Term:
Tetrad
Tetrad
Definition:
Referring to pollen grains that remain in groups of four after meiois; in most species of flowering plants the tetrads separate into four monads immediately after meiosis.
Referring to pollen grains that remain in groups of four after meiois; in most species of flowering plants the tetrads separate into four monads immediately after meiosis.
Notes:
In the Lecythidaceae, tetrads are usually associated with species that possess two types of pollen--that which germinates and carries the sperm to the egg to make possible the process of fertilization and that which does not germinate called fodder pollen which serves as a pollinator reward. Some fodder pollen is differentiated from the fertile pollen by remaining in tetrads whereas the fertile pollen is found in monads at maturity, e.g. Couroupita guianenensis. In other species, the fertile and fodder pollen can not be distinguished from one another, e.g., Lecythis pisonis (Mori et al., 1980). The location of fodder pollen is often indicated from fertile pollen by the yellow versus white color of the anthers (e.g., Corythophora amapaensis. Huang (pers. comm.) has also demonstrated that pollen tetrads occur in Allantoma lineata.
In the Lecythidaceae, tetrads are usually associated with species that possess two types of pollen--that which germinates and carries the sperm to the egg to make possible the process of fertilization and that which does not germinate called fodder pollen which serves as a pollinator reward. Some fodder pollen is differentiated from the fertile pollen by remaining in tetrads whereas the fertile pollen is found in monads at maturity, e.g. Couroupita guianenensis. In other species, the fertile and fodder pollen can not be distinguished from one another, e.g., Lecythis pisonis (Mori et al., 1980). The location of fodder pollen is often indicated from fertile pollen by the yellow versus white color of the anthers (e.g., Corythophora amapaensis. Huang (pers. comm.) has also demonstrated that pollen tetrads occur in Allantoma lineata.