Application of chlorophyll fluorescence technique as an indicator of drought tolerance in Celtis caucasica L. seedlings

Drought stress is one of the most important environmental factors limiting plant growth and development so finding the new techniques to evaluate the drought tolerance in plants, would be valuable. The purpose of this study was the application of chlorophyll fluorescence technique as a reliable method for rapid assessment of drought stress in hackberry seedlings (Celtis caucasica L.). An experiment was designed as completely randomized block with one factor (irrigation), at five levels (1, 3, 5, 7 and 9 days) with five replicates. Chlorophyll fluorescence parameters (Fv/Fm, Fm & F0), and the proline content of leaves in one-year-old seedlings of Celtis caucasica were measured. The results indicated that maximum fluorescence (Fm) had a significant reduction in the 9 days treatment. Also maximum photochemical efficiency of photosystem II (Fv/Fm) showed a significant downward trend since the 5 days treatment, while the minimum fluorescence (F0) was not significantly affected by drought. Increasing the intensity of drought was resulted in proline accumulation in leaves from 1.7 (µmol/gfw) in the 1 day treatment to 72.95 in the 9 days treatment. In afforestations and urban green spaces, measurement of chlorophyll fluorescence is a reliable method for identification of well-adapted species to environmental stress