Rate of Imposition of Water Stress Alters the Accumulation of Nitrogen-Containing Solutes by Wheat Seedlings

A rapid water stress, imposed by withholding water under a high transpirational demand or by the application of polyethylene glycol (PEG), resulted in the accumulation of glutamine, asparagine and valine in amounts equal to or greater than that of proline. However, progressive water stress imposition resulted in proline and glycinebetaine being the dominant accumulated compounds of those measured. PEG had an apparently specific effect on amino acid accumulation, particularly of the amide forms. With some exceptions, such as glycinebetaine, the stress-induced changes in the content of most solutes were reversible upon rewatering.