Untitled Lecture Notes 11. Pollination delineates prepollination flower development or a structure specialized for pollen dispersal and reception, from postpollination development or a structure to ensure fertilization and nourishment of embryo and seed. Note the growing pollen tube exchanges information with the style and ovary, and the nature of these signals is an area of current interest.
Ethylene is sufficient to promote perianth senescence in a number of flowers.
The first is active in cell wall disassembly and the second in detoxification of lipid and DNA catabolic products, plus a signaling linkage between pollination, ethylene and regulation of genes for perianth senescence. Because of diverse patterns of pigmentation changes it is likely that different biochemical mechanisms are involved. The orchid strategy only invests in female reproductive development after pollination when fertilization is all but assured. Auxin is suggested as inducer of polar nuclei fusion and is probably delivered by pollen tube. Recall seedless fruit development via treatment of ovary with auxin.