Effects of Naphthenic Acids on Rooting of In Vitro Grown Sequoia sempervirens

Abstract

The study describes the effect of naphthenates and their fractions on rooting of in vitro grown Sequoia sempervirens (Lamb. ex D. Don) Endl. shoots. Natural naphthenic acids have been isolated by alkaline extraction from the middle gas fraction of the crude oil. Sequoia sempervirens shoots (1 cm in length) were grown on Murashige and Skoog (1962) (MS) medium supplemented with either total naphthenate preparation, naphthenate fractions obtained by extraction on different pH (pH 2, pH 4, pH 7 and pH 9), or indole-3-butyric acid (IBA) in different concentrations (twenty treatments tested). The rooting testing was based on number and total length of roots formed after four weeks of in vitro growth. Similarly to total length of roots, the highest number of roots per explant (approximate to 7) was achieved in medium containing 50 mu M of the naphthenate fraction extracted at pH 2 and in medium containing 50 mu M of the fraction extracted at pH 9. That is triple higher than in the control and significantly better than in the best IBA-treatment (50 mu M IBA), where five roots per explants in average were formed. Similar to the results obtained for some agricultural and tree forest species, our results with Sequoia sempervirens confirm the possibility of rooting stimulation by naphthenates.