。该研究明确了槲皮素调控罗布红麻耐盐性的适宜浓度与关键生理机制，为盐碱地罗布红麻规模化栽培及生态修复提供了重要技术参考。

关键词: 槲皮素, 罗布红麻, 盐胁迫, 种子萌发, 幼苗生长