论文部分内容阅读
以塔里木盆地珍稀渐危种灰胡杨(Populus pruinosa Schrenk)为材料,研究其蒸腾速率(Tr)、气孔导度(Gs)、水汽压差(VPD)日变化及互动关系,以期揭示灰胡杨适应干旱荒漠环境的蒸腾耗水调控机理。结果表明,生长季灰胡杨Tr、Gs和VPD日变化均呈单峰曲线,总体随时间进程呈下降趋势;Tr、VPD峰值均滞后于Gs,这是上午时段Tr对VPD的响应阈值明显高于Gs对VPD的响应阈值所致。灰胡杨Tr与Gs、VPD及上午Gs与VPD均呈二次曲线关系,VPD对Tr、Gs均具双重作用,形成机制在于低VPD下Gs随VPD上升而增大,促进Tr升高;高VPD下Gs逐渐下降,引起Tr降低。数理统计分析表明,Gs是调控灰胡杨Tr的主导因素,而VPD通过Gs间接影响Tr。不同时段Tr的气孔调节机制不同,上午气孔调节为前馈式反应,下午为反馈式反应。综上所述,荒漠区灰胡杨Tr对Gs的响应敏感度高于对VPD,气孔调节是维持水分平衡的重要机制;VPD协同Gs来控制灰胡杨Tr,高VPD下引起叶片气孔关闭以降低蒸腾,维持树体水分平衡达到在干旱荒漠环境下生存的目的。
Populus pruinosa Schrenk, a rare and endangered species in the Tarim Basin, was used to study the diurnal variations and interactions of transpiration rate (Tr), stomatal conductance (Gs) and water vapor pressure difference (VPD) Regulation Mechanism of Transpiration and Water Consumption in Desert Environment. The results showed that the diurnal variation of Tr, Gs and VPD of Populus euphratica showed a single peak curve during the growing season, and the overall trend was declining with the progress of time. The peak values of Tr and VPD lagged to Gs, which was the response threshold of Tr to VPD in morning Gs response to VPD threshold. Trichoderma viride Tr and Gs, VPD and morning Gs and VPD showed a quadratic curve, VPD Tr and Gs have a dual role, the formation mechanism is that at low VPD Gs increases with increasing VPD, Tr increased; high VPD Under Gs gradually decreased, causing Tr decreased. Mathematical statistical analysis showed that Gs was the dominant factor controlling Populus trichocarpa and VPD indirectly affected Tr through Gs. The stomatal adjustment mechanism of Tr in different periods was different, the stomatal adjustment in the morning was a feedforward reaction, and the afternoon was a feedback reaction. In conclusion, the response of Trichoderma viride to Gs in the desert is higher than that of VPD, and stomatal adjustment is an important mechanism to maintain the water balance. VPD cooperates with Gs to control the Trichoderma viride Tr, which leads to the stomatal closure in high VPD to reduce transpiration , To maintain the balance of tree water to achieve the goal of survival in arid desert environment.