This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Duysen, M. E. Articles by Zabrocki, R. D. Search for Related Content PubMed PubMed Citation Articles by Duysen, M. E. Articles by Zabrocki, R. D. Agricola Articles by Duysen, M. E. Articles by Zabrocki, R. D.

Articles

Light and the Correlation of Chloroplast Development and Coupling of Phosphorylation to Electron Transport ¹

Department of Botany, North Dakota State University, Fargo, North Dakota 58105

Coupling of phosphorylation to electron transport was examined by measuring the photosynthetic control ratio for broken wheat plastids isolated from seedlings at different greening stages. The photosynthetic control ratio progressively increased during greening and tight coupling was noted after granal stacking and thylakoid elongation. ADP impaired nonphosphorylating (state 2) electron transport rates of plastids at extremely early stages of greening and interfered with photosynthetic control measurements. Partially developed plastids exhibited low nonphosphorylating electron flow rates but did not exhibit high phosphorylating or uncoupled electron transport rates to the same extent as nearly developed plastids. Prolamellar body dispersal, primary thylakoid production, and the development of photosynthetic control were stimulated equally by 48 minutes of low irradiance, in cycles of 2 minutes every 2 hours, or by 9 hours of continuous light of moderate irradiance. Wheat plastids that greened for 6 hours in continuous light of moderate intensity did not exhibit photosynthetic control or much differentiation beyond the etioplast stage. It is concluded that plastid differentiation and the development of photosynthetic control early in greening under continuous light were limited by developmental time (dark time) rather than by either light intensity or duration.