【摘要】 光照强度直接影响大豆-根瘤菌共生固氮体系的光合产物运向根瘤的数量和根瘤菌固氮作用的能源供应。减弱光照,就降低大豆的结瘤率和根瘤的固氮活性。光照强度从2.6万Lux降至2万Lux,根瘤固氮活性的降低率很小;从2万Lux下降至1万Lux时,降低率逐渐增大;从1万Lux下降至0.2万Lux,根瘤固氮活性直线下降。光照强度在1万和0.2万Lux时,根瘤固氮活性分别为光照2万Lux时的87％和30％左右。大豆盛花期是根瘤固氮活性最高时期,减弱光照,根瘤固氮活性的下降率增加。大豆与禾谷类作物间作,要为保证大豆健壮生长所需适宜的光照强度而规定作物间的行距和株距。更多还原

【Abstract】 Light intensity directly influenced the rate of photosynthesis and the amount of photosynthetic products transported to the root nodule used as energy source of nitrogen fixation of. rhizobium-soybean symbiotic system. When the intensity of normal daily light was reduced, the rate of nodulation and the nitrogen-fixing activity of the nodules were decreased Experiments conducted by exposing the plants with normal nodulation in different light intensities decreasing from 26,000 Lx to 1,000 Lx, the curve of decreasing rate of nitrogen fixation showed gentle decrease in the range of high light intensities and sharply decrease in the range of low intensities. The rate of nitrogen fixing activiiy of nodules in light intensities of 10,000 Lx and 1,000 Lx were 87% and 30% respectively of that in the light intensity of 20, O00Lx.In the flowering period, when the nitrogen fixation in the nodules reached an optimum stage,a slight reduction of normal illumination intensity on the plants would cause a profound decreasing effect on nitrogen fixation of nodules. Suitable distances of rows and individual plants should be kept in mixed cropping of soybean with corn or sorghum in order to have soybean plants growing under favorable illuminating condition.更多还原