3种落叶松幼苗对CO_2升高的光合生理响应

Photosynthetic physiological characteristics in response to elevated CO_2 concentration of three Larch (Larix) species seedlings

采用Li-6400便携式光合作用测定系统研究CO2升高对长白落叶松(Larix olgensisHerry.),日本落叶松(Larix kaempferiCarr.)和兴安落叶松(LarixgmeliniRupr.)当年生和1年生幼苗的光合特性的影响。结果表明:CO2升高使3种落叶松光饱和光合速率(Pmax)和呼吸速率均有不同程度的增加,其中,长白落叶松当年生和1年生幼苗Pmax分别比对照提高了91%和83%,日本落叶松当年生和1年生幼苗Pmax分别比对照提高了71%和94%,而兴安落叶松当年生和1年生幼苗Pmax分别比对照提高了32%和106%。除兴安落叶松外,CO2升高使所有落叶松当年生幼苗的光补偿点(LCP)下降,说明当年生幼苗对CO2浓度升高的反应更敏感。CO2升高使日本落叶松当年生和1年生幼苗光饱和点(LSP)都升高,反映了其光合作用提高的潜力较大。CO2升高条件下,除1年生兴安落叶松外,其他处理的落叶松最大量子效率(AQYmax)均增加。比较分析表明,在未来大气CO2浓度升高条件下,日本落叶松的生长潜能可能最大,具有较强的生态优势,长白落叶松次之,兴安落叶松最小。

The photosynthetic characteristics of current and one-year-old Larix olgensis Herry.、Larix kaempferi Carr.and Larix gmelini Rupr.needles at elevated CO2 concentration were measured with a Li-6400 portable gas analyzer.The results showed that：elevated CO2 concentration increased the maximum net photosynthetic rate（Pmax）and respiration（Rd）of the three Larix species in different degree,and the Pmax of the current and one-year-old needles of Larix olgensis Herry.increased 91% and 83% than the control needles,respectively,that of Larix kaempferi Carr.increased 71% and 94% than the control needles,respectively,and that of Larix gmelini Rupr.increased 32% and 106% than the control needles,respectively.Elevated CO2 decreased the light compensation point（LCP）of all current needles except the Larix gmelini seedlings,indicating that the current seedlings were more sensitive to the elevated CO2 concentration.Elevated CO2 concentration increased the light saturation point（LSP）of current and one-year-old Larix kaempferi seedlings,showing that the enhanced potential of photosynthetic capacity was stronger.Under the elevated CO2 concentration conditions,the maximum apparent quantum efficiency（AQYmax）of all seedlings was increased except the one-year-old Larix gmelini.We conclude that,under the elevated CO2 concentration conditions,Larix kaempferi has the greatest growth potential and the strongest ecological advantages,Larix olgensis is the second,Larix gmelini is the lastest.