Comparative physiological behavior of fig (Ficus carica L.) cultivars in response to water stress and recovery

Fig (Ficus carica L.) is a highly valued fruit crop for its nutritional and health benefits and it is widely cultivated in arid and semi-arid regions. Thus, understanding its responses to abiotic stresses is of great importance since fig fruit production and quality were affected by water shortage. In the present work, the effects of water stress and subsequent irrigation on physiological characters were investigated on two Tunisian commercial fig cultivars: Zidi 'ZD' and Bither Abiadh 'BA'. Water stress was imposed by suspending irrigation for two weeks. After that, fig plants were well re-watered in the recovery period. The experiment was conducted for two consecutive years. Results showed that gas exchange parameters: photosynthesis rate (P-N), stomatal conductance (g(s)) and transpiration rate (E) decreased significantly in drought-stressed plants in comparison to well-watered ones. The maximum photochemical efficiency of photosystem II (Fv/Fm) and chlorophyll index were also affected. Water stress induced an increase in leaf temperature and a massive leaf abscission in both cultivars, while re-hydration stimulated emergence of new leaves and restored photosynthetic apparatus function in previously stressed-plants. Water recovery promoted the vegetative growth and the duration of vegetation cycle. Both cultivars 'ZD' and 'BA' did not show differences in their water stress sensitivity and recovery. It was conclude that fig is a drought avoider that abscises leaves to reduce water loss. Although fig is able to revegetate when water becomes available, it is recommended do not exceed one week of water stress by suspending irrigation, during summer season, to avoid total leaf abscission. Our research highlighted the need for additional long term studies under different climatic and edaphic conditions to provide more information about the ecophysiology of fig tree.