CHANGES IN THE COMPOSITION OF GLOBOIDS IN CASTOR BEAN COTYLEDONS AND ENDOSPERM DURING EARLY SEEDLING GROWTH WITH AND WITHOUT COMPLETE MINERAL NUTRIENTS

The endosperm and cotyledon tissues of Ricinus communis seeds and youn g seedlings were examined for changes in the mineral nutrient composit ion of globoids during early seedling growth. The effect on globoid co mposition of providing mineral nutrients to the developing seedling wa s also investigated. Globoids in endosperm and cotyledon tissues of ca stor bean seeds contained P, Mg and K, as well as trace amounts of Ca, Fe and Zn. Irrespective of the addition of mineral nutrients, K conte nt in globoids of endosperm and cotyledon tissues declined significant ly during initial seedling growth. During early seedling growth, amoun ts of Fe, Zn and Ca increased in cotyledon globoids. Ca contents of gl oboids of endosperm tissues also increased. The changes in Fe, Zn and Ca globoid contents were not influenced by providing mineral nutrients to growing castor bean seedlings.