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草业学报 ›› 2024, Vol. 33 ›› Issue (3): 85-96.DOI: 10.11686/cyxb2023143

• 研究论文 • 上一篇    下一篇

连续间作下的紫花苜蓿/燕麦根系与碳氮代谢特性研究

汪雪(), 刘晓静(), 王静, 吴勇, 童长春   

  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,甘肃省草业工程实验室,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:2023-04-29 修回日期:2023-06-05 出版日期:2024-03-20 发布日期:2023-12-27
  • 通讯作者: 刘晓静
  • 作者简介:E-mail: liuxj@gsau.edu.cn
    汪雪(1997-),女,甘肃定西人,在读硕士。E-mail: 1512339114@qq.com
  • 基金资助:
    国家自然科学基金项目(32171674);甘肃省重点研发计划项目(20YF8NA130)

Root and carbon-nitrogen metabolism characteristics of alfalfa-oat mixed stands under continuous intercropping

Xue WANG(), Xiao-jing LIU(), Jing WANG, Yong WU, Chang-chun TONG   

  1. College of Pratacultural Science,Gansu Agricultural University,Key Laboratory of Pratacultural Ecosystem,Ministry of Education,Pratacultural Engineering Laboratory of Gansu Province,Sino-US Center for Grazingland Ecosystem Sustainability,Lanzhou 730070,China
  • Received:2023-04-29 Revised:2023-06-05 Online:2024-03-20 Published:2023-12-27
  • Contact: Xiao-jing LIU

摘要:

为探明豆/禾牧草连续间作下的根系生长特性、碳氮代谢特性及二者相互耦联机制的长期效应,通过田间框栽土培试验,以紫花苜蓿单作和燕麦单作为参照,对紫花苜蓿/燕麦间作种植后第2年、第3年(高产期)连续2年的根系特征、碳氮代谢特性及其相互协调关系开展研究。结果表明:燕麦的生物量表现为间作显著高于单作(P<0.05);燕麦的根表面积和根平均直径表现为间作显著高于单作(P<0.05);燕麦的蒸腾速率(Tr)、净光合速率(Pn)、气孔导度(Gs)、核酮糖-1,5-二磷酸羧化酶(RuBPCase)活性、4个氮代谢酶活性和碳水化合物积累量表现为间作显著高于单作(P<0.05),而紫花苜蓿与燕麦表现相反。通过相关性分析发现,生物量与光合气体交换参数、氮代谢酶活性、根系特性呈正相关;根表面积、根平均直径与TrPnGs、硝酸还原酶(NR)活性、氮积累量、蛋白总量呈显著正相关(P<0.05);根体积、根表面积、根平均直径与亚硝酸还原酶(NiR)活性、谷氨酸合酶(GOGAT)活性呈极显著正相关(P<0.01)。由此可知,紫花苜蓿与燕麦间作更有利于燕麦优化其根系形态,同时也会显著提高燕麦净光合速率和蒸腾速率,增强燕麦RuBPCase、NR和谷氨酰胺合成酶(GS)等碳、氮代谢酶活性,进而促进其体内碳水化合物及蛋白质积累以改善燕麦生物量和品质,连续间作减弱了系统内燕麦对紫花苜蓿根表面积和根体积的抑制,拓展了紫花苜蓿总根长,但整体而言,间作抑制了紫花苜蓿根系生长和碳、氮代谢水平,不利于其代谢产物及生物量的积累;且总根长、根表面积和根体积对碳、氮代谢起显著促进作用,紫花苜蓿/燕麦间作体系内根系及碳、氮代谢的协调一致可有效提高体系内生物量和蛋白总量。

关键词: 紫花苜蓿, 燕麦, 连续间作, 根系特性, 碳氮代谢特性

Abstract:

This research investigated the root growth characteristics, carbon and nitrogen metabolism characteristics, and the long-term effects of their coupling mechanisms under continuous leguminous-gramineous forage intercropping. A field frame planting, soil culture experiment was conducted to study the root characteristics, carbon and nitrogen metabolism characteristics, and their mutual co-ordination of alfalfa (Medicago sativa)-oat (Avena sativa) intercropping for two consecutive years after planting. Alfalfa monoculture and oat monoculture crops were used as a reference. It was found that the biomass of intercropped oats was significantly higher than monoculture oats (P<0.05). The root surface area and root average diameter of intercropped oats were significantly higher than monoculture oats (P<0.05). The transpiration rate (Tr), net photosynthetic ratePn), stomatal conductance (Gs), ribulose-1,5-bisphosphate carboxylase (RuBPCase) activity, the activities of four nitrogen metabolism enzymes, and carbohydrate accumulation of intercropped oats were significantly higher than monoculture oats (P<0.05), while alfalfa showed an opposite trend. Correlation analysis found that the biomass was positively correlated with photosynthetic gas exchange parameters, nitrogen metabolism enzyme activities and root characteristics. Root surface area and root average diameter were significantly positively correlated with TrPnGs, nitrate reductase (NR) activity, nitrogen accumulation, and total protein content (P<0.05). Root volume, root surface area, and root average diameter were highly significantly positively correlated with nitrate reductase activity and glutamate synthase activity (P<0.01). Thus, the intercropping of alfalfa and oat is more conducive to optimizing the root morphology of oat, while also significantly increasing the net photosynthetic rate and transpiration rate of oat, enhancing the activities of carbon and nitrogen metabolism enzymes such as RuBPCase, NR, and glutamine synthetase in oat, thereby promoting the accumulation of carbohydrate and protein to improve oat biomass and quality. Continuous intercropping weakened the inhibition of root surface area and root volume of alfalfa within the system, and expanded the total root length of alfalfa, but overall, intercropping inhibited root growth and carbon-nitrogen metabolism, which was not conducive to the accumulation of its metabolites and biomass. Moreover, total root length, root surface area, and root volume significantly promote carbon-nitrogen metabolism, the improvement of root system and carbon-nitrogen metabolism in the alfalfa/oat intercropping system effectively increased the biomass and total protein content in the system.

Key words: alfalfa, oat, continuous intercropping, root characteristics, carbon and nitrogen metabolism characteristics