Effect of High Temperature on Pollen Grain Germination, Pollen Tube Growth, and Seed Yield of Chinese Cabbage1

Abstract

Abstract Seed yield of Chinese cabbage ( Brassica campestris ssp. pekinensis Rupr.) was studied at 34–37/22–24°C (day/night) temperatures applied at different growth stages. High temperatures at first anthesis and immediately after pollination diminished seed yield mainly through reduction in seed number. Hand pollination with pollen grains from plants reared under normal temperature improved seed yield of the plant heated at first anthesis. Both male and female gametogeneses appeared to be affected by high temperature based on seed set, but the most drastic effect of high temperature on seed yield occurred after pollination. In vitro pollen viability tests indicated that the optimum temperature for pollen grain germination and pollen tube growth was 20°. Temperatures below 16° or above 28° reduced pollen grain germination and pollen tube growth mainly because of an increase in burst pollen grains.