Dopamine, Chlorogenic Acid, and Quinones as Possible Cofactors of Increasing Adventitious Rooting Potential of In Vitro Krymsk 5 Cherry Rootstock Explants

Abstract

In the present study, the effect of some not commonly used phenolic compounds was evaluated during the in vitro rooting stage of the cherry rootstock ‘Krymsk 5′ (P. fruticosa × P. lannesiana), in the absence or presence of auxin. Two sets of experiments were conducted. In the first set, the following substances were tested: the o-diphenol chlorogenic acid, in five concentrations (0 μΜ, 0.5 μΜ, 1 μΜ, 5 μΜ, and 50 μΜ) in the presence of a suboptimal indolebutyric acid (IBA) concentration (5 μΜ), the catecholamine dopamine in five concentrations (0 μΜ, 0.5 μΜ, 1 μΜ, 5 μΜ, and 50 μΜ), and the quinone 5-hydroxy-1,4-naphthoquinone in four concentrations (0 μΜ, 0.25 μΜ, 1 μΜ, and 5 μΜ) in the absence or presence of 5 μΜ IBA. In the second experiment, the quinones p-benzoquinone; 1,4-napthoquinone; and 2-hydroxy-1,4-naphthoquinone were tested in four concentrations (0 μΜ, 5 μΜ, 50 μΜ, and 100 μΜ) in the presence of 5 μΜ IBA. An application of 5 μΜ of 5-hydroxy-1,4-naphthoquinone in the auxin-free medium increased rooting potential almost 1.7 times. Rooting percentage was also enhanced up to 4.2 times by dopamine; chlorogenic acid; 5-hydroxy-1,4-naphthoquinone; p-benzoquinone; and 1,4 napthoquinone in the presence of IBA. The present results indicate a possible promotive role of quinones and dopamine during in vitro rooting, at least for Prunus species, and their potential use as rooting cofactors. Moreover, a possible mode of action of the compounds studied related to IAA-oxidase is discussed.