Temperature and pH effects on chloroplastic respiration of glucose and fructose in spinach

Conference · Sat May 01 00:00:00 EDT 1993 · Plant Physiology; (United States)

OSTI ID:6221560

Singh, K K; Gibbs, M ^[1]

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1. Brandeis Univ., Waltham, MA (United States)

Respiration was monitored principally as CO[sub 2] release in the darkened intact spinach chloroplast supplied with [sup 14]C-glucose and [sup 14]C-fructose. The rate of flucose respiration, optimum pH 7.5, increased from 15[degrees]C up to 40[degrees]C and then decreased in the presence of added ATP. In the absence of ATP, the optimum temperature for CO[sub 2] release was 25 [degrees]C and then decreased. At optimum pH 8.5, both in the absence and presence of ATP, the rate increased up to 25[degrees]C and then decreased. The negative effect of high temperature was not reversed when the chloroplast was returned to 25[degrees]C. Higher temperature (40[degrees]C vs 15[degrees]C) and higher pH (8.5 vs 7.5) increased radioactivity into starch and decreased radioactivity in CO[sub 2]. The rate of fructose respiration, optimum pH 7.5 but also at pH 8.5, increased CO[sub 2] release from 15[degrees]C to 40[degrees]C and then decreased both in the absence and presence of externally supplied ATP. Temperature and pH has no effect on radioactivity in starch and CO[sub 2] when fructose was substrate. The difference in results between glucose and fructose may reflect the localization of fructokinase in the stroma and glucokinase both in the stroma and cytosolic side of the outer chloroplastic membrane. It may be also reflect the equilibrium of phosphohexose isomerase favoring fructose-6-P.

• OSTI ID: 6221560
• Report Number(s): CONF-9307119-; CODEN: PLPHAY
• Journal Information: Plant Physiology; (United States), Vol. 102:1; Conference: 1993 joint annual meeting of the American Society of Plant Physiologists (ASPP) and the Canadian Society of Plant Physiologists (CSPP), Minneapolis, MN (United States), 31 Jul - 4 Aug 1993; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CHLOROPLASTS
GLYCOLYSIS
TEMPERATURE DEPENDENCE
PH VALUE
BIOLOGICAL EFFECTS
CARBON DIOXIDE
FRUCTOSE
GLUCOSE
RADIOACTIVITY
SPINACH
STARCH
ALDEHYDES
CARBOHYDRATES
CARBON COMPOUNDS
CARBON OXIDES
CELL CONSTITUENTS
CHALCOGENIDES
FOOD
HEXOSES
KETONES
MAGNOLIOPHYTA
MAGNOLIOPSIDA
METABOLISM
MONOSACCHARIDES
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PLANTS
POLYSACCHARIDES
REAGENTS
SACCHARIDES
VEGETABLES
550200* - Biochemistry