禾本科植物联合固氮研究及其应用现状展望

Recent advances in research and application of associated nitrogen-fixation with graminaceous plants

综述了近年来从禾本科植物体内和根际发现的内生固氮菌和根际固氮菌的种类、特征及对宿主的促生机理 ,以及固氮菌接种剂在农业生产中的应用现状和存在的问题 ,指出影响联合固氮菌接种效果的主要因素有土著微生物的竞争 ;植物基因型差异和环境条件的变化 ,如结合态氮 (氨、亚硝酸盐、硝酸盐等 )对固氮酶的合成阻遏和较高的氧分压对联合固氮菌的固氮效率影响 .提出了发掘和利用禾本科植物的生物固氮潜力的努力方向 :从自然界分离筛选获得广谱高效固氮菌株 ;应用基因工程构建耐铵、泌铵型联合固氮菌 ;诱导禾本科植物形成固氮根瘤 ;充分发挥植物内生固氮菌的优势 .

The category, characteristic of diazotrophs isolated from inside and/or rhizosphere of graminaceous plants in recent year and the mechanism of the promoting effects on their host plant were reviewed in this paper. The current status of application of associative nitrogen-fixation inoculants and the problems in inoculation were discussed. It was indicated that the main factors influencing the effects of inoculants include the competition of indigenous micro-organism with inoculants for nutritions and energy, difference of host plant genotypes in associative relationship, and variance of environmental conditions such as the concentration of ammonium in soil solution and the oxygen partial pressure in soil air. The trends of future research in this field were prospected, for example, to isolate and identify the high nitrogen fixing efficiency strains with wider environmental adaptability, to create associative nitrogen fixing bacteria strain which is able to bear or endure higher concentration of ammonium by gene engineering technique, to induce graminaceous plant forming root nodule for nitrogen fixation and to exert the predominance of endophytic diazotrophs.