Stigma (botany) proper adhesion of the correct species of pollen. Stigma can play an active role in pollen discrimination and some self-incompatibility reactions, that reject pollen from the same or genetically similar plants, involve interaction between the stigma and the surface of the pollen grain. The stigma is often split into lobes, e.g. trifid (three lobed), and may resemble the head of a pin (capitate), or come to a point (punctiform). The shape of the stigma may vary considerably: The style is a narrow upward extension of the ovary, connecting it to the stigmatic papillae. It may be absent in some plants
Decay energy Decay energy The decay energy is the energy released by a radioactive decay. Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting ionizing particles and radiation. This decay, or loss of energy, results in an atom of one type, called the parent nuclide transforming to an atom of a different type, called the daughter nuclide. The energy difference of the reactants is often written as "Q": Decay energy is usually quoted in terms of the energy units MeV (million electronvolts) or keV (thousand electronvolts). Types of radioactive decay include The decay energy is the