The stigmatic surfaces are specialized for catching and retaining the pollen. The main function of the stigma is to provide the water and the essential nutrients in the form of exudates for the pollen germination. The exudates are secreted by the stigmatic papillae of the epidermis. These exudates are highly viscous and adhesive with high refractive index. They are chemically lipids, phenols, amino acids, peptides and proteins; it helps in retention of pollen grains and also initiates the germination.
