Combined Effect of Some Growth Regulators on Growth and Gametangial Formation in the Liverwort Riccia gangetica Ahmad

The present work deals with the effect of IAA-kinetin, IAA-GA³and GA³-ABA interactions on growth and gametangial formationin Riccia gangetica in vitro. Inhibitory effect of high concentrationof IAA on vegetative growth is overcome by the co-addition ofkinetin. The best response in terms of fresh and dry weightyields of thalli is obtained by a combination of 10^–5mol dm^–3 kinetin+ 10^–7 mol dm^–3 IAA. Interactionof IAA and kinetin has an additive effect on archegonial formation.Co-addition of IAA and GA³ decreases production of archegoniaand antheridia as compared to those produced in response toIAA and GA³ alone, respectively. Combination of GA³ and ABAreduces vegetative growth, as well as the number of anthendiaand archegonia. Key words: Riccia gangetica, growth, growth regulators, gametangial formation