Mineral storage in Cucurbita embryos. III. Calcium storage as compared with storage of magnesium, potassium, and phosphorus

Abstract

Neutron activation analysis was used to measure the concentrations of Mg, K, Ca, and P stored in embryos of Cucurbita maxima, Cucurbita andreana, and their reciprocal hybrids. The embryos contained much higher concentrations of Mg, K, and P than Ca. However, Ca was the only one of the four minerals that was significantly different in the four kinds of embryos. Although all four minerals were stored in higher concentrations in the small root–shoot axes than in the large cotyledons, the proportion of total Ca stored in the axis was higher than the proportion of the other three minerals. P was the predominant mineral in the embryos, K was highest in the seed coats. Differences in mineral concentrations of embryo parts and seed coats indicated a marked selectivity in embryo mineral uptake.