Does drought stress induce physiological mechanisms in Celtis caucasica L. Seedlings?

摘要

Drought stress is an important environmental factor inhibiting plant growth. The examination of physiological reaction of different species to the drought stress is useful to recognize effective mechanisms in drought tolerance and choosing the suitable species for plantation in dry lands. In order to determine the resistance of Celtis caucasica and understand the physiological mechanisms in response to the drought condition, an experiment was designed in a completely randomized block with one factor (irrigation), at five levels (1, 3, 5, 7, and 9 days) with five replications chlorophyll fluorescence parameters (Fv/Fm, Fm and F0) and pigments content (total chlorophyll, chlorophyll a, and chlorophyll b) of leaves. The results indicated that drought stress induced a significant reduction at five percent level in maximum photochemical efficiency of photosystem II (Fv/Fm) and maximum fluorescence (Fm) while the minimum fluorescence (F0) was not significantly affected by drought. With increasing the intensity of drought, chlorophyll content in leaves was increased. Maintaining the leaf chlorophyll content under stress conditions, is one of the physiological indicators of stress resistance concluding that C. caucasica would be one of the most suitable species for afforestation plans in arid and semi- arid regions.