摘要
用Li Cor6400光合测定系统测定自然生长白栎Quercusfabri的光合速率、蒸腾速率和气孔导度对二氧化碳(CO2)浓度增加和温度升高的响应。结果表明:短期内CO2浓度增加,白栎的净光合速率增大。CO2浓度为290～450μmol·mol-1时,白栎的光补偿点、饱和点和最大净光合速率(CO2)分别为90～100μmol·m-2·s-1,1500～1700μmol·m-2·s-1和5 5～8 2μmol·m-2·s-1。CO2浓度倍增到700μmol·mol-1时,光补偿点和饱和点均有所降低,分别为10μmol·m-2·s-1和1300μmol·m-2·s-1,最大净光合速率增大,为10 6μmol·m-2·s-1。白栎光合作用在春季适宜温度为24℃,相应的光饱和点和最大净光合速率分别为800μmol·m-2·s-1和9 9μmol·m-2·s-1。夏季为28℃,光饱和点和最大净光合速率分别为1700μmol·m-2·s-1和12 8μmol·m-2·s-1。24℃和28℃的CO2曲线变化趋势相似。温度上升到32℃以后,CO2补偿点、饱和点和净光合速率下降。32℃,36℃和40℃的CO2曲线变化趋势相似。温度变化幅度较大时,与CO2浓度相互作用效应明显。蒸腾速率与叶片的气孔导度表现出相同的变化规律,随光合有效辐射增加而增大,CO2浓度的增加而降低,在低CO2浓度时受光照强度的影响大于高CO2浓度。温度是影响蒸腾速率的主要因子。春季白栎的蒸腾速率与光?
Li-Cor 6400 Photosynthesis Measure System was used to measure the responses of photosynthetic rate,transpiration rate and stomatal conductance of Quercus fabri to increase in CO_2 concentration and temperature.The findings showed that net photosynthetic rate of Quercus fabri increased when the CO_2 concentration was increased in a very short time.When CO_2 concentration was 290-450 μmol·mol^(-1),the light compensation point(P_(LC)),light saturation point(P_(LS)),and maximun net photosynthetic rate (A_(max))were 90-100,1 500-1 700 and 5.5-8.2 μmol·m^(-2)·s^(-1),respectively.When CO_2 was increased to 700 μmol·mol^(-1),P_(LC) and P_(LS) decreased to 10 μmol·m^(-2)·s^(-1) and 1 300 μmol·m^(-2)·s^(-1),but A_(max) increased to 10.6 μmol·m^(-2)·s^(-1).The optimum temperature for the photosynthesis of Quercus fabri in spring was 24 ℃ and the corresponding P_(LS) and A_(max) were 800 μmol·m^(-2)·s^(-1) and 9.9 μmol·m^(-2)·s^(-1) respectively.The optimum temperature in summer was 28 ℃ and the corresponding P_(LS) and A_(max) were 1 700 μmol·m^(-2)·s^(-1) and 12.8 μmol·m^(-2)·s^(-1).The change of CO_2 curve at 24 ℃ was similar to that at 28 ℃.When the temperature was increased to 32 ℃,the compensatio point,saturation point and net photosynthetic rate decreased.The changes of CO_2 curve at 32 ℃,36 ℃ an 40 ℃ were similar.When the temperature was changed in a wide range,the interaction between it and CO_2 concentration was significant.Transpiration rate and stomatal conductance of leaves showed the same changing rules.They increased with the increase in the effective photosynthetic radiation and decreased with the increase in CO_2 concentration.The effect of light intensity on transpiration rate and stomatal conductance at low CO_2 concentration were greater than those at high concentration.Temperature was the main factor effecting the transpiration rate.The transpiration rate of Quercus fabri in spring was closely related to the stomata regulated by photosynthesis.In summer,however,the transpiration response to temperature greatly reflected the energy balance.Temperature and CO_2 interacted with each other.At the temperature of 24 ℃,the range of transpiration rate and stomatal conductance responded to CO_2 concentration was rather small.At 28 ℃,transpiration rate and stomatal conductance decreased with the increase in CO_2 concentration.At 32 ℃,36 ℃ and 40℃,the responses of transpiration rate and stomatal conductance took on shapes of parabolas.
出处
《浙江林学院学报》
CSCD
北大核心
2004年第3期247-253,共7页
Journal of Zhejiang Forestry College
基金
国家自然科学基金重大资助项目(39899370)
国家林业局重点科研项目(2001 07)
湖南省自然科学基金资助项目(00JJY2024)
关键词
白栎
净光合速率
蒸腾速率
气孔导度
CO2浓度
温度
Quercus fabri
net photosynthetic rate
transpiration rate
stomatal conductance
CO_2 concentration
temperature
