ISHS Acta Horticulturae 51: Symposium on Protected Cultivation of Flowers and Vegetables
THE EFFECTS OF CO2 CONCENTRATION ON THE CANOPY PHOTOSYNTHESIS AND WINTER BLOOM PRODUCTION OF THE GLASSHOUSE ROSE 'SONIA' (SYN. 'SWEET PROMISE') |
| Authors: | D.W. Hand, K.E. Cockshull |
| Abstract:
In Britain growers experience difficulties in maintaining the production and quality of blooms from late October to early March due in part to low rates of photosynthesis occurring under winter light conditions. A daylit, controlled-environment cabinet was used in an investigation to determine the effect of CO2 concentration on the net canopy photosynthesis of a stand of 'Sonia' (syn. 'Sweet Promise') roses. Photosynthesis curves at concentrations of 400, 800 and 1200 vpm CO2 were obtained from experimental data by the use of a mathematical model that relates net canopy photosynthesis to light, CO2, respiration, canopy structure and the optical and photosynthetic characteristics of individual leaves. At a light level equivalent to the maximum experienced under glass at the winter solstice in Britain the net rates of CO2 uptake for stands assimilating in air enriched to 800 and 1200 vpm CO2 were respectively 1.46 and 1.70 times that for a stand assimilating in air enriched to only 400 vpm CO2. Studies in the daylit cabinet were complemented by long-term glasshouse experiments on the effect of CO2 enrichment on winter bloom production. The results obtained from three years' experimentation showed that CO2-enriched plants yielded on average 24% more marketable blooms over the period December to March than non-enriched plants. | |
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