节水抗旱稻旱优113号的根系生长对土壤水分亏缺的响应

Root Growth Responses to Soil Water Deficit for a Water-Saving and Drought-Resistant Rice Genotype Hanyou113

【目的】揭示土壤水分亏缺条件下节水抗旱稻根系的形态和生理指标的变化规律,阐明其节水抗旱的特异性生理基础。【方法】2015和2016年利用盆栽试验,以节水抗旱稻旱优113号(HY113)和高产水稻扬两优6号(YLY6)为试验材料,通过设置淹灌(对照)和干旱(土壤水势-38 k Pa左右)处理,研究干旱对节水抗旱稻与高产水稻根系形态结构和生理指标的影响及其与地上部生物量积累的关系。【结果】与淹灌相比,干旱处理显著降低了两个水稻品种的地上、地下干物质积累量,同时显著降低了节水抗旱稻HY113的根冠比(由0.18降为0.12),高产水稻YLY6的根冠比无显著变化。干旱处理下,两个品种的水稻根系活力均显著增加,但HY113的增加幅度显著高于YLY6,乳熟期HY113在2015和2016两年的平均增幅为38.7%,而YLY6为22.8%,其中2015年乳熟期HY113的根系活力从86μg·g^(-1)·h^(-1)增加至174μg·g^(-1)·h^(-1)。干旱处理下,HY113和YLY6的根系吸收面积均显著减小,但HY113的减小幅度显著低于YLY6。与高产水稻YLY6相比,节水抗旱稻HY113的根数、根体积和根干重均较少,总干物质积累量较少,但其根系活力和根系有效吸收面积较大。【结论】节水抗旱稻HY113具有根量少,但根系吸收效率高的特点,其在缺水条件下能维持较高的根系活力和根系吸收面积;在遭遇水分亏缺时HY113可通过减小根冠比,使得更多的干物质留在地上部分以保证籽粒产量。

【Objective】The objective of this paper is to reveal root morphological and physiological changing characteristics of water-saving and drought-resistant rice under soil water deficit condition, and to illuminate its specific physiological basis of water-saving and drought-resistance. 【Method】Pot experiments were conducted in 2015 and 2016, and one water-saving and drought-resistant rice genotype（HY113） and one high-yielding rice genotype（YLY6） were used under two water treatments, including flooding irrigation and drought treatment. The drought effects on root morphological and physiological traits of the two rice genotypes and their relationship with aboveground biomass accumulation were studied.【Result】Compared with flooding irrigation, drought stress significantly reduced the dry matter accumulation of the two rice genotypes, and the root-shoot ratio of HY113 was also decreased significantly（from 0.18 to 0.12）, while the root-shoot ratio of YLY6 was not changed. Under drought stress, the root activity of the two rice genotypes both increased significantly. In 2015 and 2016, the average increase percentage of HY113 was 38.7% at milky stage, while that of YLY6 was 22.8%, and the root activity of HY113 increased from 86 μg·g^（-1）·h^（-1） to 174 μg·g^（-1）·h^（-1） at milky stage in 2015. Drought treatment also significantly reduced the root absorption area of both two genotypes, but the reduction percentage of HY113 was significantly lower than that of YLY6. Compared with high-yielding rice YLY6, HY113 had smaller root number, root volume and root dry weight, and the total dry matter accumulation was also significantly lower, but its root activity and root absorption area were greater. 【Conclusion】The water-saving and drought-tolerant rice genotype HY113 possesses less root biomass but higher root uptake efficiency, and it could reduce the root-shoot ratio under drought condition to make more dry matter stay in the aboveground part, so that the relatively high grain yield could be maintained.