After detailed studies of leaf area, leaf shape index, petiole length, stomatal density, stomatal index, and carbon isotope discrimination of Ginkgo biloba L., growing in Northwest China, the change trends of these pa...After detailed studies of leaf area, leaf shape index, petiole length, stomatal density, stomatal index, and carbon isotope discrimination of Ginkgo biloba L., growing in Northwest China, the change trends of these parameters with an altitude gradient and their differences between sun and shade leaves were assessed. The results show that leaf area, petiole length, and stomatal parameters have no obvious linear relationship with altitude, but the carbon isotope discrimination shows a negative correlation with altitude, which has a potential to be an applicable paleo-altimeter. The results also suggest that the differences in stomatal density and stomatal index between sun and shade leaves had more influence on paleoelevation reconstruction than that in other parameters. Based on the linear and nonlinear correlations between carbon isotope discrimination and altitude, the paleoelevation evolution during the Middle Jurassic of the Yaojie Basin, Lanzhou in Gansu Province was estimated. The results show that the paleoelevation of the Yaojie Basin increased at first, and then decreased from the Aalenian to the early Bajocian and then to the late Bajocian in the Middle Jurassic.展开更多
The ear, together with the flag leaf, is believed to play a major role as a source of assimilates during grain filling in C3cereals. However, the intrusive nature of most of the available methodologies prevents reachi...The ear, together with the flag leaf, is believed to play a major role as a source of assimilates during grain filling in C3cereals. However, the intrusive nature of most of the available methodologies prevents reaching conclusive results in this regard. This study compares the carbon isotope composition（d13C） in its natural abundance in the water‐soluble fractions of the flag leaf blade and the ear with the d13C of mature kernels to assess the relative contribution of both organs to grain filling in durum wheat（Triticum turgidum L. var.durum）. The relative contribution of the ear was higher in landraces compared to modern cultivars, as well as in response to nitrogen fertilization and water stress. Such genotypic and environmentally driven differences were associated with changes in harvest index（HI）, with the relative contribution of the ear being negatively associated with HI. In the case of the genotypic differences, the lower relative contribution of the ear in modern cultivars compared with landraces is probably associated with the appearance in the former of a certain amount of source limitation driven by a higher HI. In fact, the relative contribution of the ear was far more responsive to changes in HI in modern cultivars compared with landraces.展开更多
Generally, plant species with shorter leaf longevity maintain a positive carbon balance by decreasing leaf mass per area (LMA) and increasing photosynthesis. However, plants at high elevations need to increase LMA aga...Generally, plant species with shorter leaf longevity maintain a positive carbon balance by decreasing leaf mass per area (LMA) and increasing photosynthesis. However, plants at high elevations need to increase LMA against environmental stresses. Therefore, plants need to increase both LMA and photosynthesis at high elevations. To examine how deciduous plants maintain a positive carbon balance at high elevations, photosynthesis and related leaf traits for deciduous broad-leaved tree Betula ermanii were measured at three elevations. LMA was greater at middle and high elevations than at low elevation. Leaf δ13C was greater at higher elevations, and positively correlated with LMA, indicating greater long-term deficiency of CO2 in leaves at higher elevations. However, the Ci/Ca ratio at photosynthetic measurement was not low at high elevations. Nitrogen content per leaf mass and stomatal conductance were greater at higher elevations. Photosynthetic rates and photosynthetic nitrogen use efficiency (PNUE) did not differ among the three elevations. Photosynthetic rate showed a strong positive correlation with stomatal conductance on a leaf area basis (R2 = 0.83, P < 0.001). Therefore, this study suggests B. ermanii compensates the deficiency of CO2 in leaves at high elevation by increasing stomatal conductance, and maintains photosynthesis and PNUE at high elevation as much as at low elevation.展开更多
基金Supported by National Basic Research Program of China (Grant No. 2006CB701401)National Natural Science Foundation of China (Grant Nos. 40802008, 40772012 and 40502005)+1 种基金Research Fund for the Doctoral Program of Higher Education (Grant No. 200807301005)Science and Technology Program of Gansu Province (Grant No. 0806RJYA016)
文摘After detailed studies of leaf area, leaf shape index, petiole length, stomatal density, stomatal index, and carbon isotope discrimination of Ginkgo biloba L., growing in Northwest China, the change trends of these parameters with an altitude gradient and their differences between sun and shade leaves were assessed. The results show that leaf area, petiole length, and stomatal parameters have no obvious linear relationship with altitude, but the carbon isotope discrimination shows a negative correlation with altitude, which has a potential to be an applicable paleo-altimeter. The results also suggest that the differences in stomatal density and stomatal index between sun and shade leaves had more influence on paleoelevation reconstruction than that in other parameters. Based on the linear and nonlinear correlations between carbon isotope discrimination and altitude, the paleoelevation evolution during the Middle Jurassic of the Yaojie Basin, Lanzhou in Gansu Province was estimated. The results show that the paleoelevation of the Yaojie Basin increased at first, and then decreased from the Aalenian to the early Bajocian and then to the late Bajocian in the Middle Jurassic.
基金supported by the project AGL2010‐20180:"Improvement ofdurum wheat for present and future Mediterranean conditions"from the Ministerio de Ciencia e Innovación,Spain
文摘The ear, together with the flag leaf, is believed to play a major role as a source of assimilates during grain filling in C3cereals. However, the intrusive nature of most of the available methodologies prevents reaching conclusive results in this regard. This study compares the carbon isotope composition（d13C） in its natural abundance in the water‐soluble fractions of the flag leaf blade and the ear with the d13C of mature kernels to assess the relative contribution of both organs to grain filling in durum wheat（Triticum turgidum L. var.durum）. The relative contribution of the ear was higher in landraces compared to modern cultivars, as well as in response to nitrogen fertilization and water stress. Such genotypic and environmentally driven differences were associated with changes in harvest index（HI）, with the relative contribution of the ear being negatively associated with HI. In the case of the genotypic differences, the lower relative contribution of the ear in modern cultivars compared with landraces is probably associated with the appearance in the former of a certain amount of source limitation driven by a higher HI. In fact, the relative contribution of the ear was far more responsive to changes in HI in modern cultivars compared with landraces.
文摘Generally, plant species with shorter leaf longevity maintain a positive carbon balance by decreasing leaf mass per area (LMA) and increasing photosynthesis. However, plants at high elevations need to increase LMA against environmental stresses. Therefore, plants need to increase both LMA and photosynthesis at high elevations. To examine how deciduous plants maintain a positive carbon balance at high elevations, photosynthesis and related leaf traits for deciduous broad-leaved tree Betula ermanii were measured at three elevations. LMA was greater at middle and high elevations than at low elevation. Leaf δ13C was greater at higher elevations, and positively correlated with LMA, indicating greater long-term deficiency of CO2 in leaves at higher elevations. However, the Ci/Ca ratio at photosynthetic measurement was not low at high elevations. Nitrogen content per leaf mass and stomatal conductance were greater at higher elevations. Photosynthetic rates and photosynthetic nitrogen use efficiency (PNUE) did not differ among the three elevations. Photosynthetic rate showed a strong positive correlation with stomatal conductance on a leaf area basis (R2 = 0.83, P < 0.001). Therefore, this study suggests B. ermanii compensates the deficiency of CO2 in leaves at high elevation by increasing stomatal conductance, and maintains photosynthesis and PNUE at high elevation as much as at low elevation.
