Chen Zhan, Cao Jixin, Yu Hao, Shang He
Key Laboratory of Forest Ecology and Environment, State Forestry Administration, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing, China.
Front Plant Sci. 2018 Nov 30;9:1764. doi: 10.3389/fpls.2018.01764. eCollection 2018.
To assess the impacts of ozone (O) on carbon metabolism of subtropical broadleaved tree species, seedlings of and were exposed to elevated O levels in open-top chambers (OTCs) from June to November 2014. Three treatments were conducted in nine total OTCs, including charcoal-filter air (CF) as a control treatment, low O treatment 'O3-1' (∼100 nl l), and high O treatment 'O3-2' (∼150 nl l). Our findings demonstrated that elevated O levels significantly decreased the net photosynthesis rates ( ) and leaf, root, and total biomass of both species, while it did not significantly affect the root/shoot ratio in and . O3-1 treatments significantly increased water soluble carbohydrates (WSC) in leaves of both tree species, while only increased the total non-structural carbohydrates (TNC) and starch in leaves of ; effects on were equivalent in comparison to the control treatment (CF). Likewise, there was no effect of treatment on the polysaccharide content of both tree species. The contents of polysaccharide, starch contents in fine roots of both species, and TNC in fine roots of increased significantly in O3-1 compared to CF. O3-2 treatment significantly decreased starch and TNC in the fine roots of , and significantly decreased polysaccharide, starch, WSC, and TNC in the fine roots of . Elevated O had no effects on leaf polysaccharide in both species, but O3-1 significantly increased polysaccharide in the fine roots of both species, and O3-1 significantly increased WSC in the leaves while decreased that in the fine roots of both species. These results suggested that elevated O levels have significant impacts on the carbon metabolism of both tree species in our study, with differential responses between tree species and among leaves and roots.
为评估臭氧（O）对亚热带阔叶树种碳代谢的影响，2014年6月至11月期间，将[树种名称1]和[树种名称2]的幼苗置于开顶式气室（OTC）中，使其暴露于升高的臭氧水平下。在总共9个OTC中进行了三种处理，包括以经过活性炭过滤的空气（CF）作为对照处理、低臭氧处理“O3 - 1”（约100 nl·l⁻¹）和高臭氧处理“O3 - 2”（约150 nl·l⁻¹）。我们的研究结果表明，升高的臭氧水平显著降低了两种树种的净光合速率（ ）以及叶片、根系和总生物量，而对[树种名称1]和[树种名称2]的根冠比没有显著影响。O3 - 1处理显著增加了两种树种叶片中的水溶性碳水化合物（WSC），而仅增加了[树种名称1]叶片中的总非结构性碳水化合物（TNC）和淀粉；与对照处理（CF）相比，对[树种名称2]的影响相当。同样，处理对两种树种的多糖含量没有影响。与CF相比，O3 - 1处理使两种树种细根中的多糖、淀粉含量以及[树种名称1]细根中的TNC显著增加。O3 - 2处理显著降低了[树种名称1]细根中的淀粉和TNC，并显著降低了[树种名称2]细根中的多糖、淀粉、WSC和TNC。升高的臭氧对两种树种的叶片多糖没有影响，但O3 - 1显著增加了两种树种细根中的多糖，并且O3 - 1显著增加了叶片中的WSC，同时降低了两种树种细根中的WSC。这些结果表明，升高的臭氧水平对我们研究中的两种树种的碳代谢有显著影响，不同树种以及叶片和根系之间存在差异响应。
