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Effects of prolonged UV-B
exposure in plants
S. W. Mpoloka
Department of Biological Sciences, University of
Botswana, P/Bag 00704, Gaborone, Botswana.
E-mail:
mpoloka@mopipi.ub.bw.
Accepted 12 December, 2008 |
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Over the
past few decades, there has been a depletion of the
stratospheric ozone layer due to emissions of
halogen-containing compounds of anthropogenic origin. This
has resulted in a concomitant increase in solar
ultraviolet-B radiation. High levels of UV-B radiation are
responsible for multiple biologically harmful effects in
both plants and animals. In plants, these effects include
DNA damage, which often causes heritable mutations affecting
various physiological processes, including the
photosynthetic apparatus, protein destruction and signal
transduction via UV-B photoreceptors. High UV-B levels
introduce a number of different lesions, predomi-nantly
cyclobutane pyrimidine dimmers (CPDs) and pyrimidine (6-4)
pyrimidinone products [(6-4) PPs] in the genome. These
could adversely affect plant growth, development and
morphology, especially the productivity of sensitive crop
species. This paper reviews the genetic effects of
long-term UV-B exposure in plants.
Key
words:
UV-B
radiation, ozone depletion, plant growth, morphology. |
