【摘要】 对自然生长的辽东栎林木用 LI-640 0测定其光合作用 ,实验包括以下内容 :在完全接近自然生长的条件下测定辽东栎叶片光合作用的日变化规律 ;控制光合有效辐射强度 ,测定叶片在不同 CO2 浓度下光合作用的变化规律 ;控制温度比对应时间段的温度高 2～ 4℃ ,并控制 CO2 浓度在 3 75～ 70 0 ml· m- 3间变化 ,测定辽东栎光合作用的变化情况。结果如下 :1自然状态下辽东栎光合作用的日变化有两个光合速率峰 ,峰高接近 ,上午的光合速率峰持续时间较下午的长。叶片气孔导度与光合速率间有很强的正相关 ,且对胞内 CO2 浓度和蒸腾速率有较大影响。气孔导度与叶片水压亏缺呈相反的变化趋势 ,而水压亏缺受光合有效辐射、气温的影响较大。 2在控制片温度、光合有效辐射不变的情况下 ,辽东栎的叶片水压亏缺变化幅度很小 ,气孔导度变化主要受 CO2 浓度的调节 ,表现出在目前 CO2 浓度至加倍 CO2 浓度下 ,随浓度增加而增大的趋势 ,与之对应光合速率增大 ,同时光补偿点也有所提高。当 CO2 浓度超过 80 0 ml· m- 3继续上升时 ,气孔导度、光合速率均下降 ,光补偿点继续升高。3对辽东栎叶片进行升温和高 CO2 浓度处理 ,在试验进行时的温度 (2 8～ 3 7℃ )下 ,发现在 3 75～ 70 0 ml· m- 3的 CO2 浓度范围内 ,升温均导致光?更多还原

【Abstract】 For the needs of evaluation of the reflection tendency of Quercus liaotungensis under the depression of greenhouse effect. The comparisons of photosynthesis characteristic in normal and controlled situations have been taken. the main elements as photosynthesis active radiation ( PAR ),CO 2 concentration(CO 2),air temperature( Ta ),leaf temperature( Tl) et al have be Measured and logged by Li 6400 portable photosynthesis system. While the photosynthesis rate ( Pn ), transpiration rate,stomotal conductance ( Cond ), intercellar CO 2 concentration ( Ci ),vapor pressure deficit ( VPD) et al . have been logged as well.Samples are taken every hour to determine the diurnal characters of them.During sunrise and sunset, the intervals are less than one hour. Keep the leaf temperature at about 24 ℃,then set the photosynthesis active radiation and change the CO 2 concentration can get the photosynthesis curve.Another content of the experiment is tracking the nature condition,then keeping all other environment factors unchanged and setting the temperature 2 ℃,4 ℃ higher than nature condition in different CO 2 concentrations to get the influence of temperatures in photosynthesis process. The results show that :(1) the diurnal variation of photosynthesis rate is midday depression pattern,the two peaks have nearly the same height.The peak occurred in morning lasts longer than the one in the afternoon.The stomatal conductance is related to photosynthesis closely, and the two keep same change trend.The Cond also affects the intercellar CO 2 concentration and transpiration rate to some degree.The vapor pressure deficit is attributes to PAR and air temperature. The diurnal variation curves of photosynthesis rate,stomatal conductance and transpiration all are two peak pattern and show similar trend during the same time. (2) When keeping leaf temperature at 24℃, VPD changes very little, so CO 2 concentration is the main factor affecting the stomatal conductance. When CO 2 concentration is change between 300～800ppm, stomatal conductance,photosynthesis rate and light compensation point ( LCP ) keep same trend with CO 2 concentration. With the CO 2 concentration keeping increasing beyond 800 ppm, stomatal conductance and photosynthesis rate will drop while LCP still increases. Under controlling condition, transpiration rate show stronger relation to stomatal conductance than in natural condition. (3) Keeping all other environment factor as nature situation, increasing air temperature by 2 and 4 ℃ and changing CO 2 concentration from 375 to 700ml·m -3 show that photosynthesis rate will drop with the air temperature and rise with CO 2 concentrations at the same time.The main conclusion is: greenhouse effect will promote the photosynthesis process of Quercus liaotungensis .更多还原