HORTICULTURE

Detailed explanation-1: -Gametes develop in the multicellular haploid gametophyte (from the Greek phyton, “plant”). Fertilization gives rise to a multicellular diploid sporophyte, which produces haploid spores via meiosis. This type of life cycle is called a haplodiplontic life cycle (Figure 20.1).

Detailed explanation-2: -Unlike animals and other organisms that use sexual reproduction, gametophytes do not produce their sex cells through meiosis. Instead, all cells within a gametophyte organism are haploid – that is, possessing only one copy of each chromosome – and these haploid organisms produce gametes through mitosis.

Detailed explanation-3: -A major function of the gametophyte generation is to produce haploid gametes. Fusion of the egg cell with the sperm cell gives rise to the sporophyte, thereby completing the life cycle (Raven et al., 1992). In many lower plants, gametophytes are the dominant and free-living generation.

Detailed explanation-4: -The haploid (n) multicellular life stage is called the gametophyte as it produces gametes (egg and sperm cells) that fuse during fertilization to form a diploid (2n) zygote. This zygote develops into a mature diploid sporophyte by mitosis, carrying both genetic information from the fused gametes.

Detailed explanation-5: -Gametophytes grow from spores, which are produced by the sporophyte in structures called sporangia. The spores themselves are produced via meiosis, and are haploid (n). The spores then undergo mitosis, growing into the gametophyte. Seed plants have distinct spore types for the different sexes of gametophyte.