呼伦贝尔典型草原四种优势植物水势日变化规律研究

Research of Diurnal Variation of Water Potential of Four Dominant Plants in Hulunbeier Typical Steppe

以呼伦贝尔典型草原区的四种优势植物委陵菜(Potentilla aiscolor Bunge)、草地麻花头(Serratula cen-tauroides L.)、糙隐子草[Cleistogenes squarrosa(Trin.)Keng]以及寸草苔(Carex duriuscula C.A.Mey.)为研究对象,在自然条件下测定了植物叶片、根系、土壤水势的日变化。结果表明:在同一土层中各植物根系水势均表现出明显的日变化,但种间水分竞争能力不同;随土壤深度增加植物根系水势波动减小,土壤水分状况趋于稳定,0～5cm土层植物根系水势波动范围是-0.3～-4.75Mpa,5～10cm土层深度植物根系水势波动范围是-1.45～-4.26Mpa;四种植物的叶片水势呈大致相同的整体下降并在某些时间段有所回升的日变化趋势;土壤水势日变化趋势与对应植物根系水势变化趋势相反,根系水势和叶片水势变化趋势基本一致,三者两两之间不存在必然联系。

Diurnal variation of water potential of four plants（Potentilla aiscolor Bunge.,Serratula centauroides Linn.,Carex duriuscula C.A.Mey.and Cleistogenes squarrosa（Trin.） Keng）in Huluneier typical steppe was studied in local natural conditions.The results showed that the root water potentials of the four plants were different in the same layer,though the diurnal variations of the four plants were all conspicuous.With increasing of soil depth,the amplitude range of root water potential was decreased,and soil water content tends to be stable,the variation range of water potential was-0.3 to-4.75 Mpa in 0～5cm soil layer,but-1.45 to-4.26 Mpa in 5～10cm soil layer.The variation trend of water potential of leaves of the four plants was similar.Soil water potential was opposite to the root water potential,while the variation trend of leaf water potential was same with root water potential,there was not certain relationship among them.