No abstract

Naphthenic acids were isolated from gas oil fractions (distillation interval 168-290 qC) of Vojvodina crude oil "Velebit", characterized and their biological activity evaluated by the biochemical changes in cuttings of Robinia pseudoacacia after treatment with naphthenate. The activities of IAA peroxidase, total peroxidases and amylase, as well as the contents of reducing sugars and total proteins, were determined in the basal parts of soft wood cuttings of black locust after treatment with sodium naphthenate or the sodium salt of 1-naphthaleneacetic acid (NAA), concentration 10 -7 mol dm -3 for 3 or 6 h. High activities of IAA oxidase and amylase, together with a low activity of peroxidase (which is known as being stimulatory for the initiation and activation of primordia) were obtained after the three-hour treatment with sodium naphthenate. Six-hour treatment had an inhibitory effect on the examined biochemical markers. The effects of three-and six-hour treatments with NAA were between those of the corresponding treatment with naphthenic acids.

The study describes the rooting effect of naphthenates and their fractions on in vitro grown Robinia pseudoacacia L. shoots. Natural naphthenic acids have been isolated by alkaline extraction from middle fraction of crude oil type ?Velebit? from Vojvodina, characterized and fractionated. Black locust shoot bases were immersed in ACM medium [Ahuja, 1984] without agar supplemented with either 10, 50 or 100 ?M of basic naphthenate preparation, naphthenate fractions obtained by extraction at different pHs (pH 2, pH 4, pH 7 and pH 9), or indole- 3-butyric acid (IBA). Treated shoots have been then grown on hormone-free medium for four weeks. Significant differences among test treatments were recorded during the third and the fourth week of in vitro cultivation. Final evaluation was performed on the basis of rooting percentage after four weeks of cultivation. The highest rooting percentage (>70%) was achieved after the treatment with solution containing 50 ?M of IBA. However, treatment with 10 ?M of naphthenate preparation achieved also positive effect on rooting (>60%). Average rooting percentage in the control treatment was just 45%. Our results with black locust confirm previous results gained with some other agricultural and forest tree species that naphthenates have the potential to stimulate rooting in shoots and cuttings.

This work presents a study of the effect of foliar and root application of low concentrations (0.1–10 µM) of potassium naphthenate on the antioxidative status of cucumber (Cucumis sativus L.), assessed for both local and systemic organs. Changes in the contents of proline and glutathione indicate that the treatment of plants with potassium naphthenate can be characterized as a mild abiotic stress. The antioxidative system of cucumber plants is sensitive to such treatment, since organs directly exposed to the chemical showed a decrease in total antioxidant activities and an increase in peroxidation. In the organs that were not directly treated, an increase in the total antioxidative activity was observed only at the lowest naphthenate concentration while at higher concentrations this activity tended to decrease. As far as the activities of antioxidant enzymes (guaiacol peroxidase, superoxide dismutase, catalase) are concerned, the responses observed differed between enzymes for a given treatment, but showed similar trends within treated local and untreated systemic organs.