African Journal of

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12209

Full Length Research Paper

Enhanced antioxidant defense after exogenous application of Ca2+ and K+ in Brassica napus seedlings under water deficit stress

Rizwan Alam1, Aqib Iqbal2*, Ikhtiar Khan1, Ijaz Ali2, Iqbal Munir2, Arshad Javed3, Inayat-ur-Rehman4 and Zahoor Ahmad Swati2
1Institute of Chemical Sciences, University of Peshawar, Pakistan. 2Institute of Biotechnology and Genetic Engineering, Khyber Pakhtunkhwa Agricultural University Peshawar, Pakistan. 3School of Biological Sciences, University of Punjab, Lahore, Pakistan. 4Pakistan Council of Scientific and Industrial Research, Peshawar, Pakistan.
Email: [email protected]

  •  Published: 19 October 2011


Supply of adequate moisture is one of the most important factors limiting agricultural extension and productivity. Ca2+ and K+ are both essential plant nutrients required in a number of developmental and metabolic processes. Both of these nutrients play an important role in ameliorating drought stress in crop plants. This experiment was designed to study whether exogenous application of Ca2+ and K+ before the drought could enhance the potential of plants to survive under limiting water conditions. Brassica napus L. cv Bulbul-98 seedlings were exposed to drought stress for 10 days after exogenous application of different concentrations of Ca2+, K+ and N through irrigation water. Exogenous Ca2+ and K+ application was associated with increased relative water content, membrane stability and chlorophyll content in seedlings exposed to water deficit. Though the quantity of Pro and activities of APX (EC: and CAT (EC: were increased after K+ application, they were strongly induced in seedlings supplemented with Ca2+ in a dose dependent manner. Increasing quantity of N application, however, had a negative effect on these parameters.


Key words: Drought, Ca2+, K+, AOS enzymes, proline, chlorophyll.


AOS, Active oxygen species; APX, ascorbate peroxidase; CAT,catalase; Chl, chlorophyll; MSI, membrane stability index; Pro, proline; RWC,relative water content; RWL, rate of water loss from excised leaves.

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