Construction of CO 2 -response model of electron transport rate in C 4 crop and its application北大核心CSCD

Aims Accurate estimation of variation tendency of photosynthetic electron flow response to CO 2 is of great significance to understand the photosynthetic processes. Methods A model of electron transport rate (J) response to CO 2 (model II) was developed based on a new model of photosynthesis response to CO 2 (model I). The data of maize (Zea mays) and grain amaranth (Amaranthus hypochondriacus) that were measured by LI-6400-40 portable photosynthetic apparatus were fitted by the two models, respectively. Important findings The results indicated that the model II could well characterize and fit the CO 2 -response curves of electron transport rate (J-C a curve) for maize and grain amaranth, and the maximum electron transport rates of maize and grain amaranth were 262.41 and 393.07 mol·m −2 ·s −1 , which were in very close agreement with the estimated values (p > 0.05), respectively. Based on these results, the allocation to other pathways of photosynthetic electronic flow were discussed. At 380 mol·mol −1 CO 2 , the photosynthetic electron flows for carbon assimilation of maize and grain amaranth carbon were 247.92 and 285.16 mol·m −2 ·s −1 , respectively, when the CO 2 for recovery of mitochondrial respiration was considered, and the photosynthetic electron flows for other pathways were 14.49 and 107.91 mol·m −2 ·s −1 , respectively. The photosynthetic electron flows for other pathways in grain amaranth were more six times than that in maize. The analysis shows that this difference is closely related to the types of catalytic decarboxylase and the locations of decarboxylation reactions. This finding provides a new perspective for investigating the differences between the two subtypes of nicotinamide adenine dinucleotide phosphate malic acid enzyme type and nicotinamide adenine dinucleotide malic acid enzyme type in C 4 species. In addition, the CO 2 -response model of electron transport rate offers us an alternative mathematical tool for investigating the photosynthetic electron flow of C4 crop. © 2018 Editorial Office of Chinese Journal of Plant Ecology. All Rights Reserved.