Quercetin is one of the main flavonoids in the human diet and mainly found in different plant tissues, including seeds, flowers, leaves, stems, and roots. However, its biological function in plant tissues, especially in seeds, is unknown. In this study, the seed germination and subsequent seedling growth of Apocynum pictum and A. venetum under osmotic stress (400 mmol L⁻¹ mannitol) supplemented with 5 μmol L⁻¹ quercetin were evaluated after 7, 14, and 21 days of germination. Results showed that quercetin improved the germination percentage and seed vigor, as indicated by the higher germination energy, shoot length, root length, dry weight, fresh weight, and chlorophyll content in A. pictum and A. venetum seedlings under the mannitol compared with those under the mannitol alone. Quercetin decreased H₂O₂ and O₂⁻ production and cell membrane damage, and mostly increased the gene expression of superoxide dismutase, peroxidase, catalase, chalcone synthase and flavonol synthase in A. pictum and A. venetum seedlings under the mannitol compared with those under the mannitol alone. In addition, the germination energy of A. pictum was 21.57% higher than that of A. venetum, and the gene expression of key enzymes in quercetin biosynthesis in A. pictum was mostly higher than that in A. venetum after 1 and 7 days of germination. These results indicated that quercetin was an effective anti-osmotic agent that alleviated the adverse effect of mannitol-induced osmotic stress on seed germination and seed vigor, and A. pictum seeds were more osmotic resistant than A. venetum seeds.

槲皮素是人类饮食中的主要类黄酮之一，主要存在于不同的植物组织中，包括种子，花朵，叶子，茎和根。但是，其在植物组织中，尤其是种子中的生物学功能尚不清楚。在这项研究中，在萌发7、14和21天后，评估了罗布麻和罗汉果在渗透胁迫下（400 mmol L ^-1甘露醇）补充5μmolL ^-1槲皮素的种子发芽和随后的幼苗生长。结果表明，槲皮素提高发芽率和种子活力，由较高发芽势，地上长，根长，干重，鲜重，和叶绿素含量所指示A. pictum和与甘露醇单独施用相比，甘露醇下的A. venetum幼苗。槲皮素h后逐渐降低₂ ö ₂和O ₂ ^-产生和细胞膜损伤，而且大多增加超氧化物歧化酶的基因表达，过氧化物酶，过氧化氢酶，查耳酮合酶和黄酮醇合成酶在A. pictum和罗布麻甘露醇下苗与这些相比仅在甘露醇下。此外，发芽能量A. pictum比的高21.57％罗布麻，而在槲皮素的生物合成的关键酶的基因的表达A. pictum主要是着高于罗布麻发芽1天和7天后。这些结果表明槲皮素是一种有效的抗渗透剂，减轻了甘露醇诱导的渗透胁迫对种子发芽和种子活力的不利影响，并且A. pictum种子比A. venetum种子具有更高的抗渗透性。