Environmental Engineering Reference
In-Depth Information
14. Conclusions
In conclusion, it can be stated that UV-B radiation has several effects on higher
plants which are not only non-damaging, but can be positive for plant development and
survival. Some of these effects are indirect, such as the possible reduction in
phylloplane fungi and the reduction in attacks by phytophagous insects. Others are
photomorphogenic and act directly on the plant. The induction of photoprotective
screening pigments and antioxidants by UV-B radiation is of obvious adaptive
advantage.
As Briggs and Olney
109
point out, it is now known that plants have at least nine
photoreceptors: five phytochromes (responding primarily to R and FR light), two
B/UV-A light photoreceptors (cryptochromes), a phototropism photoreceptor
(phototropin), and a photoreceptor with properties akin to both phytochrome and
phototropin ('superchrome'
110
. Identification of the UV-B photoreceptor(s) and the roles
played by it/them will add to our understanding of the adaptation of plants to the
shortest wavelengths of ambient solar radiation.
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