The Variation of Style Auto-fluorescence after Calmodulin Treatment on Self- and Cross-pollination in Pyrus pyrifolia Nakai. The Variation of Style Auto-fluorescence after Calmodulin Treatment on Self- and Cross-pollination in Pyrus pyrifolia Nakai. In Vitro Effects of Stylar S-RNase of Pear on the Ultra-structure of Its Pollen Tubes