Seasonal and diurnal photosynthetic behaviour of fig (Ficus carica L.) under semi-arid climatic conditions

Diurnal and seasonal variations in net photosynthetic (P-N) and transpiration (E) rates and water use efficiency (WUE) of the fig tree ( Ficus carica L.) were investigated under semi-arid climatic conditions. The two types of leaves from southern and northern parts of trees experienced natural air temperature and irradiance conditions, but differ particularly in water use efficiency. The obtained data reveal that leaf temperature, because of decrease in stomatal conductance, is the major factor limiting the gas exchange capacity of fig trees grown under rain-fed conditions. Stomatal conductance is the major control mechanism, particularly in the northern parts of the trees; however, PN was most probably decreased by both stomatal and non-stomatal resistance mechanisms such as photoinhibition under severe drought and high irradiance conditions in the southern parts of the trees.