Pollen prior to cytokinesis, whereas in successive microsporogenesis cytokinesis follows. While there may be a continuum with intermediate forms, the type of microsporogenesis has systematic significance. The predominant form amongst the monocots is successive, but there are important exceptions. During microgametogenesis, the unicellular microspores undergo mitosis and develop into mature microgametophytes containing the gametes. In some flowering plants, germination of the pollen grain may begin even before it leaves the microsporangium, with the generative cell forming the two sperm cells. Except in the case of some submerged aquatic plants, the mature pollen grain has a double wall. The vegetative and generative
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