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Title: IMPACT OF ENHANCED UV-B IRRADIATION ON PHOTOSYNTHESIS

Author
item DONAHUE, RAYMOND - UNIV OF ILLINIS CHA
item POULSON, MARY - UNIV OF ILLINOIS CHA
item WHITMARSH, CLIFFORD

Submitted to: Photosynthesis International Congress Symposium Proceedings and Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 6/28/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: We measured the effect of enhanced ultraviolet-B radiation on Photosynthesis and plant growth. Photochemistry, whole leaf photosynthesis, and growth patterns were investigated for Cucumis sativus, Pisum sativum, and flavonoid-deficient mutants of Arabidopsis thaliana. UV-absorbing compounds increased with UV-B treatment for both Pisum and Cucumis; chlorophyll concentration and a/b ratios were not affected. For C. sativus, interveinal chlorosis developed after leaf emergence and accounted for 10-15% of leaf surface area after leaf expansion for plants grown in 3xs ambient UV-B. This chlorosis and decreased stomatal conductance decreased whole leaf photosynthesis. Leaf expansion also decreased markedly for Cucumis. Electron transport capacity as measured by oxygen evolution and chlorophyll fluorescence was unaffected for Pisum and nonchlorotic leaf tissue of Cucumis. Biomass accumulation was not affected for Pisum or Cucumis. For the Arabidopsis mutants, increased UV-B decreased photosynthesis, reduced biomass accumulation, and induced severe morphological changes.