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Physiological and morphological responses to abiotic stresses in two cultivars of Stevia rebaudiana (Bert.) Bertoni
- Debnath, M., Ashwath, N., Midmore, D.J.
- South African journal of botany 2019 v.123 pp. 124-132
- Stevia rebaudiana, biomass production, cultivars, drought, flooded conditions, glycosides, greenhouses, leaves, potassium, salinity, salt stress, salt tolerance, seedlings, sodium, steviol, stevioside, sweeteners, water stress
- Stevia 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.