毛乌素沙地臭柏匍匐茎蒸腾速率和水势的日变化

采用LI-1600稳态气孔计和压力室对臭柏匍匐茎的蒸腾速率和水势进行了测定。结果表明,生长在毛乌素沙地沙丘顶部、滩地、人工造林地的来源于同一上级枝的有不定根和无不定根匍匐茎,在午前有不定根匍匐茎的蒸腾速率和气孔导度较无不定根的高,午后则相反,但日平均蒸腾速率和气孔导度没有差异(P<0.05)。无不定根匍匐茎的小枝(叶)水势比有不定根的略高,生长在沙丘顶部的臭柏,这种特征比滩地的明显。位于沙丘顶部臭柏的蒸腾速率、气孔导度和叶水势均低于滩地的,多元线性回归分析表明,臭柏蒸腾速率主要与气温、空气相对湿度、有效光幅射有关(P<0.01)。遭受切断干扰的有不定根匍匐茎,虽然能够维持其生命,但其水分生理特性受到了明显的抑制(P<0.05),干扰1周后,蒸腾速率仅能达到对照的45%。

The Diurnal Change of Transpiration Rate and Water Potential of Sabina Vulgaris Stolon in Mu Us Sandland

The transpiration rate and water potential of Sabina vulgarisstolon is mensurated by using LI-1600 steady stoma meterand pressure container.The results are as following: Stolon from the superior stolon,withorwithout adventitious roots,oron top of sand dune,lowland orartifical forest in Mu us sandland,before noon,the transpiration rate and stomatal conductance with adventitious roots are higher than that without adventitious roots,but they are contrary in afternoon.The diurnal average transpiration rate and stomatal conductance are same(P<0.05).The leaf water potential of without adventitious roots is higher than that with adventitious roots.The characteristics of leaf water potential growing on top of sand dune is more obvious than that of at lowland.The transpiration rate,stomatal conductance and leaf water potential of Sabina vulgaris being on top of sand dune are all lower than that onlowland.The transpiration rate of Sabina vulgaris is related to temperature,relative humidity and effective radiation by the multianalysis linear regression(P<0.01).It can be defined as light-temperature-humidity type.After the stolon with adventitiousroots issevered,it can maintain life,but water physiological characteristics are restrained obviously.After a week of severing,the transpiration rate is only 45% of that of control(P<0.05).