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使用热扩散探针法(TDP)监测黄土丘陵区2015年7—9月人工林中油松和沙棘树干液流密度(Js)的动态变化,并通过植物的水分利用生理特征判断2个树种的水分利用类型.结果表明:油松和沙棘的Js在降水前后均表现为单峰型日变化特征,油松生长旺盛期的Js(12.62 m L·m~(-2)·s~(-1))显著高于沙棘(2.60 m L·m~(-2)·s~(-1)).2个树种Js与光合有效辐射、水蒸汽压差、土壤体积含水量(SWC)呈显著正相关.8月和9月降水前后,2个树种的Js都主要受气象因素影响.9月降水导致SWC对沙棘Js的解释量增加4.2%,而8月和9月的降水导致SWC对油松Js的解释量均降低了0.3%.油松中午叶片水势显著高于沙棘且变异系数(7.3%)低于沙棘(11.7%),而沙棘具有较高的叶片气孔导度,因此可以判断出油松属于恒水型植物,沙棘属于变水型植物.
The dynamic changes of stem sap flow density (Js) of Pinus tabulaeformis and Hippophae rhamnoides plantation from July to September in 2015 in the loess hilly region were monitored by thermal diffusive probe (TDP), and the water content The results showed that Js of Pinus tabulaeformis and Seabuckthorn showed single peaked diurnal variation before and after precipitation, and Js (12.62 m L · m -2 · s -1) ) Was significantly higher than that of seabuckthorn (2.60 m L · m -2 · s -1) .The Js of the two tree species had a significant positive correlation with photosynthetically active radiation, water vapor pressure difference and soil water content (SWC) The Js of the two tree species were mainly influenced by meteorological factors before and after precipitation in August and September, September precipitation led SWC to interpret Js of sea buckthorn 4.2%, while precipitation in August and September caused SWC (0.3%) was lower than that of seabuckthorn (11.7%), while the seabuckthorn had higher leaf stomatal conductance, so it could be concluded that Pinus tabulaeformis Belongs to constant water plants, sea buckthorn belong to the water plant.