EFFECTS OF CO₂ CONCENTRATION ON GROWTH OF LETTUCE

Butterhead lettuce cv ‘Nanda’ and iceberg lettuce cv ‘Christallo’ were planted in winter and spring, three times in succession, under six CO₂ concentrations.
The CO₂ concentrations were maintained from one hour before sunrise until half an hour before sunset.
The planting distances of butterhead lettuce and iceberg lettuce were 20×20 cm and 25×25 cm.
During the experiment the night-day temperature setpoints in the six compartments were 8/12°C.

Until harvest samples of plants were cut with intervals to determine growth of fresh- and dry weight.
Data on growth and harvest weight in relation to CO₂ concentration are shown.

Saturation of CO₂ effects on growth rates is found near 1000 ppm, irrespective of light conditions.

Dry weight growth rates are smaller than fresh weight rates as dry weight percentages drop with plantfresh weight.

III International Symposium on Energy in Protected Cultivation

G. Heij, J.A.M. van Uffelen

https://doi.org/10.17660/ActaHortic.1984.148.77