Sexual reproduction in Plants: In plant kingdom the flowering plants are the most highly advanced plants. Flower bears the sex organs of a plant. In some plants male and female sex organs are present in the same plant. Such plants are called bisexual or hermaphrodite. When male and female sex organs are present in different plants, such plants are unisexual. We can learn the process of sexual reproduction easily in the flower of madar (Aak) or Datura. The swollen apical end of pedicel of flower is called thalamus or receptacle. The four whorls of flower namely calyx, corolla, androecium and gynoecium are inserted on thalamus.
Androecium and gynoecium are called as reproductive whorls and calyx and corolla as accessory whorls or supporting whorls. Sepals the members of calyx whorl are generally green and petals, the members of corolla whorl .are coloured and attractive. Stamen, the member of androecium, is a stalk like structure with flattened top, the anther or pollen sacs. In anther the male generative cells give rise to pollen grains. Each pollen grain divides to form two male gametes. The carpel which is the female organ and a member of gynoecium whorl has three parts. Basal swollen part is ovary which encloses the ovules. Each ovule contains one female gamete-egg. A long, tubular structure is developed above the ovary called as style. The top flat end of style is stigma.
