固氮蓝藻的农业应用研究进展

作为可固氮固碳的自养光合微生物,固氮蓝藻是一种非常重要的微生物资源。关于固氮蓝藻在农业生产上的应用始于1939年印度首次报道用固氮蓝藻肥田,之后一段时期虽然受到国际广泛关注,但最终并未实现规模化推广应用。究其原因既与化肥在世界范围内的大规模使用有关,也与自身技术相对复杂、成本高和可靠性低有关。对于前者虽然化肥的农业增产作用巨大,但其对农业自身和生态环境的负面影响日益凸显。而对于后者,新的固氮蓝藻规模化生产技术和新的接种技术的发展正在逐步消除这些缺陷。在当前国家要求农业"减量化"和"低碳化"发展的背景下,固氮蓝藻作为生态环保的生物肥料可能迎来新的发展契机。同时,除了作为生物肥料,近年来国内外的研究表明固氮蓝藻具有多重农业应用价值,可能在作物生长调节剂和生物农药开发、农业环境污染防治和农业生态环境保护等方面发挥作用。因此,本文就国内外近5年(2013—2017年)关于固氮蓝藻的农业应用进展进行了全面综述,并就存在的问题和今后的发展方向做了展望。今后固氮蓝藻作物生长调节方面需深入研究藻激素的代谢和调控机制,藻接种技术方面需深入研究生物膜中藻类和其他微生物的互作关系,抗病虫害方面需要进行更多的田间试验以评估其实际应用效果并阐明抗性机制,降解有机农药方面需深入研究降解关键酶、降解途径和大田应用技术,生态环境保护方面需评估固氮蓝藻抗旱抗盐碱实际应用效果并阐明其机理。

Research progress in agricultural application of nitrogen-fixing cyanobacteria

As autotrophic photosynthetic micro-organisms with the ability to fix nitrogen and carbon into the soil, nitrogen-fixing cyanobacteria belong to an important microbial resource. The first report on their application in agriculture came from India in 1939. Although it subsequently had global attention, large-scale popularization and application of nitrogen-fixing cyanobacteria were not implemented in the end. The reasons were related to the wholesome use of chemical fertilizers in the world and the immature application technology of nitrogen-fixing cyanobacteria with high complexity, high cost and low reliability. For the former, although chemical fertilizers promoted crop production dramatically, its negative effects on agriculture and the eco-environment were already a growing concern in the public thinking. For the latter, with the development of new technologies in large-scale production and inoculation of nitrogen-fixing cyanobacteria, these defects were gradually eliminated. In the big background of current national policy advocating for "reduction" and "low carbon" development in agriculture, the application of nitrogen-fixing cyanobacteria (as green bio-fertilizer) has ushered in a new development opportunity for future application. In addition to bio-fertilizers in agriculture, studies in recent years have shown that nitrogen-fixing cyanobacteria were used in crop growth regulation, bio-pesticide development, agricultural pollution control and agro-ecological protection. This paper reviewed the progress in studies on agricultural application of nitrogen-fixing cyanobacteria in the past five years (2013-2017) at national and international scales. Moreover, the existing problems and future development directions were discussed. It was hoped that the review provided a summary reference for the development of this field in China. In recent years, there have been new ideas and considerable progresses in the application of nitrogen-fixing cyanobacteria in crop growth regulation, bio-fertilizer production and application, pest control, agricultural pollution treatment and agro-ecological protection. However, there were still problems in this field. Before large-scale application, these problems needed to be solved through further re-search. This included research on algal hormone metabolism and regulation mechanism, metabolic interaction of micro-organisms in biofilm, field evaluation of the degree of crop protection, protection mechanism, pathways and key enzymes of pesticides degradation, field-applied technologies, and effects and mechanism of drought and salt resistance.