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 F_v/F_m 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 F_v/F_m but reduced O₂ emission. CO₂ deficiency stimulated the increase of stomatal conductance and qN but inhibited CO₂ fixation, ETR and decreased F_v/F_m. High light (từ 1600 µmol/m²/s) and heat (từ 39 ^oC) in nature together caused strong O₂ emission from Mimosa pigra L. leaves.