Initial Uptake of Aluminium in Relation to Temperature and Phosphorus Status of Wheat ( Triticum aestivum L.) Roots

Abstract

Summary Al uptake by roots of 9-day-old wheat plants ( Triticum aestivum L.) at pH = 4.1 during 2h (initial uptake) could be divided into a free diffusible component and a bound fraction which was non-exchangeable with Ca. Two types of Al-binding sites were identified: one insensitive to low temperature (2 °C) and one existing only at 22 °C. The initial uptake of Al increased under conditions which favoured leakage of P from the roots. It was concluded that at 22 °C, metabolism-dependent labile binding sites which can also bind Al exist in the free space. In the free space of high P roots Al-P complexes can be formed due to efflux of P from the symplasm.