Naphthenic acids - alternative rooting stimulators in black locust microshoots

Abstract

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 μM 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 μM of IBA. However, treatment with 10 μM 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. [Projekat Ministarstva nauke Republike Srbije, br. 43007: Studying climate change and its influence on the environment: impacts, adaptation and mitigation]

Keywords

• naphthenates
• micropropagation
• rooting stimulators
• Robinia pseudoacacia