Pollen-Pistil Interactions

• Pollination does not guarantee the transfer of right type of pollen (compatible pollen of the same species as the stigma). Often, pollen of the wrong type, either from other species or from the same plant (if it is self - incompatible) also land on the stigma.
• The pistil has the ability to recognize the pollen whether it is of the right type (compatible) or of the wrong type (incompatible). 
• If it is of right type the pistil accepts the pollen and promotes post pollination events leads to fertilization. 
• If the pollen is of wrong type, the pistil rejects the pollen by preventing pollen germination on the stigma or the pollen tube growth in the style. 
• The ability of the pistil to recognize the pollen is the result of a continuous dialogue between pollen grain and the pistil. 
• This dialogue is mediated by chemical components of pollen interacting with those of the pistil. All the events from pollen deposition on the stigma until pollen tube enters the ovule are together referred to as pollen pistil interaction. 
• It is mediated by chemical components of pollen and pistil. 
• Pollen pistil interaction is a dynamic process involving pollen recognition followed by promotion or inhibition of the pollen. 
•  It is only in recent years that botanist have been able to identify some of the pollen and pistil components and interactions leading to the recognition, followed by acceptance or rejection. 
• The knowledge gained in this area would help the plant breeder in manipulating pollen - pistil interaction, even in incompatible pollinations to get desired hybrids.