在网室水培条件下,以IR45765-3B(深水稻品种)、中浙优1号(水稻品种)和中旱221(旱稻品种)为材料,研究不同根际氧浓度[1.0 mg/L(T1,低氧浓度)、3.0 mg/L(T2)、5.5 mg/L(T3)、7.5 mg/L(饱和氧浓度,T4)]对水稻产量及其氮素吸收利用的影响。结果表明,根际氧浓度显著影响水稻产量和干物质积累,这3个水稻材料的产量表现一致(T2>T1>T3>T4),处理间差异显著。其中,IR45765-3B和中旱221产量差异主要是由每穗粒数和结实率导致的,而根际氧浓度对中浙优1号产量构成的影响,还表现在有效穗数上。在氮素吸收利用方面,水稻生长前期T1和T2处理有利于水稻对氮素的吸收;灌浆后期增氧处理在一定程度上可增加植株氮素积累,但氧浓度过高不利于氮素向籽粒中转运;这3个水稻品种以T2处理氮素利用效率最高,比低氧处理(T1)分别提高6.9%、12.8%和13.8%;根际氧浓度升高提高了水稻营养生长阶段的氮素干物质生产效率。综上所述,3.0mg/L根际氧浓度处理对不同类型水稻产量的形成及其对氮素利用优于其他处理。

Hydroponic experiments were conducted to reveal the effect of rhizosphere oxygen concentration on rice grain yield and nitrogen absorption and utilization with IR45765-3B(deep water rice), Zhongzheyou 1 (lowland rice)and Zhonghan 221 (upland rice) as material at four rhizosphere oxygen concentration levels, 1.0 mg/L (T1, hypoxia),3.0 mg/L (T2),5.5 mg/L (T3) and 7.5 mg/L(T4, saturated oxygen concentration).The results showed that under various rhizosphere oxygen concertrations the grain yield and dry matter accumulation significantly differed among cultivars, and followed a trend of T2>T1>T3>T4. For IR45765-3B and Zhonghan 221, the impact on grain yield was mainly due to grain number per panicle and seed-setting rate. For Zhongzheyou 1, it was due to the above two factors and effective panicle number. In case of nitrogen accumulation and utilization, the nitrogen absorption under T1 and T2 was enhanced during early growth stage. Aeration could increase N accumulation during late grain filling stage,but hinder N transferring to grain under excessive oxygen concentration. In addition, nitrogen utilization efficiency (NUE) in T2 was the highest, 6.9%,12.8%,13.8% higher than those in T1, meanwhile N dry matter production efficiency was enhanced due to rhizosphere aeration during vegetative growth stage. In all, rhizosphere oxygen concentration of 3.0mg/L effectively enhance grain yield and N absorption and utilization of three rice genotypes.