Abstract

Clonal propagation method through induction of adventitious rooting in hypocotyl-plus-stem (HpS) and juvenile-stem (JS) cuttings was reported in Aegiceras corniculatum (L.) Blanco (khalsi), mangrove plant of coastal Orissa, India. The induction of adventitious roots is an essential process in vegetative propagation. Adventitious rooting in above cuttings was induced by exogenous application of root promoting substances (RPS) viz. IBA and NAA in four combinations under mist house conditions. Significant increase in rooting response (76.70%) and root number (4.48 per cutting) were recorded in the HpS cuttings treated with IBA 1.0 mg/l + NAA 5.0 mg/l (T2). However, the JS cuttings under same treatment (T2) showed maximum root length (4.30 cm per cutting). Though, untreated HpS cuttings responded to induction of rooting (16.70 %), JS cuttings failed to produce any adventitious root without RPS. Anatomically, all the treated cuttings responded to rooting process by forming ‘root primordia’ after 10 days of treatment in HpS and 20 days in case of JS cuttings. The ‘root emergence’ took place after 30 days of treatment in HpS and 40 days in case of JS cuttings. Biochemically, prompt and significantly highest adventitious rooting capability (in terms of percent rooting and mean root number per cutting) of HpS cuttings might be due to presence of higher level of indigenous storage carbohydrate (starch and soluble sugar) and soluble protein in the rooting zone as compared to JS stem cuttings. The present study, thus, highlights a viable process of adventitious root formation by analyzing anatomical and biochemical evidences which may open a new avenue for mass production of planting materials through clonal propagation using cryptoviviparous hypocotyls of Aegiceras corniculatum, a naturally depleted but economically important mangrove plant of Orissa, India.

Key words: Adventitious rooting, carbohydrate, protein, root primordia, root promoting substances.