1Genetic and Plant Production Department, Agricultural Faculty of Shirvan, University of Bojnord, Bojnord, Iran
2Horticultural Sciences and Engineering Department, Faculty of Crop Sciences, Sari Agricultural Sciences and Natural Resources University, Sari, Iran
چکیده
Hormones are chemical messengers that regulate various physiological processes in plants. Stevia growth is affected by them, so this study investigated how gibberellic acid (GA) and kinetin (KN) affect it. Two RCBD experiments were conducted in 2016 in Shirvan, Iran, to study gibberellic acid (GA) and kinetin (KN) hormones. First experiment included the following GA treatments: 1. control (no GA) 2. 100 ppm 3. 200 ppm 4. 300 ppm (PPM). In the second experiment, KN was included in the treatments: 1. control (no KN) 2. 20 ppm 3. 40 ppm 4. 60 ppm. At all concentrations of KN and GA, plant height, leaf number, leaf dry matter, and biomass significantly enhanced while yield index decreased. Additionally, although GA application decreased non-reducing sugars (TSSN) and total soluble sugars (TSS), KN at 40 and 60 ppm increased TSS. In contrast to KN treatments, GA treatments improved total stevia glycosides (TSGs). Furthermore, FLV was not affected by GA, but plants treated with KN 60(KN at 60) ppm had the highest FLV. All GA concentrations induced more CHL b than control. Additionally, it boosted N, P, and K, however, only KN at 40 and 60 ppm increased N and K. Overall, the positive effects of both hormones are dose-dependent; while KN treatment was ineffective in terms of TSG productivity, GA treatment was beneficial.