Question

The haplodiplontic life cycle is common in plants and algae (but absent in animals). Briefly describe the life cycle of a flowering plant, including the name and ploidy of each stage, and the relevant structures involved in transitioning from one stage to the next.

Answer 1

Gamtes develops into multicellular haploid gametophyte , fertilization give rise to a multicellular diploid sporophyte , which produces haploid spores by meiosis. This type of life cycle is callled haplodiplontic life cycle.

Angiosperm plant body is sporophye(2n) . It also show alternation with gametophytic phase(n).The sporophyte produces microspores (n) inside microsporangia , pollengrains are produced as a result of reductional division(meiosis) of pollen mother cells(2n). The megaspores(n) are produced inside the ovule by reductional division of megaspore mother cell(2n). pollen grains produces two male gamate , in which one male gamate fused with eggcell(n) produced by female gametophyte and form zygote(2n). female gametophyte also produces 2 polar nuclei other than the egg cell. these polar nuclei fused with remaining male gamate and form endosperm (3n). the zygote (2n) develops into embryo and embryo into diploid sporophytic plant.