Profiles of light absorption and chlorophyll within spinach leaves from chlorophyll fluorescence

T. C. Vogelmann*, J. R. Evans

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    168 Citations (Scopus)

    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 epi-fluorescence 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 μm 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 μm deep, respectively.

    Original languageEnglish
    Pages (from-to)1313-1323
    Number of pages11
    JournalPlant, Cell and Environment
    Volume25
    Issue number10
    DOIs
    Publication statusPublished - Oct 2002

    Fingerprint

    Dive into the research topics of 'Profiles of light absorption and chlorophyll within spinach leaves from chlorophyll fluorescence'. Together they form a unique fingerprint.

    Cite this