磷酸盐与硒酸盐相互作用对小白菜磷和硒吸收的影响

Effects of Phosphate and Selenate Interactions on Uptake of Phosphorus and Selenium by Pak Choi

采用土培盆栽试验方法，研究了不同浓度磷酸盐与硒酸盐相互作用对小白菜生长、磷和硒吸收的影响，旨在为安全有效地进行补硒和硒污染土壤的植物修复提供理论依据。结果表明，在试验的硒浓度范围内（1．0～5．0mg·kg-1），硒酸盐对小白菜产生毒害作用，表现为单施硒酸盐处理较对照小白菜的根长、株高、地上部和地下部干重均下降，且高硒处理（5．0mg·kg-1）小白菜SPAD值显著下降。施用磷酸盐能显著增加小白菜生物量，明显缓解硒酸盐的毒害作用，且由于生物稀释效应导致小白菜地上、地下部硒浓度下降，但小白菜的硒吸收量增加。施磷小白菜地上部硒平均利用率提高至42％，且同等硒浓度低磷处理小白菜硒利用率高于高磷处理，表明适量施磷可提高硒的利用率。施磷时施硒对小白菜地上部磷浓度无显著影响，但由于硒的毒害作用导致磷吸收量下降。

Phosphate may influence movement and uptake of selenium in soil-plant systems. A pot experiment was carried out to study the effects of phosphate and selenate interactions on growth, uptake of phosphorus and selenium of pak choi. Addition of selenate alone signifi- cantly reduced the root length, shoot height and dry weight of shoots and roots, and also caused the decline of Chlorophyll Meter Readngs （SPAD values） at higher doses. Supplying phosphate increased the pak choi biomass, but significantly reduced concentrations of selenium in both roots and shoots due to the biological dilution. However,selenium accumulation by pak choi was increased by phosphate applications. Applying phosphate increased the average selenium use efficiency by up to 42% at all selenate rates（ 1.0-5.0 mg·kg-1）, with higher selenium use efficiency in low than in high phosphate treatments. Applying selenate had no effects on phosphorus concentrations of pak choi, while reduced phosphorus nccumulation by pak choi due to the selenium toxicity.