The inhibition of photorespiration can be used to improve plant carbon fixation. In order to compare the effects of three photorespiration inhibitors [glycine, NaHSO3, and isonicotinyl hydrazide (INH)], photosynthetic parameters of leaves sprayed respectively with these chemicals were examined and their inhibiting efficiency was evaluated in Caragana korshinskii. Our results showed that 5 mM glycine could reduce the photorespiratory rate (PR) effectively, while the net photosynthetic rate (PN), stomatal conductance (gs), and intercellular CO2 concentration (Ci) significantly increased. The ratio of electron flow for ribulose-1,5-bisphosphate (RuBP) carboxylation to RuBP oxygenation was elevated markedly. NaHSO3 and INH could also suppress the PR in some cases, whereas PN was not improved. The glyoxylate content increased considerably after application of low concentrations of glycine. These results suggested that low concentrations of glycine could suppress photorespiration by
feed-back inhibition of glyoxylate and enhance photosynthesis by regulating gs, Ci, and the distribution of electron flow in C. korshinskii., T. Kang, H. D. Wu, B. Y. Lu, X. J. Luo, C. M. Gong, J. Bai., and Obsahuje bibliografii
Diurnal patterns of gas exchange and chlorophyll (Chl) fluorescence parameters of photosystem 2 (PS2) as well as H2O2 content were analyzed in Reaumuria soongorica (Pall.) Maxim., a perennial semi-shrub. The rate of photorespiration was estimated by combined measurement of gas exchange and Chl fluorescence. The rate of photorespiration increased with the increasing drought stress (DS). The ratio of carboxylation electron flow to oxygenation electron flow (Jc/Jo) and the maximal photochemical efficiency of PS2 (variable to maximum fluorescence ratio, Fv/Fm) decreased with the increasing DS. Fv/Fm in isonicotinic acid hydrazide (INH)-sprayed plants was lower than that in normal plants under moderate DS, but no significant difference was observed under severe DS. H2O2 content in INH-sprayed plants was significantly lower than that in normal plants under severe DS. Taken together, photorespiration in R. soongorica consumed excess electrons and protected photosynthetic apparatus under moderate DS, whereas it accelerated H2O2 accumulation markedly and induced the leaf abscission under severe DS. and J. Bai ... [et al.].