Abstract

Pollen grains were sown on agar germination media containing increasing concentrations of the following disruptors, oryzalin and colchicines. Germination tube length was examined and results were evaluated. Treatment with oryzalin caused a slight but significant reduction in pollen germination while colchicines did not affect germination. All the microtubules (MTs) disruptors caused a decline in pollen tube length. The concentration that caused a significant reduction in tube length was 100 µM for oryzalin and 500 mM for colchicines. The effectiveness of these inhibitors varied. At the highest tested concentrations, oryzalin was more effective than colchicines in reducing tube length. In addition, MT disruptors induced tube curving. Curving was caused by disruption of the microtubules in the tip. We concluded that microtubules were involved in tip growth of pollen tubes. Therefore, the functional MT configuration is essential for the pollen tube to exert the penetration force.

Key words: Pollen germination, pollen tube growth, inhibitor treatments, gelling agent.