Abstract: In order to study the effects of different brassinolide (BR) concentrations on the allelopathy relief and the regulatory effects of continuous and non-continuous cropping alfalfa (Medicago sativa L.),four BR concentration levels,including 0 (CK),0.25%,0.50%,0.67% and 1%V/V,were set to spray branch stage alfalfa leaves,and then the morphological and physiological indexes of bud stage continuous and non-continuous cropping alfalfa were determined. The results showed that BR effectively increased the plant height,root length,whole plant biomass of continuous cropping alfalfa;the activity of peroxidase and superoxide dismutase in roots and leaves of alfalfa were significantly improved;the soluble sugar,proline and chlorophyll content in roots and leaves also increased,while the content of malondialdehyde decreased. The treatment of 0.50 ‰ BR was the best,followed by 0.25‰ treatment. This study provided a theoretical basis for exploring the techniques of plant growth regulators to break the obstacles of continuous cropping alfalfa,achieve stress resistance and increase production and increase efficiency.

Key words: Medicago sativa, Brassinolide, Continuous cropping disorder, Growth and development

摘要： 为研究不同浓度芸苔素内酯（Brassinolide，BR）对连作与非连作紫花苜蓿（Medicago sativa L.）的调控效应，了解BR对连作紫花苜蓿化感缓解效果及调控连作紫花苜蓿的基本成效，本试验通过向连作与非连作分枝期紫花苜蓿叶面喷施浓度分别为0（CK），0.25‰，0.50‰，0.67‰，1‰V/V的BR溶液，于现蕾期测定紫花苜蓿形态学、生理学指标。结果表明：喷施BR能有效提高连作条件下紫花苜蓿株高、根长、全株生物量，显著提高了紫花苜蓿根、叶的过氧化物酶、超氧化物歧化酶活性，提高了根、叶的可溶性糖、脯氨酸、叶绿素含量，同时降低了丙二醛含量；喷施0.50‰浓度BR效果最好，0.25‰浓度次之。本研究表明在紫花苜蓿连作生产中喷施BR，苜蓿生长发育较好，抗连作逆境效应明显，可达到理想的预期调控成效。本研究为探索植物生长调节剂破解紫花苜蓿连作障碍的抗逆增产增效技术提供了理论依据。

关键词: 紫花苜蓿, 芸苔素内酯, 连作障碍, 生长发育