Localization of calcium on the stigma surface of Ruscus aculeatus L. : Studies using chlorotetracycline and X-ray microanalysis.

By use of chlorotetracycline and X-ray microanalysis it is demonstrated that the receptive surface of the stigma of Ruscus aculeatus is rich in calcium. The high level of calcium is found in the epidermal cells and in the exudate covering the stigma. These results indicate that in vivo, as in vitro, calcium takes part in the regulation of pollen grain germination.