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Title: Phosphorus supply affects acclimation of photosynthesis in loblolly pine to elevated carbon dioxide

Conference · · Bulletin of the Ecological Society of America; (United States)
OSTI ID:6202331

The interactive effects of phosphorus supply and mycorrhizal status on the acclimation of photosynthesis to elevated CO[sub 2] was investigated using 12 week old loblolly pine (Pinus taeda L.) seedlings. Seedlings were grown at either 35.5 Pa or 7 1.0 Pa CO[sub 2], with (M) or without (NM) mycorrhizal inoculum and with an adequate (High P) or a limiting (Low P) supply of phosphorus. Seedlings grown and measured at 7 1.0 Pa CO[sub 2] had significantly higher net assimilation rates (A) than seedlings grown and measured at 35.5 Pa. However, A did not vary between CO[sub 2] treatments when compared at either 35.5 or 71.0 Pa. Elevated CO[sub 2] resulted in reduced rubisco activity (V[sub cmax]) and increased RuBP regeneration capacity (J[sub max]). Low P plants had lower V[sub cmax], J[sub max] and A than High P plants. There were also significant three-way interactions between CO[sub 2] supply, phosphorus supply and mycorrhizal status on estimated values of V[sub cmax] and J[sub max]. Both V[sub cmax] and J[sub max] decreased in plants grown at elevated CO[sub 2] in all nutrient treatments except Low P, NM plants, where mean values of both parameters increased. These results indicate that plant phosphorus status affects the acclimation of photosynthesis to elevated carbon dioxide. Mycorrhizal infection ameliorated phosphorus deficiency effects on photosynthetic capacity.

OSTI ID:
6202331
Report Number(s):
CONF-930798-; CODEN: BECLAG
Journal Information:
Bulletin of the Ecological Society of America; (United States), Vol. 74:2; Conference: 78. annual Ecological Society of America (ESA) meeting, Madison, WI (United States), 31 Jul - 4 Aug 1993; ISSN 0012-9623
Country of Publication:
United States
Language:
English