Abstract
Abstract Toxic agents may affect photosynthesis either by altering the diffusion of CO2 to the photosynthesizing cells or by altering the chloroplast activity for CO2 fixation. Therefore, the effect of toxic chemicals can be assessed by measurement of the rate of CO2 fixation. The effects on photosynthesis caused by altered CO2 diffusion can be distinguished from those caused at the chloroplast level by evaluating the CO2 concentration inside the leaf. If CO2 concentrations remain constant or rise as photosynthesis declines, the inhibition must act on chloroplast activity. If the CO2 concentrations decrease as photosynthesis declines, the inhibition may be caused by slower diffusion of CO2into the leaf. The latter possibility would suggest a stomatal closure to be the most probable cause of the decline of photosynthesis.
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Claims 5
Claim · model-written summary
CO2 fixation rate can assess the effects of toxic chemicals on photosynthesis.
- Outcome
- effect of toxic chemicalse0
Not reportedTaxonComparatorValue
Verbatim
e0“the effect of toxic chemicals can be assessed by measurement of the rate of CO2 fixation”
Claim · model-written summary
Internal leaf CO2 concentration can distinguish diffusion effects from chloroplast effects on photosynthesis.
Not reportedTaxon
Verbatim
e0“The effects on photosynthesis caused by altered CO2 diffusion can be distinguished from those caused at the chloroplast level by evaluating the CO2 concentration inside the leaf.”
Claim · model-written summary
Stable or rising internal CO2 during declining photosynthesis indicates chloroplast inhibition.
Not reportedTaxon
Verbatim
e0“If CO2 concentrations remain constant or rise as photosynthesis declines, the inhibition must act on chloroplast activity.”
Claim · model-written summary
Declining internal CO2 with declining photosynthesis may indicate slower diffusion into the leaf.
Not reportedTaxon
Verbatim
e0“If the CO2 concentrations decrease as photosynthesis declines, the inhibition may be caused by slower diffusion of CO2into the leaf.”
Claim · model-written summary
Stomatal closure is suggested as the probable cause of diffusion-related photosynthesis decline.
Not reportedTaxon
Verbatim
e0“The latter possibility would suggest a stomatal closure to be the most probable cause of the decline of photosynthesis.”