Glossary Details – Lecythidaceae

Glossary Details:

Title: Life cycle of a flowering plant. Drawing by M. Sashital.

Description: Life cycle of a flowering plant (= angiosperm). The life cycle of a flowering plant alternates between the gameophyte (haploid) and sporophjyte (diploid) generations. The gametophyte generation consists of the pollen grain which, at maturity, has a tube nucleus (guides the development of the pollen tube) and two sperms cells (one of which joins with the polar nuclei of the embyro sac and the other which fuses with the egg to form the embryo. The sportophyte generation which, at maturity, consists of eight nuclei, the most important of which are the two polar nuclei which fuse with a sperm nucleus to form the endosperm and another, which fuses with a second sperm to form the embryo. Because the two spores produce different types of gameotphytes, They are called heterosporous, a feature found only in a few species of ferns, Selaginella, and all of the seed plants (i.e., gymnosperms and angiosperms).

Term:

Flowering plant life cycle

Definition:

Referring to the alternation of generations between the gameophyte (haploid) and sporophyte (diploid) stages of a floweirng plant. The most conspicuous stage of the life cycle is the sporophyte generation whereas the gametophyte generation is small and inconspicuous. Flowering plants are heterosporous because they have two different kinds of spores, the pollen grain and the embryo sac which contains a egg.