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 indole3-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.

Rad opisuje efekat naftenata na ožiljavanje mikroizbojaka bagrema in vitro. Naftenske kiseline su izolovane baznom ekstrakcijom iz srednje frakcije sirove nafte tipa “Velebit”, koja je opisana u ranijim radovima. Donji deo mikroizbojka je uronjen jedan minut u tečni ACM medijum [Ahuja, 1984] u koji je dodato 10, 50 ili 100 µM osnovne mešavine natrijum-naftenata ili njenih pojedinih frakcija dobijenih ekstrakcijom na različitim pH (pH 2, pH 4, pH 7 ili pH 9), odnosno 10, 50, 100 µM ili 1g/l indol-3-buterne kiseline (IBA). Kontrolni tretman je činio ACM medijum bez ispitivanih aktivnih materija. Tretirani mikroizbojci su zatim gajeni na čvrstoj ACM podlozi bez hormona. Značajne razlike među ispitivanim tretmanima su zabeležene tokom treće i četvrte nedelje uzgoja u in vitro uslovima. Konačna ocena je izvedena na osnovu procenta ožiljavanja nakon četiri nedelje uzgoja. Najviši procenat ožiljavanja je postignut rastvorom sa 10 µM natrijum naftenata, nakon čega je ostvaren značajan pozitivan efekat na procenat ožiljavanja (>60%) u odnosu na kontrolni tretman (oko 45%). Rezultati do kojih smo došli kod bagrema potvrđuju ranije rezultate koji su dobijeni kod poljoprivrednih i šumskih drvenastih vrsta o mogućnosti stimulacije ožiljavanja mikroizbojaka i reznica solima naftenskih kiselina.