Response of photosynthesis, starch and sucrose synthesis to increased CO sub 2 and lowered O sub 2

Conference · Tue May 01 04:00:00 EDT 1990 · Plant Physiology, Supplement; (USA)

OSTI ID:5628895

Servaites, J; Shieh, Wenjang; Su, Liying; Geiger, D R ^[1]; Fondy, B ^[2]

---

1. Univ. of Dayton, OH (USA)
2. Seton Hill College, Greensburg, PA (USA)

Increasing photosynthesis rate by raising CO{sub 2} and lowering O{sub 2} usually results in measured rates lower than those expected from the kinetics of rubisco. The failure of leaves to utilize the increased efficiency of rubisco has been attributed to limitations in rates of either starch or sucrose synthesis, which lead to a lowering of Pi and a reduction in the rate of ATP synthesis. In sugar beet leaves, increasing CO{sub 2} from 350 to 600 {mu}L L{sup {minus}1} usually increased photosynthesis only about 10%, compared to the 45% expected, and lowering O{sub 2} from 2 to 21% increased photosynthesis only an additional 20%, compared to the additional 40% expected. In some cases, raising CO{sub 2} increased photosynthesis the full 30% with no further increase occurring upon lowering O{sub 2}. In all cases, rates of starch and sucrose synthesis consistently increased in proportion to increasing photosynthesis rate. Metabolites that are predominantly cytosolic changed very little following both treatments, but levels of PGA and RuBP doubled. Thee data indicate that raising CO{sub 2} and lowering O{sub 2} had little effect on starch and sucrose synthesis, but decreased both the chloroplastic Pi concentration and the activation state of rubisco.

• OSTI ID: 5628895
• Report Number(s): CONF-9007196--
• Conference Information: Journal Name: Plant Physiology, Supplement; (USA) Journal Volume: 93:1
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110
550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ATP
BIOLOGICAL EFFECTS
CARBOHYDRATES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBON-CARBON LYASES
CARBOXY-LYASES
CHALCOGENIDES
ELEMENTS
ENZYMES
KETONES
LYASES
MONOSACCHARIDES
NONMETALS
NUCLEOTIDES
ORGANIC COMPOUNDS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PENTOSES
RIBULOSE
RIBULOSE DIPHOSPHATE CARBOXYLASE
SACCHARIDES