油菜素内酯对低温胁迫下紫花苜蓿生长及生理特性的影响

打开文本图片集

中图分类号：S541.9 文献标识码：A 文章编号：1007-0435（2026）04-1492-10

Abstract：In order to explore the efects ofspraying brassinosteroid （BR） on the growth and physiological char acteristics of alfalfa（Medicago satirua）seedlings under low temperature stress，the new cold-resistant alfalfa line（P4）and Longdong alfalfa（Medicago satiua ‘Longdong'）were used as the research objects in this study. Afterl3 days of low temperature stress （4∘C ），different concentrations of exogenousBR（O.OO，O.25，0.50， 0.75，and 1.00mg⋅L-1 ，representing T0 ， T1 ， T2 ， T3 ， ΔT4 treatment，respectively）were sprayed on the leaves.After 5 days，the morphological and physiological indexes of the seedlings were measured. The results showed that low temperature stress significantly inhibited the growth of alfalfa seedlings. However，after applying diferent concentrations of BR，the plant height，leaf length，leaf width，leaf area，aboveground and underground biomass，root shoot ratio，total root length，total root surface area，root diameter，root volume，root tip number，root activity，phenylalanine ammonia lyase，cinnamic acid-4-hydroxylase，4-coumaric acid coenzyme A ligase and total flavonoid content of alfalfa seedlings were significantly higher than those of T0 （ P<0.05）

The content of malondialdehyde decreased significantly （P<0.05） . The comprehensive evaluation of membership function showed that different concentrations of BR treatments were in the order of T2>T1>T3>T4>T0 indicating that spraying 0.25-1.00mg⋅L-1 BR could alleviate the effects of low temperature on the growth of alfalfa seedlings，while the 0.5mg∙L-1 （ T2 ）BR treatment was the best. The results provided a theoretical basis for the rational use of BR to solve the problem of chilling injury in alfalfa cultivation.

Key words：Alfalfa;Low temperature stress;Brassnosteroid;Physiological Characteristics;Membership Functiol

低温胁迫是影响植物生长发育、地理分布及作物生产力的关键因素，尤其在北方及高海拔地区，由低温引起的作物损失巨大[1-2]。（剩余19183字）