| | Energy conservation in horticulture can be achieved by allowing temperatures to fluctuate within predefined bandwidths instead of using rigid
set points for heating and ventilation. In temperature integration, plants are supposed to compensate effects of temporarily deviations of the average
temperature some time later by deviations in the opposite direction. However, little is still known on the effects of integration periods exceeding 1
day. In this study, effects of temperature integration on growth and development of single-stemmed cut rose plants were determined. Pruned rose
shoots were placed in climate chambers in which light levels switched daily (2 days integration period) or weekly (14 days integration period) from
high light intensity (300 umol m-2- s-t) to low light (150 umol m-2 s- 1). Temperatures were kept continuously at 20 ~C (control) or changed with
the light intensity (phase, high temperature at high light intensity, low temperature at low light intensity) or changed opposite to the light intensity
(counter phase). Bandwidths of temperature integration were 0, 6 or 10 ~C. Under these conditions, buds grew out to harvestable shoots in
approximately 45 days. At both integration periods, shoot length was significantly reduced with increasing bandwidths of temperature integration.
Shoot dry weights were reduced when a bandwidth of I0 ~C was applied. At both integration periods, rates of photosynthesis were primarily
determined by light intensity. However, in the counter phase treatments, photosynthesis rate at high light and low temperature was reduced
compared to the high light condition of the control. Under these: conditions, starch content increased to approximately 10%, suggesting a feedback
inhibition of the rate of photosynthesis. However, this did not (yet) affect plant growth or development.文字
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2007/11/01 10:51pm 
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