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It is the interaction of pollen grains with sporophytic tissue (stigma). It begins with pollination and ends with fertilization. All the events from the deposition of pollen grain on stigma to the entry of pollen tube in the ovule (synergid) are referred as pollen - pistil interaction. Pollination does not guarantee the transfer of right type of pollen, often wrong type also land on stigma. The pistil has the ability to recognise and accept the right or compatible pollen of the same species. Thus wrong type of pollen is discarded by pistil. Compatibility incompatibility of the pollen-pistil is. determined by special proteins. This process involves pollen recognition followed by promotion or inhibition of pollen. -pollination and the The stigmatic surface of flower refuse Primula (Primrose, s/ types of flowers mers are placed at and heteroanthy). From reaching the In heteromorphic uced from anther t the same level. other wrong type or incompatible pollen grains. A physiologial mechanism operates to ensure that only intraspecific pollen germinate successfully. The compatible pollen absorbs water and nutrients from the surface of stigma, germinates and produces pollen tube. Its growth through the style is determined by specific chemicals. The stigmatic surface provides the essential prerequisites for a successful germination, which are absent in the pollen. The pollen tube is finally pushed through the ovule and reaches the embryo sac. The tip of the pollen tube enters in one of the synergids and then ruptures to release the contents. Due to pollen pistil interaction, intense competition develops even in the compatible pollen grains (gametes). It also plays important role in sexual reproduction and seed formation. Pollen grain can also be induced to germinate in a synthetic. medium. Sucrose induces pollen germination and tube growth in vitro. Addition of boric acid. facilitates and accelarates pollen germination. be monoccious, e.g. Mulberry, Papaya. s and stigmas mature isexual flower so as n. It can be further =type, androccium e gynoecium c.g. in ower. gynoecium matures ium) e.g. Gloriosa. flowers germinate in the pollen grains Apple. mite ce to prevent self lower. In plants, present between Contact of pollen e.g. Calotropis- oned above the ility) sm due to which gma of the same Co Thea ames, the plants ross pollination . wheat, rice. Sta Artificial hybridization : It is one of the major approaches used in the crop improvement. Only the desired

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Updated on: Nov 9, 2022