Amelioration of Morpho-structural and Physiological Disorders in Micropropagation of Aloe vera L. by Use of an Aromatic Cytokinin 6-(3-Hydroxybenzylamino) Purine

An in vitro regeneration method with functional morpho-structural and physiological traits has been optimized for Aloe vera L. in the present study. Among the various types and treatments of cytokinins [6-benzylaminopurine, BAP; 6-(3-hydroxybenzylamino) purine, mT (meta-topolin), and 1-phenyl-3-(1,2,3-thiadiazol-5-yl) urea, TDZ] tested for shoot induction, the best bud break response (100%) occurred on the Murashige and Skoog (MS) medium containing 1.0 mg L⁻¹ mT with the development of 5.0 shoots with 3.3 cm average length. Liquid MS medium containing a standardized combination of 0.5 mg L⁻¹ mT with 0.25 mg L⁻¹ α-naphthalene acetic acid (NAA) triggered proliferation of shoots, and maximum 42 shoots with 5.6 cm average length were obtained after 3rd subculture. Meta-topolin and NAA-derived shoots cultured on half strength MS medium containing 1.0 mg L⁻¹ Indole-3-butyric acid (IBA) resulted in maximum rhizogenesis than BAP + NAA and TDZ + NAA-derived shoots. Meta-topolin and NAA combination improved photo-pigments, net rate of photosynthesis, and morpho-anatomy of leaves as compared with other treatments. The rate of photosynthesis, transpiration, and field survival was significantly affected by the types and concentrations of cytokinins used during plantlet development. The present findings unraveled the potential of meta-topolin to alleviate in vitro induced morpho-structural and physiological anomalies and improved survival of micropropagated plantlets of A. vera.