Ge Zhiwei, Ma Yunran, Xing Wei, Wu Yongbo, Peng Sili, Mao Lingfeng, Miao Zimei
College of Biology and the Environment, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China.
NFU Academy of Chinese Ecological Progress and Forestry Development Studies, Nanjing 210037, China.
Plants (Basel). 2022 Aug 27;11(17):2225. doi: 10.3390/plants11172225.
The amount of atmospheric nitrogen-containing aerosols has increased dramatically due to the globally rising levels of nitrogen from fertilization and atmospheric deposition. Although the balance of carbon and nitrogen in plants is a crucial component of physiological and biochemical indexes and plays a key role in adaptive regulation, our understanding of how nitrogen-containing aerosols affect this remains limited; in particular, regarding the associated mechanisms. Using a fumigation particle generator, we generated ammonium nitrate solution (in four concentrations of 0, 15, 30, 60 kg N hm year) into droplets, in 90% of which the diameters were less than 2.5 μm, in the range of 0.35-4 μm, and fumigated L. and Hook. for 30 days in April and August. We found that the weight percentage of nitrogen in the upper epidermis, mesophyll tissue, and bulk of leaves decreased significantly with the N addition rate, which caused a decrease of carbon:nitrogen ratio, due to the enhanced net photosynthetic rate. Compared with Hook., L. responded more significantly to the disturbance of N addition, resulting in a decrease in the weight percentage of nitrogen in the roots, due to a lower nitrogen use efficiency. In addition, the superoxide dismutase activity of the two plants was inhibited with a higher concentration of nitrogen sol; a reduction of superoxide dismutase activity in plants means that the resistance of plants to various environmental stresses is reduced, and this decrease in superoxide dismutase activity may be related to ROS signaling. The results suggest that inorganic nitrogen-containing aerosols caused excessive stress to plants, especially for L.
由于施肥和大气沉降导致全球氮水平上升，大气中含氮气溶胶的数量急剧增加。尽管植物中碳和氮的平衡是生理和生化指标的关键组成部分，并且在适应性调节中起关键作用，但我们对含氮气溶胶如何影响这一点的理解仍然有限；特别是关于相关机制。我们使用熏蒸颗粒发生器，将硝酸铵溶液（四种浓度分别为0、15、30、60 kg N hm² 年）制成液滴，其中90%的液滴直径小于2.5μm，直径范围在0.35 - 4μm之间，并于4月和8月对海州香薷（Elsholtzia splendens）和香薷（Elsholtzia ciliata）熏蒸30天。我们发现，随着氮添加量的增加，叶片上表皮、叶肉组织和叶片整体中氮的重量百分比显著下降，这导致碳氮比降低，原因是净光合速率增强。与香薷相比，海州香薷对氮添加干扰的响应更为显著，由于氮利用效率较低，其根部氮的重量百分比下降。此外，两种植物的超氧化物歧化酶活性在较高浓度氮溶胶处理下受到抑制；植物中超氧化物歧化酶活性的降低意味着植物对各种环境胁迫的抗性降低，这种超氧化物歧化酶活性的下降可能与活性氧信号传导有关。结果表明，无机含氮气溶胶对植物造成了过度胁迫，尤其是对海州香薷。
