1.Explain why the plants growing in deserts take co2 at night and utilize it during the day in the synthesis of carbohyrates?                       2.Plants generally wilt in the afternoon and regain their freshness in the next morning.state the logical reason for this process.

Asked by nimishagupta0409 | 23rd Jun, 2015, 11:07: AM

Expert Answer:

  • Stomata not only perform gaseous exchange but also serve as passage for the exit of water vapours.
  • In case of desert plants, if stomata remain open during the day, plants will lose lot of water. To avoid this, in desert plants, stomata are closed during the day.
  • At night, the stomata open and take in carbon dioxide. PEP carboxylase fixes carbon dioxide and produces a four carbon molecule malate. The malate gets stored in the vacuoles of the mesophyll cells.
  • During day, the stored malate is pumped out of the vacuoles into the stroma of the chloroplasts and broken down into carbon dioxide and enters the Calvin cycle to produce glucose.
  • This is Crassulacean acid metabolism. This metabolism was first observed in Crassulacean plants.

Answered by Hemangi Binny | 23rd Jun, 2015, 12:20: PM