Phosphorus nutrition and the intracellular distribution of inorganic phosphate in pea root tips: A quantitative study using31P-NMR
Lee RB., Ratcliffe RG.
Pea plants (Pisum sativum L.) were supplied with external phosphate for differing periods of time, so that their phosphorus status varied, and the intracellular distribution of inorganic phosphate (P 1 ) in the roots was examined by 31 P nuclear magnetic resonance. Over the range of phosphorus nutrition investigated, the quantity of vacuolar P 1 per unit fresh weight of root tip changed considerably, whereas the quantity of cytoplasmic P 1 per unit fresh weight of root tip did not alter. The relative volumes of the cytoplasm and the vacuole in pea root tips seemed to be little affected by differences in phosphorus nutrition, and this implied that the concentration of P 1 in the cytoplasm was kept almost constant, at a level estimated to be ∼ 18 mM.The rate of absorption of 32 P-labelled phosphate was negatively correlated with the vacuolar P 1 concentration, but there was no clear correlation with the concentration of P 1 in the cytoplasm. © 1983 Oxford University Press.