Response of rice seedlings to aluminium stress with varying phosphate supplies

Abstract

In this study the effects of Al and phosphate (P) treatments on the growth and potassium influx in roots and transport toward the shoots of rice (Oryza sativa L. cv. Oryzella) was examined. Seedlings were grown hydroponically at pH 4.1 with different levels of Al and P. Increased levels of Al in the growth solution reduced root growth in accordance of the Al-concentration. Shoot growth was only moderately influenced in 14 day experiment. P (as phosphate) supply in the growth solution enabled rice plants to overcome the Al toxicity symptoms, however, the available P concentrations must exceed the Al concentration in the external medium. In short-term (6h) uptake experiments, P reduced the Al-stimulated K+(86Rb) influx anomaly in roots, which indicates a definite Al-P interaction at the plant level too. Stimulation of glutamine synthetase activity was confirmed by in vitro tests and western blot detection after native PAGE separation of enzyme isoforms.