东北薄荷幼苗对干旱胁迫的生理响应OA

[Objective]To investigate the physiological response mechanisms of Mentha sachalinensis(Briq.)Kudo.seedlings to drought stress and to improve the yield and quality of mint in Northwest China.[Method]Using Mentha sachalinensis(Briq.)Kudo.seedlings as experimental materials,seedlings were subjected to drought stress simulation via the soil water control method with treatments set at 32%(CK),28%(W1),24%(W2),20%(W3),and 16%(W4)soil moisture levels.A total of 15 morphological and physiological indicators were measured under drought stress to establish interrelationship models.[Result](1)Drought severity significantly regulated seedling morphogenesis:plant height,leaf number,leaf length,and leaf width exhibited an initial increase followed by a de-cline.Mild stress(W1)induced peak values of morphological indicators,while severe stress(W4)caused the most significant inhibition(all indicators reached minimum values).(2)Osmotic regulators(soluble protein and proline contents)and enzymatic antioxidant activities(peroxidase,POD;superoxide dismutase,SOD)increased progres-sively with drought severity(84.11%～153.79%higher than CK).However,membrane lipid peroxidation reached a regulatory threshold under moderate stress(W3),with malondialdehyde(MDA)content peaking(85.49%higher than CK).(3)Photosynthetic adaptation:Relative chlorophyll content(SPAD),nitrogen balance index(NBI),fla-vonoids,and anthocyanins accumulated significantly during the mid-to-late stress period(21～33 d),but no differ-ences were observed among treatments in the late stage(33～45 d),indicating the recovery of photosynthetic homeo-stasis.[Conclusion]Drought stress inhibits growth,induces oxidative damage,disrupts osmotic balance,and imposes photosynthetic pressure on Mentha haplocalyx seedlings.These findings provide a theoretical basis for establishing a drought tolerance evaluation system during the seedling stage.