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增温与氮添加对杉木幼苗细根化学计量学的影响

姜琦,陈光水*,郭润泉,宋涛涛,陈廷廷,陈宇辉,贾林巧,熊德成   

  1. (福建师范大学地理科学学院/湿润亚热带山地生态国家重点实验室培育基地, 福州 350007)
  • 出版日期:2020-03-10 发布日期:2020-03-10

Effects of warming and nitrogen addition on fine root stoichiometry of Chinese fir seedlings.

JIANG Qi, CHEN Guang-shui*, GUO Run-quan, SONG Tao-tao, CHEN Ting-ting, CHEN Yu-hui, JIA Lin-qiao, XIONG De-cheng   

  1. (College of Geographical Sciences, Fujian Normal University / Cultivation Base of State Key Laboratory of Humid Subtropical Mountain Ecology, Fuzhou 350007, China).
  • Online:2020-03-10 Published:2020-03-10

摘要: 全球气候变暖与氮沉降是两个同时存在的全球变化主要因素,但目前关于二者的研究多以单因子为主。细根碳(C)、氮(N)、磷(P)浓度影响着森林生态系统生产力与碳汇,然而目前关于气候变暖与N沉降对细根化学组成元素的影响尚不清楚。本研究在福建三明森林生态系统与全球变化研究站陈大观测点开展增温(W,+4 ℃)与N添加(N,+40 kg N·hm-2·a-1)双因子试验,探讨增温与N添加对杉木细根C、N、P化学计量学的影响。结果表明:(1)增温提高了春季细根N浓度,对细根C与P浓度则无显著影响;增温降低了春季细根C∶N,对细根N∶P无显著影响。(2)N添加提高了细根C浓度与春季细根N浓度,对细根P浓度则无显著影响;N添加降低了春季细根C∶N,提高了春季细根N∶P。(3)增温与N添加的交互作用对春季1~2 mm径级细根C浓度有显著影响,但对0~1 mm径级细根C浓度无显著影响,并且增温与N添加的交互作用对细根N与P浓度均无显著影响。本研究表明,增温与N添加会促进亚热带森林生态系统养分循环,N添加并未改变亚热带杉木人工林N限制现状;增温与N添加的交互作用对细根C、N、P元素的影响并不一致,受苗木C投资权衡与生长稀释效应所调节。

关键词: 地表温度, 景观格局, 森林城市

Abstract: Global warming and nitrogen deposition are two main global change drivers, often occurring simultaneously. However, most of related studies referred to only single factor. The concentrations of carbon (C), nitrogen (N) and phosphorus (P) in fine roots affect forest ecosystem productivity and C storage. The effects of climate warming and N deposition on fine root chemical components remain unclear. We conducted a two-factor experiment of warming (W, +4 ℃) and N addition (N, +40 kg N·hm-2·a-1) at the Forest Ecosystem and Global Change Research Station of Fujian Normal University in Chenda, Sanming, Fujian Province, to explore the effects of warming and N addition on the concentrations and stoichiometry of C, N and P in fine roots of Chinese fir (Cunninghamia lanceolata) seedlings. The results showed that warming increased the concentration of fine root N in spring, but did not affect fine root C and P concentration. Warming decreased C∶N ratio but not N∶P ratio of fine roots in spring. Nitrogen addition increased the concentration of fine root C and N but not P concentration in spring, N addition decreased the C∶N ratio and increased N∶P ratio of fine roots in spring. The interaction between warming and N addition had a significant effect on C concentration of fine root in 1-2 mm diameter class, but not 0-1 mm diameter class. The effects of the interaction between warming and N addition had no significant effect on the concentration of fine root N and P. Our results suggested that warming and N addition could promote nutrient cycling of subtropical forest ecosystem. Nitrogen addition did not change N limitation status of subtropical Chinese fir plantation. The interaction between warming and N addition had different effects on fine root C, N, P elements, which was regulated by seedling C investment tradeoff and the dilution effect.

Key words: landscape pattern, land surface temperature., forest city