The Regulation of Extracellular Calcium on Pollen Germination and Pollen Tube Growth of Lilium Longiflorum

Using the techniques of in vitro culture, the effects of different concentrations of extracellular Ca2+ on the germination of lily pollens and the growth of pollen tubes were studied. The results showed pollen germinated and pollen tube grew fastest at the concentration of 0.1% Ca2+. At higher or lower than this concentration, pollen germination and pollen tube growth were significantly inhibited. When pollen tubes were transplanted from culture medium of 0.1% Ca2+to that of 0.3% Ca2+, pollen tube growth were obviously slowed down in seconds. Moreover, Long-time growth at 0.3% Ca2+concentration also resulted in snaky pollen tube. This change is irreversible, because the reduction of the calcium concentration, or addition of pectinase, in the medium, pollen tubes ruptured. These results indicate that calcium served as the pollen tube growth regulatory signals, has direct and indirect effects on pollen tube growth.