PREDICTING GROWTH OF SAMANTHA ROSES AT DIFFERENT LIGHT, TEMPERATURE AND CO2 LEVELS BASED ON NET CARBON EXCHANGE
Winter time production of Rosa hybrida cv. Samantha is limited by low incident radiation in Canada. Twenty four hours of supplemental lighting improves crop yield partly by reducing night time carbon loss due to respiration. Greenhouse roses grown at low irradiance levels during the winter months and an enriched CO2 level have lower net photosynthetic rates at saturating light levels than plants grown during the summer and fall months when natural light levels are higher. However, whole plant net photosynthesis in winter grown roses is higher at lower light levels 50–200 μmol m-2 s-1 supporting the view that these plants have acclimated to lower light levels. Data on whole plant NCER (net carbon exchange rate) obtained from roses growing in specially designed controlled environmental analysis chambers (Dutton et al., 1988) predict that at a moderate (winter time) irradiation level of 450 μmol m-2 s-1 maximum NCER and growth would be achieved at about 22°C and 1250 ppm CO2.
Jiao, J., Tsujita, M.J. and Grodzinski, B. (1988). PREDICTING GROWTH OF SAMANTHA ROSES AT DIFFERENT LIGHT, TEMPERATURE AND CO2 LEVELS BASED ON NET CARBON EXCHANGE. Acta Hortic. 230, 435-442