Effect of high light, heat and carbon dioxide deficiency on photoinhibition of Mimosa pigra L. leaves

Abstract

High light (2000 μmol/m²/s), heat (40 oC), and CO2 deficiency were used to investigate photoinhibition of Mimosa pigra L. leaves. The results showed that high light caused the increase of stomatal conductance, CO2 fixation, O2 emission, non-photochemical (qN) and electron transport rate (ETR) of Mimosa pigra L. leaves. Leaves Fv/Fm ratio (Demonstrates the ability of PSII to perform photochemistry) slightly decreased under high light and recovered in the dark condition. Heat did not affect on stomatal conductance, CO2 fixation, qN, ETR and Fv/Fm but reduced O2 emission. CO2 deficiency stimulated the increase of stomatal conductance and qN but inhibited CO2 fixation, ETR and decreased Fv/Fm. High light (từ 1600 μmol/m²/s) and heat (từ 39 oC) in nature together caused strong O2 emission from Mimosa pigra L. leaves.