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A branch bag technique for simultaneous CO 2 enrichment and assimilation measurements on beech ( Fagus sylvatica L.)
Author(s) -
DUFRENE E.,
PONTAILLER J.Y.,
SAUGIER B.
Publication year - 1993
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.1996.tb02071.x
Subject(s) - fagus sylvatica , beech , transpiration , photosynthesis , assimilation (phonology) , botany , horticulture , chemistry , environmental science , biology , linguistics , philosophy
A cheap CO 2 enrichment system was designed to perform continuous gas exchange measurements of branches of mature European beech trees ( Fagus sylvatica L.). Branches were grown at ambient (350 cm 3 m ‐3 ) and elevated CO 2 (700cm 3 m ‐3 ) during the whole 1992 leafy period. Leaks resulting from airtightness defaults in the system appeared to be low enough to measure accurately net CO 2 assimilation and transpiration rates during the day. However, the CO 2 exchange rates during the night (respiration) were too low to allow accurate measurements. Elevated CO 2 had a great effect on the net assimilation rate of branches via its influence on both the C 3 photosynthetic pathway and the shade‐tolerance of beech trees (85% increase). The A/Ca curves showed no acclimation effect to high CO 2 , both control and enriched branches increasing their net assimilation in the same way. The decrease of net assimilation rates in mature leaves was similar for both control and enriched branches. The pattern of daily transpiration rates remained the same for both control and enriched branches, hence we can assume that there was no visible CO 2 effect on stomata.