Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Physiol Plant. 2013 Sep;149(1):141-50. doi: 10.1111/ppl.12044. Epub 2013 Apr 2.
Photorespiration has been indicated as an important mechanism for maintaining CO2 assimilation and alleviating photodamage under conditions of high light and low CO2 . We tested the hypothesis that plants grown under a high temperature had greater electron flow for photorespiration compared with those grown under a relative low temperature. Responses of photosynthetic electron flow and CO2 assimilation to incident light intensity and intercellular CO2 concentration were examined in leaves of tobacco cultivar 'k326'. Plants were cultivated at three sites with different ambient temperatures (Zhengzhou, Zunyi and Jiangchuan). Under high light, plants grown in Zhengzhou (with the highest growth temperature in the three sites) showed higher effective quantum yield of photosystem II and total electron flow through photosystem II than that in Zunyi and Jiangchuan. However, regardless of light intensity and intercellular CO2 status, there were no significant differences among sites in the photosynthetic CO2 assimilation rate or electron flow devoted to the carboxylation of ribulose-1,5-bisphosphate (RuBP). As a result, plants grown at high temperature showed higher electron flow devoted to oxygenation of RuBP than plants grown at low temperature. These results suggested that enhancement of electron flow for photorespiration is an important strategy in tobacco for acclimating to high growth temperature.
光呼吸被认为是在高光和低 CO2 条件下维持 CO2 同化和减轻光损伤的重要机制。我们检验了这样一个假设，即在相对较低的温度下生长的植物比在高温下生长的植物具有更大的用于光呼吸的电子流。在烟草品种“K326”的叶片中，我们检测了光合作用电子流和 CO2 同化对入射光强度和胞间 CO2 浓度的响应。这些植物在三个具有不同环境温度的地点（郑州、遵义和江川）进行栽培。在高光下，在三个地点中生长温度最高的郑州的植物表现出比遵义和江川更高的光系统 II 有效量子产量和通过光系统 II 的总电子流。然而，无论光照强度和胞间 CO2 状况如何，三个地点的光合 CO2 同化率或用于核酮糖-1,5-二磷酸（RuBP）羧化的电子流没有显著差异。因此，在高温下生长的植物比在低温下生长的植物具有更高的用于 RuBP 加氧的电子流。这些结果表明，增强光呼吸的电子流是烟草适应高温生长的重要策略。
