Exogenous application of indole acetic acid (IAA) and giberrelic acid (GA3) induces changes in carbon and nitrogen metabolisms that affect tobacco (Nicotiana tabacum L.) production

Abstract

Experiments, both pot and field trial, were conducted to examine the effects of exogenously applied IAA and GA3 (at 0, 10, 20 and 30 days after topping) individually or in combination, on growth and C and N metabolisms of tobacco (Nicotiana tabacum L.). Application of IAA or GA3, at low concentrations had a promising effect in terms of promoting the yield and quality of tobacco. The key enzymes' activities were also enhanced by low PGRs concentrations, which is known to be involved in the C and N metabolisms. The combined treatment of the two PGRs was more effective than the PGRs applied individually in improving the activities of nitrate reductase (NR), invertase (INV) and amylase (AMY) finally resulting in improved soluble sugars, reducing sugars, starch, total C and N, soluble proteins and nicotine content. The optimum levels for improvement of C and N metabolites were found to be GA3 at 50 mg/L and IAA at 30 mg/L.

Temperature and GA3 on ROS and cytogenetic stability during in vitro cultivation of strelitzia zygotic embryos

“…This higher activity may have contributed to the improved development of the seedlings, since this enzyme is responsible for the reduction of nitrate to nitrite, which is the first reaction in the assimilation of nitrogen, an element present in many essential macromolecules (Krapp, 2015). This increase in nitrate reductase activity may be a result of the exogenous application of GA 3 (Qin et al, 2019). Regardless of the GA 3 concentration used, there was an increase in nitrate reductase activity in the roots (719.95 µM NO 2 min -1 mg -1 protein), and this value was 41% higher than that in the shoots (427.86 µM NO 2 min -1 mg -1 protein) (Figure 2B and 3).…”