Song Mengya, Yu Lei, Jiang Yonglei, Lei Yanbao, Korpelainen Helena, Niinemets Ülo, Li Chunyang
Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, Sichuan, China.
University of Chinese Academy of Sciences, Beijing 100039, China.
Tree Physiol. 2017 Jun 1;37(6):799-814. doi: 10.1093/treephys/tpx017.
In this study, intra- and interspecific competition were investigated in early successional Salix rehderiana Schneider and later-appearing Populus purdomii Rehder under non-fertilized (control) and nitrogen (N)-fertilized conditions in the Hailuogou glacier retreat area. Our aim was to discover whether N is a key factor in plant-plant competition and whether N drives the primary succession process in a glacier retreat area. We analyzed differences in responses to intra- and interspecific competition and N fertilization between P. purdomii and S. rehderiana, including parameters such as biomass accumulation, nutrient absorption, non-structural carbohydrates, photosynthetic capacity, hydrolysable amino acids and leaf ultrastructure. In the control treatments, S. rehderiana individuals subjected to interspecific competition benefited from the presence of P. purdomii plants, as indicated by higher levels of biomass accumulation, photosynthetic capacity, N absorption, amino acid contents and photosynthetic N-use efficiency. However, in the N-fertilized treatments, P. purdomii individuals exposed to interspecific competition benefited from the presence of S. rehderiana plants, as shown by a higher growth rate, enhanced carbon gain capacity, greater amino acid contents, and elevated water-use efficiency, whereas the growth of S. rehderiana was significantly reduced. Our results demonstrate that N plays a pivotal role in determining the asymmetric competition pattern among Salicaceae species during primary succession. We argue that the interactive effects of plant-plant competition and N availability are key mechanisms that drive primary succession in the Gongga Mountain glacier retreat area.
在本研究中，我们在海螺沟冰川退缩区未施肥（对照）和施氮（N）条件下，对早期演替的红皮柳（Salix rehderiana Schneider）和后期出现的太白杨（Populus purdomii Rehder）进行了种内和种间竞争调查。我们的目的是探究氮是否是植物间竞争的关键因素，以及氮是否驱动冰川退缩区的初级演替过程。我们分析了太白杨和红皮柳对种内和种间竞争以及施氮的响应差异，包括生物量积累、养分吸收、非结构性碳水化合物、光合能力、水解氨基酸和叶片超微结构等参数。在对照处理中，受到种间竞争的红皮柳个体受益于太白杨植株的存在，表现为更高的生物量积累水平、光合能力、氮吸收、氨基酸含量和光合氮利用效率。然而，在施氮处理中，受到种间竞争的太白杨个体受益于红皮柳植株的存在，表现为更高的生长速率、增强的碳固定能力、更高的氨基酸含量和提高的水分利用效率，而红皮柳的生长则显著降低。我们的结果表明，氮在决定杨柳科物种在初级演替过程中的不对称竞争模式方面起着关键作用。我们认为，植物间竞争和氮有效性的交互作用是驱动贡嘎山冰川退缩区初级演替的关键机制。
