Calcium distribution and function during anther development of Torenia fournieri (Linderniaceae)

Potassium antimonite was used to locate calcium in the anthers of Torenia fournieri (Linderniaceae). Abundant calcium precipitates accumulate in the microsporocyte cytoplasm. After meiosis, calcium precipitates are abundant on the microspore wall, as well as the callosic wall of each tetraspore. A large number of calcium precipitates also occur on the outer membranes of the tapetal cells, and in the intercellular spaces of the endothecium and middle layer. The quantity of calcium precipitates in the cytoplasm and nucleus increases at the early microspore stage, then gradually deceases until pollen maturation. Calcium precipitates on the pollen wall gradually increase from the early microspore stage until pollen maturation. Numerous calcium precipitates are observed around the Ubisch bodies. The relation between the distribution of calcium and mitosis, nuclear displacement, the formation of the pollen cell wall, as well as the possible functions of anther walls and Ubisch bodies in the transportation of calcium to the mature pollen are discussed.