水稻基因型(94D-64)中磷对砷解毒生理机理的研究

Physiological Mechanism of Arsenate Detoxification by Phosphate in Rice Genotype 94D-64

水稻基因型94D-64是比较特殊的基因型,这是因为随着Pi浓度增加,根部和地上部As的浓度变化模式截然不同。随着Pi处理浓度的增加,水稻(Oryza sativaL.)基因型(94D-64)地下部As浓度降低,而地上部As浓度增加,为此采用水培养实验方法,研究了水稻94D-64根部和地上部各种生理指标的应答模式是否与组织As浓度密切相关。将水稻幼苗在4个Pi(10、50、150和450μmol·L^(-1)KH_2PO_4)浓度和10μmol·L^(-1)Na_3AsO_4处理11d,结果表明,随着Pi浓度的增加,(1)根部丙二醛(malondialdehyde,MDA)含量降低,而地上部MDA含量则增加;(2)根部K和As的外渗降低;(3)地上部非蛋白巯基(Non-protein-thiols,NPT)和CAT含量亦降低。这些指标与根部As浓度降低而地上部As浓度增加的现象相吻合,说明植物具有良好的抵御重金属伤害的应答防御体系。

With increasing external phosphorus （P） concentrations, there was a different trend for arsenic （As） concentrations in shoot and root in rice （Oryza sativa L.） genotype 94D-64. The study was to investigate whether the response of physiological indexes was in correlation with tissue As concentrations. Seedlings were treated with four concentrations of P （10, 50, 150 and 450 I^M KH2PO4） and a constant As concentration （10 μM Na3AsO4） for 11 days. With increasing P concentrations, the concentrations of malondialdehyde （MDA） decreased in root but increased in shoot. Furthermore, with increasing P concentrations, K and As concentrations in exosmotic solution decreased and NPT and CAT concentrations in shoot decreased, too, which coincided with the phenomena that the concentrations of As decreased in root while increased in shoot, indicating that plant had an excellent response way against metalloid heavy metal damage.