Evaluation of sodium nitroprusside and putrescine on polyethylene glycol induced drought stress in Stevia rebaudiana Bertoni under in vitro condition

The present work aimed to regenerate Stevia rebaudiana Bertoni under in vitro drought condition induced by different concentrations (0%, 5%, 10 % and 15 %) of polyethylene glycol (PEG) 6000, and to investigate the mitigating effect of sodium nitroprusside (SNP; nitric oxide donor) and putrescine in relation to efficient multiplication. Varying concentrations of SNP (50, 100, 250 and 500 mu M) and putrescine (0.05, 0.1, 0.3 and 0.5 mM), used singly or in combination in the MS medium, along with best selected concentration of plant growth regulator (kinetin 0.2 mg l(-1)) under in vitro drought imposed by 10 % PEG were taken for studies at 20, 40 and 60 days after inoculation (DAI). The best response with maximum values on the basis of morphological parameters was recorded; number of shoot and number of leaves were observed in half strength MS media supplemented with combination of both SNP and putrescine treatment i.e. SNP 100 mu M + putrescine 0.05 mM followed by other treatments as compared to remaining treatments as well as control (10 % PEG only). On the basis of present investigation, it is concluded that in vitro drought stress significantly reduced the number of shoot, length of shoot (cm), number of leaves, number of roots, length of root (cm) and survival percentage. However, treatment with SNP and putrescine, alone or in combination, alleviated the negative impacts of drought stress up to a great extent. The production of more number of stevia leaves even under drought condition as a result of ameliorative treatment with SNP and putrescine has implication in R&D industries to target for production of maximum content of stevioside and rebaudioside, key principles in treating diabetes, if there is an increase in their content.