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United States Department of Agriculture

Agricultural Research Service

Title: Factors Associated with Low Photosynthetic Activity in Maize Leaves at Low Growth Temperatures

item Baker, Neil - UNIV OF ESSEX, UK
item Fryer, Michael - UNIV OF ESSEX, UK
item Oxborough, Kevin - UNIV OF ESSEX, UK
item Nie, Gui-Ying - UNIV OF ESSEX, UK
item Robertson, Elizabeth - UNIV OF YORK, UK
item Leech, Rachel - UNIV OF YORK, UK
item Ort, Donald

Submitted to: Photosynthesis International Congress Symposium Proceedings and Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: June 28, 1995
Publication Date: N/A

Technical Abstract: Low growth temperatures restrict chloroplast development and prevent attainment of photosynthetic competence in maize leaves. The effects of low temperatures on chloroplast development are complex. Although the number and structure of chloroplast are not modified the levels of all thylakoid proteins and photosynthetic pigments are reduced and some chloroplast-encoded gene products are markedly under represented relative to nuclear-encoded proteins in the membranes. These factors contribute to the depressed photosynthetic capacity of the leaves. Immunocytology has demonstrated that the effects on thylakoid proteins are heterogeneous with adjacent mesophyll cells often responding quite differently. The low light-use efficiency for CO2 assimilation is primarily attributable to zeaxanthin-related quenching of absorbed excitation energy at PSII. Despite the photoprotection afforded by this quenching, a significant and persistent depression of photosynthetic efficiency results from chill-induced inhibition of the rate of repair of damaged PSII reaction centres.

Last Modified: 4/22/2015
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