Inhibition of chloroplastic respiration by osmotic dehydration. [Spinacia oleracea L]

Journal Article · Sat Apr 01 04:00:00 EST 1989 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.89.4.1158· OSTI ID:6610047

Willeford, K O; Ahluwalia, K J.K.; Gibbs, M ^[1]

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1. Brandeis Univ., Waltham, MA (USA)

The respiratory capacity of isolated spinach (Spinacia oleracea L.) chloroplasts, measured as the rate of {sup 14}CO{sub 2} evolved from the oxidative pentose phosphate cycle in darkened chloroplasts exogenously supplied with ({sup 14}C)glucose, was progressively diminished by escalating osmotic dehydration with betaine or sorbitol. Comparing the inhibitions of CO{sub 2} evolution generated by osmotic dehydration in chloroplasts given C-1 and C-6 labeled glucose, 54% and 84%, respectively, indicates that osmotic dehydration effects to a greater extent the recycling of the oxidative pentose phosphate intermediates, fructose-6P and glyceraldehyde-3P. Respiratory inhibition in the darkened chloroplast could be alleviated by addition of NH{sub 4}Cl (a stromal alkylating agent), iodoacetamide (an inhibitor of glyceraldehyde-3P dehydrogenase), or glycolate-2P (an inhibitor of phosphofructokinase). It is concluded that the site which primarily mediates respiratory inhibition in the darkened chloroplast occurs at the fructose 1,6-bisphosphatase/phosphofructokinase junction.

• DOE Contract Number: AC02-76ER03231
• OSTI ID: 6610047
• Journal Information: Plant Physiology; (USA), Journal Name: Plant Physiology; (USA) Vol. 89:4; ISSN 0032-0889; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
CARBOHYDRATES
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CELL CONSTITUENTS
CHALCOGENIDES
CHLOROPLASTS
DEHYDRATION
ELECTROMAGNETIC RADIATION
ENZYME INHIBITORS
ENZYMES
FOOD
GLUCOSE
HEXOSES
INHIBITION
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MONOSACCHARIDES
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHOTRANSFERASES
PLANTS
RADIATIONS
RESPIRATION
SACCHARIDES
SPINACH
TRACER TECHNIQUES
TRANSFERASES
VEGETABLES
VISIBLE RADIATION