Abstract
Abstract Chlorophyll fluorescence was used to estimate profiles of absorbed light within chlorophyll solutions and leaves. For chlorophyll solutions, the intensity of the emitted fluorescence declined in a log–linear manner with the distance from the irradiated surface as predicted by Beer's law. The amount of fluorescence was proportional to chlorophyll concentration for chlorophyll solutions given epi‐illumination on a microscope slide. These relationships appeared to hold for more optically complex spinach leaves. The profile of chlorophyll fluorescence emitted by leaf cross sections given epi‐illumination corresponded to chlorophyll content measured in extracts of leaf paradermal sections. Thus epifluorescence was used to estimate relative chlorophyll content through leaf tissues. Fluorescence profiles across leaves depended on wavelength and orientation, reaching a peak at 50–70 µ m depth. By infiltrating leaves with water, the pathlengthening due to scattering at the airspace : cell wall interfaces was calculated. Surprisingly, the palisade and spongy mesophyll had similar values for pathlengthening with the value being greatest for green light (550 > 650 > 450 nm). By combining fluorescence profiles with chlorophyll distribution across the leaf, the profile of the apparent extinction coefficient was calculated. The light profiles within spinach leaves could be well approximated by an apparent extinction coefficient and the Beer–Lambert/Bouguer laws. Light was absorbed at greater depths than predicted from fibre optic measurements, with 50% of blue and green light reaching 125 and 240 µ m deep, respectively.
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Claims 8
Claim · model-written summary
Epifluorescence estimated relative chlorophyll content through spinach leaf tissues, and the leaf cross-section fluorescence profile corresponded to chlorophyll content measured in leaf paradermal extracts.
- Taxon
- spinach
Spinacia oleraceat0 - Organ / stage
- leaf tissuese1
- Outcome
- relative chlorophyll contente1
- Comparator
- chlorophyll content measured in extracts of leaf paradermal sectionse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Profiles of light absorption and chlorophyll within spinach leaves from chlorophyll fluorescence”
e1“Thus epifluorescence was used to estimate relative chlorophyll content through leaf tissues”
e2“corresponded to chlorophyll content measured in extracts of leaf paradermal sections”
Claim · model-written summary
Fluorescence profiles across spinach leaves peaked at a depth of 50–70 µ m.
- Taxon
- spinachSpinacia oleraceat0
- Outcome
- peake3
- Value
- 50–70 µ me3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Profiles of light absorption and chlorophyll within spinach leaves from chlorophyll fluorescence”
e3“reaching a peak at 50–70 µ m depth”
Claim · model-written summary
Fluorescence profiles across spinach leaves depended on wavelength and orientation.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- wavelength and orientatione5
- Outcome
- fluorescence profilese5
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Profiles of light absorption and chlorophyll within spinach leaves from chlorophyll fluorescence”
e5“Fluorescence profiles across leaves depended on wavelength and orientation”
Claim · model-written summary
Pathlengthening in the palisade and spongy mesophyll of spinach leaves had similar values.
- Taxon
- spinachSpinacia oleraceat0
- Organ / stage
- palisade and spongy mesophylle4
- Outcome
- pathlengtheninge4
- Qualifier
- similar valuese4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Profiles of light absorption and chlorophyll within spinach leaves from chlorophyll fluorescence”
e4“Surprisingly, the palisade and spongy mesophyll had similar values for pathlengthening with the value being greatest for green light (550 > 650 > 450 nm)”
Claim · model-written summary
Pathlengthening in spinach leaves was greatest for green light.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- green lighte4
- Outcome
- pathlengtheninge4
- Direction
- greateste4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Profiles of light absorption and chlorophyll within spinach leaves from chlorophyll fluorescence”
e4“Surprisingly, the palisade and spongy mesophyll had similar values for pathlengthening with the value being greatest for green light (550 > 650 > 450 nm)”
Claim · model-written summary
Light profiles within spinach leaves were well approximated by an apparent extinction coefficient and the Beer–Lambert/Bouguer laws.
- Taxon
- spinachSpinacia oleraceat0
- Outcome
- light profilese6
- Comparator
- Beer–Lambert/Bouguer lawse6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Profiles of light absorption and chlorophyll within spinach leaves from chlorophyll fluorescence”
e6“The light profiles within spinach leaves could be well approximated by an apparent extinction coefficient and the Beer–Lambert/Bouguer laws”
Claim · model-written summary
Light was absorbed at greater depths in spinach leaves than predicted from fibre optic measurements.
- Taxon
- spinachSpinacia oleraceat0
- Outcome
- absorbed at greater depthse7
- Comparator
- predicted from fibre optic measurementse7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Profiles of light absorption and chlorophyll within spinach leaves from chlorophyll fluorescence”
e7“Light was absorbed at greater depths than predicted from fibre optic measurements, with 50% of blue and green light reaching 125 and 240 µ m deep, respectively”
Claim · model-written summary
Fifty percent of blue and green light reached 125 and 240 µ m deep in spinach leaves, respectively.
- Taxon
- spinachSpinacia oleraceat0
- Outcome
- blue and green light reachinge7
- Value
- 125 and 240 µ me7
- Qualifier
- 50%e7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Profiles of light absorption and chlorophyll within spinach leaves from chlorophyll fluorescence”
e7“Light was absorbed at greater depths than predicted from fibre optic measurements, with 50% of blue and green light reaching 125 and 240 µ m deep, respectively”