Govt. Exams
Entrance Exams
The funiculus (also called funicle) is the stalk that attaches the ovule to the placenta. The raphe is a ridge formed by the fusion of funiculus with the integument in some ovules.
Antipodal cells (typically three) are located at the chalazal end and are vegetative in nature, containing vacuoles for nutrient storage. They eventually degenerate.
Gram (chickpea) is a legume with a monocarpellary ovary showing marginal placentation where ovules are attached along the ventral suture.
Protandry is when anthers mature and release pollen before the stigma of the same flower becomes receptive, preventing self-pollination and encouraging cross-pollination.
The generative cell typically divides after pollination (not before pollen release) to form two sperm cells. In some plants it divides before release, but this is not the general pattern.
Apomixis includes apospory (diploid egg from vegetative cells), apomeiosis (unreduced spore formation), and parthenogenesis (unfertilized egg development), all bypassing meiosis and fertilization.
Integuments are the outer layers of the ovule that develop into the seed coat (testa) after fertilization, providing protection to the seed.
Angiosperm life cycle: diploid sporophyte (2n) → haploid spores (n) → haploid gametophyte (n) → diploid zygote (2n) after fertilization, and triploid endosperm (3n) after double fertilization.
Pollen dimorphism is associated with heterostyly, where plants like Primula produce different-sized pollen grains corresponding to different floral forms to promote cross-pollination.
In most angiosperms, pollen is released at the two-celled stage (bicellular pollen) consisting of a large vegetative cell and smaller generative cell. Second mitosis occurs after pollination.
