An improved micropropagation and ex vitro rooting of a commercially important crop Henna (Lawsonia inermis L.).

Abstract

An improved micropropagation protocol has been developed for a cosmetically important, dye yielding crop, henna (Lawsonia inermis). Quality of henna product is governed by naphthoquinone based pigment lawsone, thus in vitro multiplication of superior healthy plant to achieve enhanced productivity in terms of dye content and biomass deserve due attention. In the present study, nodal explants collected from an elite plant screened on the basis of superiority in lawsone content was cultured on MS medium supplemented with 0.5μM benzyl adenine (BA) gave significantly (p < 0.05) high number of shoots (24.33). The explants placed on MS medium augmented with 0.5μM BA and 2-isopentenyladenine (2-iP) resulted in the formation of maximum number of shoots (43.67) and was elongated (12.57cm) within 4weeks of culture period. Enhanced axillary bud proliferation and production of mass number of micro shoots was achieved by the continuous subculture in MS medium containing 0.5μM BA and 2-iP. In vitro raised micro shoots were dipped in 0.44mM NAA for 5min followed by planting in polyethylene pots containing a soil: vermiculite (1:1 v/v) mixture produced rooted plantlets (100%). Different auxin types and its concentrations had significant role rooting of L. inermis. Rooting response of various size shoots of L. inermis treated with 0.44mM NAA showed 100% rooting in 4.1-5cm size class shoots. After two months of potting, survived (95%) plants were successfully transferred to medicinal plant garden of the Department. The lawsone content of one-year-old micropropagated plants (23.04mg/gdw) growing in normal environmental conditions and elite mother plant (22.84mg/gdw) was almost similar. Through the present study, efficient cloning of superior germplasm of L. inermis was established.