低磷胁迫对水稻生长及生理特性的影响

Effects of Low Phosphorus on Growth and Physiological Characteristics of Rice(Oryza satuvia L.)

以3种不同基因型水稻为材料,采用水培方式分别对水稻植株进行正常供磷(+P,0.323 mmol·L-1)和低磷(-P,0.013 mmol·L-1)培养。通过对植株的表型观察,根系形态的扫描,生物量及部分理化指标的测定,研究低磷对水稻生长的影响,明确水稻对低磷胁迫的适应机制。结果表明,与正常供磷水稻植株相比,低磷处理的水稻植株矮小,叶面积减小,分蘖数及穗粒数减少;同时,根长增长,根系活力减弱,根系分泌酸性磷酸酶(APase)活性增强,根系分泌酸(H+)增多;此外,低磷处理水稻植株相对含水率下降,地上部干质量下降,根部干质量增加,根冠比增大。即在磷营养供应不足时,水稻通过改变根系形态、增加根系分泌酸和提高酸性磷酸酶活性等适应机制,增加对土壤中磷元素的吸收和利用,以适应低磷环境。

Three different genotypes of rice were cultivated in the low phosphorus stress with a hydroponic method to reveal the adaptation mechanism of rice in both IRRI(+P)and(-P).The phenotypes of the plants were observed,the root morphology was scanned,the biomass and some physical and chemical indexes were determined.The effects of low phosphorus on the growth of rice were studied to clarify the adaptation mechanism of rice to low densities.The results showed that rice was short,the leaf area reduced,and the number of tillers and grains per panicle decreased.Meanwhile,the root length increased,root activities weakened,the activities of acid phosphatase secreted and the acid(H+)secreted increased by root.In addition,the relative water content of rice plants decreased,the dry mass of over ground parts decreased,the dry mass of root parts increased,and the ratio of root to cap increased under low phosphorus treatments.That was to say,when the phosphorus nutrient supply was insufficient,rice could increase the absorption and utilization of phosphorus in soil to adapt to the low-phosphorus environment through adaptation mechanisms,such as changing root morphology,increasing root acid secretion and increasing acid phosphatase activities.