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Carlos L Ballare - One of the best experts on this subject based on the ideXlab platform.
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solar <B>UltravioletB> B Radiation and insect herBivory trigger partially overlapping phenolic responses in nicotiana attenuata and nicotiana longiflora
Annals of Botany, 2007Co-Authors: Miriam M Izaguirre, Carlos A Mazza, Ales Svatos, Ian T Baldwin, Carlos L BallareAbstract:†Background and Aims Plants exposed to solar <B>UltravioletB>-B Radiation (UV-B, 280‐315 nm) frequently suffer less insect herBivory than do plants that receive attenuated levels of UV-B. This anti-herBivore effect of solar UV-B exposure, which has Been documented in several ecosystems, is in part mediated By changes in plant tissue quality. Exposure to UV-B can modify the aBundance of a numBer of secondary metaBolites, including phenolic compounds with potential impacts on insect herBivores. The aim of this study is to assess the potential antiherBivore role of UV-B-induced phenolic compounds By comparing the phenolic profiles induced By UV-B and simulated insect herBivory in two wild species of the genus Nicotiana. †Methods Plants grown under field and glasshouse conditions were exposed to contrasting levels of UV-B. Half of the plants of the attenuated UV-B treatment were given a simulated herBivory treatment, where leaves were mechanically damaged and immediately treated with oral secretions of Manduca sexta caterpillars. This treatment is known to mimic the impact of real herBivory on the expression of plant defences in Nicotiana. Phenolic profiles induced By UV-B and simulated herBivory were characterized using high-performance liquid chromatography‐ mass spectrometry (HPLC‐MS). †Key Results UV-B induced the accumulation of several UV-aBsorBing phenolic compounds that are known to play a significant role in UV-B screening. Interestingly, there was a significant convergence in the phenolic profiles induced By UV-B and simulated herBivory: chlorogenic acid and dicaffeoylspermidine isomers, in particular, displayed a similar pattern of response to these stimuli. In contrast, rutin, the only flavonoid that accumulated in significant quantities in the experiments, was only induced By UV-B. †Conclusions The results suggest that the anti-herBivory effect induced By UV-B may Be mediated at least in part By the accumulation of phenylpropanoid derivatives that are similar to those induced By the plant in response to insect herBivory.
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impacts of solar <B>UltravioletB> B Radiation on terrestrial ecosystems of tierra del fuego southern argentina an overview of recent progress
Journal of Photochemistry and Photobiology B-biology, 2001Co-Authors: Carlos L Ballare, Peter S Searles, Martyn M Caldwell, Cecilia M Rousseaux, Johann G Zaller, Carla Valeria Giordano, Matthew T Robson, Osvaldo E Sala, Ana L ScopelAbstract:The southern part of Tierra del Fuego, in the southernmost tip of South America, is covered By dense Nothofagus spp. forests and Sphagnum-dominated peat Bogs, which are suBjected to the influence of ozone depletion and to increased levels of solar <B>UltravioletB>-B Radiation (UV-B). Over the last 5 years we have studied some of the Biological impacts of solar UV-B on natural ecosystems of this region. We have addressed two general proBlems: (i) do the fluctuations in UV-B levels under the influence of the Antarctic ozone ‘hole’ have any measuraBle Biological impact, and (ii) what are the long-term effects of solar (amBient) UV-B on the Tierra del Fuego ecosystems? In this paper, we provide an overview of the progress made during the first 4 years of the project. We highlight and discuss the following results: (1) amBient UV-B has suBtle But significant inhiBitory effects on the growth of herBaceous and graminoid species of this region (growth reduction ≤12%), whereas no consistent inhiBitory effects could Be detected in woody perennials; (2) in the species investigated in greatest detail, Gunnera magellanica, the inhiBitory effect of solar UV-B is accompanied By increased levels of DNA damage in leaf tissue, and the DNA damage density in the early spring is clearly correlated with the dose of weighted UV-B measured at ground level; (3) the herBaceous species investigated thus far show little or no acclimation responses to amBient UV-B such as increased sunscreen levels and DNA repair capacity; and (4) amBient UV-B has significant effects on heterotrophic organisms, included marked inhiBitory effects on insect herBivory. The results from the experiments summarized in this review clearly indicate that UV-B influences several potentially important processes and ecological interactions in the terrestrial ecosystems of Tierra del Fuego.
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<B>UltravioletB> B Radiation enhances a phytochrome B mediated photomorphogenic response in araBidopsis
Plant Physiology, 2001Co-Authors: Hernan E Boccalandro, Carlos A Mazza, Agustina M Mazzella, Carlos L BallareAbstract:<B>UltravioletB> B Radiation (UV-B, 290–315 nm) can cause damage and induce photomorphogenic responses in plants. The mechanisms that mediate the photomorphogenic effects of UV-B are unclear. In etiolated AraBidopsis seedlings, a daily exposure to 2.5 h of UV-B enhanced the cotyledon opening response induced By a suBsequent red light (R) pulse. An R pulse alone, 2.5 h of UV-B terminated with a far-red pulse, or 2.5 h of continuous R caused very little cotyledon opening. The enhancing effect of UV-B increased with fluence rate up to approximately 7.58 μmol m −2 s −1 ; at higher fluence rates the response to UV-B was greatly reduced. The phyA , phyA cry1 , and cry1 cry2 mutants Behaved like the wild type when exposed to UV-B followed By an R pulse. In contrast, phyB , phyB cry1 , and phyB phyA mutants failed to open the cotyledons. Thus, phytochrome B was required for the cotyledon opening response to UV-B → R treatments, whereas phytochrome A and cryptochromes 1 and 2 were not necessary under the conditions of our experiments. The enhancing effect of low doses of UV-B on cotyledon opening in uvr1 uvr2 and uvr1 uvr3 mutants, deficient in DNA repair, was similar to that found in the wild type, suggesting that this effect of UV-B was not elicited By signals derived from UV-B-induced DNA lesions (cycloButane pyrimidine dimers and 6-4 photoproducts). We conclude that low doses of UV-B, perceived By a receptor system different from phytochromes, cryptochromes, or DNA, enhance a de-etiolation response that is induced By active phytochrome B.
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The effects of solar <B>UltravioletB>-B Radiation on the growth and yield of Barley are accompanied By increased DNA damage and antioxidant responses
Plant Cell and Environment, 1999Co-Authors: C. A. Mazza, A. M. Zima, M. Szwarcberg-bracchitta, C. V. Giordano, Diego Di Battista, Ana L Scopel, Ashley Acevedo, Carlos L BallareAbstract:There is limited information on the impacts of present-day solar <B>UltravioletB>-B Radiation (UV-B) on Biomass and grain yield of field crops and on the mechanisms that confer tolerance to UV-B Radiation under field conditions. We investigated the effects of solar UV-B on aspects of the Biochemistry, growth and yield of Barley crops using replicated field plots and two Barley strains, a catalase (CAT)deficient mutant (RPr 79/4) and its wild-type mother line (Maris Mink). Solar UV-B reduced Biomass accumulation and grain yield in Both strains. The effects on crop Biomass accumulation tended to Be more severe in RPr 79/4 (≃ 32% reduction) than in the mother line (≃ 20% reduction). Solar UV-B caused measuraBle DNA damage in leaf tissue, in spite of inducing a significant increase in UV-aBsorBing sunscreens in the two lines. Maris Mink responded to solar UV-B with increased CAT and ascorBate peroxidase (APx) activity. No effects of UV-B on total superoxide dismutase (SOD) activity were detected. Compared with the wild type, RPr 79/4 had lower CAT activity, as expected, But higher APx activity. Neither of these activities increased in response to UV-B in RPr 79/4. These results suggest that growth inhiBition By solar UV-B involves DNA damage and oxidative stress, and that constitutive and UV-B-induced antioxidant capacity may play an important role in UV-B tolerance.
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solar <B>UltravioletB> B Radiation affects seedling emergence dna integrity plant morphology growth rate and attractiveness to herBivore insects in datura ferox
Plant Physiology, 1996Co-Authors: Carlos L Ballare, Ana L Scopel, Ann E Stapleton, Marcelo J YanovskyAbstract:To study functional relationships Between the effects of solar <B>UltravioletB>-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.
Juha Merilä - One of the best experts on this subject based on the ideXlab platform.
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effects of <B>UltravioletB> B Radiation on metamorphic traits in the common frog rana temporaria
Chemosphere, 2003Co-Authors: Maarit Pahkala, Juha Merilä, Indrek Ots, Anssi LaurilaAbstract:Effects of <B>UltravioletB>-B Radiation on metamorphic traits in the common frog Rana temporaria
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carry over effects of <B>UltravioletB> B Radiation on larval fitness in rana temporaria
Proceedings of The Royal Society B: Biological Sciences, 2001Co-Authors: Maarit Pahkala, Juha Merilä, Anssi LaurilaAbstract:A numBer of studies have failed to find evidence for negative effects of <B>UltravioletB>-B Radiation (UVBR) on amphiBian early-emBryonic performance, leading to the conclusions, first, that the emBryonic stages of many species are tolerant to UVBR, and second, that the increased amount of UVBR reaching the Earth's surface is not likely to have any direct negative effects on many amphiBian populations. However, possiBle carry-over effects of exposure to UVBR in the emBryonic stages to the larval stages have received less attention. We studied the effects of UVBR experienced during the emBryonic stages (age less than 11 days) on the later performance (age 11-75 days) of common frog, Rana temporaria, larvae. In a factorial laBoratory experiment, newly fertilized emBryos were divided into three different UVBR treatments (no UVBR (control), 1.25 kJm(-2) (normal) and 1.58 kJm(-2) (26% enhanced)), after which the individual larvae were raised until metamorphosis in the aBsence of UVBR. No effects of UVBR on emBryonic survival rates, frequency of developmental anomalies or hatchling size were found, corroBorating the earlier results indicating that R. temporaria emBryos are tolerant to UVBR. However, analyses of larval performance revealed that larvae exposed to enhanced levels of UVBR as emBryos suffered from an increased frequency of developmental anomalies and metamorphosed later and at a smaller size than larvae that had Been protected from UVBR as emBryos. These results suggest, in contrast to the earlier studies, that UVBR has direct negative effects on R. temporaria emBryos, But these effects are expressed mostly or only during the later life stages. To this end, our results support the contention that carry-over effects from one life stage to another may Be an important source of phenotypic variation in fitness.
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amBient <B>UltravioletB> B Radiation reduces hatchling size in the common frog rana temporaria
Ecography, 2000Co-Authors: Maarit Pahkala, Anssi Laurila, Juha MeriläAbstract:Effects of amBient UV-B Radiation and pH on hatchaBility and early development of Rana temporaria emBryos were studied in field experiments conducted at two sites in Sweden. In neither of the populations did we find clear evidence for reduced hatchaBility
Jiyuan Tian - One of the best experts on this subject based on the ideXlab platform.
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changes in ultrastructure and responses of antioxidant systems of algae dunaliella salina during acclimation to enhanced <B>UltravioletB> B Radiation
Journal of Photochemistry and Photobiology B-biology, 2009Co-Authors: Jiyuan Tian, Juan YuAbstract:ABstract Because of depletion of the stratospheric ozone layer, levels of solar <B>UltravioletB>-B (UV-B) Radiation (280–315 nm), which penetrates the water column to an ecologically-significant depth, are increasing. In order to assess changes in ultrastructure and responses of antioxidant systems of algae during acclimation to enhanced <B>UltravioletB>-B Radiation, Dunaliella salina was treated with higher dose of UV-B Radiation (13.2 kJ m−2 d−1 dose) in this study. As compared to the control panel (8.8 kJ m−2 d−1), the treatment D. salina had many changes in ultrastructures: (1) thylakoids Became swelled, and some of them penetrated into the pyrenoid; (2) lipid gloBules accumulated; (3) the amounts of starch grains increased; (4) cristae of mitochondria disintegrated; (5) inclusions in vacuoles reduced; and (6) cisternae of Golgi dictyosomes Became loose and swollen. Enhanced UV-B irRadiation also induced different responses of the antioxidant systems in D. salina: (1) contents of TBARS (thioBarBituric acid reacting suBstance) and H2O2 increased significantly (p 0.05). In addition, growth curve displayed that enhanced UV-B Radiation prominently inhiBited increase of cell concentration when compared with control panel (p
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changes in ultrastructure and responses of antioxidant systems of algae dunaliella salina during acclimation to enhanced <B>UltravioletB> B Radiation
Journal of Photochemistry and Photobiology B-biology, 2009Co-Authors: Jiyuan TianAbstract:Because of depletion of the stratospheric ozone layer, levels of solar <B>UltravioletB>-B (UV-B) Radiation (280-315 nm), which penetrates the water column to an ecologically-significant depth, are increasing. In order to assess changes in ultrastructure and responses of antioxidant systems of algae during acclimation to enhanced <B>UltravioletB>-B Radiation, Dunaliella salina was treated with higher dose of UV-B Radiation (13.2 kJm(-2) d(-1) dose) in this study. As compared to the control panel (8.8 kJm(-2) d(-1)), the treatment D. salina had many changes in ultrastructures: (1) thylakoids Became swelled, and some of them penetrated into the pyrenoid; (2) lipid gloBules accumulated; (3) the amounts of starch grains increased; (4) cristae of mitochondria disintegrated; (5) inclusions in vacuoles reduced; and (6) cisternae of Golgi dictyosomes Became loose and swollen. Enhanced UV-B irRadiation also induced different responses of the antioxidant systems in D. salina: (1) contents of TBARS (thioBarBituric acid reacting suBstance) and H(2)O(2) increased significantly (p 0.05). In addition, growth curve displayed that enhanced UV-B Radiation prominently inhiBited increase of cell concentration when compared with control panel (p<0.05). Our results indicated that enhanced UV-B Radiation caused ultrastructural changes of D. salina and induced different responses of antioxidant systems in D. salina.
Anssi Laurila - One of the best experts on this subject based on the ideXlab platform.
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effects of <B>UltravioletB> B Radiation on metamorphic traits in the common frog rana temporaria
Chemosphere, 2003Co-Authors: Maarit Pahkala, Juha Merilä, Indrek Ots, Anssi LaurilaAbstract:Effects of <B>UltravioletB>-B Radiation on metamorphic traits in the common frog Rana temporaria
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carry over effects of <B>UltravioletB> B Radiation on larval fitness in rana temporaria
Proceedings of The Royal Society B: Biological Sciences, 2001Co-Authors: Maarit Pahkala, Juha Merilä, Anssi LaurilaAbstract:A numBer of studies have failed to find evidence for negative effects of <B>UltravioletB>-B Radiation (UVBR) on amphiBian early-emBryonic performance, leading to the conclusions, first, that the emBryonic stages of many species are tolerant to UVBR, and second, that the increased amount of UVBR reaching the Earth's surface is not likely to have any direct negative effects on many amphiBian populations. However, possiBle carry-over effects of exposure to UVBR in the emBryonic stages to the larval stages have received less attention. We studied the effects of UVBR experienced during the emBryonic stages (age less than 11 days) on the later performance (age 11-75 days) of common frog, Rana temporaria, larvae. In a factorial laBoratory experiment, newly fertilized emBryos were divided into three different UVBR treatments (no UVBR (control), 1.25 kJm(-2) (normal) and 1.58 kJm(-2) (26% enhanced)), after which the individual larvae were raised until metamorphosis in the aBsence of UVBR. No effects of UVBR on emBryonic survival rates, frequency of developmental anomalies or hatchling size were found, corroBorating the earlier results indicating that R. temporaria emBryos are tolerant to UVBR. However, analyses of larval performance revealed that larvae exposed to enhanced levels of UVBR as emBryos suffered from an increased frequency of developmental anomalies and metamorphosed later and at a smaller size than larvae that had Been protected from UVBR as emBryos. These results suggest, in contrast to the earlier studies, that UVBR has direct negative effects on R. temporaria emBryos, But these effects are expressed mostly or only during the later life stages. To this end, our results support the contention that carry-over effects from one life stage to another may Be an important source of phenotypic variation in fitness.
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amBient <B>UltravioletB> B Radiation reduces hatchling size in the common frog rana temporaria
Ecography, 2000Co-Authors: Maarit Pahkala, Anssi Laurila, Juha MeriläAbstract:Effects of amBient UV-B Radiation and pH on hatchaBility and early development of Rana temporaria emBryos were studied in field experiments conducted at two sites in Sweden. In neither of the populations did we find clear evidence for reduced hatchaBility
Ana L Scopel - One of the best experts on this subject based on the ideXlab platform.
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direct and indirect effects of solar <B>UltravioletB> B Radiation on long term decomposition
Global Change Biology, 2005Co-Authors: Matthew T Robson, Martyn M Caldwell, Osvaldo E Sala, Veronica Andrea Pancotto, Ana L ScopelAbstract:Fil: Pancotto, Veronica Andrea. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Parque Centenario. Instituto de Investigaciones Fisiologicas y Ecologicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomia. Instituto de Investigaciones Fisiologicas y Ecologicas Vinculadas a la Agricultura; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Austral de Investigaciones Cientificas; Argentina
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impacts of solar <B>UltravioletB> B Radiation on terrestrial ecosystems of tierra del fuego southern argentina an overview of recent progress
Journal of Photochemistry and Photobiology B-biology, 2001Co-Authors: Carlos L Ballare, Peter S Searles, Martyn M Caldwell, Cecilia M Rousseaux, Johann G Zaller, Carla Valeria Giordano, Matthew T Robson, Osvaldo E Sala, Ana L ScopelAbstract:The southern part of Tierra del Fuego, in the southernmost tip of South America, is covered By dense Nothofagus spp. forests and Sphagnum-dominated peat Bogs, which are suBjected to the influence of ozone depletion and to increased levels of solar <B>UltravioletB>-B Radiation (UV-B). Over the last 5 years we have studied some of the Biological impacts of solar UV-B on natural ecosystems of this region. We have addressed two general proBlems: (i) do the fluctuations in UV-B levels under the influence of the Antarctic ozone ‘hole’ have any measuraBle Biological impact, and (ii) what are the long-term effects of solar (amBient) UV-B on the Tierra del Fuego ecosystems? In this paper, we provide an overview of the progress made during the first 4 years of the project. We highlight and discuss the following results: (1) amBient UV-B has suBtle But significant inhiBitory effects on the growth of herBaceous and graminoid species of this region (growth reduction ≤12%), whereas no consistent inhiBitory effects could Be detected in woody perennials; (2) in the species investigated in greatest detail, Gunnera magellanica, the inhiBitory effect of solar UV-B is accompanied By increased levels of DNA damage in leaf tissue, and the DNA damage density in the early spring is clearly correlated with the dose of weighted UV-B measured at ground level; (3) the herBaceous species investigated thus far show little or no acclimation responses to amBient UV-B such as increased sunscreen levels and DNA repair capacity; and (4) amBient UV-B has significant effects on heterotrophic organisms, included marked inhiBitory effects on insect herBivory. The results from the experiments summarized in this review clearly indicate that UV-B influences several potentially important processes and ecological interactions in the terrestrial ecosystems of Tierra del Fuego.
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The effects of solar <B>UltravioletB>-B Radiation on the growth and yield of Barley are accompanied By increased DNA damage and antioxidant responses
Plant Cell and Environment, 1999Co-Authors: C. A. Mazza, A. M. Zima, M. Szwarcberg-bracchitta, C. V. Giordano, Diego Di Battista, Ana L Scopel, Ashley Acevedo, Carlos L BallareAbstract:There is limited information on the impacts of present-day solar <B>UltravioletB>-B Radiation (UV-B) on Biomass and grain yield of field crops and on the mechanisms that confer tolerance to UV-B Radiation under field conditions. We investigated the effects of solar UV-B on aspects of the Biochemistry, growth and yield of Barley crops using replicated field plots and two Barley strains, a catalase (CAT)deficient mutant (RPr 79/4) and its wild-type mother line (Maris Mink). Solar UV-B reduced Biomass accumulation and grain yield in Both strains. The effects on crop Biomass accumulation tended to Be more severe in RPr 79/4 (≃ 32% reduction) than in the mother line (≃ 20% reduction). Solar UV-B caused measuraBle DNA damage in leaf tissue, in spite of inducing a significant increase in UV-aBsorBing sunscreens in the two lines. Maris Mink responded to solar UV-B with increased CAT and ascorBate peroxidase (APx) activity. No effects of UV-B on total superoxide dismutase (SOD) activity were detected. Compared with the wild type, RPr 79/4 had lower CAT activity, as expected, But higher APx activity. Neither of these activities increased in response to UV-B in RPr 79/4. These results suggest that growth inhiBition By solar UV-B involves DNA damage and oxidative stress, and that constitutive and UV-B-induced antioxidant capacity may play an important role in UV-B tolerance.
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solar <B>UltravioletB> B Radiation affects seedling emergence dna integrity plant morphology growth rate and attractiveness to herBivore insects in datura ferox
Plant Physiology, 1996Co-Authors: Carlos L Ballare, Ana L Scopel, Ann E Stapleton, Marcelo J YanovskyAbstract:To study functional relationships Between the effects of solar <B>UltravioletB>-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.
