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选用氮素利用高效型和低效型具有代表性的12个粳稻品种,研究了225kghm-2施氮条件下根系形态和生理指标的差异及其与氮素利用效率的相互关系。结果表明,有效分蘖临界叶龄期、拔节期、抽穗期和成熟期,氮高效型水稻的根干重、根系体积、总吸收表面积、活跃吸收表面积和活跃吸收表面积比均显著或极显著大于氮低效型水稻。有效分蘖临界叶龄期和拔节期,氮高效类型水稻的根冠比显著大于氮低效型,而抽穗和成熟期则表现相反趋势。成熟期前,氮高效型水稻的根系α-NA氧化量极显著大于氮低效型,而成熟期,氮高效型中杂交水稻的根系α-NA氧化量略低于个别氮低效型水稻品种。相关性分析表明,有效分蘖临界叶龄期、拔节期、抽穗期和成熟期,水稻的根干重、根系体积、根系的α-NA氧化量、总吸收表面积、活跃吸收表面积和活跃吸收表面积比与氮素利用效率呈显著或极显著正相关。有效分蘖临界叶龄期和拔节期,植株的根冠比与氮素利用效率呈显著正相关,而抽穗和成熟期则呈极显著负相关。氮高效型水稻在其一生中具有良好的根系形态和保持较强的根系活力,为植株大量吸收和高效利用氮素奠定了良好基础。同时,在水稻的生长过程中,地下部与地上部的合理比例及协调生长也是促进植株高效吸收利用氮素的重要因素。
Nitrogen utilization 12 representative japonica rice varieties with high efficiency and low efficiency were used to study the differences of root morphological and physiological indexes under 225kghm-2 nitrogen application and their correlations with nitrogen use efficiency. The results showed that the root dry weight, root volume, total absorption surface area, active absorption surface area and active absorption surface area ratio of nitrogen-efficient rice were significantly or extremely significantly higher than those of nitrogen at the effective leaf tillering stage, jointing stage, heading stage and maturity stage Inefficient rice. At the critical leaf-tillering and jointing stages of effective tillering, the root-shoot ratio of nitrogen-efficient rice was significantly greater than that of nitrogen inefficient rice, while the heading and maturity of rice showed the opposite trend. Before maturity, the α-NA oxidation of roots of nitrogen-efficient rice was significantly greater than that of nitrogen inefficient. At maturity, the α-NA oxidation of roots of hybrid rice was slightly lower than that of some nitrogen-inefficient rice cultivars . Correlation analysis showed that the critical leaf age, jointing stage, heading stage and maturity stage of the effective tillering, the root dry weight of rice, the root volume, the α-NA oxidation of the root, the total absorption surface area, the active absorption surface area and the active absorption surface area ratio And nitrogen utilization efficiency was significant or very significant positive correlation. At the critical leaf age and jointing stage of effective tillering, there was a significant positive correlation between the plant root and shoot ratio and nitrogen use efficiency, but a significant negative correlation between heading and maturity. Nitrogen-efficient rice has a good root morphology and strong root activity in its lifetime, which lays a good foundation for plant to absorb and use nitrogen efficiently. At the same time, the reasonable proportion and coordinated growth of underground and aboveground parts of rice during rice growth are also important factors to promote the efficient nitrogen uptake and utilization by plants.