Hypocotyl function in seedling development of the red mangrove, Rhizophora mangle L.

Propagules of the red mangrove (Rhizophora mangle L.) were subjected to a variety of growing conditions in which light level, anatomical exposure to light, application of the photosynthetic inhibitor DCMU, and genotype were used to infer possible interactions between autonomous photosynthesis and the utilization of internal reserves for the development of roots and shoots. The outgrowth of these organs from hypocotyls was significantly enhanced under conditions favorable for photosynthesis, and chlorophyll-deficient propagules exhibited reduced development compared to sibling wild types. The results suggest that photosynthesis augments processing of carbohydrates derived from maternal sources during early development and differentiation of the hypocotyl, and in combination represent an adaptive trait.