Sweet potato (Ipomoea batatas L.) plants were cultivated in vitro in Murashige and Skoog (MS) medium with 20 and 40 g L-1 of sucrose under two different photon flux densities (21 and 60 µmol m-2 s-1). Leaves developed in vitro mostly showed high variable to maximum fluorescence ratio (F V/F M) , indicating good development of photosynthetic apparatus. This ratio decreased during leaf aging, especially in the plants cultivated in vitro on medium with higher sucrose concentration and higher photon flux. Leaves developed ex vitro showed high F V/F M ratio during whole experiment. The effective photochemical efficiency (F V'/F M') was maximum at 15th day after emergence of leaves. Photosynthetic potential rate was higher in leaves developed in vitro than in leaves originated ex vitro.
culture medium; photon flux density; photosystem; sucrose
