Flowering and Seed Set

Abstract

Plant reproduction is central to survival of the species. This process is accomplished asexually and/or sexually. Asexual reproduction often is the result of modification of vegetative structures such as stems or roots that possess sufficient fleshy tissue for energy storage. Such structures include rhizomes (bluegrass), corms (gladiolas), bulbs (onion), and tubers (potato). Another form of asexual reproduction is apomixis. Two types of apomixis result in the formation of seedlike structures: vivipary and agamospermy. Vivipary is often expressed by the conversion of the vegetative spikelet or leaf into a somatic structure with reproductive capability. Agamospermy occurs when nucellar (unfertilized) tissue in the embryo sac develops into a diploid egg cell that further differentiates into a “seed.” This form of asexual reproduction requires pollination even though fertilization does not occur. Most plants that reproduce primarily through apomixis also have a limited amount of sexual reproduction. This form of asexual reproduction is generally confined to certain grasses such as Kentucky bluegrass.