Effect of 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin on callus induction and growth of Physalis angulata L. leaf explants

Physalis angulata L. is an annual herbaceous plant used as traditional medicine. The roots, stems and leaves are used to treat diabetes, hypertension, fever and headaches. The fruit contains lots of provitamin A and has antitumor, antihyperglycemic, anti-inflammatory, antidiabetic and immunomodulatory activities. P. angulata leaves also contain secondary metabolites of alkaloids, flavonoids, saponins, steroids, tannins, physalin A, physalin B, glycosides and stearic acid. The use of plants as a source of medicine is not only very dangerous for the survival of plants, but also not standardized. Secondary metabolites can be produced in callus by in vitro culture induced with appropriate growth regulators. Through callus culture, secondary metabolites or chemical substances from plants can be produced. This study aims to determine the effect of growth regulators 2,4-D and kinetin on callus induction time, the percentage of explants forming callus, fresh weight, dry weight, and callus morphology. This study was a laboratory experimental with a completely randomized design and 5 treatments (0.0 mg/L 2,4-D + 2.0 mg/L kinetin; 0.5 mg/L 2,4-D + 1.5 mg/L kinetin; 1.0 mg/L 2,4-D + 1.0 mg/L kinetin; 1.5 mg/L 2,4-D + 0.5 mg/L kinetin; 2.0 mg/L 2,4-D + 0.0 mg/L kinetin), each treatment consisted of five replications. The data obtained has been analyzed qualitatively and quantitatively. Qualitative data were obtained from callus morphological (color and texture) descriptions. Quantitative data obtained from callus induction time, the percentage of explants forming callus, fresh weight and dry weight of callus were analyzed using SPSS 24 with a significance value of 0,05. Data analysis on the effect of 2,4-D and kinetin concentrations used the ANOVA test. Difference between treatments were tested using the Duncan´s multiple range test. The results showed that the suitable growth regulator for inducing callus growth in leaf explants of P. angulata L was 2.0 mg/L 2.4D + 0.0 mg/L kinetin. Growth regulator 2.0 mg/L 2,4-D + 0.0 mg/L kinetin induced callus in a short time i. e. 10.60 days after culture, resulting in the highest fresh and dry weight of callus i.e., 0.35 g and 0.03 g, as well as the percentage of explants forming callus 100%. Callus has a compact texture with a variety of colours.