ISHS Acta Horticulturae 148: III International Symposium on Energy in Protected Cultivation
EFFECTS OF CO2 CONCENTRATION ON GROWTH OF LETTUCE |
| Authors: | G. Heij, J.A.M. van Uffelen |
| Abstract:
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 20x20 cm and 25x25 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. | |
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