Characterization of Male Reproductive Organs in Durian; Anther Dehiscence and Pollen Longevity

We characterized the pollen germination and longevity in durian (Durio zibethinus Murr.) under in vitro conditions and observed the morphological changes during anther dehiscence. Approximately 10 anthers aggregate on a filament; these merge with others at the base to form five phalanges in the flower. Anther dehiscence occurred at 19:00, at the same time as floral anthesis. Observation with a low-vacuum scanning electron microscope revealed pollen grains clinging to the anther even after the anther had dehisced. In vitro pollen germination was highest at a sucrose concentration of 10%. In the test of pollen germination on Brewbaker and Kwack (BK) medium, the germination rate was highest (59.1%). The germination rate was decreased (5.0% to 46.0%) when any of the minerals of B, Ca, Mg, and K was removed. The pollen germination rate at anthesis was 40.4 to 50.6% in four cultivars (‘Mon Thong’, ‘Chanee’, ‘Kradum Thong’, and ‘Phaung Manee’), and the rate was maintained at more than 40% until 24 h after anthesis and then decreased gradually. When pollen was stored under desiccating conditions with silica gel, pollen following 120-h storage could germinate after rehydration. Rehydration for 12 h achieved the best results, with 47.0% germination occurring after this rehydration period.