C3 plants close their stomata on hot, dry days to limit water loss. Carbon dioxide enters the Calvin cycle and the first product of fixation is 3-phosphoglycerate. When stomata closed, CO2 concentration in the leafs air spaces falls, slowing down the Calvin cycle.
C4 plants opened their stomata during the day. C4 plants fix carbon dioxide into 4 carbon compounds. Co2 is first added to PEP with adis of PEP carboxylase resulting 4 carbon compound formed in mesophyll cells. These compounds are able to transport through bundle-sheath cells. Compounds are broken down to release CO2, which initiate the Calvin cycle.
The CAM plants open their stomata during the night. In doing so, they reverse the performance of regular plants. The light reactions are conducted during the night while the Calvin cycle occurred during the day. These plants are commonly cactus. In the desert, it would be beneficial because the day time is usually really hot and these plants would conserve water during the day.
Totally wrong about C3 plants, they DO NOT close their stomata during the day. That is for CAM plants only.
ReplyDeleteC3 plants keep their stomata open during the day, so if they were in a hot, desert environment they would not be able to survive well.
You are wrong, commenter above. C3 plants close their stomata to utilize evapotranspiration inside the leaf mesophyll spaces. This mechanism also produces pressure which pulls water from the roots via the xylem towards the leaf. Eventually, the stomatal aperture occurs and this releases water vapor built up in the leaf space, this also allows CO2 to enter the leaf space.
ReplyDeleteStomatal opening is REGULATED in order to; mitigate water loss from transpiration, regulate CO2 gas exchange, and pull water through the organism via the xylem.
The intensity of aperture also changes during the day due to light, humidity, and other environmental changes. This can also be shown on large trees where some leaves receive more light at the top and less at the bottom, which can also show physical traits in leaf size and morphology.
http://5e.plantphys.net/article.php?ch=4&id=100&search=stomatal%20aperture