水稻根际含氧量对根系生长的影响

以多个水稻品种为材料, 采用营养液培养试验, 通过气泵增加水稻根际的含氧量, 研究水稻根际含氧量与根系生长的关系。结果表明, 在水稻生长过程中, 抽穗期根系吸收氧气的能力最强, 需氧量最大。根际含氧量对水稻根系形态与分布有影响, 增氧显著增加根长, 提高根系自根基到根尖10~20 cm、＞20 cm部分所占的生物量比例, 同时减少根数; 而在缺氧环境下生长的水稻根数增多, 根长缩短。氧溶量对水稻根系活力的影响存在品种间差异, 提高水稻根际的氧溶量, 杂交稻汕优63和国稻1号齐穗期根系的活跃吸收面积和根系活力显著增加; 根系活力较高的常规籼稻湘早籼11和甬粳18在充氧处理中的根系活力也明显提高, 但根际氧含量的增加对根系活力较低的水稻品种湘早籼24和春江06的根系活力并无明显作用; 缺氧环境下生长的水稻根系的活力降低。

Influence of Rhizosphere Oxygen Concentration on Rice Root Growth

The growth of rice root needs oxygen, which is consumed in root respiration and contained in soil also influencing the ecological environment of rhizosphere. Although rice plant can transport atmospheric oxygen from its shoot through its continuous aerenchymatous system to its roots, rice can not grow well in submerged, anoxic soil; there exists affinitive relation between the aeration condition of soil and the growth of rice plant. In this study, various rice cultivars were cultivated in hydropotic to study the influence of rhizosphere oxygen concentration enhanced by aeration on rice root growth. The results showed that aeration significantly increased the oxygen concentration of hydroponic solution during the whole plant growth stage. Rice plant had the highest oxygen absorption ability at heading stage, compared to the no rice planting treatment, the oxygen concentration at this stage was decreased 73.62% for Guodao 1 and 68.50% for Shanyou 63, and the decrease extent was more than that at booting stage and grain filling stage. Compared to control, length of single root, length of the longest root of rice planted in higher oxygen concentration solution were longer, the dry weight percent of rice root ranging from 10 to 20 cm and longer than 20 cm from root base to tip increased accordingly, and the number of roots per plant was less. While in the treatment with anoxic condition, the number of rice root increased and the length decreased. Genotype difference existed in the influence of rhizosphere oxygen con-centration on root vitality. Under aeration condition, the root active absorption area per plant and root vitality of hybrid rice Guo-dao 1 and Shanyou 63 increased significantly at full heading stage; the root vitality of conventional rice genotype Xiangzaoxian 11 and Yongjing 18 which had high root vitality also increased significantly, while the root vitality changed little in low root vital-ity genotype Xiangzaoxian 24 and Chunjiang 06. When rice growed in anoxic condition, root vitality decreased.