In-vitro Studies on Callus and Shoot Induction of Eichhornia crassipes

Abstract

Eichhornia crassipes, a monocotyledonous plant species finds various uses including environmental bioremediation, biotechnological and medicinal applications. There are only very few in vitro studies conducted on Eichhornia and no successful in vitro callus and shoot regeneration protocols have been developed till date rendering Eichhornia as one of the recalcitrant species holding development of any transgenics and tapping its various biotechnological applications. The present study is the first extensive effort made towards in vitro callus and shoot regeneration response of Eichhornia. We have optimized the best sterilization protocol most suitable for the naturally grown Eichhornia explants collected from two wet and marshy ex situ locations. Different types and different strengths of salts provided through MS and LS media combinations and different growth regulator combinations such as 2,4-D in presence and absence of NAA (0.5 mg/L) and IAA (1 mg/L) were checked for callus induction from different explants of Eichhornia. Similarly, different types and different strengths of salts provided through MS and LS media combinations and growth regulator combinations such as BAP, TDZ and Zeatin in presence and absence of NAA were checked for shoot induction from different explants of Eichhornia. Alternate approaches such as culturing various explants of Eichhornia on two-layered media (lower solid media overlayed with upper liquid media) composed of different strengths (1X, 2X and 4X) of MS and LS combinations along with different combinations of suitable growth regulators were tested for callus and shoot induction responses. In spite of trying various salt concentrations, media and different growth regulator combinations as solid or solid:liquid media, no successful callus and shoot regeneration could be achieved from different explants of Eichhornia. Present study provides a base to take up further extensive studies in future to develop first callus and shoot regeneration protocols for Eichhornia crassipes so far, a recalcitrant monocotyledonous species which holds promise as one of the important biotechnologically and environmentally-relevant potential plant species.