Tolerance and physiological response of young Ficus carica L. plants irrigated with saline water

Preliminary results were obtained from an experiment carried out on 2-year-old potted fig (Ficus carica L.) plants of two cultivars ('Dottato' and 'Brogiotto') to evaluate the effect of saline water on plant water status, leaf gas exchange and fruit growth. Plants were irrigated for 7 weeks with pure water (Control) or saline water (T100) at 100 mM NaCl concentration. Stem water potential (SWP), stomatal conductance (g(s)) and net photosynthetic rate (Pn) were measured at 4, 27 and 47 (53 for SWP) days after the beginning of salinization (DABS). Significant differences in SWP were already evident between treatments 4 DABS and lasted until the last date of measurement (53 DABS). The highest and lowest values of SWP were measured at 53 DABS in Dottato Control (-0.5 MPa) and Dottato T100 (-1.7 MPa), respectively. Significant differences in gs, Pn and intrinsic water use efficiency (iWUE) between treatments were evident at all dates of measurement, with the exception of Pn at 4 DABS. Differences in gs, Pn and iWUE between 'Dottato' and 'Brogiotto' were observed at 4 and 27 (only iWUE) DABS. Significant differences were found between treatments regarding the fruit diameter increment whereas the fruits number per plant was similar at each date of measurement. The highest and lowest increase in fruit diameter was measured in 'Brogiotto' Control (7.9 mm) and Dottato Control (2.9 mm) plants, respectively. The highest decrease in fruits number per plant at 41 DABS, with respect to the initial (5 DABS) measurement, was measured in 'Brogiotto' T100 plants (-57%), followed by the 'Brogiotto' Control (-50%) and 'Dottato' T100 (-9%) plants, whereas a slight increase in fruits number per plant (+5%) was showed by 'Dottato' Control plants.