Sexual Reproduction In Flowering Plants

Answer (d) Two polar nuclei

Autogamy (self-pollination) involve participation of just one flower for pollination. The devices for self-pollination are homogamy, bisexuality, cleistogamy etc.

In porogamy, pollen tube enters the ovule through the micropyle. It is the most common way of the entry of pollen tube inside ovule.

Bisexual flowers which do not open at all are called cleistogamous. In such flowers anthers and stigma lie close to each other. Viola (common pansy) has both cleistogamous and chasmogamous flowers. Chasmogamous flowers remain open with exposed anthers and stigma.

Young anther of plant contains sporogeneous tissue. An anther lobe has cavities (pollen sac) and has outermost epidermis, endothecium (fibrous layer) and middle middle layer of parenchyma cells the inner most layer is called tapetum. Microspore mother cell are derived from primary microsporogeneous cell or archesporial cells present in pollen sac and they receive nutrition from tapetal by diffusion or being invaded by tapetal cell.