摘要
为揭示全球变暖背景下杉木人工林幼苗与其伴生的其它植物间的对土壤养分的竞争关系和适应性,本研究采用埋设加热电缆进行土壤增温(+5℃)技术,在福建省三明市陈大国有采育场内建立杉木(Cunninghamia lanceolata)幼苗试验小区,包括对照(NW)与增温(WNW)处理(均不除草)。采用内生长环法与土钻法相结合,测定增温对杉木幼苗及伴生的其他植物(主要为山油麻Helicteres angustifolia、东南野桐Mallotus lianus)等细根生物量、呼吸、形态、及根组织氮浓度的短期影响。结果表明,(1)增温显著降低了杉木<1mm细根生物量,而显著增加了其他植物<1mm细根生物量。增温显著提高了其他植物<1mm细根的氮浓度,显著降低了其比根长(SRL)和比表面积(SRA);同时降低了比根呼吸(参比温度18℃,SRR_(18)),表明细根呼吸对增温产生了驯化现象。而增温对杉木细根的氮浓度没有显著影响,却显著提高了<1mm细根比表面积;同时增温对杉木SRR_(18)没有显著影响,表明杉木细根呼吸没有产生驯化现象。(2)SRR_(18)与比根长间的关系受到增温的显著影响,但树种以及增温×树种的交互作用没有显著影响,表明杉木和其他植物细根竞争能力与维持成本间的平衡关系均受到增温的共同影响。综上结果显示,相较于杉木,伴生的其他植物在增温环境中对地下资源的竞争具有更强的优势,能通过增加细根生物量迅速抢夺吸收因增温而加速矿化的土壤养分,同时通过生理和形态的调整,减少根系单位质量的维持成本,从而提高其对全球变暖的适应性;而杉木在增温条件下面临其他植物的强烈竞争,细根生物量降低,处于不利地位,为了满足生长所需,需增大比根长和比根表面积,且因细根呼吸没有产生驯化现象,从而增加了细根单位质量的维持成本,说明杉木对全球变暖的适应性低于其他植物。该研究结果对于全球变暖下杉木人工�
Based on a soil warming experiment, this study aimed to study the effects of global warming on nutrient acquisition capabilities of subtropical Chinese fir （Cunninghamia lanceolata） seedlings and the associated plants, such as Helicteres angustifolia and Mallotus lianus. Three soil warming （WNW） and three non-warming （NW） 2m×2m Chinese fir seedling plots, both with no weeding, were established in Chenda State-Own Forest Farm, Sanming, Fujian. Soil warming was accomplished by buried heating cable technology, with soil temperature elevated to ＋5℃ above ambient. Fine root biomass was measured by soil coring, and ingrowth cores were used to extract root samples to measure root respiration, morphology and N concentration. Specific root respiration rates were measured by the Clark-type Oxygen Electrode and root tissue N concentration were determined by the vario EL Ⅲ Element analyzer. Root samples were scanned by the Epson scanner at 300dpi, and root architecture and morphology were analyzed by WinRHIZO Pro 2009b software. The results showed that：（1） Soil warming significantly decreased root （〈1mm） biomass of Chinese fir, but significantly increased root （〈1mm） biomass of the associated plants. N concentration was significantly increased, and specific root length （SRL） and specific root area （SRA） decreased significantly in the 〈1mm roots of the associated plants. Furthermore, the specific root respiration （SRR18, measured at reference temperature of 18） in the 〈1mm roots of the associated plants was decreased under warming, indicating acclimation of root respiration to warming. For Chinese fir seedlings, soil warming had no significant effect on SRR18 and root tissue N concentration, except that the SRA of the 〈1mm roots significantly increased. （2） Soil warming had significant influence on the relationship between SRR18 and SRL; however, tree species and interaction between warming and tree species had no significant effect, indicating that the balance betwee
出处
《生态学报》
CAS
CSCD
北大核心
2017年第4期1232-1243,共12页
Acta Ecologica Sinica
基金
国家自然科学基金优秀青年基金项目(31422012)
国家自然科学基金资助项目(31500408)
国家973前期专项课题资助项目(2014CB460602)
福建省杰出青年基金项目滚动资助项目(2014J07005)
关键词
增温
竞争
适应性
比根呼吸速率
细根形态
根组织氮浓度
驯化
warming
competition
adaptability
specific root respiration
fine root morphology
root tissue N concentration
acclimation
