Research Article Open Access

EFFECTS OF UV-B ON PHOTOSYNTHETIC PARAMETERS, LIPID PEROXIDATION, FLAVONOIDS AND GROWTH TRAITS OF CONOCARPUS LANCIFOLIUS (ENGL.)

Patrice Suleman1, Amina Redha1, Mohamad Afzal1 and Redha Al-Hasan1
  • 1 Kuwait University, Kuwait

Abstract

Conocarpus lancifolius is a perennial ornamental plant adapted to the semi-arid conditions of Kuwait. It accumulates most of its biomass during the stressful summer conditions which includes UV-B irradiation. The study evaluated equivalent UV-B irradiation intensities that plants would normally experience sometime during the course of a year in Kuwait. Leaf area, plant height, photosynthetic parameters, Lipid Peroxidation (LP) and Phenyl Alanine Lyase (PAL) were measured in C. lancifolius plants exposed to different UV-B treatments. UV-B treatments decreased leaf area and plant height but induced the formation of lateral branches. Chlorophyll content, photosynthesis, chlorophyll fluorescence measured as maximum quantum efficiency of photosystem II (Fv/Fm) and Electron Transport Rate (ETR) decreased in the short term or the first 10-20 days after treatment. Lipid Peroxidation (LP) measured in terms of Malondiadehyde (MDA) content decreased in the long term after a short term increase but Phenyl Alanine Lyase (PAL) activity increased linearly by 41.2, 66.8 and 78.6% after 30 days. There was also Positive Linear Correlation between UV-B dosage and total flavonoid accumulation which was localized in epidermal cell walls, trichomes and cuticular layer. The response of C. lancifolius to ameliorate and/or tolerate UV-B stress involved multiple mechanisms that included increased concentrations of PAL activity, increased flavonoids production; and reduced lipid peroxidation. The net effect of flavonoid accumulation and PAL enzyme activity probably contributed significantly to the protection or tolerance of the species to the effects of UV-B.

American Journal of Agricultural and Biological Sciences
Volume 9 No. 1, 2014, 55-63

DOI: https://doi.org/10.3844/ajabssp.2014.55.63

Submitted On: 11 November 2013 Published On: 23 December 2013

How to Cite: Suleman, P., Redha, A., Afzal, M. & Al-Hasan, R. (2014). EFFECTS OF UV-B ON PHOTOSYNTHETIC PARAMETERS, LIPID PEROXIDATION, FLAVONOIDS AND GROWTH TRAITS OF CONOCARPUS LANCIFOLIUS (ENGL.). American Journal of Agricultural and Biological Sciences, 9(1), 55-63. https://doi.org/10.3844/ajabssp.2014.55.63

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Keywords

  • UV-B Radiation
  • Chlorophyll Fluorescence
  • Phenyl Alanine Lyase
  • Flavonoids
  • Lipid Peroxidation