不同耐低磷水稻基因型秧苗对难溶性磷的吸收利用

选取4个典型耐低磷水稻基因型99011、508、580和99112，并以2个磷敏感基因型99012和99056为参照，采用营养液培养和砂培的方法，研究不同磷处理对秧苗生长的影响以及不同耐低磷基因型对3种难溶性磷源(有机磷、铝磷和磷矿粉)吸收利用能力的差异。结果表明，不同无机磷处理，6个基因型生物量和根干重基本上均为全磷处理（P）>对照+铝磷（CK+Al-P）>对照+磷矿粉（CK+RP）> 对照（CK）；4个耐低磷基因型根干重和根冠比均大于2个磷敏感基因型；对于根冠比，耐低磷基因型580和99011为对照+磷矿粉（CK+RP）>对照+铝磷（CK+Al-P）> 对照（CK）> 全磷处理（P），耐低磷基因型508、99112和磷敏感基因型99012为CK> CK+RP> CK+Al-P > P，磷敏感基因型99056为CK+Al-P > CK+RP > P>CK；缺磷处理，秧苗活化吸收难溶性磷源的能力均为OP> Al-P> RP，且不同基因型的分解吸收能力对OP为99011> 508> 580> 99012> 99112> 99056（表2），对Al-P为580> 99011> 99112> 508> 99056> 99012（表3），对RP为580> 99112> 99011> 508> 99012> 99056（表2）。此外，缺磷即CK处理，508对低浓度的磷吸收最多(表2和表3)，而580对磷的利用效率显著高于其他基因型（表3），这些特征可能也是它们耐低磷的重要贡献因子之一。

Uptake and Use of Sparingly Soluble Phosphorus by Rice Genotypes with Different P-efficiency

Four low-P tolerant rice genotypes named 99011,580,508 and 99112 were used with two low-P sensitive rice genotypes named 99012 and 99056 as reference,to investigate the genetic differences for growth as influenced by different inorganic phosphorus supply,and availability and uptake ability to three insoluble P named organic P,Al-P and RP,using solution culture and sand quartz culture respectively.The results demonstrated that biomass and root dry weight of rices were reduced by low P,but R/S was affected by both supplied P level and uptake ability of plant to low P.Under the condition of low P,the biomass and root dry weight with different inorganic phosphorus treatments were P>CK Al-P>CK (RP>CK;root dry) weight and root shoot ratio of four low-P tolerant rice genotypes were larger than those of two low-P sensitive rice genotypes;For R/S,580 and 99011 were CK RP>CK Al-P>CK>P,508,99112 and 99012 were CK>CK RP>CK Al-P>P,but 99056 was CK Al-P>CK RP>P>CK.The availability of sparingly soluble phosphates and organic phosphorus absorbed by rice seedlings was OP>Al-P>RP,but different rice cultivars had significant difference in response to three insoluble P compounds.P uptake amount for organic phosphorus was 99011>508>580>99012>(99112>99056,for Al-P was) 580>99011>99112>508>99056>99012,and for RP was 580>99112>99011>508>99012>99056.Furthermore 508 had highest uptake efficiency to low phosphorus;580 has highest P utilization efficiency,and absorbed more sparingly soluble phosphorus especially Al-P and RP than others;They are maybe one of the important reasons in 508 and 580 for low-P tolerance in 508 and 580.Low-P tolerant rice genotype 99112,a special material,has small biomass and achieve high relative grain yield.As for low-P sensitive rice genotype 99056,its utilization efficiency to phosphorus is not low,but it just has small root system,only active and uptake a little sparingly soluble phosphorus,and can not absorb low concentration phosphorus.Rice genotypes with different P efficiency have some identical mechanism,they just have different contributory ability.So,the mechanism of rice tolerance to low-P stress is very complex,the main factors and genes related to phosphorus efficiency should be founded to apply in rice breeding.