Influence of indole-3-acetic acid and gibberellin A₃ on elongation of regal lily (Lilium regale) pollen tube

Pollen grains of Regal Lily (Lilium regale), which had been washed thrice in distilled water, produced shorter pollen tubes than did unwashed ones or washed ones grown in washings of pollen grains, suggesting that pollen grains contain some adhering substance (s) which influence pollen tube elongation. In washed pollen grains, combined use of indoleacetic acid (IAA) and gibberellin A₃ (GA) increased the elongation of pollen tubes to a greater extent than did either of them individually. However, there was no synergism between the two. In unwashed pollen grains or in washed ones grown with washings of pollen grains in the basal medium, IAA+GA produced shorter pollen tubes than did either individually. The presence of sucrose, however, negated this effect of adhering substances.