Measurement of Plant Stomas under Several CO_2 Conditions using Microscopic Images

The objective of this study was to create a model of the plant stoma response process under CO2 conditions (100 to 3000ppm) after lighting. In this study, a real-time measurement system was developed to observe living plant stomas continuously for a long period in a growth chamber using a microscope and a color TV camera. Six treatments were conducted by changing the CO2 density, ranging from 100 to 3000ppm, under the conditions of a 2-hour on/off light cycle. From the experimental results, it was observed that the pore size was drastically changed in response to the CO2 conditions. Lower CO2 density caused larger-size pores under conditions of less than 1000ppm CO2 density, while the pore size was almost constant under conditions of greater density. With CO2 density of over 2000ppm, pores continued opening after 60 minutes had elapsed. The transient response with the 1 st-order lag element could well express the stoma response, and its desired value had a high correlation with CO2 density.