论文部分内容阅读
用配有Ｌｉ－６１０露点发生器的Ｌｉ－ｃｏｒ６２００在温室中测定了４个杨树无性系叶水平上的气孔导度（Ｃｓ）和净光合速率（Ｐｎ）．在３个相对湿度（ＲＨ）水平（７０％，５０％和３０％）控制下，不同温度（２５℃，３０℃和３５℃）条件下，杨树无性系的Ｐｎ、Ｃｓ、蒸腾速率（Ｅ）和胞间ＣＯ２浓度（Ｃｉ）表现出显著差异（Ｐ＜０．０００１）．随着空气湿度的减小，Ｅ、Ｃｓ、Ｃｉ明显下降．结果表明：ＲＨ低时，而不是ＶＰＤ高时，气孔关闭在调节蒸腾速率和胞间ＣＯ２浓度中起更大作用．另外，还选用了净光合速率－光照模型和Ｃｓ－Ｐｎ复合模型模拟了不同光照、温度和相对湿度条件下Ｐｎ和Ｃｓ间的关系．尽管无性系、温度和湿度间存在差异，但在模拟Ｐｎ对光照的关系上净光合速率－光照模型最合适．关于Ｃｓ－Ｐｎ模型，检验了Ｌｅｕｎｉｎｇ模型，建立了新的Ｃｓ－Ｐｎ模型：Ｃｓ＝Ｃｓ０＋ａ０Ｐｎ／［（ＣＯ２－Γ）（１＋ｆ（Ｔ）（１－ＲＨ／１００）／Ｄ０）］．基于它们之间的关系，式中加入了反映温度和ＲＨ的变量，代替了ＶＰＤ变量．与田间数据模拟结果相比较，新模型和Ｌｅｕｎｉｎｇ模型一样适合．并且，为了预测气孔和气体交换的行为，可以用净光合速率－光照模型修正Ｃｓ－Ｐ?
Stomatal conductance (Cs) and net photosynthetic rate (Pn) of four poplar clones at leaf level were measured in a greenhouse using Li-cor6200 with a Li-610 dew point generator. Under the control of three relative humidity (RH) levels (70%, 50% and 30%), the Pn, Cs and transpiration rate of poplar clones at different temperatures (25 ℃, 30 ℃ and 35 ℃) ) And intercellular CO2 concentration (Ci) showed significant differences (P <0.0001). With the decrease of air humidity, E, Cs, Ci obviously decreased. The results show that stomatal closure plays a greater role in regulating transpiration rate and intercellular CO2 concentration at low RH, but not at high VPD. In addition, the net photosynthesis rate - light model and Cs-Pn composite model were chosen to simulate the relationship between Pn and Cs under different light, temperature and relative humidity. Despite clones, there is a difference between temperature and humidity, but the net photosynthetic rate-light model is most suitable in simulating the relationship of Pn to light. For the Cs-Pn model, the Leuning model was tested and a new Cs-Pn model was established: Cs = Cs0 + a0Pn / [(CO2-Γ) (1 + f (T) (1-RH / 100) / D0)]. Based on the relationship between them, a variable reflecting temperature and RH is added instead of a VPD variable. Compared with the field data simulation results, the new model is just as suitable as the Leuning model. And, in order to predict the behavior of stomatal and gas exchange, net photosynthetic rate - light model can be used to correct Cs-P?