CROP RESPONSES TO AERIAL CARBON DIOXIDE – REFEREED PAPER –

Crops are subjected to a global bulk atmosphere that contains a supra-optimal oxygen concentration and a sub-optimal carbon dioxide concentration.
It is expected that the present increase in atmospheric CO₂ concentration will continue, that a doubling will occur during the next century and that eventually values of over 2500 ppm will be reached.
Until then greenhouse crops should be CO₂ enriched.

The potential of intermittent CO₂ enrichment (pulse CO₂ enrichment) for yields enhancement and pollution avoidence will be described.

The main changes in crops due to elevated CO₂ seem to be secondary effects of enhanced photosynthesis but some morphogenetic changes, for instance increased branching, are interpreted as partial suppression of apical dominance and appear to show that CO₂ concentration has additional hormone-like effects.

Though over 1000 papers on CO₂ enrichment have been published there is only an incomplete understanding of whether other organs than leaves are sensitive to CO₂ concentration and whether elevated CO₂ has a trigger effect or a threshold effect on morphogenesis of crops.
Some of the research questions that should be asked in order to improve our understanding of how CO₂ enrichment influences plant productivity will be discussed.

IV International Symposium on CO2 in Protected Cultivation

H. Enoch

https://doi.org/10.17660/ActaHortic.1990.268.1