摘要
为了揭示中国重要人工林树种杉木(Cunninghamia lanceolata)对全球变暖的地下响应及其适应性,通过在福建省三明市陈大国有林场设置杉木幼苗土壤增温实验(增温5℃和不增温2个处理,各5个重复),采用内生长环法,在增温后的第2年和第3年进行4次(2015年1月、7月,2016年1月、7月)细根(分0~1 mm和1~2 mm 2个分级)取样,研究土壤增温对杉木幼苗细根化学计量学特征(C、N、P浓度,C/N和N/P)的影响。结果表明:1)增温处理使2015年1月0~1 mm细根C浓度显著降低,但在2016年的2次取样中则显著降低了1~2 mm细根的C浓度。增温使前2次取样中0~1 mm细根和前3次取样中1~2 mm细根N浓度显著提高、C/N降低;但此后由于增温对土壤N有效性的促进作用减弱,增温对细根N浓度的影响不显著甚至降低,细根C/N提高。2)增温使第3次、第4次取样中0~1 mm细根和第4次取样中1~2 mm细根的P浓度显著降低;同时在大部分取样时间中增温提高了细根的N/P。3)随着苗木的生长,细根呈现出C浓度和C/N升高、N浓度和N/P降低的趋势;而P浓度则仅在对照0~1 mm细根表现出上升的趋势。可见,土壤增温引起了细根N富集,细根P浓度降低,N/P升高,因而杉木生长可能受P限制。
Global warming is expected to have profound effects on plant growth. The effects of global climate change on the aboveground parts of plants have been reported in many studies in the past decades. A field soil cable warming experiment was conducted in Chenda State-Own Forest Farm,Sanming,Fujian Province. The experiment included two treatments： soil warming（W,ambient ＋ 5 ℃）and non-warming（CT,ambient）,both had 5 replicate 2 m × 2 m mini-plots. Four Chinese fir（Cun-ninghamia lanceolata） seedlings were planted in each mini-plot. We measured changes in fine root stoichiometry（C,N,P,C/N and N/P） of Chinese fir seedlings using soil ingrowth donut methods during the second（January and July 2015） and the third year（January and July 2016） after soil warming. The results showed that：（1） with soil warming,C concentration in the 0 ～ 1 mm fine roots decreased significantly in January 2015,whereas C concentration in the 1 ～ 2 mm fine roots decreased significantly in 2016. Soil warming significantly decreased N concentrations in the 0 ～ 1 mm fine roots in the first two samplings and decreased N concentrations in the 1 ～ 2 mm fine roots in the first three samplings,which hence reduced the C/N ratios in fine roots. In the late sampling,however,soil warming had no effect on or even reduced fine root N concentrations,which in turn increased fine root C/N ratios.（2） Soil warming had no effect on fine root P concentration during the early samplings,but had decreased fine root P concentration during the late samplings; the N/P ratios in fine roots had been increased by soil warming in most of the samplings,which might indicate an impaired P absorption capacity of fine roots;（3） Along with seedling growth,the fine roots showed the trends of increased C concentrations and C/N ratios and decreased N concentration and N/P ratios,mainly indicating the dilution effect of seedling growth on fine root N concentrations. P concentrations of the 0 ～ 1 mm fine roots in the CT showed a increasing trend with seedling growth,which might be a result of developing capacity of fine roots to uptake soil P. From the perspective of fine root stoichiometry,soil warming,to some extent,can alleviate N limitation but induce P limitation in of Chinese fir seedlings.
作者
陈廷廷
史顺增
熊德成
冯建新
郭润泉
宋涛涛
蔡瑛莹
陈望远
陈光水
杨玉盛
CHEN Tingting;SHI Shunzeng;XIONG Decheng;Feng Jianxin;GUO Runquan;Song Taotao;CAI Yingying;CHEN Wangyuan;CHEN Guangshui;YANG Yusheng(School of Geographical Sciences;State Key Laboratory for Subtropical Mountain Ecology of the Ministry of Science and Technology and Fujian Province,Fujian Normal University,Fuzhou 350007,China)
出处
《亚热带资源与环境学报》
2018年第2期13-21,共9页
Journal of Subtropical Resources and Environment
基金
国家自然科学基金(31500408)
973前期专项课题(2014CB460602)
福建省杰出青年基金项目滚动资助项目(2014J07005)
关键词
生态学
土壤增温
细根
化学计量学
杉木
稀释效应
ecology；soil warming；fine roots；stoichiometry；Chinese fir （ Cunninghamia lanceolata）
dilution effect
