Govt Exams
Marginal placentation occurs when ovules develop along the ventral suture (margins) of the carpel, commonly seen in legumes.
The transition from pteridophytes to gymnosperms shows complete terrestrial adaptation through development of pollen (no free sperm in water) and seeds (no gametophyte dependence).
Sexual reproduction involves fusion of two gametes from different parents, resulting in genetic variation and equal parental contribution in diploid offspring.
Both dicots and monocots possess vascular tissue. They differ in cotyledon number (2 vs 1), bundle arrangement, and floral parts (mostly in whorls of 4-5 vs 3).
Endosperm is a nutritive tissue produced by triple fusion nuclei, stores nutrients (starch, protein, oils) and nourishes the developing embryo during seed maturation and germination.
The integument (outer layer of ovule) develops into the testa (seed coat) after fertilization, protecting the developing embryo.
Wind-pollinated flowers are typically small, inconspicuous, and produce copious amounts of light, dry pollen that can be easily dispersed by wind.
Anthers develop from microsporophylls (stamens) and contain four pollen sacs (microsporangia) where microspores develop into pollen grains.
The mature female gametophyte (embryo sac) in angiosperms is typically 7-celled with an egg apparatus (1 egg + 2 synergids) and 3 antipodal cells.
The pollen grain is the immature male gametophyte that further develops after pollination to form the mature male gametophyte.