Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Stomatal and non-stomatal limitation to photosynthesis in two trembling aspen (Populus tremuloides Michx.) clones exposed to elevated CO2 and/or O3 (2001)
    Oxford, UK : Blackwell Science Ltd
    Plant, cell & environment 24 (2001), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Leaf gas exchange parameters and the content of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) in the leaves of two 2-year-old aspen (Populus tremuloides Michx.) clones (no. 216, ozone tolerant and no. 259, ozone sensitive) were determined to estimate the relative stomatal and mesophyll limitations to photosynthesis and to determine how these limitations were altered by exposure to elevated CO2 and/or O3. The plants were exposed either to ambient air (control), elevated CO2 (560 p.p.m.) elevated O3 (55 p.p.b.) or a mixture of elevated CO2 and O3 in a free air CO2 enrichment (FACE) facility located near Rhinelander, Wisconsin, USA. Light-saturated photosynthesis and stomatal conductance were measured in all leaves of the current terminal and of two lateral branches (one from the upper and one from the lower canopy) to detect possible age-related variation in relative stomatal limitation (leaf age is described as a function of leaf plastochron index). Photosynthesis was increased by elevated CO2 and decreased by O3 at both control and elevated CO2. The relative stomatal limitation to photosynthesis (ls) was in both clones about 10% under control and elevated O3. Exposure to elevated CO2 + O3 in both clones and to elevated CO2 in clone 259, decreased ls even further – to about 5%. The corresponding changes in Rubisco content and the stability of Ci/Ca ratio suggest that the changes in photosynthesis in response to elevated CO2 and O3 were primarily triggered by altered mesophyll processes in the two aspen clones of contrasting O3 tolerance. The changes in stomatal conductance seem to be a secondary response, maintaining stable Ci under the given treatment, that indicates close coupling between stomatal and mesophyll processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-3040.2001.00678.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Changes in ethylene and polyamines in relation to mRNA levels of the large and small subunits of ribulose bisphosphate carboxylase/oxygenase in ozone-stressed potato foliage (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 16 (1993), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Potato plants (Solanum tuberosum L. cv‘Norland’) were subjected to acute and chronic exposures of ozone (O3). Periodically following or during the exposures, foliage of different physiological ages were sampled for tissue analysis. Measurement of the following parameters were included: ethylene, 1-aminocyclopropane-1-carboxylic acid (ACC), N-malonyl 1-aminocyclopropane-1-carboxylic acid (MACC), and ACC oxidase activity, putrescine, spermidine, and spermine levels, and ornithine decarboxylase (ODC) activity, and levels of mRNA transcripts for the large and small subunits of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) (rbcL and rbcS, respectively). Ozone increased emission of ethylene and the concentration and activity of all associated metabolites and enzymes. Putrescine titre increased in response to O3 as did ODC activity. Some increases in spermidine were also detected. Ozone decreased the levels of mRNA for rbcL and rbcS, with the latter transcript exhibiting greater sensitivity. After acute exposures were terminated, the rbcL and rbcS transcript in younger leaves returned to levels of nonstressed plants; effects were less likely to be reversed in older tissue. The potential relationship between the changes in rbcL and rbcS and ethylene and polyamines are discussed in the context of O3 induction of accelerated senescence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.1993.tb00503.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Nitrogen dynamics during O3-induced accelerated senescence in hybrid poplar (2002)
    Oxford, UK : Blackwell Science, Ltd
    Plant, cell & environment 25 (2002), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Experiments were conducted to determine the fate of nitrogen (N) remobilized as a result of ozone (O3)-induced accelerated senescence in hybrid poplar subjected to declining N availability concurrent with O3 stress. Cuttings were grown in sand culture where the supply of N to the plant could be controlled on a daily basis and reduced in half of the plants when desired. Plants all initially received 3·57 mm N daily until approximately the 20 leaf stage after which daily supply of N was reduced to 0·71 mm. Plants were grown in open-top chambers in the field (Rock Springs, PA, USA) and received charcoal-filtered air, half also received supplemental O3 to a level of 0·08 µL L−1. Allocation of newly acquired N was determined with 15N. The specific allocation (mg labelled N mg−1 total N) of labelled N to upper, expanding leaf N was not affected by O3, but was strongly affected by N treatment. However, O3 increased the relative partitioning of labelled N to the expanding leaves and the roots. The balance between partitioning of newly acquired N to the upper leaves and roots was not affected by O3, but was reduced by N withdrawal. Calculated net N flux was strongly negative in the lower leaves of O3-exposed, N withdrawal plants. Nitrogen uptake was not reduced by O3. The allometric relationships between the roots and shoots were not affected by O3 or N availability. The relative contribution of newly acquired versus remobilized N to new growth appears to be determined by N supply. Ozone exposure alters the allocation of newly acquired N via alterations in plant size, whereas N availability exerts a strong effect upon both plant size and N allocation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-3040.2002.00828.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Differential response of four tree species to ozone-induced acceleration of foliar senescence (1999)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 22 (1999), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Ozone (O3)-induced accelerated senescence of leaves was measured in four tree species: black cherry (Prunus serotina), hybrid poplar (Populus maximowizii x trichocarpa, clone 245), northern red oak (Quercus rubra) and sugar maple (Acer saccharum). Seedlings or ramets of the four species were subjected to chronic O3 exposures and designated leaves harvested periodically from emergence to senescence. Gas exchange was analysed, and concentrations of total soluble protein and ribulose-1,5-bisphosphate carboxylase/oxygenase were measured as indicators of leaf senescence. Total antioxidant potential and ascorbate peroxidase and glutathione reductase activities also were determined. Black cherry and hybrid poplar exhibited O3-induced accelerated leaf senescence, whereas sugar maple and northern red oak did not. When the O3 effects were related to cumulative uptake of the gas, black cherry was the most sensitive of the four species. Although hybrid poplar exhibited similar symptoms of O3-induced accelerated senescence after the same exposure period as did black cherry, this species took up much greater quantities of O3 to achieve the same response. The O3-induced increase in glutathione reductase activity in hybrid poplar was consistent with the capacity of this species to take up high concentrations of the gas. Relative tolerance of northern red oak and sugar maple could be explained only in part by lower cumulative O3 uptake and lower rate of uptake. Sugar maple had the highest antioxidant potential of all four species, which may have contributed to O3 tolerance of this species. Ascorbate peroxidase activity, when expressed on a fresh weight basis, could not account for differential sensitivity among the four species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-3040.1999.00449.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Influence of ozone on transgenic tobacco plants expressing reduced quantities of Rubisco (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 20 (1997), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: RbcS-antisense transformed tobacco plants (Nicotiana tabacum cv. Petit Havana) expressing reduced quantities of Rubisco protein were used to examine the role of Rubisco quantity in determining ozone (O3) sensitivity. Transformed and wild-type plants were exposed to O3 in the greenhouse and in the field. Stomatal conductance, net photosynthesis and Rubisco protein quantity were measured at various times. Antisense-transformed genotypes responded to O3 by exhibiting rapid, severe foliar necrosis. The wild-type plants responded more slowly, exhibiting limited injury. Decreases in stomatal conductance, net photosynthesis or Rubisco quantity in plants exposed to O3 were not observed in asymptomatic leaves. Total biomass was lower for the transformed genotypes and decreased in both genotypes after exposure to O3. Shoot–root ratio and specific leaf area were higher in the transformed genotypes and increased in both genotypes with exposure to O3. Measurements of intercellular airspace demonstrated the presence of larger intercellular spaces in the transformed plants. The indirect effects of the rbcS antisense transformation, including morphological changes in the leaf, probably rendered the transformed plants more sensitive to the oxidant. The decreased quantity of Rubisco is not thought to be directly related to increased O3 sensitivity in the transformed plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-3040.1997.d01-168.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...