20份黄花首蓿种质低温胁迫生理响应及抗寒性评价

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中图分类号：S541.9 文献标识码：A 文章编号：1007-0435（2026）02-0611-13

Abstract：To screen cold-tolerant Medicago falcata germplasms and to clarify their physiological response mechanisms to low-temperature stress，this study systematically evaluated the physiological and chlorophyl fluorescence characteristics of 2O accessions under gradient low-temperature stresses （ 25∘C ， 10∘C ， 5∘C ， 0∘C ） By measuring seven key indicators，it was found that the contents of malondialdehyde（MDA），soluble sugar （SS），and proline（Pro），as well as the level of initial fluorescence （F） ，exhibited upward trendswith decreas ing temperature，all significantly increasing at 0∘C （ P<0.05） ；while the relative chlorophyll content（Soil and plant analyzer development，SPAD），maximum fluorescence （Fm） ，and maximum photochemical efficiency of PS I （Maximal photochemical efficiency of photosystem I1， Fv/Fm ）showed downward trends. A comprehensive evaluation using the membership function method combined with the standard deviation coefficient weightingmethod identified M4 ， M1 ，and M10 as accessions with stronger cold tolerance. Stepwise regression analysis further established a cold tolerance prediction model （ R2=0.932 ），confirming Fv/Fm and SS content as critical evaluation indices.These results provide excelent germplasm resourcesand a theoretical basis for cold-tolerance breeding of alfalfa，and it is recommended that future research integrate omics technologies to further eluci date the underlying molecular regulatory networks.

Key words：Medicago falcata;Low-temperature stress;Physiological response; Chlorophyllfluorescence; Cold resistance evaluation

低温是限制植物生长发育的关键非生物胁迫因子，通过破坏细胞膜完整性、抑制光合作用及代谢活性，直接影响作物越冬存活率和品质[1]。（剩余21969字）