High Efficiency Direct Shoot Organogenesis from Leaf Segments of Aerva lanata (L.) Juss. Ex Schult by Using Thidiazuron

An efficient protocol for direct shoot organogenesis has been developed for the medicinal plant Aerva lanata (L.) Juss. ex Schult. Regeneration was achieved from leaf segments of 20 days old in vitro plantlets raised on Murashige and Skoog (MS) medium containing 0.25-2.0 mg L(-1) thiadiazuron (TDZ), 3% sucrose, and 0.8% agar. After 21 days of culture incubation, maximum number of shoot organogenesis (23.6 ± 0.16) was obtained on medium containing 1.0 mg L(-1) TDZ. The shoots were able to produce in vitro flowers on medium containing 1.0 mg L(-1) TDZ in combination with 0.25-0.5 mg L(-1)  α-naphthaleneacetic acid (NAA). Histological observation showed that the epidermal cells of the leaf explants exhibited continuous cell division led to formation of numerous dome shaped meristematic protrusions and subsequently developed into adventitious shoots. Upon transfer of shootlets to half strength MS medium containing 1.0 mg L(-1) indole-3-butyric acid (IBA), around 86% of the regenerated shoots formed roots and plantlets. Rooted plants were hardened and successfully established in the soil at the survival rate of 92%. The regeneration protocol developed in this study provides an important method of micropropagation of this plant. Furthermore, this protocol may be used for a large scale production of its medicinally active compounds and genetic transformations for further improvement.