Plant regeneration from thin cell layers in Spinacia oleracea

Abstract

Caulogenesis and somatic embryogenesis were induced from transverse thin cell layers (tTCLs) of two European (Spinacia oleracea L.) spinach genotypes. Regeneration occurred mostly when tTCLs had been excised from seedlings grown on a preconditioning medium consisting of White's macroelements, Nitsch's microelements, Murashige and Skoog's (MS) vitamins, 6 g l⁻¹ agar and 20 g l⁻¹ glucose. The explants were cultured on MS medium supplemented with sucrose (10, 30, 50 or 80 g l⁻¹) or fructose (5, 10 or 30 g l⁻¹) and several combinations of indole-3-acetic acid (IAA), α-naphtalene acetic acid (NAA), 6-benzylaminopurine (BAP) and gibberellic acid (GA₃). Most of the regeneration events were obtained from root explants of the cultivar Carpo. The best result was observed on MS medium supplemented with 50 g l⁻¹ sucrose, 100 μM NAA, 1 μM BAP and 10 μM GA₃. After an 8-week culture, the calluses were transferred onto MS medium where shoots and somatic embryos appeared 1 week later. The best root development was obtained on MS medium supplemented with 4.9 μM indole-3-butyric acid (IBA) and 8 g l⁻¹ Phytagel. The plantlets were, then, transferred to soil and developed into well-conformed, fertile plants.