Response of Photosynthetic Rate and Stomatal Conductance of Oat to Light Intensity and CO_2 Concentration and Its Modeling

The response of photosynthetic rate and stomatal conductance of oat to light intensity and CO2 concentration was studied using LI-6400 in Inter Mongol China.Generally,photosynthetic rate increased with light intensity(PPFD),which could be expressed by Michaelis-Menten function.The maximum photosynthetic rate(Pmax,i) was 18.63 μmol/(m2·s) under natural CO2 concentration.The photosynthetic rate increased with CO2 concentration,which could be expressed by Michaelis-Menten function too.The maximum photosynthetic rate(Pmax,c) was 110.28 μmol/(m2·s) under saturated light intensity(PPFD) while →∞.The response of stomatal conductance to light intensity could be expressed by Michaelis-Menten function too,because stomatal conductance increased with light intensity(PPFD),but the stomatal conductance will decrease with increase of CO2 concentration.The stomata limitation increased with light intensity(PPFD) and CO2 concentration,but when 200 μmol/mol,stomata limitation kept constant.