Dynamics of nutrient remobilization during germination and early seedling development in wheat

Abstract

The changes in nutrient content of grain parts and seedling parts in wheat (Triticum aestivum L. cv RAC655) were followed from germination to early seedling development (8 days). The grain was separated into seed coat, endosperm and embryo and the seedling into roots and shoots. The dry weight of the seed coat did not change throughout the experimental period whereas that of the endosperm rapidly declined from day 4 onwards. The seed coat contained the most nutrients of all grain parts, except for sulphur (S) and nitrogen (N). The endosperm contained between 20–35% of the total grain nutrients (except S, 50%). The embryo generally contained little nutrient, between 4–10%, except for zinc [(Zn) 20%], manganese [(Mn) 17%], and boron [(B) 13%]. Large amounts of potassium (K) were remobilized from the seed coat whereas no magnesium (Mg), Zn, copper (Cu), or B was remobilized. Nutrients were rapidly mobilized from the endosperm, particularly K and S. The shoots generally received a greater proportion of nutrients compared to the roots, except for Zn, Mn, and Cu which were distributed between them evenly. The dynamics of nutrient remobilization are discussed in relation to the distribution of nutrients within the grain and the consequences for early seedling vigor.