Effect of exogenous application of IAA and GA3 on growth, protein content, and antioxidant enzymes of Solanum tuberosum L. grown in vitro under salt stress

Abstract

Indole-3-acetic acid (IAA) and gibberellic acid (GA3) are essential for the growth and development of plants. In the present study, the ameliorative potential of these phytohormones on growth, protein content, and antioxidant enzymes was investigated in in vitro-grown Solanum tuberosum L. cultivars ‘Cardinal’ and ‘Desiree’ under salt stress. A 4 × 3 factorial combination of 0, 40, 60, or 80 mM NaCl with 0, 7, or 14 μM IAA, or 0, 14, or 21 μM GA3, were added to Murashige and Skoog (MS) basal medium, followed by inoculation of nodal explants or callus cultures. The data for root and shoot number and length, number of nodes and leaves, fresh weight of plants, increase or decrease in fresh weight of callus cultures, total soluble protein, and superoxide dismutase (SOD) and peroxidase (POD) activities were recorded after 30 d. The growth of both callus cultures and nodal explants subjected to NaCl stress was substantially reduced compared with the control. Both IAA and GA3 successfully alleviated the harmful effects of salt stress on all of the growth parameters studied. Salt stress resulted in decreased protein content, which increased when the media also contained phytohormones. The activities of SOD and POD were increased with either IAA or GA3 under NaCl stress. Therefore, the exogenous application of both IAA and GA3 not only played a positive role in terms of in vitro potato growth but also significantly affected the biochemical parameters tested.