不同品种连作晚稻钾素生理效率差异机理的初步研究

PRELIMINARY STUDY ON THE MECHANISM OF VARIATION IN POTASSIUM PHYSIOLOGICAL EFFICIENCY OF DIFFERENT LATE RICE

采用盆栽、^(14)C同位素示踪等方法研究了三个具有不同钾素生理效率晚稻品种的生理特征及与施钾的关系。结果表明,施钾明显提高水稻植株功能叶的含钾量和K/N值,增加各生育期叶片的光合速率,促进^(14)C同化物向穗和其它部位的运转,增加穗部光合产物的累积。在常规施钾水平下,供试的三个品种钾素生理效率依次为9194>浙粳66>浙湖904。9194品种钾素生理效率较高,主要是其生育后期剑叶含钾量高于其它品种17.7％～23.7％,植株体内钾素运转和再利用能力较强;施钾使灌浆期叶片光合速率提高78.0％,钾对光合速率的促进作用明显高于其它品种,达到最佳光合速率所需的供钾水平较低;光合产物在各部位分配合理,经济系数高,光合产物运输和穗部累积的最适施钾量较低。

Pot culture and C tracer experimental methods etc. were used to determine the mechanism of K physiological efficiency (Dry matter or grain (kg) / K absorbed (kg)) difference in various rice varieties in relation to K application. Results showed that potassium application markedly increased the K content and K/N ratio in function leaves of late rice, stimulated the photosynthetic rate at different rice growth stages, enhanced the transportation of 14C-photosynthate from labelled leaf to panicle and other parts of rice plant and increased the accumulation of 14C-photosynthate in panicle. With normal level of K application, the K physiological efficiency of three rice varieties tested was in the order of 9194>ZG66>ZH904. Physiological features which may contribute the higher K physiological efficiency in the typical variety 9194 are as follows: 1) The higher K transportation and reutilization in rice plants and higher content of K in active leaves at rice grain filling stage; 2) The more sensitive response of photosynthesis to K application and lower rate of K requirement for maximum photosynthetic rate; 3) The favourable distribution of photosynthate in panicle, the higher harvest index and lower K requirement for optimum transportation and distribution of photosynthate.