The role of amino acids and polyamines in increasing the stevioside of the stevia plant (Stevia rebaudiana Bertoni) in vitro

Abstract

This study was conducted in the Plant Tissue Culture Laboratory at the College of Agriculture, Diyala University, for the period 2022-2023. It aims to identify the role of amino acids and polyamines in increasing the stevioside compound of the stevia plant in vitro. The histological and field experiments included the use of the amino acids glutamine and arginine,  the polyamine putyrcine at three different concentrations, in addition to the control treatment, which is 0, 50, 100, and 150 mg.L^-1. The results showed that putyrcine gave the highest plant height of 12.6 cm. The arginine at a concentration of 50 mg. L^-1 and putyrcine at 150 mg. L^-1 gave the highest number of branches reached 2.2 branches. Plant^-1. The arginine treatment at 50 mg.L^-1 gave the highest wet weight of 0.483 grams, and the treatment at 150 mg.L^-1 gave the highest sweetening for all amino acids used. It was the highest for putyrcine, which reached 251.6 micrograms ml, and the lowest sweetening for the control treatment and for all treatments. The highest average content of stevioside in the leaves of the stevia plant was when the plants were sprayed in the field with putyrcine at a concentration of 150 mg.L^-1, reaching 462.473 µg ml-1. All experiments were carried out in a completely randomized design (CRD)