干旱胁迫和不同株高基径条件下的白刺液流速率特征差异

Characteristics of Sap Flow Rate of Nitraria tangutorum Under Drought Stress and Different Plant Height and Basal Diameter

[目的]揭示内蒙古荒漠环境中不同株高基径的白刺液流差异,阐明不同形态白刺对干旱环境的适应情况,为干旱区荒漠绿洲植被恢复的白刺种植提供参考。[方法]在乌兰布和沙漠选择高株高组(HS)和粗基径组(BD)的典型白刺,并模拟防止水分横向流失的隔水处理条件(CG),采用野外定点观测的方法监测和分析白刺生长季液流速率变化情况及其与环境因子的关系。[结果](1)白刺液流速率在月尺度上的大小顺序为8月>7月>6月>9月>5月,隔水组(WS)白刺液流速率较正常组(NW)变化幅度大,液流速率中值分别为1.021 g/h,0.387 g/h;基径大植株矮组(LS)白刺液流速率较基径小植株高组(SH)变化幅度大,液流速率中值分别为0.472 g/h,0.261 g/h。(2)在土壤水分长期匮缺的条件下,液流速率与气温(Ta)、风速(WVEL)呈显著正相关,与光合有效辐射(PAR)呈显著负相关,与空气湿度(RH)相关性不明显,环境因子对液流速率影响程度依次为:PAR>Ta>VPD>WVEL>RH;30—150 cm深度土层土壤含水率对白刺液流速率均呈显著的正相关关系。(3)白刺液流速率与环境因子的回归方程表明,LS组较SH组液流速率受气象因子的影响更大,WS组白刺液流速率仅受30—50 cm土层土壤含水率的影响。[结论]大基径矮植株白刺较小基径高植株的白刺更能适应当地干旱的气候条件,粗矮形态的白刺更适应在缺水环境下生存。

[Objective]The differences in the sap flow of Nitraria tangutorum in different plant height base diameters in the desert environment of Inner Mongolia were revealed,and the adaptation of different forms of Nitraria tangutorum to arid environment was elucidated,and the planting of Nitraria tangutorum in desert oasis vegetation restoration in arid area was provided.[Methods]Nitraria tangutorum of the tall plant height group(HS)and coarse basal diameter group(BD)were selected in Wulanbuhe desert,and water separation treatment(CG)was simulated,insitu observation was used to measure and analyze the change of sap flow rate and its relationship with environmental factors during growing season.[Results](1)The sap flow rate of Nitraria tangutorum was in the order:August>July>June>September>May on the monthly scale,and the sap flow rate of Nitraria tangutorum in water separation treatment(WS)was larger than that in non water tight treatment(NW),the mean values of sap flow rate were 1.021 g/hand 0.387 g/h,respectively.The sap flow rate of Nitraria tangutorum(LS)with large basal diameter was larger than that with small basal diameter and high plant(SH),the mean flow rates were 0.472 g/h and 0.261 g/h,respectively.(2)Under the condition of long-term soil moisture deficiency,the sap flow rate was positively correlated with air temperature(Ta)and wind velocity(WVEL),and negatively correlated with photosynthetic effective radiation(PAR),but not significantly correlated with air humidity(Rh),the influence degree of environmental factors on sap flow rate followed the order:PAR>Ta>VPD>WVEL>Rh,and soil water content in the depth of 30—150 cm had significant positive correlation with sap flow rate of Nitraria tangutorum.(3)The regression equation between the sap flow rate of Nitraria tangutorum and environmental factors showed that the sap flow rate of LS group was more affected by meteorological factors than that of SH group,and the liquid flow rate of WS group was only affected by the soil moisture content of 30—50 cm soil layer.[Conclusion]Dwarf Nitraria tangutorum with large base diameter is more suitable for local arid climatic conditions than high Nitraria tangutorum with smaller base diameter,and Nitraria tangutorum in large base diameter and dwarf form is more suitable for survival in water-scarce environments.