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供氮和增温对倍增二氧化碳浓度下荫香叶片光合作用的影响

孙谷畴 赵平 饶兴权 蔡锡安 曾小平   

  1. 中国科学院华南植物研究所,广州 510650
  • 收稿日期:2004-09-14 修回日期:2005-01-04 出版日期:2005-08-18

Effects of nitrate application on alleviating photosynthesis restriction of Cinnamomum burmannii leaves under elevated CO2 concentration and enhanced temperature

SUN Guchou,ZHAO Ping,RAO Xingquan,CAI Xi'an,ZENG Xiaoping   

  1. South China Institute of Botany,Chinese Academy of Sciences,Guangzhou 510650,China

  • Received:2004-09-14 Revised:2005-01-04 Online:2005-08-18

摘要: 供给0~0.6 mg N的盆栽荫香(Cinnamomum burmannii)幼树分别生长在倍增CO 2(+CO2,731 μmol·mol-1)和正常空气CO 2浓度(CO 2,365 μmol·mol-1)的生长箱内,昼夜温度分别为25/23 ℃和32/25 ℃,自然光照下生长30 d.以生长在CO2和25/23 ℃下的植株为对照研究增温和氮对+CO2叶片光合作用的影响.结果表明,在+CO2和25/23 ℃下无氮和氮处理植株的平均光合速率(Pnsat)较+CO2和32/25 ℃下的叶片高5.1%,温度增高降低叶片Pnsat;而Pnsat随供氮而增高.在+CO2条件下,生长在32/25 ℃下的叶片Rubisco最大羧化速率(Vcmax)和最大电子传递速率(Jmax)较25/23 ℃下的低(P<0.05),温度增高降低+CO2下叶片的Vcmax和Jmax在+CO2下叶片光合呼吸速率(Rp)较低,生长温度增高提升Rp.在CO2下生长温度从25/23 ℃增至32/25 ℃,叶片的Rubisco含量(NR)和Rubisco活化中心浓度(M)降低,而供氮能增高NR和M.供氮能减缓温度增高对倍增CO2下荫香叶片光合作用的限制.

关键词: 林地, 生态需水, 蒸散, 土壤水分, 黄淮海地区

Abstract: In this study,potted C.burmannii saplings were cultured in a top-closed cha mber with elevated CO2(CO2,365 μmol·mol-1) and ambient CO2 (CO2,365 μmol·mol-1),and at diurnal temperature(day/night) 25/23 ℃ and 32/25 ℃,respectively.The gas exchange,calculated photosynthesis parameter, Rubisco content,and activated state of Rubisco were examined.The results showed that under +CO2and at 25/23 ℃,the mean photosynthetic rate(Pnsat) of sapling leaves was 5.1%higher than that under +CO2and at 32/25 ℃.Temperature enhancement declined Pnsat,while nitrate addition increased it.Under +CO2,saplings had lower Vcmax and Jmax at 32/25 ℃ than at 25/23 ℃.Temperatureenhancement under +CO2 also declined Vcmax and Jmax. Under +CO2,lower photorespiration rate(Rp) occurred in leaves,but temperature enhancement could increase Rp.Under +CO2,Rubisco content(NR) and its active site per unit leaf area(M) decreased as diurnal temperature changed from 25/23 ℃ to 32/25 ℃.Meanwhile,nitrate addition could increase NR and M.It may be suggested that nitrate addition could alleviate the restriction of photosynthesis under elevated CO2 concentration and enhanced temperature.

Key words: Forestland, Ecological water requirement, Evapotranspiration, Soil moisture content, Huang-Huai-Hai region