Plant seeds as mineral nutrient resource for seedlings - A comparison of plants from calcareous and silicate soils

Abstract

Mineral nutrients of seeds constitute a significant source of essential elements to seedlings and developing individuals of vascular plants. In spite of their potential ecological significance, seed nutrient pools have attracted little attention with respect to calcifuge-calcicole behaviour of plants. The objectives of this study were, therefore, to compare concentrations of 13 macro- and micronutrients (K, Rb, Mg, Ca, Mn, Fe, Co, Cu, Zn, Mo, B, P and S) in seeds and leaves of 35 mainly herbaceous vascular plant species growing on both limestone (calcareous) and silicate (non- calcareous) soils. Concentrations of Rb and Co in seeds of plants originating from limestone soils were, on average, about half of those from silicate soils. Concentrations of Mn, Mg, Zn and P of seeds were, or tended to be, lower or slightly lower in limestone-soil plants, whereas mean Ca and Mo concentrations were higher. Comparing seed and leaf concentrations of the same species from limestone and silicate soils generally demonstrated a high P enrichment ratio, but a particularly low K enrichment ratio in seeds, valid for both types of soil. It was also apparent that Fe and Mn, micronutrients which are less readily solubilized and taken up by plants on limestone soils, had significantly higher seed:leaf concentration ratios in plants from limestone than from silicate soils, whereas the opposite was true for Ca. This indicates a 'strategy' to satisfy the demand of seedlings for elements which are less readily available in the soil.