COMBINED EFFECTS OF ALUMINIUM, IRON AND PHOSPHORUS ON ION UPTAKE AND YIELD OF RICE PLANTS (ORYZA SATIVA L) IN NUTRIENT SOLUTION [French]

摘要

Rice (var IR60A) was grown in nutrient solutions at different concentrations of aluminium (74, 185, 370 mu M), iron (18, 125, 357 mu M), and phosphorus (28, 70, 140 mu M). The 27 combinations of concentrations were tested in duplicate. The uptake rates of ammonium and P were measured at different growth stages, namely after 45 days (tillering) and 80 days (flowering). Shoot and root biomass and grain yield were measured at maturity (108 days). Phosphate uptake rate did not affect plant biomass, but increased grain yield, ie, it alleviated the yield losses due to increased Al and Fe concentrations. Stepwise multiple regression showed that the grain yield was strongly correlated (r(2) = 0.86) to the Al3+ and Fe2+ concentrations as calculated by a speciation program; increased P uptake rates result in the formation of AI-P complexes that reduce the Al3+ concentration. The grain yield at maturity was also closely related (r(2) = 0.75) to the uptake rate of ammonium at tillering: a single relationship was observed for all Al-Fe-P treatments.