水稻根表铁氧化物胶膜对水稻吸收磷的影响

本文采用营养液培养方法研究了根表铁氧化物胶膜对水稻吸收磷的影响。结果表明，水稻报表的铁氧化物胶膜随营养液中Fe2+浓度的增加而增加。铁氧化物胶膜可富集生长介质中的磷，根表铁膜数量越多，富集的磷量也越多。根表铁股可促进水稻对磷的吸收，但这种促进作用的大小依赖于根表铁膜数量。根表铁膜数量为24570mp／kg时，促进作用达到最大，此后随着铁膜数量的增加，水稻吸收磷的数量下降，但仍高于根表没有铁膜的水稻。因此，水稻根表形成的铁氧化物胶膜在一定程度上是一个磷富集库，对水稻吸收磷起促进作用。在此过程中，缺铁条件下水稻根分泌物中的植物铁载体对淀积铁氧化物胶膜的水稻根系吸收磷没有明显的作用。

EFFECT OF ROOT IRON PLAQUE ON PHOSPHORUS UPTAKE BY RICE PLANT

In anaerobic condition, release of oxygen by roots to rhyzosphere caused the formation of red plaque of iron oxides or hydroxides on root surface of rice. The effect of iron plaque on P uptake was investigated with solution culture in greenhouse, arid the results are seen in the following: The amount of iron plaque was increasing with the increase of Fe²⁺ in medium. The plaque on rice root could adsorb P in growth medium, arid amount of P adsorbed on plaque increased with the increase of iron plaque. When there is iron plaque on rice root, P uptake by rice plant was enhanced.and the enhancement reached peak when amount of iron plaque was 24570mg/kg.Further increase in amount of iron plaque, P amount absorbed by rice plant decreased,but which was still high thari by rice root without plaque. In addition, phytosiderophore which was released by root of Fe deficient rice had no effect of P uptake by rice whose root was coated by iron plaque. So iron plaque on root was a P reservoir for rice plant.