GROWTH AND PHOTOSYNTHESIS OF CO₂-ENRICHED PRIMROSE – REFEREED PAPER –

Primula obconica potted plants were cultivated in a glasshouse at normal (350±50 μl/l) or enriched (800±100 μl/l) CO₂ concentration in the air.
Final growth and yield were measured : fresh and dry matter were significantly increased by CO₂-enrichment (+94% and +77% respectively). Similarly leaf number increased but flower number did not.
Plant quality was better.

Net CO₂-gas exchange rates were measured on a small population (10 pots =30 plants =1 m²) in a growth chamber where irradiance and CO₂ could be controlled.
Net photosynthesis curves were the same for both control and enriched plants: there was no CO₂ adaptive effect.

The effect of temperature (14°C and 18°C) on photosynthesis was not significant.
At high irradiance (450 μE PAR m^-2s^-1) and low CO₂ concentration (350 μl/l) some plants sets displayed lowered photosynthesis rate, probably due to photoinhibition.

Ageing (5 to 13 weeks after transplantation) caused a reduction of photosynthesis rate except at 350 μl/l.
Hence CO₂-enrichment should be applied preferably at the beginning of cultivation.

IV International Symposium on CO2 in Protected Cultivation

L. Combe, J.M. Bertolini, P. Quétin, P. Locher

https://doi.org/10.17660/ActaHortic.1990.268.4