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Joseph N.T. Darbah Mark E. Kubiske Katre Kets Anu Sober David F. Karnosky 《Environmental pollution (Barking, Essex : 1987)》2010,158(4):983-19373
Photosynthetic acclimation under elevated carbon dioxide (CO2) and/or ozone (O3) has been the topic of discussion in many papers recently. We examined whether or not aspen plants grown under elevated CO2 and/or O3 will acclimate after 11 years of exposure at the Aspen Face site in Rhinelander, WI, USA. We studied diurnal patterns of instantaneous photosynthetic measurements as well as A/Ci measurements monthly during the 2004-2008 growing seasons. Our results suggest that the responses of two aspen clones differing in O3 sensitivity showed no evidence of photosynthetic and stomatal acclimation under either elevated CO2, O3 or CO2 + O3. Both clones 42E and 271 did not show photosynthetic nor stomatal acclimation under elevated CO2 and O3 after a decade of exposure. We found that the degree of increase or decrease in the photosynthesis and stomatal conductance varied significantly from day to day and from one season to another. 相似文献
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The prawn Macrobrachium idae
Heller carries 40 to 160 eggs depending upon the body size of the mother animal. After incubation, 63, 35 and 2% eggs are hatched on the first, second and third hatching nights, respectively. Mean dry weight of a single larva relased on the first night is 420 g (equivalent to 2.86 cal). Larvae released on the second or third hatching nights weighed 380 g (=2.56 cal) or 308 g (=2.02 cal). The total reserve yolk-energy available in a larva hatched on the first night is 1 cal. There is a definite shift from protein to fat metabolism as hatching is delayed. Oxygen consumption of developing eggs awaiting release on the first or second hatching night is 1.9 l/mg dry weight/h. In comparison to larvae released on the first night, those released on the second night exhibit 2% increase in total body-length and 2.4 or 14.3% decrease in the lengths of the 6th abdominal segment or the orbit. Larvae released on the first, second or third hatching nights, on exposure to starvation stress, survive for 3.8, 2.3 or 1.5 days. The swimming speed of larvae released on the first or second night is 1.0 or 0.6 cm/sec. Larvae released on the subsequent hatching nights committed nearly 2 times greater number of mistakes per cm distance in the horizontal plane. Since hatching of all developing eggs simultaneously on the first hatching night is possible by means of artificial technique(s), it is possible to improve survival rate of decapod larvae. 相似文献
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Katre Kets Joseph N.T. Darbah Johanna Riikonen David F. Karnosky 《Environmental pollution (Barking, Essex : 1987)》2010,158(4):1000-1007
The diurnal changes in light-saturated photosynthesis (Pn) under elevated CO2 and/or O3 in relation to stomatal conductance (gs), water potential, intercellular [CO2], leaf temperature and vapour-pressure difference between leaf and air (VPDL) were studied at the Aspen FACE site. Two aspen (Populus tremuloides Michx.) clones differing in their sensitivity to ozone were measured. The depression in Pn was found after 10:00 h. The midday decline in Pn corresponded with both decreased gs and decreased Rubisco carboxylation efficiency, Vcmax. As a result of increasing VPDL, gs decreased. Elevated [CO2] resulted in more pronounced midday decline in Pn compared to ambient concentrations. Moreover, this decline was more pronounced under combined treatment compared to elevated CO2 treatment.The positive impact of CO2 on Pn was relatively more pronounced in days with environmental stress but relatively less pronounced during midday depression. The negative impact of ozone tended to decrease in both cases. 相似文献
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