Pollen Morphology and Viability of Wild Noni (Morinda tomentosa Heyne Ex Roth)

The objective of this study was to ascertain pollen morphology, pollen viability with an acetocarmine test and germination test of pollen in assorted concentrations of sucrose and boric acid solution. The physiology of pollen, mainly germination and viability have considerable attention for its application in plant breeding, conservation, adaptation and understanding of physiological behavior of fertilizing pollen grains. The present investigation was undertaken at the experimental farm of the Central Horticultural Experiment Station (CIAH), Vejalpur, Panchmahals, Gujarat, where 31 diverse accessions of wild Noni (Morinda tomentosa Heyne ex Roth) collected from forest areas of Panchmahals, Kheda and Dantiwada during 2007-08. The mean size of pollen grains varied in different media with comparatively larger size in distilled water. The pollen viability varied between 83.47 to 95.53 percent among the accessions. Fifteen to twenty percent solo sucrose medium appeared precise for pollen germination. The boric acid addition irrespective of concentration (0.005 and 0.01 percent) in sucrose medium of different concentrations impacted the pollen germination. The germination was highest (85.26 percent) when 0.005 per cent boric acid was added to 10 per cent sucrose solution. Further, the lower concentration of boric acid (0.005 percent) displayed better germination of pollen grains than a higher concentration of boric acid. The average pollen tube length was maximum (62.42 µ) in 15 percent sucrose solution while it was minimum (14.36 µ) in 30 percent sucrose solution indicating an intermediate concentration of sucrose medium as appropriate for the growth of the pollen tube. The addition of boric acid to the sucrose medium evinced a clear impact on the growth of pollen tube with a maximum average pollen tube length of 120.74µ recorded in 15 percent sucrose medium fortified with 0.005 percent boric acid. Further research could explore the underlying mechanisms behind the observed effects of sucrose and boric acid on pollen behavior, enhancing our understanding of plant reproductive biology and facilitating improved agricultural practices.