Journal of Light & Visual Environment
Online ISSN : 1349-8398
Print ISSN : 0387-8805
ISSN-L : 0387-8805
Paper
Pulsed Light at Lower Duty Ratios with Lower Frequencies is Less Advantageous than Continuous Light for CO2 Uptake in Cos Lettuce
Tomohiro JishiKazuhiro FujiwaraKyohei NishinoAkira Yano
著者情報
ジャーナル フリー

2012 年 36 巻 3 号 p. 88-93

詳細
抄録

The CO2 uptake rate (CUR) of the aerial part of cos lettuce (Lactuca sativa) was measured in pulsed and continuous light at an average photosynthetic (wavelength range: 400–700 nm) photon flux density (PPFD) of 100 μmol m-2 s-1 from white light-emitting diodes (LEDs). Three duty ratios of 25, 50, and 75%, combined variously with eight frequencies of 0.1, 0.2, 0.4, 0.8, 1.6, 3.2, 6.4, and 12.8 kHz were used for pulsed light irradiation. The CURs were significantly lower at a duty ratio of 50% for frequencies of 0.1–0.8 kHz and at a duty ratio of 25% for all frequencies than those in continuous light although the average PPFD was unchanged. These results indicate that pulsed light at lower duty ratios, combined with lower frequencies, makes CUR of cos lettuce lower than that attained in continuous light. We infer, based on a PPFD-CUR curve obtained with cos lettuce plant used in the experiment, that when greater PPFD is provided, pulsed light at lower duty ratios with lower frequencies is less advantageous than continuous light for photosynthesis.

著者関連情報
© 2012 The Illuminating Engineering Institute of Japan
前の記事 次の記事
feedback
Top