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Inhibition of photosynthesis by Colletotrichum lindemuthianum in bean leaves determined by chlorophyll fluorescence imaging
Author(s) -
Meyer S.,
SaccardyAdji K.,
Rizza F.,
Genty B.
Publication year - 2001
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1046/j.0016-8025.2001.00737.x
Subject(s) - photosynthesis , chlorophyll fluorescence , stomatal conductance , biology , irradiance , botany , horticulture , respiration , chlorophyll , photoinhibition , chlorophyll a , rubisco , electron transport chain , photosystem ii , physics , quantum mechanics
Infection of bean leaves by Colletotrichum lundemuthianum causes vein necrosis and subsequent localized wilting of the blade. The effect of infection on photosynthesis was investigated by imaging leaf chlorophyll fluorescence as a means of mapping stomatal and metabolic inhibition of photosynthesis. During infection, CO 2 assimilation ( An ), stomatal conductance to water vapour, and photosynthetic electron transport rate ( J t ) decreased, whereas dark respiration increased. An decreased more than was expected from the reduction in green leaf area, showing that photosynthesis was inhibited in apparently healthy areas. Under subsaturating irradiance, images of J t in air showed that photosynthesis decreased gradually, with this effect shifting from green to necrotic areas. Sudden increase in CO 2 concentration to 0·74% in the atmosphere around the leaf only partially reversed this inhibition, showing that both stomatal and metabolic inhibition occurred. Under limiting irradiance, decreases in J t and in maximal J t during high CO 2 exposure as leaf damage severity increased suggested that metabolic inhibition was mediated through an inhibition of Ribulose 1·5‐bisphosphate (RuBP) regeneration. Finally, the importance of our data in terms of assessing the loss of photosynthetic yield from visible symptoms – as is currently performed in epidemiology – is discussed.