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HZAU’s Progress in Interaction of Photosynthesis and Environment

Recently, Associate Professor Li Yong from HZAU’s College of Plant Science & Technology and Professor Margaret Barbour from University of Sydney have jointly published a research paper entitled The role of leaf water potential in the temperature response of mesophyll conductance on New Phytologist. Associate Prof. Li is the first and corresponding author.

Before carbon assimilation in photosynthesis, CO2 needs to be transported from the atmosphere through the pores to the intercellular space, and then pass through the cell wall, membrane, cytoplasm, chloroplast membrane and chloroplast stroma to reach the carboxylation loci of the Rubisco enzyme (the key enzyme of Calvin cycle). The conductivity (the reciprocal of resistance) of CO2 from the intercellular space to the Rubisco enzyme carboxylation loci is called the mesophyll conductance, which is one of the main factors limiting photosynthesis. In the context of global warming, to study the response law and mechanism of mesophyll conductance is of great significance to the improvement of high temperature resistance of photosynthesis.

Previous studies show that the response of mesophyll conductance to temperature among different plants is different. Some plants (such as rice and tobacco) have a higher conductance with increasing temperature, but the conductance of other plants (such as wheat and Arabidopsis) is not sensitive to it. At present, there is no reasonable explanation for this difference internationally. With rice and wheat as the research objects, this paper indicated that the leaf water potential of wheat decreased with the increase of temperature, while the leaf water potential of rice was relatively insensitive to it. The relationship between mesophyll conductance and water potential was established by short-term drought stress under two different temperatures. It was found that the mesophyll conductance of wheat rose as the temperature increased under the same water potential. This indicates that the difference in leaf water potential response to temperature between different crops affects the response of mesophyll conductance to temperature. At last, the authors optimized the model of mesophyll conductance response to temperature, and systematically elucidated the factors affecting the temperature adaptability of mesophyll conductance and regulation measures.

Associate Prof. Li also published a relevant research paper entitled Increase rate of light-induced stomatal conductance is related to stomatal size in the genus Oryza in Journal of Experimental Botany in May this year. The paper clarifies the influence and mechanism of stomatal structure on the light-induced opening speed of pores, which gives insight into the increase in crop adaptability to climate changes and the efficient utilization of irradiance. Doctoral student Zhang Qiangqiang is the first author of the paper, and Associate Prof. Li is the corresponding author.