Effect of increased CO sub 2 and decreased O sub 2 on photosynthesis, and carbon allocation in source leaves

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

OSTI ID:5631671

Fondy, B R ^[1]; Geiger, D R; Shieh, W -J ^[2]

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

The effect of raising the rate of photosynthesis on the allocation of carbon between sucrose and starch was studied by means of steady-state radiolabeling. Sugar beet source leaves on intact plants were exposed to ambient levels of CO{sub 2} and O{sub 2} for 3 hrs. Next CO{sub 2} was raised to 600 {mu}LL{sup {minus}3} for 3 hrs then O{sub 2} was decreased to 2% for 3 hrs. Rates of net carbon exchange (NCE), export, and starch and sucrose synthesis were measured. NCER increased by 30% under the combined treatments and the proportion of photosynthate allocated to starch and to sucrose did not change. When O{sub 2} concentration was lowered, NCER increased but export did not and sucrose accumulated. This observation, and our earlier conclusion that export rate usually equals sucrose synthesis rate, lead us to conclude that low O{sub 2} directly inhibited export. Low O{sub 2} treatment causes sucrose to accumulate in a sugar beet leaf which usually accumulates little sucrose.

• OSTI ID: 5631671
• Report Number(s): CONF-9007196--
• Conference Information: Journal Name: Plant Physiology, Supplement; (USA) Journal Volume: 93:1
• Country of Publication: United States
• Language: English

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BIOLOGICAL EFFECTS
CARBOHYDRATES
CARBON COMPOUNDS
CARBON DIOXIDE
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OXYGEN
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