GIBBERELLIN APPLICATION INFLUENCES ON EX VITRO GROWTH, FLOWERING AND STEVIOL GLYCOSIDE ACCUMULATION OF STEVIA REBAUDIANA BERTONI

Abstract

Stevia (Stevia rebaudiana Bertoni) is a small perennial herb with incredible sweetening property. Stevia is known to contain steviol glycosides (SGs), which are about 300 times sweeter than sucrose at their concentration of 4% (w/v). However, the growth of stevia plants and their SGs production are known to be influenced by external and internal factors. In this study, an ex-vitro experiment was conducted to determine the effect of exogenous GA₃ application on the growth, flowering and steviol glycoside (stevioside and rebaudioside A) accumulation in stevia under Philippine condition. A previously established tissue culture-derived plant was used as mother plants and categorized into two groups: (1) non-flowering (NF) and (2) flowering (F). Stevia stem cuttings were sprayed with GA₃ solutions of various concentrations: 0, 50, 100 and 200 mg L^-1 at 1-week interval for 5 weeks. NF plants sprayed with GA₃ showed significant difference in shoot length, number of shoot tips, length of longest primary branches compared to the control. NF plants produced more leaves than F at any GA level but without significant difference. Application of gibberellic acid (GA₃) neither delayed nor inhibits flowering of ex vitro stevia plant but significantly reduced the flowering intensity of the plant. Exogenously applied GA₃ also did not affect SG accumulation in the leaves and flowers.

Keywords

• Stevia rebaudiana Bertoni,steviol glycosides,gibberellin,steviol glycosides

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