In vitro drought effects on morphological and physiological indices of two fig (Ficus carica L.) cultivars

Abstract

In vitro responses of two fig cultivars, ‘Sabz’ and ‘Siah’, were evaluated in MS media containing four levels of polyethylene glycol (PEG) (0, 2, 4, 6%) as a simulation of water stress. The results showed that in Sabz cultivar, shoot length, shoot fresh and dry weights were 43, 36 and 25%, respectively, lower than control in drought treatments caused by 4% PEG, while the leaf area and specific leaf area were not significantly (P>0.05) affected. In Siah cultivar, shoot length, fresh and dry weights were 57, 58 and 40%, respectively, lower in stressed media in comparison to control. In contrast to Sabz cultivar, leaf area and specific leaf area of Siah cultivar were significantly reduced by addition of 6% PEG (56 and 21.5%, respectively). Naturally, the amount of proline in ‘Sabz’ was higher than in ‘Siah’ (81.8 µmole g-1 versus 16.7 µmole g-1). However, in both cultivars, with the addition of PEG in culture media, leaf proline content was increased, in comparison to control. With increasing PEG% in culture media, the amount of leaf soluble sugars content increased and the amount of starch decreased. The results show that ‘Siah’ is more sensitive to drought than ‘Sabz’ and that in vitro culture can be used to evaluate drought tolerance of cultivars.