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Study of Efficient Lighting Periods Based on Plant Stoma Reaction
Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.org
Citation: Paper number 064096, 2006 ASAE Annual Meeting . (doi: 10.13031/2013.21116) @2006Authors: Kazuhiko Namba, Naoshi Kondo, Mitsuji Monta, Akira Sasao
Keywords: lighting period, plant stoma reaction, photosynthesis benefit, real-time measurement system, carbon dioxide absorption
The objective of this study was to detect the plant stoma response under the lighting
conditions of continuous and 1 to 15 minutes of lighting. In this study, a real-time measurement
system was developed to observe a living plant stoma continuously for a long period in a growth
chamber, using a microscope and a color TV camera. A video recording system was adopted to
obtain details of stoma movement, and images were captured every 30 seconds.
From the experimental results, it was observed that the stoma opened slowly 5 minutes after the
lights were turned on, and then opened rapidly until it reached the maximum pore size. In guard
cells, light stimulus activates a proton pump, the resulting hyper polarization of the plasma membrane opens voltage-sensitive K+ channels, and then the water entering the guard cells opens
the stoma after the K+ ions have entered. This process may cause 5 minutes of delay, and delay was
also observed after the light was turned off. 10 minutes of lighting opened the stoma to the maximum
size.
For better utilization of lighting, it was suggested to turn a light on 10 minutes at 30 minuets before
the lighting period to open stomata widely at the beginning of the lighting period, so then plants can
start the photosynthesis immediately without any effect of the response of stomata opening. To prove
this, carbon dioxide absorptions were measured and as a result 8 % of the photosynthesis benefit
was given with these on/off controls.