水分胁迫下榆科3种幼苗生理生化指标的变化

Variation of Physiological and Biochemical Indexes in Seedlings of Three Ulmaceae Species Under Water Stress

为了解喀斯特地区榆科树种对水分胁迫的反应和适应,比较其抗旱性,采用人工模拟水分胁迫的方法,研究了青檀、朴树、榔榆幼苗部分生理生化指标的变化。结果表明:水分胁迫条件下,榆科3种幼苗抗旱生理生化指标的变化趋势一致。随胁迫程度加剧,水分饱和亏缺增大,水势降低,质膜透性增大,膜伤害程度增加,渗透调节物质脯氨酸含量增加,膜脂过氧化产物MDA含量表现出“增加→下降→再增加”的变化过程,但各指标的变化程度因树种不同而异。用坐标综合评定法对3个树种幼苗抗旱能力的初步评价结果表明,榔榆幼苗的综合抗旱能力最强,青檀次之,朴树较差。

For knowing the reaction and adaptation of Ulmaceae species in karst areas to water stress and comparing their drought-resistant ability,the variation of physiological and biochemical indexes in seedlings of Pteroceltis tatarinowii,Celtis sinensis and Ulmus parvifolia were studied by experiments of simulating water stress.The results showed the tendency of physiological and biochemical indexes in three seedlings under water stress were similar.The relative water deficit(RWD),plasma membrance permeability,proline content and injured degree of membrance raised as increasing of water stress level,and the xylem water potential(Ψ W) decreased.The content of MDA raised first,declined then,and increased continually later,but the variation level of indexes in three seedlings were different.By coordinate composite evaluation,the results indicated that the drought-resistance ability of Ulmus parvifolia seedlings were first,the Pteroceltis tatarinowii seedlings were second,and the Celtis sinensis seedlings were inferior.