摘要
为探究红松不同叶龄针叶沿冠层垂直梯度对光斑的光合响应特性,本研究依托长白山森林生态系统定位站林冠塔吊平台,以优势树种红松为研究对象,选取冠层上、中、下部(平均高度为23.26、16.55、11.15 m)的当年生和一年生针叶,利用Li-6400便携式光合仪模拟光斑出现到消退的动态变化过程(光合有效辐射PAR从50μmol·m^(-2)·s^(-1)荫蔽态阶跃至1200μmol·m^(-2)·s^(-1)光斑态,再降至50μmol·m^(-2)·s^(-1)光斑消退),测定针叶的光合诱导、光合恢复响应特征及气孔动力学过程。结果表明:叶龄与冠层高度显著影响光合生理过程,二者存在交互作用。在光合诱导阶段,冠层下部当年生针叶最大反应速率(RS_(max))最高(18.41 nmol·m^(-2)·s^(-1)),而冠层上部一年生针叶RS_(max)最高(17.39 nmol·m^(-2)·s^(-1));在光合恢复阶段,冠层下部当年生针叶RS_(max)最高(2.93 nmol·m^(-2)·s^(-1)),而冠层上部一年生针叶RS_(max)最高(0.66 nmol·m^(-2)·s^(-1)),表明不同叶龄针叶对光斑的响应在冠层间呈现互补策略。气孔动力学响应存在垂直梯度差异。在气孔打开阶段,冠层上部当年生和一年生针叶的RS_(max)分别比下部加快145.5%和104.4%;在气孔关闭阶段,冠层上部当年生和一年生针叶的RS_(max)分别比下部减慢40.2%和34.5%,表明上层针叶能更有效地利用光斑,这种互补的光斑利用策略有利于最大化阔叶红松林冠层整体的光合碳同化能力。
To investigate the photosynthetic responses of needles with different ages(current-year and annual-year)in Pinus koraiensis to sunflecks along the vertical gradient of canopy,we conducted an experiment at the Changbai Mountain Forest Ecosystem Positioning Station utilizing a canopy tower crane platform.We selected current-year and annual-year needles from the upper(mean height:23.26 m),middle(16.55 m),and lower(11.15 m)layers of the canopy of dominant species P.koraiensis,to simulate photosynthetically active radiation(PAR)abruptly increasing from a shaded state(50μmol·m^(-2)·s^(-1))to a sunfleck state(1200μmol·m^(-2)·s^(-1))and then decreasing back to 50μmol·m^(-2)·s^(-1)by using Li-6400 portable photosynthesis system.We measured the physiological response of needles during photosynthetic induction and photosynthetic recovery,as well as stomatal dynamic process.The results showed that leaf age and canopy height had significant effects on photosynthetic induction.During photosynthetic induction,the highest maximum reaction rate(RS_(max))was recorded in current-year needles at the lower canopy(18.41 nmol·m^(-2)·s^(-1))and in annual-year needles at the upper canopy(17.39 nmol·m^(-2)·s^(-1)).During photosynthetic recovery,current-year needles at the lower canopy showed the highest RS_(max)(2.93 nmol·m^(-2)·s^(-1)),while annual-year needles at the upper canopy exhibited the highest RS_(max)(0.66 nmol·m^(-2)·s^(-1)).This result indicated complementary strategies in sunfleck response between needle ages across canopy layers.There was a significant vertical gradient in stomatal kinetics.In the stomatal opening stage,the RS_(max) for both current-year and annual-year needles was significantly higher at the upper canopy compared to the lower canopy(145.5%faster and 104.4%faster,respectively).During the stomatal closing stage,the RS_(max) was lower for both needle ages at the upper canopy compared to the lower canopy(40.2%slower and 34.5%slower,respectively).These stomatal dynamics indicated that upper-canopy needles utilized sunflecks more effectively.Collectively,the complementary strategies in sunfleck utilization across needle ages and canopy heights would contribute to maximizing the overall photosynthetic carbon assimilation capacity of the broad-leaved Korean pine forest canopy.
作者
赵义蓉
苏宝玲
李亚楠
周莉
于大炮
王庆伟
ZHAO Yirong;SU Baoling;LI Yanan;ZHOU Li;YU Dapao;WANG Qingwei(College of Life Science and Engineering,Shenyang University,Shenyang 110044,China;CAS Key Laboratory of Forest Ecology and Silviculture,Institute of Applied Eco-logy,Chinese Academy of Sciences,Shenyang 110016,China;Changbaishan Xipo National Field Observation and Research Station for Forest Ecosystem,Baishan 134506,Jilin,China)
出处
《应用生态学报》
北大核心
2025年第8期2307-2316,共10页
Chinese Journal of Applied Ecology
基金
国家自然科学基金面上项目(32071553)
国家自然科学基金优秀青年科学基金项目(32122059)
中国科学院“百人计划”项目
辽宁省自然科学基金联合基金项目(1700211020675)资助。
关键词
阔叶红松林
碳汇
冠层高度
叶龄
光合诱导
气孔动力学
broad-leaved Korean pine forest
carbon sink
canopy height
leaf age
photosynthetic induction
stomatal dynamics
