Sulphur nutrition changes the sources of S in vegetative tissues of wheat during generative growth
AbstractDuring generative growth, developing wheat grains require nitrogen and sulphur to synthesize storage proteins. The hypothesis that the S required for grain growth can be derived from vegetative tissues was examined by growing plants in nutrient culture containing either 50 ॖM S (low-S) or 200 ॖM S (high-S) and terminating the nutrient supply at various times during generative growth. After terminating the nutrient supply, high-S plants redistributed soluble S to developing grains from pools in roots and leaves, whereas low-S plants remobilized insoluble S (protein-S) from the leaves to the grains. A model for the cycling of S within mature leaves during generative growth is presented. Keywords: Grain sulphur, protein sulphur, sulphur nutrition, sulphur sinks, sulphur sources, wheat.