Rook D A, Corson Marilyn J
New Zealand Forest Service, Forest Research Institute, Private Bag, Rotorua, New Zealand.
Oecologia. 1978 Jan;36(3):371-382. doi: 10.1007/BF00348063.
Carbon dioxide exchange rates were recorded for different ages and positions of foliage and parts of the main stem of a 7-m tall Pinus radiata D. Don tree growing in a large, artificially lit, controlled-environment room. Irradiance levels were varied from dark to approximately full sunlight, and air temperatures from 10° to 35°C in 5°C steps. Leaf temperatures within the cuvettes used for CO exchange measurements, however, were up to 5°C higher than the room air temperature set but this varied with position in the tree crown, the shaded lower crown being at approximately room temperature. A balance sheet was prepared to show the photosynthetic gains and respiratory losses of different parts of the crown over 24 h at each air temperature and at irradiances of 400, 270, and 135 W m during the 8-h photosynthetic period. The greatest daily photosynthetic gain was at 10° C, although this temperature is considered sub-optimal for growth. At temperatures greater than 25° C, even at the greatest irradiance level for 8 h, total respiration was greater than photosynthesis.
在一个大型的、人工照明的可控环境室内，对一棵7米高的辐射松（Pinus radiata D. Don）树的不同年龄、叶片位置以及主茎部分的二氧化碳交换率进行了记录。光照强度从黑暗变化到接近全日照，气温以5°C为步长从10°C变化到35°C。然而，用于二氧化碳交换测量的比色皿内的叶片温度比设定的室内空气温度高5°C，但这随树冠位置而变化，树冠下部遮荫处的温度约为室温。编制了一份资产负债表，以显示在每个气温下以及在8小时光合作用期间400、270和135 W m的光照强度下，树冠不同部分在24小时内的光合增益和呼吸损失。最大的每日光合增益出现在10°C时，尽管这个温度被认为对生长并非最佳。在高于25°C的温度下，即使在8小时的最大光照强度下，总呼吸作用也大于光合作用。
