from malic acid when stomata are closed. . During day time stomata are closed and CO is not taken but continue their photosynthesis. .
Stomata are closed during the day time and help the plants to avoid transpiration and water loss. . Photorespiration or C2 Cycle or Photosynthetic Carbon Oxidation (PCO) Cycle Respiration is a continuous process for all living organisms including plants. Decker ( ) observed that rate of respiration is more in light than in dark.
Photorespiration is the excess respiration taking place in photosynthetic cells due to absence of CO Check your grasp! C plants requires ATPs and NADPH H to synthesize one glucose, but C plants requires only ATPs and NADPH H to synthesize one glucose molecule. If then, how can you say C plants are more advantageous? Solution: C plants are more advantageous than C plants because most of the energy lost during photo respiration in C plants.
. Crassulacean Acid Metabolism or CAM cycle It is one of the carbon pathways identified in succulent plants growing in semi-arid or xerophytic condition. This was first observed in crassulaceae family plants like Bryophyllum , Sedum , Kalanchoe and is the reason behind the name of this cycle. It is also noticed in plants from other families Examples: Agave , Opuntia , Pineapple and Orchids.
The stomata are closed during day and are open during night (Scotoactive). This reverse stomatal rhythm helps to conserve water loss through transpiration and will stop the fixation of CO during the day time. At night time CAM plants fix CO with the help of Phospho Enol Pyruvic acid (PEP) and produce oxalo acetic acid Figure . : CAM cycle CO uptake and fixation leaf acidification Atmospheric CO Open stoma permits entry of CO and loss of H O PEP carboxylase Phosphoenol- pyruvate Oxaloacetate NAD + malic dehydro genase Malate NADH NAD + Triose phosphate Starch Chloroplast Malic acid Vacuole Decarboxylation of stored malate and refixation of internal CO deacidification