de Souza Vinícius Fernandes, Gonçalves José Francisco de Carvalho, Rasulov Bakhtier, Talts Eero, Morfopoulos Catherine, Junior Sérgio Duvoisin, Albuquerque Patrícia Melchionna, Niinemets Ülo
Institute of Agricultural and Environmental Sciences Estonian University of Life Sciences Tartu Estonia.
Laboratory of Plant Physiology and Biochemistry National Institute for Amazonian Research - INPA Manaus Brazil.
Plant Environ Interact. 2025 May 2;6(3):e70053. doi: 10.1002/pei3.70053. eCollection 2025 Jun.
The suppression of isoprene emissions by high CO levels can be mitigated by increasing temperature; however, little is known about why and to what extent species differ in their temperature-dependent release from high CO inhibition. We studied leaf photosynthetic characteristics and isoprene emissions over a 25°C-40°C temperature range at CO concentrations of 150, 400, and 1000 μmol mol in two species with contrasting heat resistance. In the temperate species , rising temperatures above 30°C shifted electron flow from photosynthesis to isoprene synthesis, reducing CO inhibition due to enhanced isoprene synthase activity and decreased sensitivity of the DMADP pool. Conversely, the tropical species showed greater heat tolerance in its photosynthetic apparatus, maintaining electron flow for CO fixation, and exhibited a consistent CO suppression of isoprene emissions throughout the experiment. These findings indicate that species differences in relative sensitivity of light and dark reactions of photosynthesis play crucial roles in modulating isoprene emissions under combined high CO and temperature conditions.
高浓度二氧化碳对异戊二烯排放的抑制作用可通过升高温度来缓解；然而，对于不同物种在高温抑制下温度依赖性释放为何存在差异以及差异程度如何，我们却知之甚少。我们研究了两种耐热性不同的物种在150、400和1000 μmol mol的二氧化碳浓度下，25°C至40°C温度范围内的叶片光合特性和异戊二烯排放。在温带物种中，温度升至30°C以上时，电子流从光合作用转向异戊二烯合成，由于异戊二烯合酶活性增强和DMADP库敏感性降低，从而减轻了二氧化碳抑制作用。相反，热带物种在其光合机构中表现出更高的耐热性，维持用于二氧化碳固定的电子流，并且在整个实验过程中异戊二烯排放受到一致的二氧化碳抑制。这些发现表明，在高二氧化碳和温度共同作用的条件下，光合作用光反应和暗反应相对敏感性的物种差异在调节异戊二烯排放方面起着关键作用。
