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大气中含有非常丰富的氮,高达80%。如何充分发挥根瘤的固氮作用,是很重要的。根瘤菌是土壤中的一种细菌,它们依靠土壤中腐烂的植物根、茎、叶等生活,它在土壤中不能固氮,只当进入适合的豆科植物的根部并成为类苗体后,才具有固氮本领。根瘤菌的特性(一)感染性:根瘤菌进入豆科植物根内,经生长繁殖形成根瘤。长成的根瘤可分为四个区,即分生区、皮层区、中央菌区和维管束区。固氮作用主要发生在中央菌区。据研究,根瘤菌所固定的氮素,除少部分用来建造自身外,大部分供给共生植物和分泌到土壤中去。以氨基酸形式分泌到土壤中的氮素,约占总固定量的一半,这就是种植豆科植物能肥田的道理。
The atmosphere contains very rich nitrogen, up to 80%. How to give full play to the role of nitrogen fixation of nodules is very important. Rhizobium is a kind of bacteria in the soil. They depend on the decaying roots, stems and leaves of the soil. They can not fix nitrogen in the soil. Only when they enter the root of suitable legume and become the seedling body, With nitrogen fixation skills. Rhizobium characteristics (A) Infectious: Rhizobium into the legume roots, the growth and reproduction of nodules. Growing nodules can be divided into four areas, namely meristematic area, cortical area, central bacteria area and vascular bundle area. Nitrogen fixation occurs mainly in the Central Bacteria area. According to the research, rhizobium immobilized nitrogen, except for a small part to build itself, most of the supply of symbiotic plants and secretion to the soil. Nitrogen, which is secreted into the soil as amino acids, accounts for about half of the total fixed amount, which is why it is possible to grow legumes.