Amelioration of Uv‐b Damage Under High Irradiance. I: Role of Photosynthesis

Adamse, P.; Britz, Steven J.

doi:10.1111/j.1751-1097.1992.tb02216.x

Cited by 95 publications

(55 citation statements)

References 28 publications

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“…The response of leaves to UV-B exposure in combination with photosynthetically active radiation (PAR) is different from the response to UV-B exposure in the absence of PAR, demonstrating the PAR-mediated alleviation of UV-B induced damage (Adamse and Britz 1992, Kolb et al 2001, Bergo et al 2003, Pradhan et al 2006. Similar protective role of low irradiance by "white light" against UV-B induced impairment in photosynthetic apparatus of cyanobacterium Spirulina platensis was also found (Rajagopal et al 2005).…”

Section: Introductionmentioning

confidence: 83%

Developmental phase-dependent photosynthetic responses to ultraviolet-B radiation: damage, defence, and adaptation of primary leaves of wheat seedlings

Pradhan¹,

Nayak²,

Joshi³

et al. 2008

Photosynt.

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Alterations in photosynthetic capacity of primary leaves of wheat seedlings in response to ultraviolet-B (UV-B; 280-320 nm; 60 μmol m -2 s -1 ) exposure alone and in combination with photosynthetically active radiation (PAR; 400-800 nm; 200 μmol m -2 s -1 ) during different phases of leaf growth and development were assessed. UV-B exposure resulted in a phase-dependent differential loss in photosynthetic pigments, photochemical potential, photosystem 2 (PS2) quantum yield, and in vivo O 2 evolution. UV-B exposure induced maximum damage to the photosynthetic apparatus during senescence phase of development. The damages were partially alleviated when UV-B exposure was accompanied by PAR. UV-B induced an enhancement in accumulation of flavonoids during all phases of development while it caused a decline in anthocyanin content during senescence. The differential changes in these parameters demonstrated the adaptation ability of leaves to UV-B stress during all phases of development and the ability was modified in UV-B+ PAR exposed samples.

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Section: Introductionmentioning

confidence: 83%

Developmental phase-dependent photosynthetic responses to ultraviolet-B radiation: damage, defence, and adaptation of primary leaves of wheat seedlings

Pradhan¹,

Nayak²,

Joshi³

et al. 2008

Photosynt.

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“…Although none of the above exclusion studies assessed UV-B effects on photosynthesis, Ballaré et al (1996) suggested that the reductions in biomass production they observed were not due to impairments in photosynthesis, since the growth analysis parameter net assimilation rate (dry mass produced per leaf area per time) was not affected by UV-B level. In other UV-B studies, reductions in vegetative growth or changes in canopy architecture due to UV-B often occur in the absence of changes in photosynthetic rates per unit leaf area (Beyschlag et al, 1988;Barnes et al, 1990;Adamse and Britz, 1992;Searles et al, 1995;González et al, 1996González et al, , 1998Allen et al, 1998; Hunt and McNeil, 1998), and Fiscus and Booker (1995) and Allen et al (1998) concluded that photosynthesis in acclimated plants growing outdoors does not appear at risk from UV-B. Consistent with this we found that exposure to substantial, natural increases in UV-B had no effect on leaf area-based rates of POE.…”

Section: Uv-b Exposure Does Not Affect Leaf Area-based Photosyntheticmentioning

confidence: 99%

Effect of Solar Ultraviolet-B Radiation during Springtime Ozone Depletion on Photosynthesis and Biomass Production of Antarctic Vascular Plants

2001

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We assessed the influence of springtime solar UV-B radiation that was naturally enhanced during several days due to ozone depletion on biomass production and photosynthesis of vascular plants along the Antarctic Peninsula. Naturally growing plants of Colobanthus quitensis (Kunth) Bartl. and Deschampsia antarctica Desv. were potted and grown under filters that absorbed or transmitted most solar UV-B. Plants exposed to solar UV-B from mid-October to early January produced 11% to 22% less total, as well as above ground biomass, and 24% to 31% less total leaf area. These growth reductions did not appear to be associated with reductions in photosynthesis per se: Although rates of photosynthetic O 2 evolution were reduced on a chlorophyll and a dry-mass basis, on a leaf area basis they were not affected by UV-B exposure. Leaves on plants exposed to UV-B were denser, probably thicker, and had higher concentrations of photosynthetic and UV-B absorbing pigments. We suspect that the development of thicker leaves containing more photosynthetic and screening pigments allowed these plants to maintain their photosynthetic rates per unit leaf area. Exposure to UV-B led to reductions in quantum yield of photosystem II, based on fluorescence measurements of adaxial leaf surfaces, and we suspect that UV-B impaired photosynthesis in the upper mesophyll of leaves. Because the ratio of variable to maximal fluorescence, as well as the initial slope of the photosynthetic light response, were unaffected by UV-B exposure, we suggest that impairments in photosynthesis in the upper mesophyll were associated with light-independent enzymatic, rather than photosystem II, limitations.

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“…The partial protection by higher irradiance of gene expression during UV-B exposure might be due to increases in photosynthesis, or photoprotection and photorepair of DNA, or both. That increased photosynthesis confers greater resistance towards UV-B, at least for morphological features, was demonstrated by the exposure of Cucumis sativus seedlings to UV-B under normal or enhanced partial pressure of CO2: the latter treatment led to higher photosynthetic rates, and less UV-B damage (Adamse and Britz 1992). It is possible that the actual ratio of UV-B radiation to visible light is an important factor (Wilson and Greenberg 1993).…”

Section: Photosynthetic Genesmentioning

confidence: 99%

UV-B damage and protection at the molecular level in plants

1994

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Influx of solar UV-B radiation (280-320 nm) will probably increase in the future due to depletion of stratospheric ozone. In plants, there are several targets for the deleterious UV-B radiation, especially the chloroplast. This review summarizes the early effects and responses of low doses of UV-B at the molecular level. The DNA molecules of the plant cells are damaged by UV due to the formation of different photoproducts, such as pyrimidine dimers, which in turn can be combatted by specialized photoreactivating enzyme systems. In the chloroplast, the integrity of the thylakoid membrane seems to be much more sensitive than the activities of the photosynthetic components bound within. However, the decrease of mRNA transcripts for the photosynthetic complexes and other chloroplast proteins are among very early events of UV-B damage, as well as protein synthesis. Other genes, encoding defence-related enzymes, e.g., of the flavonoid biosynthetic pathway, are rapidly up-regulated after commencement of UV-B exposure. Some of the cis-acting nucleotide elements and trans-acting protein factors needed to regulate the UV-induced expression of the parsley chalcone synthase gene are known.

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Amelioration of Uv‐b Damage Under High Irradiance. I: Role of Photosynthesis

Cited by 95 publications

References 28 publications

Developmental phase-dependent photosynthetic responses to ultraviolet-B radiation: damage, defence, and adaptation of primary leaves of wheat seedlings

Developmental phase-dependent photosynthetic responses to ultraviolet-B radiation: damage, defence, and adaptation of primary leaves of wheat seedlings

Effect of Solar Ultraviolet-B Radiation during Springtime Ozone Depletion on Photosynthesis and Biomass Production of Antarctic Vascular Plants

UV-B damage and protection at the molecular level in plants

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