摘要:氮是限制农业生产的最重要因素之一。随着人工固氮技术的发展, 氮肥的施用在提高作物产量、解决人类温饱问题的同时, 导致了土壤板结、酸化、氮素流失及温室气体排放(N2O)等环境问题。与人工合成氨相比, 生物固氮是一种绿色经济的固氮方式, 其包括共生固氮和非共生(自生固氮及联合固氮)固氮, 且每年固定的氮可占总固定量的50%以上。与共生固氮相比, 非共生固氮存在范围广, 如甘蔗、水稻、玉米和小麦等禾本科作物均能进行非共生固氮(联合固氮)。本文主要从禾本科植物的联合固氮菌种类及其作用机理、固氮活性及调控方式以及联合固氮菌的资源及应用3个方面进行综述, 发现相比较共生固氮而言, 联合固氮菌易受到土著微生物、氮素水平等环境因素影响, 其研究难度更大, 需要筛选纯化更多的联合固氮菌, 为其固氮机制研究提供良好材料; 氮、磷、钼、铁等肥料的适量添加可有效促进固氮菌的固氮效率; 固氮菌不仅可以提高土壤固氮量, 而且有利于植物根系激素调节, 从而增加植物抗病抗逆能力, 促进植物更健康的生长。本文最后对禾本科植物联合固氮的农艺管理措施及固氮菌剂的实际应用方面做了展望, 以期为提高禾本科植物联合固氮效率及推动生物固氮菌在农业生产中的应用提供理论依据。
关键词:禾本科植物/
联合固氮/
固氮菌种类/
固氮活性/
固氮菌应用
Abstract:Nitrogen is one of the most important factors restricting agricultural production. With the development of artificial nitrogen fixation technology, the application of nitrogen fertilizers can increase crop yields and solve problems related to the fulfilment of the basic human needs of food and clothing. However, it has also caused environmental problems, such as soil compaction, acidification, nitrogen loss, and greenhouse gas emissions (e.g., nitrous oxide, N2O). Compared with synthetic ammonia, biological nitrogen fixation is a green and economical nitrogen fixation method, which entails symbiotic nitrogen fixation and non-symbiotic nitrogen fixation (autogenous nitrogen fixation and combined nitrogen fixation, respectively). Annually, biologically fixed nitrogen can account for more than 50% of the total fixed amount. Compared with symbiotic nitrogen fixation, non-symbiotic nitrogen fixation exists in many plants, for example, sugarcane, rice, maize, wheat, and other gramineous crops that carry out non-symbiotic nitrogen fixation (combined nitrogen fixation). This article reviewed the species of combined nitrogen-fixing bacteria in gramineous plants and their mechanism of action and nitrogen-fixing activity and regulation methods, as well as the resources and applications of these combined nitrogen-fixing bacteria. Compared with symbiotic nitrogen fixation, combined nitrogen-fixing bacteria are more vulnerable to indigenous microorganisms. Research on combined nitrogen-fixing bacteria is more difficult owing to the influence of environmental factors, such as nitrogen levels. It is necessary to screen and purify more combined nitrogen-fixing bacteria to provide optimum materials for research into the nitrogen fixation mechanism. Appropriate levels of nitrogen, phosphorus, molybdenum, iron, and other fertilizers can promote the nitrogen fixation efficiency of bacteria. Nitrogen-fixing bacteria not only increase the extent of soil nitrogen fixation but also facilitate the regulation of plant root hormones, thereby increasing plant disease resistance and stress resistance, promoting healthier plant growth. Finally, agronomic management measures for combined nitrogen fixation through gramineous plants and the practical application of the nitrogen-fixing bacteria are proposed to provide a theoretical basis for improving the efficiency of combined nitrogen fixation through gramineous plants and to promote the application of the nitrogen-fixing bacteria in agricultural production.
Key words:Gramineae/
Combined nitrogen fixation/
Species of nitrogen-fixing bacteria/
Nitrogen fixation activity/
Application of nitrogen-fixing bacteria
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