Effects of the lighting cycle on CO2 absorption and sugar uptake by Petunia cuttings cultured in vitro
2000
Ogasawara, N. (Yamagata univ., Tsuruoka (Japan). Faculty of Agriculture) | Kikuchi, M. | Takagi, H.
Petunia cuttings were cultured in vitro for 50 days under a long lighting cycle (16-hr photoperiod) and a short lighting cycle (2 hr light/1 hr dark) in separate ventilated vessels. When the plantlets were supplied with CO2 by a continuous air flow, the short lighting cycle did not enhance plant growth, which indicates that it has no promotive effect. However, in naturally ventilated vessels, plant growth and the daily CO2 absorption and sugar uptake under the short lighting cycle were greater than those under the long lighting cycle. The increased sugar uptake in the short lighting cycle condition probably resulted from the increased CO2 uptake. With the increased CO2 uptake, the ratio of the dry weights of cuttings to sugar uptake under the short lighting cycle was greater than under the long lighting cycle. These results indicate that the short lighting cycle promotes plant growth in vitro by increasing the re-absorption of respiratory CO2 during the dark period
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