Evaluation of optimum concentration of naphthalene acetic acid on <i>in vitro</i> rooting and acclimatization of tissue culture date palm (<i>Phoenix dactylifera</i> L.) plantlets

Abstract

A major limitation in large scale application of micropropagation technology is high mortality experienced by in vitro raised plants during laboratory to land transfer. This study was aimed at investigating the best concentration of Naphthalene acetic acid (NAA) on in vitro rooting and also develop protocol for successful plant acclimatization with high survival rate. Date palm plantlets were rooted on Murashige and Skoog (MS) basal medium with different NAA concentrations (0.0, 0.1, 0.5 1.0, 1.5 and 2 mg/l) without activated charcoal. Result showed that all the NAA concentrations supported root formation. The optimal initiation and growth of roots of the plantlets were observed at NAA concentration of 1.0 mg/l (87 %) and least with Basal MS without NAA (47 %). Results also showed that root number and lengths increased with increasing NAA concentrations up to 1.0 mg/l and decreased thereafter. The culture mixture of peat moss + soil (2:1) gave the highest survival percentage of 80 % for plant acclimatization. This investigation had shown that accurate assessments of responses to medium at various stages should be considered as specific requirement for successful plant acclimatization. Keywords: date palm, in vitro , plantlets, acclimatization