Pollen dispersion in Myrica esculenta (Myricaceae): a dioecious anemophilous tree species of Himalaya

摘要

Myrica esculenta is an important dioecious medicinal tree species of the Himalayan region. The role of floral morphology and pollen flow between the sexes in M. esculenta is unknown. Therefore, a study on floral morphology, pollen production, germination and pollen dispersal in M. esculenta was undertaken in a Himalayan temperate forest during 2015-2016 for one reproductive season. Pollen production and dispersion were observed in two habitat conditions, viz. tree outside forest (TOF) and natural forest (NF). Pollen flow was observed by exposing jelly-coated slides at geometrically increasing distances under two habitat conditions, i.e. TOF and NF. The pollen production per tree was significantly higher in TOF conditions (two times more than the NF). The total pollen production in the trees of outside forest was 3.10 x 10(11) +/- 0.58 x 10(11) pollen per tree which was 1.60 x 10(11) +/- 0.42 x 10(11) pollen per tree in natural forest condition. The fruit set was 6% more in TOF condition than the NF, indicating pollen limitation fecundity in M. esculenta. Pollen dispersal strongly differed between TOF and NF.