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light-stimulated cell expansion in bean (phaseolus vulgaris l.) leaves. i. growth can occur without photosynthesisCell expansion in dicotyledonous leaves is strongly stimulated by bright white light (WL), at least in part as a result of light-induced acidification of the cell walls. It has been proposed that photosynthetic reactions are required for light-stimulated transport processes across plasma membranes of leaf cells, including proton excretion. The involvement of photosynthesis in growth and wall acidification of primary leaves of bean has been tested by inhibiting photosynthesis in two ways: by reducing chlorophyll content of intact plants with tentoxin (TX) and by treating leaf discs with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). Exposure to bright WL stimulated growth of intact leaves of TX-treated plants. Discs excised from green as well as from TX-or DCMU-treated leaves also responded by growing faster in WL, as long as exogenous sucrose was supplied to the photosynthetically inhibited tissues. The WL caused acidification of the epidermal surface of intact TX-leaves, but acidification of the incubation medium by mesophyll cells only occurred when photosynthesis was not inhibited. It is concluded that light-stimulated cell enlargement of bean leaves, and the necessary acidification of epidermal cell walls, are mediated by a pigment other than chlorophyll. Light-induced proton excretion by mesophyll cells, on the other hand, may require both a photosynthetic product (or exogenous sugars) and a non-photosynthetic light effect.
Document ID
Document Type
Reprint (Version printed in journal)
Van Volkenburgh, E.
(University of Washington Seattle 98195, United States)
Cleland, R. E.
Date Acquired
August 21, 2013
Publication Date
August 1, 1990
Publication Information
Publication: Planta
Volume: 182
Issue: 1
ISSN: 0032-0935
Subject Category
Life Sciences (General)
Distribution Limits
NASA Discipline Number 29-20
NASA Program Space Biology
NASA Discipline Plant Biology
Non-NASA Center