Influence of Growth Regulators on Germination of Pollen of Three Tree Species

The influence of IAA, GA₃ and ABA, both individual and in combination on pollen germination was studied. IAA enhanced pollen germination and tube length in Anacardium occidentale Linn. at low concentrations and decreased the same in Bauhinia purpurea Linn and Millingtonia hortensis L.F. GA₃ invariably enhanced the tube growth whereas ABA inhibited considerably. The interaction of these growth regulators on pollen tube growth showed that the inhibitory effect of ABA was overcome by GA₃ rather than IAA. The relevance of these effects has been discussed.