Histological and morphological studies of pollen grains from elongata, reduced elongata and staminate flowers in Carica papaya L.

摘要

The quality and quantity of pollen from three types of flowers; elongata, reduced elongata and staminate from the commercialized Thai papaya cultivar 'Khak Nual' were determined using pollen morphology, pollen physical characters and pollen development processes. Pollen development progressed at the same pace in the three types of pollen-producing flowers and was consistent with pollen development in many angiosperms. Pollen morphology showed that papaya pollen grains are tricolporate, with three apertures, and there is no significant difference in diameter (25.18-25.72 micro m) and weight (11.76-15.45 ng) among pollen sources. The staminate flower shows the lowest amount of pollen, with 12,368 pollen per anther, but higher viability and germination rates of 95.53% and 53.64%, respectively. In contrast, the elongata type shows the highest amount of pollen grains with 14,884 pollen per anther and the lowest viability and germination rates, 93.06% and 46.33% respectively. The physical characteristics of pollen grains from reduced elongate and elongate flowers are similar. Reduced elongate flower type can donate pollen without self-pollinating.