Solar ultraviolet-B radiation affects plant-insect interactions in a natural ecosystem of Tierra del Fuego (southern Argentina)

Rousseaux, M. Cecilia; Ballaré, Carlos L.; Scopel, Ana L.; Searles, Peter S.; Caldwell, Martyn M.

doi:10.1007/s004420050618

Cited by 109 publications

(96 citation statements)

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“…G. magellanica is one of the first species to resume growth at the end of the winter in the southern part of Tierra del Fuego. Our previous work in the National Park shows that, during early spring, G. magellanica leaf area expansion is inhibited by solar UVB (13). Therefore, in the spring of 1997, we collected leaf samples to investigate whether the spikes of solar UV that are commonly observed during ozone-hole days (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…We selected a field site in the Tierra del Fuego National Park, which is covered by Nothofagus spp. forests and has extensive bogs, scrublands, and heathlands (13)(14)(15). In the spring of 1996, we marked 20 permanent plots to study the long-term responses to partial UVB exclusion of a scrub ecosystem near Laguna Negra.…”

Section: Methodsmentioning

confidence: 99%

“…Ecophysiological studies have provided indirect, correlative evidence suggesting that the plant growth inhibition caused by high (10) and ambient (11,12) UVB doses may be related to DNA damage. Our recent work in Tierra del Fuego indicated that current levels of solar UVB in the early spring can inhibit leaf area expansion in the perennial herb Gunnera magellanica (13). Therefore, this species was chosen to study the impacts of ozone depletion on DNA integrity.…”

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Ozone depletion and UVB radiation: Impact on plant DNA damage in southern South America

Rousseaux

Ballaré

Giordano

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

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132

108

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The primary motivation behind the considerable effort in studying stratospheric ozone depletion is the potential for biological consequences of increased solar UVB (280 -315 nm) radiation. Yet, direct links between ozone depletion and biological impacts have been established only for organisms of Antarctic waters under the influence of the ozone ''hole;'' no direct evidence exists that ozone-related variations in UVB affect ecosystems of temperate latitudes. Indeed, calculations based on laboratory studies with plants suggest that the biological impact of ozone depletion (measured by the formation of cyclobutane pyrimidine dimers in DNA) is likely to be less marked than previously thought, because UVA quanta (315-400 nm) may also cause significant damage, and UVA is unaffected by ozone depletion. Herein, we show that the temperate ecosystems of southern South America have been subjected to increasingly high levels of ozone depletion during the last decade. We found that in the spring of 1997, despite frequent cloud cover, the passages of the ozone hole over Tierra del Fuego (55°S) caused concomitant increases in solar UV and that the enhanced ground-level UV led to significant increases in DNA damage in the native plant Gunnera magellanica. The fluctuations in solar UV explained a large proportion of the variation in DNA damage (up to 68%), particularly when the solar UV was weighted for biological effectiveness according to action spectra that assume a sharp decline in quantum efficiency with increasing wavelength from the UVB into the UVA regions of the spectrum.cyclobutane pyrimidine dimer ͉ global change ͉ Gunnera ͉ Tierra del Fuego T he most important consequence of the depletion of stratospheric ozone is the increased transmission of solar UVB radiation to the Earth's surface. Present levels of stratospheric ozone are at the lowest point since measurements began in the 1970s (1). Ozone depletion is most pronounced over the Antarctic continent, where ozone levels commonly decline by more than 70% during late winter and early spring [data available in the NASA Total Ozone Mapping Spectrometer (TOMS) site: http:͞͞jwocky.gsfc.nasa.gov͞TOMSmain.html]. Acute effects of ozone depletion on native organisms have been documented only for marine ecosystems of Antarctic waters (for a review, see ref.2). For example, it has been shown that increased UVB can reduce phytoplankton photosynthesis in the marginal ice zone when the ozone hole is overhead (3), reduce phytoplankton cell densities (4), and increase the DNA damage burden in icefish eggs (5). Virtually nothing is known about the consequences of ozone depletion and increased solar UVB on natural ecosystems located outside Antarctica.We have set up a long-term experiment to study the responses of terrestrial ecosystems to elevated solar UVB resulting from stratospheric ozone reduction near Ushuaia, Tierra del Fuego, Argentina. The area, dominated by temperate forests, is on the southern tip of South America, across the Drake Passage from the Antarctic Peninsula, an...

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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Ozone depletion and UVB radiation: Impact on plant DNA damage in southern South America

Rousseaux

Ballaré

Giordano

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

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132

108

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“…A much larger impact of solar UV-B has been documented for plant-herbivore interactions. Field experiments in a broad spectrum of ecosystems show that the intensity of insect herbivory frequently increases when the UV-B component of solar radiation is experimentally attenuated using filters (Bothwell et al, 1994;Ballaré et al, 1996;Rousseaux et al, 1998;Mazza et al, 1999b;Zavala et al, 2001). In some cases, at least part of this effect of solar UV-B could be attributed to direct behavioral responses of insects to UV-B photons (Mazza et al, 2002).…”

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“…However, insect growth and choice bioassays have demonstrated that UV-B effects on herbivory are in many cases indirect; i.e. mediated by UV-B-induced changes in plant tissues, which in turn affect insect feeding behavior and growth performance (Ballaré et al, 1996;Rousseaux et al, 1998;Mazza et al, 1999b;Zavala et al, 2001). The nature of these changes is unknown.…”

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Convergent Responses to Stress. Solar Ultraviolet-B Radiation and Manduca sexta Herbivory Elicit Overlapping Transcriptional Responses in Field-Grown Plants of Nicotiana longiflora

et al. 2003

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The effects of solar ultraviolet (UV)-B (280-315 nm) on plants have been studied intensively over the last 2 decades in connection with research on the biological impacts of stratospheric ozone depletion. However, the molecular mechanisms that mediate plant responses to solar (ambient) UV-B and their interactions with response mechanisms activated by other stressors remain for the most part unclear. Using a microarray enriched in wound-and insect-responsive sequences, we examined expression responses of 241 genes to ambient UV-B in field-grown plants of Nicotiana longiflora Cav. Approximately 20% of the sequences represented on the array showed differential expression in response to solar UV-B. The expression responses to UV-B had parallels with those elicited by simulated Manduca sexta herbivory. The most obvious similarities were: (a) down-regulation of several photosynthesis-related genes, and (b) up-regulation of genes involved in fatty acid metabolism and oxylipin biosynthesis such as HPL (hydroperoxide lyase), ␣-DIOX (alpha-dioxygenase), LOX (13-lipoxygenase), and AOS (allene oxide synthase). Genes encoding a WRKY transcription factor, a ferredoxin-dependent glutamate-synthase, and several other insect-responsive genes of unknown function were also similarly regulated by UV-B and insect herbivory treatments. Our results suggest that UV-B and caterpillar herbivory activate common regulatory elements and provide a platform for understanding the mechanisms of UV-B impacts on insect herbivory that have been documented in recent field studies.UV-B induces multiple responses in terrestrial plants. These responses have been studied using a variety of experimental approaches, from controlledenvironment experiments to large-scale field trials, and covering a broad spectrum of scales, from molecular to ecosystem level processes. Controlledenvironment experiments have contributed most of the information presently available on responses at the molecular level. However, this type of experiment, particularly those that are based on the use of heavily unbalanced light sources (i.e. with unnaturally high ratios of UV-B to photosynthetically active radiation [PAR] or UV-B to UV-A [315-400 nm]), are frequently criticized on the grounds that they lack functional and ecological realism (Fiscus and Booker, 1995;Caldwell and Flint, 1997). It has been shown clearly that treatments with high UV-B to PAR ratios, which are the norm in controlled-environment exposures, tend to result in greatly exaggerated effects of UV-B on photosynthesis and growth inhibition. Because these effects have been hard to duplicate under field conditions, it is unclear to what extent the molecular and mechanistic data that have been produced under spectrally unbalanced conditions (which commonly involve PAR levels lower than 1:10 of full sunlight) contribute to our understanding of the normal physiological responses of plants to ambient UV-B stress. In fact, it has been clearly demonstrated that the level of PAR strongly modulates the effect of UV-B on...

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UV radiation is the primary factor driving the variation in leaf phenolics across Chinese grasslands

Chen

Niu

et al. 2013

Ecology and Evolution

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Due to the role leaf phenolics in defending against ultraviolet B (UVB) under previously controlled conditions, we hypothesize that ultraviolet radiation (UVR) could be a primary factor driving the variation in leaf phenolics in plants over a large geographic scale. We measured leaf total phenolics, ultraviolet-absorbing compounds (UVAC), and corresponding leaf N, P, and specific leaf area (SLA) in 151 common species. These species were from 84 sites across the Tibetan Plateau and Inner Mongolian grasslands of China with contrasting UVR (354 vs. 161 mW/cm2 on average). Overall, leaf phenolics and UVAC were all significantly higher on the Tibetan Plateau than in the Inner Mongolian grasslands, independent of phylogenetic relationships between species. Regression analyses showed that the variation in leaf phenolics was strongly affected by climatic factors, particularly UVR, and soil attributes across all sites. Structural equation modeling (SEM) identified the primary role of UVR in determining leaf phenolic concentrations, after accounting for colinearities with altitude, climatic, and edaphic factors. In addition, phenolics correlated positively with UVAC and SLA, and negatively with leaf N and N: P. These relationships were steeper in the lower-elevation Inner Mongolian than on the Tibetan Plateau grasslands. Our data support that the variation in leaf phenolics is controlled mainly by UV radiation, implying high leaf phenolics facilitates the adaptation of plants to strong irradiation via its UV-screening and/or antioxidation functions, particularly on the Tibetan Plateau. Importantly, our results also suggest that leaf phenolics may influence on vegetation attributes and indirectly affect ecosystem processes by covarying with leaf functional traits.

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Solar ultraviolet-B radiation affects plant-insect interactions in a natural ecosystem of Tierra del Fuego (southern Argentina)

Cited by 109 publications

References 37 publications

Ozone depletion and UVB radiation: Impact on plant DNA damage in southern South America

Ozone depletion and UVB radiation: Impact on plant DNA damage in southern South America

Convergent Responses to Stress. Solar Ultraviolet-B Radiation and Manduca sexta Herbivory Elicit Overlapping Transcriptional Responses in Field-Grown Plants of Nicotiana longiflora

UV radiation is the primary factor driving the variation in leaf phenolics across Chinese grasslands

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