Journal of Environmental Biology

Influence of drought stress on cellular ultrastructure and antioxidant system in tea cultivars with different drought sensitivities

Akan Das^1,4*, Mainaak Mukhopadhyay¹, Bipasa Sarkar^2,5, Dipanwita Saha³ and Tapan K. Mondal^{1, 6}

¹Biotechnology Laboratory, Faculty of Horticulture, Uttar Banga Krishi Viswavidyalaya, Cooch Behar-785 165, India

²Department of Chemistry, Faculty of Science, University of North Bengal, Darjeeling-734 013, India

³Department of Biotechnology, Faculty of Science, University of North Bengal, Darjeeling-734 013, India

⁴Department of Bioengineering and Technology, Gauhati University-Institute of Science and Technology, Assam-781014, India

5Division of Agricultural Chemicals, Indian Agricultural Research Institute, Pusa, New Delhi-110012, India

⁶Division of Genomic Resources, National Bureau of Plant Genetic Resources, IARI Campus, Pusa, New Delhi, 110012, India

*Corresponding Author?s Email : dasakan@gmail.com

 Publication Data

Paper received:

01 January 2014

Revised received:

07 September 2014

Accepted:

10 October 2014

Abstract

Drought is the major yield-limiting abiotic factor of tea cultivation. In the present study, influence of drought stress on cellular ultrastructure and antioxidants was studied drought-tolerant (TV-23) and -sensitive (S.3/A3) tea cultivars by imposing drought stress for 21 days. Drought stress led to considerable structural alterations in mitochondria, chloroplast and vacuole. Lesser membrane integrity and higher structural damage was observed in S.3/A3. Chlorophyll a, chl-b and carotenoids content in leaves decreased in each cultivar; however, the decrement was more brisk in S.3/A3. Proline, total soluble sugar, ascorbic acid and abscisic acid were elevated in TV-23 whereas hydrogen peroxide, superoxide anion, lipid peroxidation and electrolyte leakage increased rapidly in S.3/A3. Starch content decreased both in leaves and roots of each cultivar and was more pronounced in roots of TV-23. Under drought, enhanced activities of ascorbate peroxidase, catalase, peroxidase and superoxide dismutase were recorded in both roots and leaves of each cultivar, but the rate of enhancement was more in TV-23. This indicated that tolerant cultivar exhibited higher antioxidant capacity and a stronger protective mechanism such that their ultrastructural integrity was better maintained during exposure to drought stress.   

 Key words

Antioxidant, Camellia sinensis, Drought, Ultrastructure

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