低磷胁迫下不同水稻品种根系吸收能力差异的生理与遗传本质

在低磷（1mg L-1)和适磷水平（10mg L^-1)下，分别以混合培养方式研究了粳稻京系17（Oryza sativa ssp.japonica)(JX17)和粘稻窄叶青8号（Oryza sativa ssp.indica)(ZYQ8)对磷营养的反应。结果表明，低磷胁迫下，JX17较ZYQ8吸收更多磷素，干物重也显著增加。相反，ZYQ8则受到更强的磷胁迫，吸磷量和干物重降低，主要是因为JX17具有较高的吸磷速度，单位根长吸磷量大，即根系高亲和力磷酸盐转运蛋白表达强，最大限度地吸收可能利用的磷素，从而改善植株营养状况，同时又有较多的磷被分配到根系，使根第，根表面积和根干重相应提高，进一步增加了其在低磷胁迫条件下的竞争磷营养的优势。图3表2参17

GENETIC AND PHYSIOLOGICAL MECHANISM OF P-UPTAKE ABILITY DIFFERENCE BETWEEN DIFFERENT RICE (ORYZA SATIVA L.) GENOTYPES UNDER LOW-P STRESS

Under low (1 mg L -1 ) and sufficient (10 mg L -1 ) phosphorus (P) levels, response to P stress by two rice genotypes, JX17 ( Oryza sativa ssp. japonica ) and ZYQ8 ( Oryza sativa ssp. indica ), was studied by mixed culture method. The results showed that JX17 absorbed more P and had higher biomass under P stress. On the contrary, ZYQ8 suffered from P stress to a large extent with lower P uptake and biomass. JX17 had higher P uptake rate expressed as P amount per root length. The main reason was that JX17 possessed higher express of high affinity phosphate transporter, which played an important role in P uptake. With the improvement of P status in plant, P allocation to root increased so well in JX17 that enhanced its root length and root surface area, which, in return, contributed to a greater advantage in P uptake under P stress. Fig 3, Tab 2, Ref 17