plant cells take in oxygen & release carbon dioxide as a result of aerobic respiration
plants photosynthesize and respire during the day
plants only respire at night
rate of photosynthesis is higher than respiration during the day
daytime
net diffusion of CO2 into plant & O2 out of plant is high
nighttime
net diffusion of CO2 out of plant & O2 into plant is high
when there's low light intensity during the day, rate of photosynthesis and respiration is equal. therefore, there is no net movement of O2 or CO2 in either direction
yellow colour indicates high carbon dioxide level (respiration)
red colour indicates carbon dioxide level is equal to atmosphere