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在臭柏长期室内石砾土栽培条件下,通过培养液中加入PEG以调节溶液渗透势,设置对照区(pF值3.0)、水分胁迫区(pF值2.3)2种处理,并分别从匍匐茎中部人工培养不定根,测定有不定根和无不定根匍匐茎小枝的蒸腾速率、气孔导度及其水势的日变化和叶片水分特性。结果表明:1)在水分胁迫条件下,匍匐茎先端小枝通过降低正午水势提高吸水能力;基部小枝通过控制蒸腾,维持枝条水势防止失水。2)有不定根的匍匐茎通过降低质壁分离时的水势(ψtwlp)和充分吸水时的渗透势(ψssat)提高吸水能力,而且增加细胞弹性率,迅速降低膨压保证失水时能尽快关闭气孔;而无不定根匍匐茎虽然吸水能力较差,但细胞壁柔软,即使蒸腾失水,也能在较长时间内维持膨压,保证生命活动进行。
Under the conditions of long-term indoor stone gravel soil cultivation, two solutions of control (pF = 3.0) and water stress (pF: 2.3) were set up by adding PEG to the solution to control osmolality of the solution. Adventitious roots were cultured artificially, and the transpiration rate, stomatal conductance and water potential of adventitious roots and non-adventitious stoloniferous branches were measured to determine the diurnal variation and leaf water characteristics. The results showed that: 1) Under the condition of water stress, the apex of stolons increased the water absorption capacity by reducing the noon water potential; the basic branchlets maintained the water potential of the branches to prevent water loss by controlling transpiration. 2) Adventitious roots of stolons increase water absorption capacity by reducing the water potential (ψtwlp) at the time of plasmolysis and the osmotic potential (ψssat) during full water absorption, and increase the cell elasticity rate to rapidly reduce turgor to ensure stomatal closure as soon as possible when water loss occurs; Without adventitious root stolons although water absorption capacity is poor, but the cell wall is soft, even if the transpiration dehydration, but also in a long time to maintain turgor pressure, to ensure that the activities of life.