铝胁迫下磷对水稻苗期生长的影响及水稻耐铝性与磷效率的关系

选用两个耐铝性差异较大的水稻品种武运粳7号(耐铝品种)和扬稻6号(铝敏感品种)作为实验材料,利用水培铝-磷交替处理试验研究了磷对水稻铝胁迫下苗期生长的影响及水稻耐铝性与磷效率之间的关系。结果表明,从水稻铝-磷交替处理下的生物量和根系形态等指标来看,P缓解了Al对两个水稻品种的毒害作用,且对敏感品种扬稻6号的缓解作用更加明显。铝-磷交替处理下,武运粳7号的体内磷含量显著高于扬稻6号的,而根部铝含量显著低于扬稻6号,因此武运粳7号体内的P/Al显著高于扬稻6号;同时,虽然两个品种间根表及根自由空间中Al浓度没有差别,而武运粳7号根表及根自由空间中P浓度显著高于扬稻6号,表现出耐铝品种更强的质外体解铝毒能力,这可能与武运粳7号较强的磷吸收效率有关。此外,与耐铝品种武运粳7号相比,铝敏感品种扬稻6号虽然磷吸收效率低,但利用效率高,即两个水稻品种的耐铝性与水稻的磷吸收效率和利用效率不一致,这为酸性土壤水稻育种提供了理论基础,即选育适应酸性土壤的水稻基因型不仅要关注其耐铝性还要关注其磷利用效率。

Effects of P on growth of rice seedling under Al stress and relationship between Al tolerance and P efficiency of the rice

Two rice cultivars Wuyunjing 7 (Al-tolerant) and Yangdao 6 (Al-sensitive), differing sharply in aluminum tolerance, were selected as subjects in a hydroponic experiment to investigate effects of P on growth of the rice seedling under Al stress and relationship between Al tolerance and P efficiency of the rice through alternation of Al and P treatments for two weeks. Results show that in the aspect of biomass and root parameters, P application alleviated toxic effects of Al on both cultivars. The concentration of P was obviously higher in Cultivar Wuyunjing 7 than in Cultivar Yangdao 6, while the concentration of Al in root was lower in the former than in the latter, and as a result, the P/Al ratio was significantly higher in the former than in the latter. However, though the two cultivars did not differ in Al concentration in the root surface and inter-root free space, Cultivar Wuyunjing 7 was significantly higher than Cultivar Yangdao 6 in P concentration therein, demonstrating that the rice cultivar, high in Al tolerance, is higher in capability of its apoplast of detoxifying Al, which may be related to the higher P uptake efficiency of Wuyunjing 7. In addition, compared with Wuyunjing 7, Yangdao 6 was though lower in P uptake efficiency, it was higher in P utilization efficiency, which suggests that the Al tolerances of the two cultivars do not consist with their P uptake efficiencies and P utilization efficiencies, which may serve as a theoretical basis for selecting and breeding rice seeds for paddy fields of acid soil, that is to say, to select and breed rice of genotypes suitable to acid paddy soils, it is essential to focus on Al tolerance and P utilization efficiency as well.