Abstract
To study functional relationships between the effects of solar ultraviolet-B radiation (UV-B) on different aspects of the physiology of a wild plant, we carried out exclusion experiments in the field with the summer annual Datura ferox L. Solar UV-B incident over Buenos Aires reduced daytime seedling emergence, inhibited stem elongation and leaf expansion, and tended to reduce biomass accumulation during early growth. However, UV-B had no effect on calculated net assimilation rate. Using a monoclonal antibody specific to the cyclobutane-pyrimidine dimer (CPD), we found that plants receiving full sunlight had more CPDs per unit of DNA than plants shielded from solar UV-B, but the positive correlation between UV-B and CPD burden tended to level off at high (near solar) UV-B levels. At our field site, Datura plants were consumed by leaf beetles (Coleoptera), and the proportion of plants attacked by insects declined with the amount of UV-B received during growth. Field experiments showed that plant exposure to solar UV-B reduced the likelihood of leaf beetle attack by one-half. Our results highlight the complexities associated with scaling plant responses to solar UV-B, because they show: (a) a lack of correspondence between UV-B effects on net assimilation rate and whole-plant growth rate, (b) nonlinear UV-B dose-response curves, and (c) UV-B effects of plant attractiveness to natural herbivores.
Full Text
The Full Text of this article is available as a PDF (1.1 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Beggs C. J., Stolzer-Jehle A., Wellmann E. Isoflavonoid Formation as an Indicator of UV Stress in Bean (Phaseolus vulgaris L.) Leaves : The Significance of Photorepair in Assessing Potential Damage by Increased Solar UV-B Radiation. Plant Physiol. 1985 Nov;79(3):630–634. doi: 10.1104/pp.79.3.630. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bothwell M. L., Sherbot D. M., Pollock C. M. Ecosystem response to solar ultraviolet-B radiation: influence of trophic-level interactions. Science. 1994 Jul 1;265(5168):97–100. doi: 10.1126/science.265.5168.97. [DOI] [PubMed] [Google Scholar]
- Buchholz G., Ehmann B., Wellmann E. Ultraviolet Light Inhibition of Phytochrome-Induced Flavonoid Biosynthesis and DNA Photolyase Formation in Mustard Cotyledons (Sinapis alba L.). Plant Physiol. 1995 May;108(1):227–234. doi: 10.1104/pp.108.1.227. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Naidu S. L., Sullivan J. H., Teramura A. H., DeLucia E. H. The effects of ultraviolet-B radiation on photosynthesis of different aged needles in field-grown loblolly pine. Tree Physiol. 1993 Mar;12(2):151–162. doi: 10.1093/treephys/12.2.151. [DOI] [PubMed] [Google Scholar]
- Pang Q., Hays J. B. UV-B-Inducible and Temperature-Sensitive Photoreactivation of Cyclobutane Pyrimidine Dimers in Arabidopsis thaliana. Plant Physiol. 1991 Feb;95(2):536–543. doi: 10.1104/pp.95.2.536. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Stapleton A. E., Walbot V. Flavonoids can protect maize DNA from the induction of ultraviolet radiation damage. Plant Physiol. 1994 Jul;105(3):881–889. doi: 10.1104/pp.105.3.881. [DOI] [PMC free article] [PubMed] [Google Scholar]