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

Jin B, Wang L, Wang J, Jiang KZ, Wang Y, Jiang XX, Ni CY, Wang YL, Teng NJ - BMC Plant Biol. (2011)

Bottom Line: 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, 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.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: College of Biological Sciences and Biotechnology, Yangzhou University, Yangzhou 225009, PR China.

ABSTRACT

Background: The 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.

Results: The 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.

Conclusions: The 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.

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Cross sections of leaves of Arabidopsis grown at three temperatures. Samples were taken at ambient temperature (A and B), elevated temperature I (C and D), and elevated temperature II (E and F). Note that the leaf at elevated temperature II was the thinnest of the three temperatures. In addition, there were more chloroplasts per cell at ambient temperature and elevated temperature I than elevated temperature II. Bars, 150 μm (A, C and E); 50 μm (B, D and F).
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Figure 2: Cross sections of leaves of Arabidopsis grown at three temperatures. Samples were taken at ambient temperature (A and B), elevated temperature I (C and D), and elevated temperature II (E and F). Note that the leaf at elevated temperature II was the thinnest of the three temperatures. In addition, there were more chloroplasts per cell at ambient temperature and elevated temperature I than elevated temperature II. Bars, 150 μm (A, C and E); 50 μm (B, D and F).

Mentions: Leaf thickness and cell size were not significantly different between ambient temperature and elevated temperature I, but at elevated temperature II they were significantly reduced by approximately 8.2% and 21.1%, respectively, compared to those at ambient temperature. However, no difference was observed in the number of cell layers among the three temperatures. Therefore, the changes in leaf thickness were mainly due to changes in cell size since the number of cell layers was not markedly affected by temperature (Table 1, Figure 2).


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

Jin B, Wang L, Wang J, Jiang KZ, Wang Y, Jiang XX, Ni CY, Wang YL, Teng NJ - BMC Plant Biol. (2011)

Cross sections of leaves of Arabidopsis grown at three temperatures. Samples were taken at ambient temperature (A and B), elevated temperature I (C and D), and elevated temperature II (E and F). Note that the leaf at elevated temperature II was the thinnest of the three temperatures. In addition, there were more chloroplasts per cell at ambient temperature and elevated temperature I than elevated temperature II. Bars, 150 μm (A, C and E); 50 μm (B, D and F).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3045891&req=5

Figure 2: Cross sections of leaves of Arabidopsis grown at three temperatures. Samples were taken at ambient temperature (A and B), elevated temperature I (C and D), and elevated temperature II (E and F). Note that the leaf at elevated temperature II was the thinnest of the three temperatures. In addition, there were more chloroplasts per cell at ambient temperature and elevated temperature I than elevated temperature II. Bars, 150 μm (A, C and E); 50 μm (B, D and F).
Mentions: Leaf thickness and cell size were not significantly different between ambient temperature and elevated temperature I, but at elevated temperature II they were significantly reduced by approximately 8.2% and 21.1%, respectively, compared to those at ambient temperature. However, no difference was observed in the number of cell layers among the three temperatures. Therefore, the changes in leaf thickness were mainly due to changes in cell size since the number of cell layers was not markedly affected by temperature (Table 1, Figure 2).

Bottom Line: 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, 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.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: College of Biological Sciences and Biotechnology, Yangzhou University, Yangzhou 225009, PR China.

ABSTRACT

Background: The 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.

Results: The 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.

Conclusions: The 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.

Show MeSH