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草业学报 ›› 2025, Vol. 34 ›› Issue (10): 132-150.DOI: 10.11686/cyxb2025030

• 研究论文 • 上一篇    

中华根瘤菌株QL2与不同紫花苜蓿品种共生效应的差异

韩宜霖(), 康文娟(), 师尚礼(), 杜媛媛, 何富强, 汪艳, 侯文璐, 谢西琳   

  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,甘肃 兰州 730070
  • 收稿日期:2025-02-01 修回日期:2025-02-20 出版日期:2025-10-20 发布日期:2025-07-11
  • 通讯作者: 康文娟,师尚礼
  • 作者简介:shishangli@gsau.edu.cn
    E-mail: kangwj@gsau.edu.cn
    韩宜霖(2000-),女,甘肃张掖人,在读硕士。E-mail: hanyl@st.gsau.edu.cn
  • 基金资助:
    中国农业大学对口支援科研联合基金(GSAU-DKZY-2024-002)

Studies of the difference in symbiotic interaction between Sinorhizobium meliloti strain QL2 and different alfalfa varieties

Yi-lin HAN(), Wen-juan KANG(), Shang-li SHI(), Yuan-yuan DU, Fu-qiang HE, Yan WANG, Wen-lu HOU, Xi-lin XIE   

  1. Pratacultural College,Gansu Agricultural University,Key Laboratory of Grassland Ecosystem of Ministry of Education,Lanzhou 730070,China
  • Received:2025-02-01 Revised:2025-02-20 Online:2025-10-20 Published:2025-07-11
  • Contact: Wen-juan KANG,Shang-li SHI

摘要:

为明确中华根瘤菌株QL2共生不同紫花苜蓿品种的固氮效应差异特征,提高紫花苜蓿的结瘤固氮能力和天然氮素利用效率。以中华根瘤菌QL2和8个紫花苜蓿 [3个国外引进品种(WL168HQ、WL298HQ和WL319HQ)、我国3个育成品种(甘农3号、甘农5号和甘农9号)及2个地方品种(清水苜蓿和陇中苜蓿)]为材料,通过结瘤、固氮、饲草生物量和营养品质等指标,研究接种QL2后在共生、固氮和促生效应等方面的差异特征。结果表明:接种根瘤菌QL2后,我国育成型紫花苜蓿品种的有效根瘤单颗重、根瘤直径以及根瘤组织被侵染细胞数目均显著优于地方品种和国外引进品种70%以上。固氮效应方面,国外引进品种固氮率(52.62%~63.49%)和我国育成品种的固氮率(53.30%~62.41%),均显著高于地方品种(43.05%~46.72%)。层次分割分析表明结瘤因子(根瘤组织被侵染细胞数目、单株有效根瘤数、单颗有效根瘤重和根瘤直径)和固氮因子(固氮酶活性、固氮率和固氮量)对地上干重具有63%的解释率,其中固氮因子的贡献率达89.56%,结瘤因子的贡献率仅占13.55%。相关性分析表明接种根瘤菌QL2后,不同类型品种固氮率均与地上干重显著正相关,即国外引进品种整体的地上干重增长率最大,最高达48.08%,其次为我国育成型和地方型品种。固氮率也与饲草营养品质的产量显著正相关,接种根瘤菌可普遍提高紫花苜蓿粗蛋白产量,最高增长率达51.08%(P<0.05),降低中性洗涤纤维和酸性洗涤纤维产量,最高分别降低40.55%和53.96%,可使饲草等级跃升1~2个等级。因此,固氮率对地上干重和饲草营养品质均会产生显著的积极影响,说明其在紫花苜蓿的产量提升和营养品质改善方面发挥着更为关键的作用,本研究结果为精准调控豆科植物-根瘤菌组合的固氮效应以及优化紫花苜蓿饲草品质提供了重要依据。

关键词: 紫花苜蓿, 根瘤菌, 固氮率, 苜蓿品种效应, 饲草品质

Abstract:

Inocculum of Sinorhizobium meliloti strain QL2 was applied to plants of eight alfalfa varieties (three imported varieties: WL168HQ, WL298HQ, and WL319HQ; three domestically bred varieties: Gannong No. 3, Gannong No. 5, and Gannong No. 9; and two local varieties: Qingshui and Longzhong) to clarify the differences in nitrogen fixation effects, with a view to improving the nodule formation and nitrogen fixation capacity of alfalfa and the efficiency of natural nitrogen utilization. Indicators such as nodule formation, nitrogen fixation, forage biomass, and nutritional quality were evaluated to study the differences in symbiosis, nitrogen fixation, and growth-promoting effects after inoculation with S. meliloti QL2. Results demonstrated that in domestically bred varieties, inoculating with S. meliloti QL2 significantly increased the weight of individual root nodules, as well as the root nodule diameter and the number of infected cells in the root nodules of by over 70% compared to both local and imported varieties. Regarding nitrogen fixation efficiency, the imported varieties (52.62% to 63.49%) and domestically bred varieties (53.30% to 62.41%) exhibited significantly higher fixation rates compared to local varieties (43.05% to 46.72%). Hierarchical segmentation analysis showed that nodulation factors (the number of infected cells in the root nodules, the number of effective root nodules per plant, the single effective root nodule weight and root nodule diameter) and nitrogen fixation factors (nitrogenase activity, nitrogen fixation percentage and nitrogen fixation amount) explained 63% of the variation in the above-ground dry weight. Of the explained variation, 89.56% was contributed by nitrogen fixation factors, and only 13.55% by nodulation factors. A correlation analysis revealed that after inoculation with S. meliloti QL2, the nitrogen fixation percentage of different categories of variety was significantly positively correlated with above-ground dry weight. That is, the growth rate (as reflected by above-ground dry weight) of imported varieties was the largest compared with CK, of which WL319HQ-QL2 had the highest growth rate of 48.08 %, followed by domestic bred varieties and local varieties. The nitrogen fixation percentage was also significantly positively correlated with the forage nutritional quality. Inoculation with rhizobia generally increased the crude protein yield of alfalfa with the highest increase being 51.08% (P<0.05), while reducing the yields of neutral detergent fiber and acid detergent fiber by 40.55% and 53.96%, respectively. These changes in nutritional composition resulted in an elevation of the forage quality score by 1 to 2 grades. In summary, a high nitrogen fixation rate has a significant positive impact on both above-ground dry weight and forage nutritional quality, meaning that it plays the critical role in improving the yield and nutritional quality of alfalfa. This study lays a foundation for development of materials to optimize nitrogen fixation efficiency in legume-rhizobia symbioses and improve alfalfa forage quality.

Key words: alfalfa, rhizobia, nitrogen fixation percentage, alfalfa variety effect, forage quality