Kinetics of element profile pattern during life cycle stage of morning-glory

Abstract

We present the kinetics of seven element profiles, macroscopic elements, Na, Mg, Cl, K and Ca, as well as Al and Br, in every tissue of morningglory (Ipomoea nil L. c.v. Murasaki), from seedling to flowering stage. Barriers for the elements were formed even in the same tissue during different growing phases. Most of Na and Al remained in root tissue, showing the first barrier to the upper part of the plant. During the juvenile phase, the tissues lower than cotyledon stored the elements, especially Ca and Mg. The barrier at cotyledon did not disappear completely until seed ripening stage, except for K. Generally, late developing stem showed lower accumulation of the elements, which seemed to regulate the inflow of Mg, Ca, Cl and Br into flowering tissue. The concentrations of K, Ca, Cl and Br in leaf were kept constant in spite of twice or three times higher concentration of these elements in leaf petiole. After flowering, selective element accumulation was observed during seed development, where most of the elements were accumulated into seed wall, not in seed. Higher concentration of the elements in elder leaf, which falls into ground and will be reused as plant nutrient, might reflect the recycling system of the elements in plants.