Through a gradient experiment controlling CO2 concentration and illumination intensity, the photosynthetic physiological characters of two C4 pathway plants, Setaria viridis and Pennisetum flaccidum, w...Through a gradient experiment controlling CO2 concentration and illumination intensity, the photosynthetic physiological characters of two C4 pathway plants, Setaria viridis and Pennisetum flaccidum, were measured on the Songnen Plains of China. The results showed that the net photosynthetic rate (Pn) of S.viridis was higher than P.flaccidum. As the CO2 concentration increased, Pn of the two species both increased until the CO2 concentration reached approximately 600 μmol/mol, after which Pn decreased. At the same time, the light compensation points of the two species gradually dropped. This is related to the inhibition of dark respiration with high CO2 concentration.展开更多
Carbon isotope ratios (δ^(13)C) of 89 C_4 plant samples were determined fromthe loess area in North China. δ^(13)C values vary between -10.5per thousand and -14.6per thousandwith a mean of -12.6per thousand. Along a...Carbon isotope ratios (δ^(13)C) of 89 C_4 plant samples were determined fromthe loess area in North China. δ^(13)C values vary between -10.5per thousand and -14.6per thousandwith a mean of -12.6per thousand. Along a precipitation gradient from the semi-moist area to thesemiarid area, then to the arid area, the δ^(13)C values of C_4 plants show a slight decreasingtrend. The δ^(13)C values of C_4 plants in the dry season are found lower than those in the wetseason. These trends are opposite to those observed for C_3 species.展开更多
The nature and dynamics of climate change in central Asia since the late Pleistocene are controversial. Moreover,most of the published studies focus mainly on the evolution of moisture conditions, and there have been ...The nature and dynamics of climate change in central Asia since the late Pleistocene are controversial. Moreover,most of the published studies focus mainly on the evolution of moisture conditions, and there have been few attempts to address changes in seasonality. In this study, records of δ^(13)C_(org), TOC, TN, C/N and grain size were obtained from lacustrine sediments at Yili Basin, Xinjiang, NW China. Our aim was to reconstruct the trend in seasonality of precipitation from the last glaciation to the Holocene. The organic matter content of the sediments is derived predominantly from terrestrial plants. The δ^(13)C_(org)values vary from-19.4‰ to-24.8‰, indicating that the vegetation was dominated by C_3 plants. Winter-spring precipitation is identified as the factor determining the relative proportions of C_3 and C_4 plants in the region. A negative trend in δ^(13)C_(org)corresponding to an increase in the relative abundance of C_3 plants indicate a trend of increasing winter-spring precipitation from the last glaciation to the Holocene. The increased incidence of wintertime storms in the interior of Asia is suggested to result in the increase of winterspring precipitation in the Holocene.展开更多
文摘Through a gradient experiment controlling CO2 concentration and illumination intensity, the photosynthetic physiological characters of two C4 pathway plants, Setaria viridis and Pennisetum flaccidum, were measured on the Songnen Plains of China. The results showed that the net photosynthetic rate (Pn) of S.viridis was higher than P.flaccidum. As the CO2 concentration increased, Pn of the two species both increased until the CO2 concentration reached approximately 600 μmol/mol, after which Pn decreased. At the same time, the light compensation points of the two species gradually dropped. This is related to the inhibition of dark respiration with high CO2 concentration.
基金supported by the National Natural Science Foundation of China(Grants Nos.40273006,40072059,49925307 and 90102001).
文摘Carbon isotope ratios (δ^(13)C) of 89 C_4 plant samples were determined fromthe loess area in North China. δ^(13)C values vary between -10.5per thousand and -14.6per thousandwith a mean of -12.6per thousand. Along a precipitation gradient from the semi-moist area to thesemiarid area, then to the arid area, the δ^(13)C values of C_4 plants show a slight decreasingtrend. The δ^(13)C values of C_4 plants in the dry season are found lower than those in the wetseason. These trends are opposite to those observed for C_3 species.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB26000000)the National Natural Science Foundation of China (Grant Nos. 41772371, 41572161 & 41730319)+2 种基金the National Basic Research Program of China (Grant No. 2015CB953803)the Youth Innovation Promotion Association CASthe Australian Nuclear Science and Technology Organization
文摘The nature and dynamics of climate change in central Asia since the late Pleistocene are controversial. Moreover,most of the published studies focus mainly on the evolution of moisture conditions, and there have been few attempts to address changes in seasonality. In this study, records of δ^(13)C_(org), TOC, TN, C/N and grain size were obtained from lacustrine sediments at Yili Basin, Xinjiang, NW China. Our aim was to reconstruct the trend in seasonality of precipitation from the last glaciation to the Holocene. The organic matter content of the sediments is derived predominantly from terrestrial plants. The δ^(13)C_(org)values vary from-19.4‰ to-24.8‰, indicating that the vegetation was dominated by C_3 plants. Winter-spring precipitation is identified as the factor determining the relative proportions of C_3 and C_4 plants in the region. A negative trend in δ^(13)C_(org)corresponding to an increase in the relative abundance of C_3 plants indicate a trend of increasing winter-spring precipitation from the last glaciation to the Holocene. The increased incidence of wintertime storms in the interior of Asia is suggested to result in the increase of winterspring precipitation in the Holocene.
