外源褪黑素对低磷胁迫下紫花苜蓿生长及生理特性的影响

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中图分类号： S551+ .7;Q945.78 文献标识码：A 文章编号：1007-0435（2026）02-0632-11

Abstract：To investigate the efects of exogenous Melatonin（MT）on the growth and physiological characteristics of alfalfa （Medicago sativa） under low phosphorus stress，germplasms ⋅7890⋅ and ⋅15578， were used as materials. The normal phosphorus（NP， 1.0mmol⋅L-1KH2PO4） and low phosphorus（LP，O.O1 mmol·L-1 KH2PO4） stresses were imposed by nutrient solution sand culture method.Five different concentrations of MT were applied to the roots of alfalfa seedlings under LP stress to determine their morphology and physiological indicators. The results show that ： 90μmol⋅L-1N IT has the best effect in alleviating low phosphorus stress in alfalfa.The plant height，leaf area，aboveground and underground biomass，relative water content，root vitality，transpiration rate，stomatal conductance，net photosynthetic rate，contents of chlorophyll a，chlorophyllb， carotenoids，chlorophyll，proline，soluble sugar and soluble protein，as wellas the activities of superoxide dismutase，peroxidase and catalase were allsignificantly increased.The concentrations of malondialdehyde and intercellular CO2 were significantly reduced.Principal component analysis indicated that chlorophyll content， soluble sugar content，and leaf stomatal conductance could be used as key indicators for the growth and develop ment of alfalfa under low phosphorus stress by MT. In conclusion，exogenous MT can enhance the activity of antioxidant enzymes and the content of osmotic regulatory substances in alfalfa seedlings under LP stress，and improve their tolerance to low phosphorus.

Keywords：Alfalfa;Melatonin;Low phosphorus stress;Peroxidase

紫花苜蓿（Medicagosatiua）是全球范围内广泛栽培的优质多年生豆科牧草，因其蛋白质含量高、营养价值丰富，被誉为“牧草之王”。（剩余19040字）