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草业学报 ›› 2025, Vol. 34 ›› Issue (2): 81-93.DOI: 10.11686/cyxb2024102

• 研究论文 • 上一篇    下一篇

外源激素对紫花苜蓿种子内生根瘤菌增殖及幼苗生长的影响

杜媛媛(), 康文娟(), 师尚礼(), 韩宜霖, 何富强   

  1. 甘肃农业大学草业学院,草业生态系统教育部重点实验室,中-美草地畜牧业可持续发展研究中心,甘肃 兰州 730070
  • 收稿日期:2024-04-02 修回日期:2024-05-08 出版日期:2025-02-20 发布日期:2024-11-27
  • 通讯作者: 康文娟,师尚礼
  • 作者简介:shishl@gsau.edu.cn
    E-mail: kangwj@gsau.edu.cn
    杜媛媛(2000-),女,甘肃定西人,在读硕士。E-mail: 2922348392@qq.com
  • 基金资助:
    草业生态系统教育部重点实验室(甘肃农业大学)开放课题(KLGE202201);苜蓿NCRs多肽与根瘤菌表面多糖SPS的互作机制研究和苜蓿种子内生根瘤菌的根瘤发生机制研究(0722125)

Effects of exogenous hormones on the proliferation of endophytic fluorescent labeled rhizobia in seeds and growth of the seedlings

Yuan-yuan DU(), Wen-juan KANG(), Shang-li SHI(), Yi-lin HAN, Fu-qiang HE   

  1. Pratacultural College,Gansu Agricultural University,Key Laboratory of Grassland Ecosystem of Ministry of Education,Sino-U. S. Centers for Grazing Land Ecosystem Sustainability,Lanzhou 730070,China
  • Received:2024-04-02 Revised:2024-05-08 Online:2025-02-20 Published:2024-11-27
  • Contact: Wen-juan KANG,Shang-li SHI

摘要:

紫花苜蓿根瘤的形成发育及幼苗生长受到多重植物激素的调控。激素对外源根瘤菌的增殖和促生效应已有研究,但激素对内生根瘤菌的增殖及促生效应研究较少。因此,筛选出对根瘤菌SM12531f生长有促进作用的3-吲哚乙酸、6-苄氨基嘌呤和28-高油菜素内酯的浓度,然后用这3种浓度分别浸泡含有青色荧光蛋白标记的内生根瘤菌SM12531f的苜蓿种子并种植,分析外源激素对苜蓿植株组织中内生根瘤菌数量、植株结瘤及植株生长的影响。结果表明,3-吲哚乙酸、6-苄氨基嘌呤和28-高油菜素内酯这3种激素的最适浓度分别为14 mg·L-1、18 mg·L-1和2.97 mg·L-1。幼苗期对植株内生根瘤菌增殖、结瘤及生长有益的是6-苄氨基嘌呤和28-高油菜素内酯,且前者的促进效果更明显,前者内生根瘤菌在根部的定殖数量最多,在稀释100倍时定殖数量为1167 cfu·g-1、地上鲜重为1.99 g·株-1。同样在分枝期对植株有益的是6-苄氨基嘌呤,且内生根瘤菌在根部研磨液稀释100倍时定殖数量为833 cfu·g-1、地上鲜重为5.03 g·株-1。因此,对苜蓿内生根瘤菌增殖及苜蓿生长最适的激素是18 mg·L-1的6-苄氨基嘌呤,该发现对精准利用种子内生根瘤菌的结瘤固氮效应提供理论依据,为紫花苜蓿-根瘤菌共生育种奠定了基础。

关键词: 内生根瘤菌, 增殖, 促生, 生长素, 细胞分裂素, 油菜素内固醇

Abstract:

The formation, development, and seedling growth of alfalfa nodules are regulated by multiple plant hormones. The proliferation and growth promoting effects of hormones on exogenous rhizobia have been studied, but there is relatively little research on the proliferation and growth promoting effects of hormones on endogenous rhizobia. To address this knowledge gap, three concentrations of 3-indoleacetic acid (IAA), 6-benzylaminopurine (6-BA), and 28-homobrassinolide (HBR), which promote the growth of rhizobium SM12531f, were evaluated. Alfalfa seeds containing cyan fluorescent protein labeled endophytic rhizobia SM12531f were soaked in solutions of one of these three concentrations, and planted. The effects of the exogenous hormones on the number of endophytic rhizobia in alfalfa plant tissue, plant nodulation, and plant growth were analyzed. The results showed that the optimal concentrations for promotional activity of these three hormones were 14 mg·L-1 for IAA, 18 mg·L-1 for 6-BA, and 2.97 mg·L-1 for HBR. During the seedling stage, 6-BA and HBR were beneficial for the proliferation, nodulation, and growth of endophytic rhizobia in plants, and the former had a more significant growth promotion effect. The hormone 6-BA resulted in the highest number of endophytic rhizobia colonizing in the roots, with a colony density of 1167 cfu·g-1 at a dilution of 100 times and aboveground fresh weight of 1.99 g·plant-1. 6-BA was also beneficial to plants during the branching stage. The endophytic rhizobia formed 833 cfu·g-1 in plants with an aboveground fresh weight of 5.03 g·plant-1, when diluted 100 times in a ground root solution. Therefore, in these test conditions, the most suitable hormone for promoting proliferation and growth of alfalfa endophytic rhizobia was 6-BA at 18 mg·L-1 concentrration. These results provide a theoretical basis for the precise utilization of the nodulation nitrogen fixation effect of endophytic rhizobia in seeds, and lays a foundation for the symbiotic breeding of alfalfa rhizobia.

Key words: endophytic rhizobia, proliferation, promoting growth, auxin, cytokinin, brassinosteroid