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Pak. J. Bot., 48(3): 877-883, 2016.

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IMPACT OF ASCORBIC ACID ON GROWTH AND SOME PHYSIOLOGICAL ATTRIBUTES OF CUCUMBER (CUCUMIS SATIVUS) PLANTS UNDER WATER-DEFICIT CONDITIONS

HIRA NAZ¹, NUDRAT AISHA AKRAM^1* AND MUHAMMAD ASHRAF^2,3

Abstract: Cucumber (Cucumis sativus L.) is a very popular vegetable, which is utilized all-over the world. In the current research, two cultivars of cucumber, Local and Hybrid were chosen to look at the effect of foliar-applied ascorbic acid on some key physio-biochemical attributes under varying water regimes. After one week of seed germination, the plants of both cucumber cultivars were subjected to 100% field capacity (control) and 60% field capacity (water deficit conditions. After one month of water stress treatment, ascorbic acid (AsA) at the rate of 0 (control), 50 and 100 mg L^-1 was applied foliarly. After 15-day AsA application, the data were recorded which showed that drought stress significantly reduced the plant growth, chlorophyll contents, relative water contents (RWC), rate of photosynthesis (A), stomatal conductance, internal CO₂ concentration (C_i) and C_i/C_a, while drought caused  an increase  in  relative membrane permeability (RMP), and proline and glycine betaine contents. AsA improved the shoot fresh and dry weights, chlorophyll a, RWC, C_i, C_i/C_a and proline contents. No change was observed in both cucumber cultivars under water-deficit and AsA treatments. Overall, growth improvement of cucumber plants under dry arid climate could be attributed to AsA-induced stimulation in the chlorophyll a, proline, RWC contents and C_i concentration. 

Key words: Cucumis sativus, Water deficit stress, Gas exchange characteristics, Glycine betaine.
 

¹Department of Botany, Government College University, Faisalabad, Pakistan

²Pakistan Science Foundation, Islamabad, Pakistan

³Department of Botany and Microbiology, King Saud University, Riyadh, Saudi Arabia

^*Corresponding author's email: nudrataauaf@yahoo.com