水稻不同层次根量与活性的关系及其对氮素吸收的影响

在大田栽培条件下,于结实期对水稻不同层次根量、根的呼吸强度及氮素吸收量等进行了研究。结果表明:(1) 水稻品种间根量差异很大,但主要由上层根量不同所造成。(2) 根量与根的平均呼吸强度、上层根量与下层根呼吸强度均呈线性负相关,相关系数分别为-0.8687、-0.9171。(3) 上层根呼吸强度与下层根呼吸强度呈极显著线性正相关,品种间表现一致。(4) 结实期氮素吸收量与上层根量、下层根呼吸强度关系密切(R_(y.12)=+0.9899)。前者的影响力比后者大。由此认为,增加上层根量是提高水稻结实期氮素吸收量的重要途径之一。

Relationship Between the Root Weight and the Root Activity of Different Soil Layers and Their Influence on N Absorption

By using 4 different rice vareties under 2 water management treatments-draining and control, the root weight and the respiratory intensity of root in different soil layers, the dry weight of each aerial past and the N content in each plant organ were measured at the panicls primordium initiation stage and at an interval of 7 days after the heading respectively. The results were summarized as follows: 1. The root weight varied to a considerable extent with rice varieties and the difference was significant at 1% possibility level. However, itdiffered mainly in the weight of the upper layer root. 2. At the maturing stage, there existed a negative correlation between the root weight of the individual plant and the average root respiratory intensity, and the weight of the upper layer root reversely correlated with the respiratory intensity of the lower layer root with both correlation coefficents at 1%possibility level. 3. The activity of the upper root was positively correlated to the activity of the lower root while no considerabie differ ence between them was observed at maturing, and in this aspect, all the 4 rice varieties showed no difference. 4. At the maturing stage, the amount of N absorbed by the plant was primarily affected by the activity of the upper and the lower root, and path-coefficient analysis found that it was more affected by the former than the latter. Therefore it may be one of important ways to raise the amount of N absorption at maturing by increasing the upper root weight.