Effect of Differential Sulfur Nutrition on the Specific Activity of ATP Sulfurylase in Mature Grain From Five Wheat Cultivars (Triticum aestivum L.)

Abstract

Wholemeal grists of five wheat cultivars (T. aestivum L.) - Gabo, Olympic, Stockade, Insignia and Summit - grown in sand culture supplied with low (10 µM), medium (375 µM) and high (875 µM) concentrations of sulfur, were analysed for their specific activities of ATP sulfurylase (EC 2.7.7.4, ATP:sulfate adenylyltransferase). Under sulfur deficient conditions, residual activities were significantly higher in Gabo, Olympic and Stockade. Olympic maintained significantly higher activities at both the medium and high sulfur concentrations. All cultivars except Summit showed significantly lower activities when the sulfur deficiency was corrected. The results are discussed in relation to grain yield per plant, yield components, grain N, S, P contents and Pelshenke quality data. Grain yield per plant and ATP sulfurylase activity were positively correlated at all sulfur levels.