夜间增温对亚高山针叶林主要树种无机氮吸收的影响  

Effects of night warming on the uptake of inorganic nitrogen by two dominant species in subalpine coniferous forests

作　　者：唐波[1,2] 杨欢[1,2] 尹春英[1] 孙誉育[1,2] 郑东辉[1,2] 刘庆[1] 

机构地区：[1]中国科学院成都生物研究所,中国科学院山地生态恢复与生物资源利用重点实验室,生态恢复与生物多样性保育四川省重点实验室,成都610041 [2]中国科学院大学,北京100049

出　　处：《植物生态学报》2016年第6期543-553,共11页Chinese Journal of Plant Ecology

基　　金：基金项目国家自然科学基金(31370495和31070533)

摘　　要：吸收营养物质是植物根系的主要生理功能。氮素吸收是植物体内氮代谢的第一步,也是最关键的一步。为了全面地认识亚高山针叶林在全球气候变化背景下对两种主要无机氮(NH_4^+和NO_3~–)吸收特点的变化,该研究以川西亚高山针叶林优势树种——云杉(Picea asperata)和岷江冷杉(Abies fargesii var.faxoniana)为材料,通过红外辐射加热器模拟增温,利用非损伤微测技术(non-invasive micromeasurement technology)研究了这两个树种吸收NH_4^+和NO_3~–特点的变化,同时还探究了NH_4^+和NO_3~–之间的相互作用对植物吸收这两种离子的影响。研究结果显示:在云杉根系中,NH_4^+和NO_3~–的最大吸收速率分别发生在距离根尖最顶端17–18 mm区域和17 mm处,而岷江冷杉对这两种离子的最大吸收速率分别发生在距离根尖顶端11 mm和11.5mm处。增温对云杉和岷江冷杉根系吸收NH_4^+和NO_3~–有促进作用。在增温条件下,NO_3~–能够促进云杉根系对NH_4^+的吸收,而NH_4^+则抑制了其对NO_3~–的吸收。无论是否增温,岷江冷杉对NH_4^+的吸收都不受NO_3~–的影响,而在增温条件下,NH_4^+会抑制岷江冷杉对NO_3~–的吸收。Aims Plant roots play a critical role in the uptake of nutrients, and nitrogen（N） absorption is considered as the first step and a pivotal process in N metabolism of plants. Our objective was to better understand the absorption of two major inorganic N forms（NH^＋4 and NO^–3） in subalpine coniferous forests under global warming. Methods Experimental warming using infrared heater was applied to two dominant species in subalpine coniferous forests of Sichuan, China, Picea asperata and Abies fargesii var. faxoniana. The non-invasive micromeasurement technology was used to investigate the effects of warming on the uptake rates of NH^＋4 and NO^–3 and the potential interactions between these two ions. Important findings Results showed that the maximal net root uptake of NH^＋4 and NO^– 3occurred at a distance of 17–18 mm and 17 mm from root tips, respectively for P. asperata. and at a distance of 11 mm and 11.5 mm from root tips respectively for A. fargesii var. faxoniana. Experimental warming elevated the uptake rates of NH^＋4 and NO^–3 in both species, but the interactions between NH^＋4 and NO^–3 differed between the two species. While NO^–3uptake was inhibited in the presence of NH^＋4 for both P. asperata and A. fargesii var. faxoniana, net NH^＋4 uptake was promoted by NO^–3 supply only in P. asperata roots under experimental warming.

关 键 词：夜间增温 N吸收 针叶树 高山森林 

分 类 号：S718.43[农业科学—林学]