POLLEN GRAINS AND POLLINATION IN DURIAN, DURIO ZIBETHINUS MURR.
Pollen grains are rounded, sticky, and released in clumps indicating little transfers by wind. At the time of anthesis, a receptive stigma is moist with stigmatic fluid upon which pollen grains can stick readily. Durian flowers are receptive before anthesis and the receptivity is considerably reduced in the following day.
Pollen viability of four commercial cultivars, namely Mon-Thong, Kradum-Thong, Chanee, and Kan Yao was assessed with Alexander's pollen stain. High viability ranging from 83 to 96% at 1 day prior to anthesis as well as at the day of anthesis was observed. Two days after anthesis, the viability decreased to 75, 77, 92 and 93% in cv. Mon-Thong, Kradum-Thong, Chanee, and Kan Yao, respectively.
Germination and pollen tube growth in vitro were maximum in wide range of concentration, i.e. 20–35% sucrose with 30–60 ppm B, 50–90 ppm Ca, and 15–30 ppm K and Mg. Pollen tube emergence was visible within 2 hours after pollination.