NODULATION AND NITROGEN-FIXATION IN EXTREME ENVIRONMENTS
NODULATION AND NITROGEN-FIXATION IN EXTREME ENVIRONMENTS
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DOI：
10.1007/bf02183092
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发表时间：
1994-04-01
期刊：
影响因子：
4.9
通讯作者：
PREVOST, D
中科院分区：
文献类型：
--
作者：
BORDELEAU, LM;PREVOST, D
生物固氮是所有已知生态系统中都存在的现象。共生固氮取决于宿主植物基因型、根瘤菌菌株以及这些共生体与土壤气候因素和环境条件的相互作用。极端 pH 值会减少根瘤菌在土壤和豆科植物根际的定植，从而影响结瘤。高酸性土壤（pH 8.0）往往富含氯化钠、碳酸氢盐和硼酸盐，并且通常与高盐度相关，从而降低固氮作用。在较宽的温度范围内观察到结瘤和固氮作用，最佳温度为 20-30 摄氏度。升高的温度可能会延迟根瘤的萌生和发育，并干扰温带豆科植物的根瘤结构和功能，而在热带豆科植物中，固氮效率主要受到影响。此外，温度变化影响根瘤菌菌株的竞争能力。低温减少了温带豆科植物的根瘤形成和固氮作用；然而，在北极高纬度的极端环境中，本土豆科植物结瘤和固氮的速度与温带气候下豆科植物观察到的速度相当，这表明植物及其根瘤菌都已成功适应北极条件。除了低温之外，北极豆科植物还面临生长季节短、光周期长、降水量少和土壤氮含量低的问题。在这篇综述中，我们提出了许多结构和生理特征的结果，这些特征使北极豆科植物能够在极端环境中发挥作用。
Biological nitrogen fixation is a phenomenon occurring in all known ecosystems. Symbiotic nitrogen fixation is dependent on the host plant genotype, the Rhizobium strain, and the interaction of these symbionts with the pedoclimatic factors and the environmental conditions. Extremes of pH affect nodulation by reducing the colonization of soil and the legume rhizosphere by rhizobia. Highly acidic soils (pH 8.0) tend to be high in sodium chloride, bicarbonate, and berate, and are often associated with high salinity which reduce nitrogen fixation. Nodulation and N-fixation are observed under a wide range of temperatures with optima between 20-30 degrees C. Elevated temperatures may delay nodule initiation and development, and interfere with nodule structure and functioning in temperate Iegumes, whereas in tropical legumes nitrogen fixation efficiency is mainly affected. Furthermore, temperature changes affect the competitive ability of Rhizobium strains. Low temperatures reduce nodule formation and nitrogen fixation in temperate legumes; however, in the extreme environment of the high arctic, native legumes can nodulate and fix nitrogen at rates comparable to those observed with legumes in temperate climates, indicating that both the plants and their rhizobia have successfully adapted to arctic conditions. In addition to low temperatures, arctic legumes are exposed to a short growing season, a long photoperiod, low precipitation and low soil nitrogen levels. In this review, we present results on a number of structural and physiological characteristics which allow arctic legumes to function in extreme environments.