土壤增温对幼龄杉木细根化学计量学特征的影响
首发时间:2018-03-19
摘要:为了揭示我国最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 ℃和不增温两个处理,各5个重复),采用内生长环法,在增温后的第二年和第三年进行4次(2015年1月、7月,2016年1月、7月)细根(分0-1 mm和1-2 mm两个分级)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比和n/p比)的影响。结果表明:(1)增温处理使2015年1月0-1mm细根c浓度显著降低,但在2016年的两次取样中则显著降低了1-2mm细根c浓度。增温使前两次取样中0-1mm细根和前三次取样中1-2mm细根n浓度显著提高、c/n比降低;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比提高。(2)增温使第三次、第四次取样中0-1mm细根和第四次取样中1-2mm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比。(3)随着苗木的生长,细根呈现出c浓度和c/n比升高、n浓度和n/p比降低的趋势;而p浓度则仅在对照0-1mm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比升高,从而杉木生长可能受p限制。
关键词: 生态学;细根;化学计量学;杉木;稀释效应
for information in english, please click here
effects of soil warming on fine root stoichiometry of young chinese fir seedlings
abstract:in this paper a field soil cable warming experiment was conducted in chenda state-own forest farm, sanming, fujian province.limited information regarding how warming affects root processes has restricted our ability to predict how roots will respond to elevated temperatures. the experiment included two treatments: soil warming (w, ambient 5℃) and non-warming (ct, ambient), and each had 5 replicate 2m×2m mini-plots.four chinese fir (cunninghamia lanceolata) seedlings were planted in each mini-plot.we measured changes in fine root stoichiometry (c, n, p,c/n和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 1~2mm 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; (4)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 0~1mm 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.
keywords: ecology soil warming, fine roots stoichiometry chinese fir (cunninghamia lanceolata), dilution effect
基金:
论文图表:
引用
导出参考文献
no.****
动态公开评议
共计0人参与
勘误表
土壤增温对幼龄杉木细根化学计量学特征的影响
评论
全部评论0/1000