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Table 2 Summary of sub-ambient CO2 effects on daily canopy gas exchange parameters and water use efficiency (WUE) from December 26 to January 8

From: A whole canopy gas exchange system for the targeted manipulation of grapevine source-sink relations using sub-ambient CO2

  CO2 exchange (g vine−1 day−1)Water use (L vine− 1 day− 1)WUE (g C02 L− 1 H2O)
 Average [CO2]DayNightNetDayNightTotal 
10 day treatment period
 Ambient412 ppm69.0−3.865.29.00.539.57.1
 Sub-ambient235 ppm33.2−3.130.010.10.4810.53.0
 Change −52%− 20%−54%+ 12%− 11%+ 11%−58%
4 day treatment period
 Ambient408 ppm77.4−3.074.49.00.509.57.9
 Sub-ambient408 ppm76.6−2.674.08.90.559.57.9
 10 daysTreatment0.0030.1000.005ns0.086ns0.002
 Day< 0.0010.012< 0.001< 0.001< 0.001< 0.001< 0.001
 Treatment x Day0.008ns0.007ns0.023ns< 0.001
 4 daysTreatmentNsnsnsnsnsnsns