The photosynthetic acclimation of Lolium perenne growing in a free-air CO₂ enrichment (FACE) system

Thesis/Dissertation · Mon Oct 31 23:00:00 EST 1994

DOI:https://doi.org/10.2172/10109180· OSTI ID:10109180

Bryant, Jonathan B. ^[1]

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1. Univ. of Essex, Colchester (United Kingdom)

Stands of Ryegrass (Lolium perenne L. cv. Bastion) were grown in the field at ambient or elevated (600μmol/mol) CO₂ concentration, high (560Kg/ha) or low (140Kg/ha) nitrogen addition and with a frequent (every 4 weeks) or infrequent (every 8 weeks) cutting regime. Plants were in the second year of a 3 year experiment. Exposure to elevated CO₂ was carried out with a Free-Air CO₂ Enrichment (FACE) system which provides the most "realistic" system of CO₂ fumigation currently available. Elevated CO₂ increased diurnal CO₂ assimilation by between 34 and 88% whilst reducing rates of stomatal conductance by between 1 and 42%. However, analysis of the A vs. Ci response showed considerable acclimation of the photosynthetic apparatus in response to elevated CO₂ - Vc_max as an in vivo measure of RubisCO activity, decreased by between 29 and 35% in high CO₂, whilst J_max, as a measure of the RubP regeneration capacity, showed no significant change. Two out of three additional perennial grassland species studied showed similar acclamatory behavior to Ryegrass. Diurnal assimilation rate, J_max and, in most cases, Vc_max, increased significantly directly after cutting of Ryegrass stands, but nitrogen treatment had little effect on any of these parameters. Neither stomatal density, stomatal index nor stomatal pore length of Ryegrass were significantly altered by growth in elevated CO₂. The results are discussed in terms of the limitation imposed on maximizing photosynthetic and growth responses of Ryegrass at elevated CO₂, by the ability of perennial species to increase long-term sink capacity under these conditions.

• Research Organization: Brookhaven National Lab. (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 10109180
• Report Number(s): BNL--61079; ON: DE95004954
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540120
550500
551000
560400
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
A/Ci response
BIOLOGICAL ADAPTATION
CARBON DIOXIDE
CARBON DIOXIDE FIXATION
CARBON SINKS
CHEMICALS MONITORING AND TRANSPORT
COMPARATIVE EVALUATIONS
DENSITY
ECOLOGICAL CONCENTRATION
GRAMINEAE
GREENHOUSE GASES
METABOLISM
NITROGEN
OTHER ENVIRONMENTAL POLLUTANT EFFECTS
PHOTOSYNTHESIS
PHYSIOLOGICAL SYSTEMS
PLANT GROWTH
STOMATA
acclimation
free-air CO2 enrichment
lolium perenne
photosynthesis
stomatal density