The effect of plant hormones on pollen germination and pollen tube growth of almond cultivars

Abstract

The effects of two plant hormones (auxin -IAA and gibberellin - GA(3)) on pollen germination and pollen tube growth in vitro were investigated in five almond cultivars: 'Tuono', 'Nessebar', 'Ferragnes', 'Ikar' and 'Exinogard' during 2014 and 2015. Germination rate and pollen tube growth were determined on a culture medium containing 15% sucrose and 0.7% agar. Pollen germination in the control variant (without application of hormones) ranged from 23.56% ('Ferragnes') to 51.81% ('Tuono'). Plant hormones mainly influenced an increase in pollen germination. The more pronounced effect of plant hormones was manifested on the length of pollen tubes. Thus, in the pollen treated with auxin, length of pollen tubes increased by 23 to 86%, and in pollen treated with gibberellins by 6 to 22%, depending on the cultivar. The exception was only the cultivar 'Nessebar' in which the gibberellin influenced the decrease in the length of pollen tubes.