Effects of different light treatments on the nocturnal transpiration and dynamics of stomatal closure of two rose cultivars.
Blom-Zandstra, M.; Sander Pot, C.; Maas, F. M.; Schapendonk, A. H. C. M.;
Scientia Horticulturae Year: 1995 Vol: 61 Issue: 3/4 Pages: 251-262 Ref: 23 ref.
1995
บทคัดย่อ
In the cultivation of roses, supplementary lighting is thought to cause an increase in nocturnal transpiration and consequent low turgidity of the cut flowers, leading to problems with quality. Two cultivars with different tolerances of this phenomenon were subjected to high and low light intensities, followed by periods of supplementary lighting of different duration and with different spectral composition. Daily water consumption varied between cultivars. Supplementary lighting, both with respect to its duration and its spectral composition, had hardly any effect on water usage or nocturnal stomatal conductance, but increased stomatal opening during the day. The diurnal rhythm of stomatal movement, measured with a computer-modulated high-intensity light source, appeared to be determined by the integrated irradiance in the previous light period. High irradiance caused faster stomatal opening during the next light period. Similarly, stomatal closing rates were also stimulated by high light inten
sity during the previous day. The observed effects were most pronounced for the cultivar reported to be the least sensitive to postharvest damage by excessive transpiration. It is concluded that supplementary lighting does not have a negative impact on the water use efficiency of cut roses. In addition, the stomatal dynamics suggest that flower quality would be improved if cut flowers were transfered to darkness following a period of several hours of high light intensity.