Effects of auxin and cytokinin on the regeneration and growth of shoot tomato ( Solanum lycopersicum L.) in drought stress

Abstract

Tomato is one of the most popular foods in the world. However, drought stress has strongly decreased the growth and yield of tomatoes. Therefore, the study on drought-tolerant tomatoes is essential. In this paper, tomato cultivar TN704, which is popularly grown in Vietnam's Southeast and Vietnam's Mekong Delta was selected. The combination of auxin (IAA, indoleacetic acid) and cytokinin (zeatin) at different concentrations was investigated to determine the effective regeneration media. Then, the drought pretreatment was applied to obtain drought-tolerant shoots. The drought tolerance of regenerated shoots was checked by culture in the drought stress condition after two generations (F1 and F2). The physiological and biochemical changes of regenerated shoots in the drought stress condition were analyzed. The MS 1 2 medium supplemented with 0.2 mg/L IAA and 0.5 mg/L zeatin was the effective medium for in vitro shoot regeneration from tomato leaves. The drought pretreatment (MS 1 2 with 20 g/L mannitol) increased the number of regenerated shoots which can develop in the drought stress condition. The regenerated shoots in the F1 and F2 generations grew strongly under drought conditions. The content of chlorophyll, carotenoid and proline, the intensity of respiration and photosynthesis, and the activity of auxin and cytokinin in leaves of F1 and F2 plant were higher than the control.