Evidence of Hydropassive Movement in Stomatal Oscillations of Glycyrrhiza inflata under Desert Conditions

Stomatal conductance was found to change from steady-state to a slate of oscillations during daytime when vapour pressure deficit (VPD) increased to a value of 1 kPa in Glycyrrhiza inflata Batalin grown under the conditions of arid desert in north-west China. The injected metabolic inhibitors (NaN3 or carbonyl cyanide-m-chlorophenyl-hydrazone (CCCP)) slightly reduced the stomatal conductance but did not significantly decrease the intensity of stomatal oscillations (amplitude/average). The oscillation intensity was found to he significantly correlated with VPD and root resistance, but not with the respiration rate. There might exist a minimum threshold of VPD (0.8 kPa) and root resistance (1/4 relative value) that induced stomatal oscillations. These results suggested that stomatal oscillations induced by atmospheric drought stress and root resistance were mainly a type of hydropassive movement.

在大气干旱条件下胀果甘草气孔振荡的RLC电路模拟

建立了植物水分输导和蒸腾的电阻(R)、电感(L)、电容(C)电路模型。实验测定出的胀果甘草气孔振荡发生、持续和衰减的阈值与模型分析结果一致。当蒸腾拉力(F)大于输导阻力(R)时气孔开始振荡并使振幅逐渐加大;当F=R时气孔振荡的振幅和频率不变;当0<(R-F)<2(1/2)/(L/C)时气孔振荡开始减弱;当(R-F)>2(1/2)/(L/C)时气孔不会出现振荡。在本实验条件下胀果甘草的R=3.1×10~9MPa·m^(-3)·s,2(1/2)/(L/C)=3.11-3.64×10~5MPa·m^(-3)·s。

胀果甘草气孔振荡实测结果的解析表达及计算机模拟

给出了反映胀果甘草气孔振荡规律的解析表达式，它为Ｊ＝Ａ０＋Ａ１ｃｏｓ（ω＇ｔ＋）＋Ａ２ｅ－ｔＡ３ｃｏｓ（ω＇ｔ＋３）ｃｏｓ（ωｔ＋）．由实测结果确定各待定常数后，计算机模拟作出的图象与实测图极其吻合．