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为探讨外来杂草反枝苋(Amaranthus retroflexus)在入侵农田生态系统过程中对氮素资源波动的适应规律及与作物的竞争机制,采用人工模拟不同氮素波动条件的方法,比较研究了反枝苋和大豆(Glycine max)体内氮素同化关键酶——硝酸还原酶活性的变化情况。结果表明,大豆和反枝苋不同器官的硝酸还原酶活性均能对环境中的氮素添加作出快速的响应,这可能与硝酸还原酶是一种诱导酶有关;大豆硝酸还原反应主要在叶和根部进行,而反枝苋则主要在茎和繁殖器官中进行;无论是大豆还是反枝苋,在单栽其各器官的硝酸还原酶活性均大于混栽,说明种间竞争作用要明显大于种内竞争,种间竞争会显著降低植物体内氮代谢的水平。
In order to explore the adaptive rules and the competitive mechanism of exotic resource Amaranthus retroflexus to cropland ecosystem during its invasion to farmland ecosystems, artificial fluctuating conditions of different nitrogen sources were studied. Changes of Nitrogen Assimilation Enzyme Activity, Nitrogen Assimilation Enzyme, in Amaranth and Glycine Max. The results showed that the nitrate reductase activity of different organs of soybean and Amaranthus retroflexus could respond rapidly to the nitrogen addition in the environment, which may be related to nitrate reductase as an inducible enzyme; Root and Amaranthus retroflexus were mainly in stems and reproductive organs; whether it is soybean or Amaranthus retroflexus, nitrate reductase activity in all organs of single planted were greater than the mixed planting, indicating that the interspecific competition was significantly greater than the species Internal competition, interspecific competition will significantly reduce the level of nitrogen metabolism in plants.