Physiological behaviour of fig tree (Ficus carica L.) under different climatic conditions

Abstract

Climatic conditions in many regions, especially in the Mediterranean basin, have been characterized by the scarcity and seasonal variability of rainfall associated with prolonged high temperatures during summer. Climate change might trigger biodiversity loss and lead to higher selection pressure on plant species. The study of water stress impacts is one of the essential agronomic issues. It allows better management of water resources and a better understanding of adaptation traits that trees may develop to maintain their fruit productivity and quality and survive in different climate disturbances. The fig (Ficus carica L.) tree, one of the oldest cultivated fruit crops globally, is being affected by global warming and changes in the distribution of precipitations. The combined effects of high temperatures and frequent drought have increased the aridity of the already arid fig cultivation regions. Even though fig trees have been widely cultivated in the Mediterranean basin, few studies on fig resilience to climate change. In this context, the present chapter presents the most recent findings on the ecophysiological behaviour of fig tree and their responses to abiotic stresses, particularly high temperatures and water stress. It has been demonstrated that fig cultivars showed two different strategies, (1) an avoidance strategy to cope with extreme heat and water stresses, expressed by the ability to optimize the leaf morphology through stomatal closure and leaf abscission, and (2) an adaptive strategy by maintaining low rates of active photosynthesis and stomatal conductance and reducing water loss. These responses mainly depend on the duration and the intensity of stress and are cultivar-dependent. Fig has also revealed drought stress memorizing by showing a rapid re-growth once the stress is relieved, leading to the extension of the vegetation cycle and biomass production. Chlorophyll degradation and the decrease of stomatal conductance were the first ecophysiological indicators of water stress on the fig tree. Finally, the fig could be considered a drought-stress resilient species considering its rapid growth recovery.