干旱胁迫对紫锥菊幼苗生长及生理指标的影响

Effects of Drought Stress on Growth and Physiological Indicators of Echinacea purpurea Seedlings

为探究干旱胁迫对紫锥菊幼苗生长及生理指标的影响,分别采用5%、10%、15%聚乙二醇(PEG6000)模拟干旱胁迫处理紫锥菊幼苗,研究不同浓度PEG模拟干旱胁迫对紫锥菊生物量、叶绿素含量及叶片和根系主要渗透调节物质脯氨酸、可溶性蛋白和可溶性糖含量积累的影响。随着干旱胁迫时间的延长、干旱程度的加重,紫锥菊幼苗长势和干鲜重呈下降趋势;紫锥菊幼苗叶片及根系的脯氨酸、可溶性蛋白呈上升趋势。而胁迫后6 d,在PEG浓度达到15%时,紫锥菊幼苗叶片的脯氨酸、幼苗叶片及根系可溶性蛋白均开始下降;可溶性糖随着干旱胁迫时间的延长和程度的加重呈上升趋势;叶绿素含量先保持正常合成,当PEG浓度达到15%时呈上升趋势。紫锥菊幼苗对轻度和中度干旱胁迫具有较强耐受性,可利用形态变化、物质代谢、生理调节等多种机制来适应干旱胁迫,而对长时间、高浓度的胁迫耐受性较差,蛋白质分解加速,细胞受损严重,生长受到明显抑制。

The paper aims to investigate the effects of drought stress on the growth and physiological indexes of Echinacea purpurea seedlings.The seedlings were treated with 5%,10%and 15%polyethylene glycol(PEG 6000)simulated drought stress,respectively,to study the effects of simulated drought stress with different concentrations of PEG on biomass,chlorophyll content,and the accumulation of proline,soluble protein and soluble sugar in leaves and roots of E.purpurea.With the extension of drought stress time and the severity of drought,the growth and dry and fresh weight of E.purpurea seedlings showed a decreasing trend.The proline and soluble protein in leaves and roots of E.purpurea seedlings showed an increasing trend.On the 6th day after stress,when the PEG concentration reached 15%,the proline,soluble protein in leaves and roots of E.purpurea seedlings began to decrease.The soluble sugar increased with the duration and severity of drought stress.Chlorophyll content maintained normal synthesis at first,and showed an upward trend when PEG concentration reached 15%.E.purpurea seedlings have strong tolerance to mild and moderate drought stress,and can adapt to drought stress by various mechanisms such as morphological change,material metabolism,physiological regulation,etc.,but the tolerance to long-term and high concentration stress is poor,protein decomposition is accelerated,cell damage is serious,and growth is significantly inhibited.