Abstract: The characteristics of phosphorus (P) nutrition in different Pefficiency rice genotypes under lowP stress were studied at different growth stages in a pot experiment. At the tillering stage, except rice line 99112T, low Ptolerant genotype had a higher P uptake rate and utilization efficiency than Psensitive genotype. At the booting stage, low Ptolerant genotype still had a higher P uptake rate under low P stress, but there were no significant differences in P utilization efficiency between the two genotypes. At the maturity stage, the contribution factors to P efficiency of rice genotypes were in the sequence as follows: utilization efficiency, uptake rate and transportation efficiency. The lesser phosphorus efficiency of rice line 99012S was mainly caused by the lower absorbability of phosphorus at different growth stages. The lower uptake rate and the utilization efficiency of phosphorus at the early growth stage and the lower P utilization efficiency at the later growth stage become the main influencing factors of another low Psensitive genotype 99056S. Furthermore, the P uptake rate of low Psensitive genotype was lagged by low phosphorus stress, which could be intensified with the further phosphorus stress.

Key words: rice, low phosphorus stress, genotype, phosphorus nutrition, growth stage

摘要： 采用盆栽试验研究了低磷胁迫条件下不同磷效率基因型水稻在分蘖期、孕穗期和成熟期的磷营养特征。在分蘖期，耐低磷基因型水稻吸磷量无论在何种磷处理条件下均显著高于低磷敏感基因型，低磷胁迫时，除99112T外其他耐低磷基因型水稻的磷利用效率也显著高于低磷敏感基因型；到孕穗期，耐低磷基因型水稻在低磷胁迫时仍具有较高的吸磷量，但是磷利用效率与低磷敏感基因型相比却没有明显差异；至成熟期，耐低磷基因型水稻的磷效率的贡献因子依次为：磷利用效率、吸收效率和转运效率。较低的吸磷量是99012S（低磷敏感基因型）在不同生育时期磷效率低下的主因，在生育前期磷吸收和利用效率低下及后期磷利用效率低下是另一个低磷敏感基因型99056S磷效率低下的主要原因。低磷胁迫还滞后了低磷敏感基因型的磷吸收，并随着低磷胁迫的加剧而增强。

关键词: 水稻, 低磷胁迫, 基因型, 磷营养, 发育时期