光合作用对光和二氧化碳响应的观测方法探讨

用便携式光合仪LI-6400观测自然条件下生长的盆栽蚕豆叶片光合作用对光和二氧化碳的响应发现：（1）用未经过光合诱导的叶片观测光合作用对光的响应会得到即使在全太阳光强下光合作用仍然不饱和的假象；（2）利用某些经验方程计算的饱和光强远低于实际观测值；（3）在观测光合作用对CO2的响应过程中，每一次CO2浓度变化都应当伴随一次光合仪的匹配步骤，否则所得结果偏差很大；（4）在不饱和光下观测光合作用对CO2的响应，会导致对叶片光合能力的低估。

Exploring the Observation Methods of Photosynthetic Responses to Light and Carbon Dioxide

Through observing the responses of photosynthesis in leaves of broad bean grown un-der natural conditions to light and CO2 using a por-table photosynthetic analyzer LI-6400,the follow-ing findings were obtained. (1) Observing the re-sponse of photosynthesis to light using a leaf with-out being induced by light might lead to an artifact that photosynthesis was not saturated even under full sunlight (Fig.1). (2) The calculated saturating light intensity of photosynthesis by some empiri-cal equations was much lower than actual value obtained by observing (Fig.2). (3) During obser-vation of photosynthetic response to CO2,each step of changing CO2 concentration should be accom-panied by a match step of the photosynthetic analyzer,otherwise,there will be substantial de-viations in the results obtained (Figs.3,4; Table 1). (4) Observing photosynthetic response to CO2 at non-saturating light might lead to an underestima-tion of leaf photosynthetic capacity (Fig.5; Table 2).