干旱胁迫对喀斯特地区适生灌木种子萌发的影响

摘要

为岩溶石漠化地区的生态恢复与重建提供依据，以不同浓度 PEG-6000溶液（0％，5％，10％，20％）模拟干旱胁迫，研究胡枝子（Lespedeza bicolor Turcz）、截叶铁扫帚（Lespedeza cuneata G．Don）、白刺花（Sophora davidii Skeels）和木豆（Cajanus cajan Millsp）种子发芽率及萌发期的生理生化指标对干旱胁迫的响应，探讨喀斯特地区灌木种子萌发对干旱环境的适应机制。结果表明：干旱胁迫下4种灌木种子发芽率均显著降低（p＜0．05）。随着 PEG-6000浓度的增加，4种灌木种子萌发期的 SOD 活性呈现不同的变化趋势，胡枝子和截叶铁扫帚种子萌发期 SOD 活性呈先上升后降低的趋势（p ＜0．05），白刺花和木豆种子SOD 活性逐渐上升；4种灌木种子萌发期的 POD 活性变化趋势相同，均呈下降趋势，CAT 活性与 GSH 含量呈先上升后降低的趋势；胡枝子、铁扫帚与木豆种子萌发期 SP 含量呈先显著上升（p ＜0．05）后降低的趋势，白刺花却逐渐显著上升（p＜0．05）。白刺花对干旱胁迫适应能力最强，其次是铁扫帚和胡枝子。%To provide a reference for ecological restoration and reestablishment in karst regions,the seed germination, physiological and biochemical indexes of Lespedeza bicolor , Lespedeza cuneata , Sophora davidii and Cajanus cajan were investigated under different concentrations of PEG-6000 solution (0,5%,10% and 20%)in germinating period.Adaptive mechanism of shrub seed germination in arid environment was discussed either.Results: Seed germination of four species of shrubs significantly decreased under drought stress(p <0.05).With increasing PEG concentration,the SOD activity showed different trends between different materials,the L.bicolor and L.cuneata generally first increased and then decreased(p<0.05),but the SOD activity of S.davidii and C.cajan increased gradually;POD activity of four species of shrubs showed the same downward trend;The activity of CAT and GSH content first increased and then decreased;The soluble protein content of L.bicolor,L.cuneata and C.cajan also first increased significantly (p < 0.05 ) and then decreased; But the S.davidii increased significantly (p<0.05).In conclusion from the present study,S.davidii had the strongest ability to adapt to the drought stress,followed by L.cuneata and L.bicolor.