The effect of experimental warming on leaf functional traits, leaf structure and leaf biochemistry in Arabidopsis thaliana

Abstract

BackgroundThe leaf is an important plant organ, and how it will respond to future global warming is a question that remains unanswered. The effects of experimental warming on leaf photosynthesis and respiration acclimation has been well studied so far, but relatively little information exists on the structural and biochemical responses to warming. However, such information is very important to better understand the plant responses to global warming. Therefore, we grew Arabidopsis thaliana at the three day/night temperatures of 23/18°C (ambient temperature), 25.5/20.5°C (elevated by 2.5°C) and 28/23°C (elevated by 5°C) to simulate the middle and the upper projected warming expected within the 21st century for this purpose.ResultsThe 28/23°C treatment significantly reduced the life span, total biomass and total weight of seeds compared with the other two temperatures. Among the three temperature regimes, the concentrations of starch, chlorophyll, and proline were the lowest at 28/23°C, whereas the total weight of seeds, concentrations of chlorophyll and proline, stomatal density (SD), stomatal conductance (gs), net CO2 assimilation rate (A) and transpiration rate (E) were the highest at 25.5/20.5°C. Furthermore, the number of chloroplasts per cell and mitochondrial size were highest at 25.5/20.5°C and lowest at 28/23°C.ConclusionsThe conditions whereby the temperature was increased by 2.5°C were advantageous for Arabidopsis. However, a rise of 5°C produced negative effects, suggesting that lower levels of warming may benefit plants, especially those which belong to the same functional group as Arabidopsis, whereas higher levels of warming may produce negative affects. In addition, the increase in A under moderately warm conditions may be attributed to the increase in SD, chlorophyll content, and number of chloroplasts. Furthermore, starch accumulation in chloroplasts may be the main factor influencing chloroplast ultrastructure, and elevated temperature regulates plant respiration by probably affecting mitochondrial size. Finally, high SOD and CAT activities may enable plants grown at elevated temperatures to exhibit relatively high tolerance to temperature stress, thus alleviating the harmful effects of superoxide anion radicals and hydrogen peroxide.

Positive effects of night warming on physiology of coniferous trees in late growing season: Leaf and root

“…Hence, one possible explanation for the decrease of NSC concentrations is the enhancements of leaf and root respiration which could result in increased consumption of NSC. Similar results have also been reported in Scots pine (Zha et al, 2001), Douglas-fir (Tingey et al, 2003), Arabidopsis thaliana (Jin et al, 2011), A. faxoniana and Eucalyptus sideroxylon (Smith et al, 2012). Besides, in order to absorb water and nutrient effectively, concentration of NSC generally decreases in plants grown under warm circumstances due to the accelerated root respiration.…”

“…Consequently, a cascade of studies have investigated plants responses to global warming (Lemmens et al, 2006;Vicca et al, 2007;Danby and Hik, 2007;Leppalammi et al, 2013;Zheng et al, 2013), such as structure, physiology and function of leaves (Jin et al, 2011;Zheng et al, 2013), root lifespan and physiology (Bai et al, 2012;Yin et al, 2014), plant phenology (K€ orner and Basler, 2010) and carbon gain (Gimeno et al, 2012) as well as net primary productivity (Hudson and Henry, 2009). It is reported that globally averaged maximum and minimum temperatures have both increased since 1950 (IPCC, 2013), which tends to affect carbon assimilation and consumptions in plants, because photosynthesis in most plants occurs during the daytime and is more sensitive to daily maximum temperature, whereas plants respiration occurs throughout the whole day (Atkin et al, 2013), and is therefore influenced by both daily maximum and minimum temperature (Peng et al, 2013).…”

Climate warming alters nitrogen dynamics and total non-structural carbohydrate accumulations of perennial herbs of distinctive functional groups during the plant senescence in autumn in an alpine meadow of the Tibetan Plateau, China

“…Therefore, our initial hypothesis was partially confirmed, as different functional groups showed contrasting responses to treatments. Changes in air and soil temperature have been shown to result in pronounced effects on growth and leaf chemistry, which also vary depending on warming rates (Hudson et al, 2011;Jin et al, 2011). In our study, although the magnitudes of warming observed in air and soil temperatures were lower than that in most of the previous OTCs studies (Norby et al, 2000;Aerts et al, 2007), signifficant changes in plant senescence occurred, implying that the current warming rates (within the range tested here) are already exerting a significant influence on terrestrial ecosystems.…”

Structure and function of the tentpole in the reproductive process of Ginkgo biloba L.

“…The samples were cut into 70-nm thick sections with a diamond knife, and then stained with 1% (w/v) uranyl acetate and 1% (w/v) lead citrate. 29 The top and surface cells of the tentpole were observed and photographed under a Philips Tecnai 12 TEM (JEOL Ltd).…”