Shoot Organogenesis from Tetrastigma hemsleyanum Leaf and Petiole Explants, and Subsequent Plant Regeneration and Acclimatization

Tetrastigma hemsleyanum is a perennial evergreen vine of the Vitaceae. The entire herb is used in traditional Chinese medicine as a broad-spectrum plant-based antibiotic, so it has high economic and social value. Wild T. hemsleyanum resources are scarce, so it has been declared an endangered and rare medicinal plant. Seed yield is low and vegetative propagation by cuttings results in limited plant production, so development of the T. hemsleyanum industry requires optimized propagation protocols and the development of new biotechnologies to proliferate this plant in commercial quantities. In this study, shoot organogenesis was successfully induced from leaves and petioles. Two plant growth regulators, 6-benzyladenine (BA) and thidiazuron, induced callus and adventitious shoots, but the ideal adventitious shoot induction medium was Murashige and Skoog (MS) medium containing 1.0 mg L-1 BA and 0.1 mg L-1 alpha-naphthaleneacetic acid (NAA). This resulted in a shoot proliferation coefficient (SPC) of 6.73 within 30 d at a light intensity of 100 mu mol m(-2)s(-1). When light intensity was increased from 50 to 200 mu mol m(-2) s(-1), SPC (7.35), chlorophyll a (Chl a), Chl b, and total Chl (a + b) content increased. On MS medium containing 0.1-2.0 mg L-1 NAA or indole-3-butyric acid, 100% of adventitious shoots formed adventitious roots. Plantlets showed no obvious morphological variation, and their survival exceeded 98% on a substrate of peat and river sand (v:v = 2:1). This study's protocols allow for the mass production of adventitious shoots for conservation purposes, and potentially for the commercial propagation of T. hemsleyanum.