Root restriction as a factor in photosynthetic acclimation of cotton seedlings grown in elevated carbon dioxide. [Gossypium hirsutum L]

Journal Article · Sat Jun 01 04:00:00 EDT 1991 · Plant Physiology; (United States)

DOI:https://doi.org/10.1104/pp.96.2.627· OSTI ID:7248879

Thomas, R B; Strain, B R ^[1]

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1. Duke Univ., Durham, NC (United States)

Interactive effects of root restriction and atmospheric CO{sub 2} enrichment on plant growth, photosynthetic capacity, and carbohydrate partitioning were studied in cotton seedlings (Gossypium hirsutum L.) grown for 28 days in three atmospheric CO{sub 2} partial pressures (270, 350, and 650 microbars) and two pot sizes. Reduction of root biomass resulting from growth in small pots was accompanied by decreased shoot biomass and leaf area. When root growth was less restricted, plants exposed to higher CO{sub 2} partial pressures produced more shoot and root biomass than plants exposed to lower levels of CO{sub 2}. In small pots, whole plant biomass and leaf area of plants grown in 270 and 350 microbars of CO{sub 2} were not significantly different. Plants grown in small pots in 650 microbars of CO{sub 2} produced greater total biomass than plants grown in 350 microbars, but the dry weight gain was found to be primarily an accumulation of leaf starch. Reduced photosynthetic capacity of plants grown at elevated levels of CO{sub 2} was clearly associated with inadequate rooting volume. Reductions in net photosynthesis were not associated with decreased stomatal conductance. Reduced carboxylation efficiency in response to CO{sub 2} enrichment occurred only when root growth was restricted suggesting that ribulose-1,5-bisphosphate carboxylase/oxygenase activity may be responsive to plant source-sink balance rather than to CO{sub 2} concentration as a single factor. When root-restricted plants were transplanted into large pots, carboxylation efficiency and ribulose-1,5-bisphosphate regeneration capacity increased indicating that acclimation of photosynthesis was reversible.

• OSTI ID: 7248879
• Journal Information: Plant Physiology; (United States), Journal Name: Plant Physiology; (United States) Vol. 96:2; ISSN 0032-0889; ISSN PLPHA
• Country of Publication: United States
• Language: English

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