NEET BIOLOGY

Detailed explanation-1: -The transfer of pollen grains from the anther to stigma of a flower is called pollination.

Detailed explanation-2: -Chemocyanin protein is expressed strongly in the stigma and style and to a lesser extent in the leaf, ovary, and petal. No signal was detected in 5 h in vitro grown pollen tubes (data not shown), mature anthers, or roots (Fig.

Detailed explanation-3: -When pollen grains land on the stigma, compatible grains germinate and pollen tubes elongate from them. The process of pollen germination is related to Ca2+ metabolism of pistil tissues.

Detailed explanation-4: -Ionic elements, such as boron and calcium, that are involved in the metabolism during pollen tube growth, and at different concentrations can stimulate or inhibit it. Naturally occurring polyamines such as spermine also stimulate pollen tube germination and elongation when they are sprayed on the stigma.