Rotation benefit and population changes of soil hydrogen oxidizing bacteria in legume crop fields

豆科作物田土壤氧化细菌轮作效益及种群变化

• 批准号: 218055-2006
• 负责人: Dong, Zhongmin
• 金额: $ 1.41万
• 依托单位: Saint Mary's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2006
• 资助国家: 加拿大
• 起止时间: 2006-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=330998
• 关键词: Rotation; benefit; population; changes; soil

Root nodules of legumes (e.g. soybeans, alfalfa, etc.) have intracellular bacteria that can fix nitrogen gas into a form of nitrogen that the plant can use to make protein and nuclei acids. Hydrogen gas is a byproduct of the nitrogen fixing enzyme, nitrogenase, claiming about 33% of the energy that flows to the enzyme (the other 67% is used to reduce nitrogen gas). Legume nodules produce a large quantity of hydrogen gas, and release this into soils. For example, in Canadian alfalfa crop alone, we have estimated that there may be as much as 2.4 thousand million liters of hydrogen gas released to Canadian agricultural soils every year. If other legume crops are considered, the national hydrogen gas production rate may be twice as high. This hydrogen gas production can use up to 6% of the net daily gain of photosynthetically derived energy of the entire plant. We do not understand why evolutionary processes, plant breeding of agricultural crops, or selection of optimal nitrogen fixing bacteria has not reduced this energy loss in all legumes. Legumes are ideal crops to use in rotation with other crops (especially cereal crops), resulting in a significant increase in the growth and yield of the subsequent crop. Researchers have not been able to determine the basis for this yield enhancement. Only about 25% of the increase in the growth of the non-legume crop can be attributed to improved nitrogen nutrition. The remaining 75% of the effect have eluded explanation. We are proposing that the hydrogen released by nodules stimulates and support growth of certain soil hydrogen oxidizing bacteria.  These bacteria in return promote plant growth.  This hydrogen fertilization of soils may account for the beneficial effects of legumes on non-legume growth. The purposes of this study are to 1) analyze the soil bacterial community structure changes adjacent to nodules, 2) identify and characterize the hydrogen oxidizing bacteria in soil, 3) understanding the relationship between the hydrogen oxidizing bacteria in soils and soil fertility. The long-term goal of my research is to understand the relationship between the plant roots and soil microorganisms, especially the ones promoting the non-legume crop plants, to provide the practical protocols or inoculants for agriculture.

豆科植物（如大豆、苜蓿等）的根瘤有胞内细菌，可以将氮气固定成一种植物可以用来制造蛋白质和核酸的氮。氢气是固氮酶（即氮酶）的副产品，约占流向固氮酶的能量的33%（另外67%用于减少氮气）。豆科根瘤产生大量氢气，并将其释放到土壤中。例如，仅在加拿大的苜蓿作物中，我们估计每年可能有多达240亿升的氢气释放到加拿大的农业土壤中。如果考虑到其他豆科作物，全国氢气产量可能会高出一倍。这种氢气生产可以使用整个植物光合作用衍生能量的净日增益的6%。我们不明白为什么进化过程、农作物的植物育种或最佳固氮细菌的选择没有减少所有豆科植物的能量损失。豆类是与其他作物（特别是谷类作物）轮作的理想作物，可显著提高后续作物的生长和产量。研究人员还不能确定这种增产的基础。在非豆科作物的生长增长中，只有约25%可归因于氮营养的改善。其余75%的影响无法解释。我们提出根瘤释放的氢刺激和支持某些土壤氧化氢细菌的生长。这些细菌反过来促进植物生长。这种土壤的氢施肥可能解释了豆科植物对非豆科植物生长的有益影响。本研究的目的是：1)分析根瘤附近土壤细菌群落结构变化；2)鉴定和表征土壤氧化氢细菌；3)了解土壤氧化氢细菌与土壤肥力的关系。我的长期研究目标是了解植物根系与土壤微生物的关系，特别是对非豆科作物植物的促进作用，为农业提供实用的方案或接种剂。