生态学报2018，Vol.38Issue(6)：2065-2073,9.DOI:10.5846/stxb201703180460
模拟CO2浓度升高和降雨量变化对红砂生物量分配及碳氮特征的影响
Influence of elevated CO2 and precipitation regimes on biomass allocation and carbon and nitrogen content characteristics of Reaumuria soongorica
摘要
Abstract
Atmospheric CO2 concentrations are predicted to increase from approximately 350μmol/mol today to over 700μmol/mol in the late 21th century.In the future,elevated CO2 levels are likely to have profound effects on precipitation.This change would seriously affect the desert ecosystem,above-and belowground biomass,and carbon and nitrogen allocations of desert plants,leading to changes in ecosystem structure and function.Although many studies have examined the effects of precipitation and CO2,the interactions between changing precipitation and CO2 on desert plants have attracted little attention to date.A pot experiment was conducted to study the interaction of elevated CO2 concentration and changing precipitation with biomass allocation,and carbon and nitrogen content characteristics in roots,stem,and leaf of Reaumuria soongorica,a dominant species of the desert steppe in the arid region of China,in order to assess the possible effect of global climate change on desert ecosystems.The main plot included two CO2 concentrations (350 and 700pmol/mol) and five precipitation conditions(natural precipitationas control [0],precipitation minus 30％ [-30％],precipitation minus 15％ [-15％],precipitation plus 15％ [15％],precipitation plus 30％ [30％]).The results showed that:(1) aboveand belowground biomass of R.soongorica were increased significantly with elevated CO2,and this effect was promoted or inhibited when precipitation increased or decreased,respectively;When the CO2 concentration was increased from 350 to 700μmol/mol,the aboveground biomass increased by 61.28％with precipitation plus 30％ (P＜0.05),whereas root biomass was increased by an average 84％ with precipitation 30％,and 3.21％ with precipitation-30％,respectively (P＜ 0.05);Therefore,the root/shoot ratio (R/S) of R.soongorica with precipitation plus was greater than that with precipitation minus,and this effect was significantly inhibited by elevated CO2(P＜0.05).(2) Elevated CO2 significantly increased the carbon content in the root,stem,and leaf of R.soongorica,and significantly decreased nitrogen content in those organs;this effect was promoted or inhibited with precipitation plus or minus.The C/N ratio of the root,stem,and leaf of R.soongorica increased by 80.22％ (root),103.02％ (stem) and 199.88％ (leaf) with precipitation 30％ (P＜0.05),whereas,the C/N ratio of those organs increased by 24.99％ (root),30.27％ (stem),and 104.45％ (leaf) (P＜0.05) with precipitation-30％,and elevated CO2 significantly promoted the effect (P＜0.05).(3)These results suggested that,under future conditions of elevated CO2,R.soongorica would be restored due to sufficient carbon and water resources in the area where precipitationis increased;Whereas,in areas where precipitation is decreased,R.soongorica would retain its dominant position for the high root/shoot ratio,because there would be compensation of elevated CO2 to drought stress.关键词
CO2浓度升高/降雨量变化/生物量分配/碳氮比/红砂Key words
elevated CO2 concentration/precipitation/biomass allocation/C/N ratio/Reaumuria soongorica引用本文复制引用
种培芳,刘晟彤,姬江丽,李毅..模拟CO2浓度升高和降雨量变化对红砂生物量分配及碳氮特征的影响[J].生态学报,2018,38(6):2065-2073,9.基金项目
国家自然科学基金项目(41461044,31360205) （41461044,31360205）
甘肃省自然科学基金项目(1606RJZA023) （1606RJZA023）
甘肃省高等学校科研项目(2016A-029) （2016A-029）
