水稻苗期磷高效基因型筛选研究

Screening methodology for rice (Oryza sativa) genotypes with high phosphorus use efficiency at their seedling stage.

采用难溶性磷酸盐Ca3 (PO4) 2 为唯一磷源 ,在pH值为 5 .5条件下产生相对高浓度低磷胁迫及以NaH2 PO4为磷源配制P浓度为 0 .5mg·L-1的相对低浓度低磷胁迫的两个水培环境 ,分别对不同基因型水稻的磷效率进行评价 .以相对分蘖干重 (RTW )、相对总生物量 (RPW )、相对分蘖数 (RTN)、相对根系干重(RRW )、相对地上部干重 (RSW )、相对叶龄 (RLA)和相对株高 (RPH)作为耐性指标进行相关分析 .结果表明 ,供试材料的磷效率存在极显著差异 ,若以能产生分蘖的相对高浓度低磷胁迫进行筛选时 ,相对分蘖干重、相对地上部干重、相对总生物量可作为较好的筛选指标 ,其中相对分蘖干重不仅与其它指标间的相关性强 ,且品种间差异和变异系数均较大 ,能准确、灵敏地反映不同基因型间的耐低磷胁迫能力 ;若采用相对低浓度的低磷胁迫对不同基因型水稻进行耐低磷种质筛选时 ,筛选指标则不同 ,最好的单一筛选指标应是相对地上部干重或相对总生物量 .

Under hydroponic culture,the responses of rice ( Oryza sativa ) genotypes to low P stress were respectively evaluated by means of relatively higher P concentration in a controlled system with insoluble phosphate source (Ca 3 (PO 4 ) 2) and of relatively lower concentration with 0.5 mg P/L in which NaH 2PO 4 was the soluble phosphate. Relative indices such as relative dry weight of tillers (RTW),total relative plant dry weight (RPW),relative number of tillers (RTN),relative dry weight of root (RRW),relative dry weight of shoot (RSW),relative leaf age (RLA) and relative plant height (RPH) were used to screen as the tolerant indices to P deficiency,and the correlations among screening criteria per se were analyzed. The results showed that there were significant differences of tolerant indices to P deficiency in the test rice genotypes. When the rice cultivars were exposed to low P stress with the relatively higher P concentration to be screened,the relative tiller dry weight (RTW),relative shoot dry weight (RSW) and total relative plant dry weight (RPW) could be used as the better screening criteria,especially RTW was considered as a sensitive and reliable screening criterion because its coefficient of variation (CV) and the variable range of data among the test varieties should be large. However,when rice genotypes were grown in the stress condition with relatively lower P concentration,the screening criteria were diffenent,and it suggested that relative shoot dry weight (RSW) or total relative plant dry weight (RPW) was the best single screening criterion.