You are not currently logged in.
Access JSTOR through your library or other institution:
If You Use a Screen ReaderThis content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Chlorophyll Fluorescence and Photon Yield of Oxygen Evolution in Iron-Deficient Sugar Beet (Beta vulgaris L.) Leaves
Fermín Morales, Anunciación Abadía and Javier Abadía
Vol. 97, No. 3 (Nov., 1991), pp. 886-893
Published by: American Society of Plant Biologists (ASPB)
Stable URL: http://www.jstor.org/stable/4273927
Page Count: 8
You can always find the topics here!Topics: Fluorescence, Plants, Photons, Sugar beets, Leaves, Absorptance, Oxygen, Carotenoids, Chlorophylls, Quantum efficiency
Were these topics helpful?See something inaccurate? Let us know!
Select the topics that are inaccurate.
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Preview not available
The response of sugar beet (Beta vulgaris L.) leaves to iron deficiency can be described as consisting of two phases. In the first phase, leaves may lose a large part of their chlorophyll while maintaining a roughly constant efficiency of photosystem II photochemistry; ratios of variable to maximum fluorescence decreased by only 6%, and photon yields of oxygen evolution decreased by 30% when chlorophyll decreased by 70%. In the second phase, when chlorophyll decreased below a threshold level, iron deficiency caused major decreases in the efficiency of photosystem II photochemistry and in the photon yield of oxygen evolution. These decreases in photosystem II photochemical efficiency were found both in plants dark-adapted for 30 minutes and in plants dark-adapted overnight, indicating that photochemical efficiency cannot be repaired in that time scale. Decreases in photosystem II photochemical efficiency and in the photon yield of oxygen evolution were similar when measurements were made (a) with light absorbed by carotenoids and chlorophylls and (b) with light absorbed only by chlorophylls. Leaves of iron-deficient plants exhibited a room temperature fluorescence induction curve with a characteristic intermediate peak I that increases with deficiency symptoms.
Plant Physiology © 1991 American Society of Plant Biologists (ASPB)