Differences in the photosynthetic and physiological responses of Leymus chinensis to different levels of grazing intensity
Differences in the photosynthetic and physiological responses of Leymus chinensis to different levels of grazing intensity
复制标题
不同放牧强度下羊草光合和生理反应的差异
DOI：
10.1186/s12870-019-2184-1
复制
发表时间：
2019-12-16
影响因子：
5.3
通讯作者：
Hou, Xiangyang
中科院分区：
文献类型：
--
作者：
Liu, Min;Gong, Jirui;Hou, Xiangyang
背景
放牧是我国北方重要的土地利用方式。总体而言，不同放牧强度对植物形态和生理特性的影响不同，尤其是光合能力。研究了羊草对轻、中、重放牧强度的响应，并与禁牧对照进行了比较。
结果
在轻度放牧条件下，L.结果表明，中国对虾的光合能力下降。叶绿素和类胡萝卜素含量低，限制了光能的转化和耗散，Rubisco活性低，限制了羧化效率。此外，受损的光合机构积累活性氧（ROS）。随着放牧强度的增加，更多的能量被用于热耗散，胡萝卜素含量和非光化学猝灭程度增加，而光合电子传递最低。光合作用的显著降低降低了叶片碳含量。植物通过增加能量耗散降低了ROS引起的风险。在高放牧强度下，植物通过光合补偿改变了生存策略。更多的能量被分配给光合电子传递。虽然重度放牧破坏了叶绿体超微结构，但内部机制的调整增加了补偿光合作用，并且增加的分蘖数促进了放牧后的再生长。
结论
总的来说，植物通过调整它们的新陈代谢和生长来应对不断变化的环境，采取了不同的策略。
Background
Grazing is an important land use in northern China. In general, different grazing intensities had a different impact on the morphological and physiological traits of plants, and especially their photosynthetic capacity. We investigated the responses of Leymus chinensis to light, medium, and heavy grazing intensities in comparison with a grazing exclusion control.
Results
With light grazing, L. chinensis showed decreased photosynthetic capacity. The low chlorophyll and carotenoid contents constrained light energy transformation and dissipation, and Rubisco activity was also low, restricting the carboxylation efficiency. In addition, the damaged photosynthetic apparatus accumulated reactive oxygen species (ROS). With medium grazing, more energy was used for thermal dissipation, with high carotene content and high non-photochemical quenching, whereas photosynthetic electron transport was lowest. Significantly decreased photosynthesis decreased leaf C contents. Plants decreased the risk caused by ROS through increased energy dissipation. With high grazing intensity, plants changed their strategy to improve survival through photosynthetic compensation. More energy was allocated to photosynthetic electron transport. Though heavy grazing damaged the chloroplast ultrastructure, adjustment of internal mechanisms increased compensatory photosynthesis, and an increased tiller number facilitated regrowth after grazing.
Conclusions
Overall, the plants adopted different strategies by adjusting their metabolism and growth in response to their changing environment.