Physiological and morphological responses to abiotic stresses in two cultivars of Stevia rebaudiana (Bert.) Bertoni

Ashwath, N ORCiD: 0000-0002-4032-4507Stevia rebaudiana (Bert.) Bertoni is cultivated for its sweet leaves as they contain steviol glycoside sweeteners such as stevioside and rebaudioside A. Two cultivars of S. rebaudiana, Shoutian-2 and Fengtian, were evaluated in a greenhouse for their tolerance to abiotic stresses. The seedlings were exposed to salinity, drought or waterlogging stresses for 4 weeks. The cultivars differed significantly in their biomass accumulation, tissue ion concentrations and steviol glycoside accumulation. The salt tolerant cv. Fengtian contained higher concentrations of K + which led to higher K + /Na + ratio in the leaves, as compared to the less salt tolerant cv. Shoutian-2. Reduced biomass accumulation in cv. Shoutian-2 coincided with increased Na + and Cl ˗ concentrations in the leaves. The waterlogging stress reduced growth of both cultivars, but the salinity stress increased rebaudioside A concentration in the tolerant cv. Fengtian, and the drought stress increased stevioside concentration in the cv. Shoutian-2. This study concludes that the two cultivars of S. rebaudiana differ in their tolerances to salinity and drought stresses. © 2019 South African Association of Botanist