Responses of plants in polar regions to UVB exposure: a meta‐analysis

Abstract

We report a meta-analysis of data from 34 field studies into the effects of UV-B radiation on Arctic and Antarctic bryophytes and angiosperms. The studies measured plant responses to decreases in UV-B radiation under screens, natural fluctuations in UV-B irradiance, or increases in UV-B radiation applied from fluorescent UV lamps. Exposure to UV-B radiation was found to increase the concentrations of UV-B absorbing compounds in leaves or thalli by 7% and 25% (expressed on a mass or area basis, respectively). UV-B exposure also reduced aboveground biomass and plant height by 15% and 10%, respectively, and increased DNA damage by 90%. No effects of UV-B exposure were found on carotenoid or chlorophyll concentrations, net photosynthesis, Fv/Fm or ΦPSII, belowground or total biomass, leaf mass, leaf area or specific leaf area (SLA). The methodology adopted influenced the concentration of UV-B absorbing compounds, with screens and natural fluctuations promoting significant changes in the concentrations of these pigments, but lamps failing to elicit a response. Greater reductions in leaf area and SLA, and greater increases in concentrations of carotenoids, were found in experiments based in Antarctica than in those in the Arctic. Bryophytes typically responded in the same way as angiosperms to UV-B exposure. Regression analyses indicated that the percentage difference in UV-B dose between treatment and control plots was positively associated with concentrations of UV-B absorbing compounds and carotenoids, and negatively so with aboveground biomass and leaf area. We conclude that, despite being dominated by bryophytes, the vegetation of polar regions responds to UV-B exposure in a similar way to higher plant-dominated vegetation at lower latitudes. In broad terms, the exposure of plants in these regions to UV-B radiation elicits the synthesis of UV-B absorbing compounds, reduces aboveground biomass and height, and increases DNA damage.

A novel palaeoaltimetry proxy based on spore and pollen wall chemistry

“…Meta-analysis on whole plant responses to UV-B confirms that, in response to increased UV-B radiation flux, the up-regulation of UACs is one of the most consistent responses across a wide a variety of species (Searles et al, 2001;Newsham et al, 2009), with a 10% increase in UACs in response to growth at elevated UV-B (Searles et al, 2001). Metaanalysis also shows that plants can rapidly acclimate to UV-B exposure through the production of UACs (Newsham et al, 2009). Additionally, recent work has identified the protein (UVR8) responsible for the perception and subsequent upstream regulation of plant responses to UV-B radiation (Rizzini et al, 2011).…”

The spatial structure of Antarctic biodiversity

“…Increased UV-B radiation as a result of the ozone hole occurs between September and early December, so has little effect within the main Antarctic continent, as vegetation activity occurs mainly within the period December to early February. Enhanced levels do occur on the Antarctic Peninsula, but there is evidence that the bryophytes at least can rapidly acclimate to changes in UV radiation (Newsham 2003, Newsham and Robinson 2009). Exposure does result in damage to biochemical constituents of cells (e.g., DNA and photosystems [Green et al 2000, George et al 2002, Lud et al 2002, Robinson and Waterman 2013), but these effects are transient.…”

The effect of foliar spray fertilizers on the tolerance of Hordeum vulgare to UV-B radiation and drought stress

“…Literature indicates that UVB radiation has been shown to increase (Poulson et al 2006), decrease (Qaderi et al 2007) or have no effect on chlorophyll content (Newsham and Robinson 2009). It is known, that carotenoids are anti-stress pigments, shield chlorophyll from the miseries of light, excess of light or UV-B like harmful radiations and also act as antioxidants (Yadav et al 2016).…”