Effects of Calcium Ion and the Protective Action on Survival and Growth Inhihition of Pollen

Abstract

Abstract Studies were conducted on the protective action of Ca against growth inhibition and death of pollen from Crinum asiaticum and Catharanthus roseus . Ca ions not only promoted pollen germination and pollen tube growth, but also were antagonistic to pollen injuries induced by various chemical and physical treatments. Most of the chemicals used seemed to act as osmotic inhibitors. Among the chemical agents tested, DNP inhibited pollen germination more strikingly with Ca than without it, whereas pollen tube growth was enhanced. Another metabolic inhibitor, low temperature, showed a similar effect on pollen germination. Insignificant or no protective action of Ca was observed when IAA, TIBA and coumarin, were applied. Large populations of pollen when grown in cultural media witbout Ca showed a partial protective action. The protective action of Ca in pollen growth against various inhibitors required other cations such as Mg and K ions. The promoting of pollen growth by Ca also required tbese otber cations. The protective action of Ca is considered to be based on its binding in tbe pollen cell walls, particularly in the pectic regions. This gives rise to a decreased permeability and increased structural rigidity against tbe chemical and physical inhibitors.