Effect of temperature on the time requirement of pollen tubes to penetrate into the embryo sac after pollination in cherimoya (Annona cherimola Mill.).

摘要

An experiment was conducted to determine the effect of various temperatures on pollen viability of Annona cherimola. Flowers were incubated immediately after hand pollination at different temperatures for sufficient time to complete fertilization, and observed ovary cross-sections by fluorescence microscopy to determine the abortive temperature range for pollen tubes before reaching the ovule. Then, pollen-tube growth were observed hourly within the attainable temperature range to estimate the time requirement for pollen tubes to reach the embryo sac after pollination. Pollen-tube growth rate tended to be faster at higher temperatures within attainable temperature range under 27 degrees C. Pollen-tube growth was greater at 20-27 degrees C than at 18 degrees C, and was slowest at 15 degrees C. At 30 degrees C, although the growth was rapid at the beginning, the growth rate slowed after passing the ovary, and at 32 degrees C, many of the pollen tubes stopped growing before reaching the middle part of the ovary.