荻幼苗对复合盐碱胁迫的生理响应

Physiological Responses of Miscanthus sacchariflorus Seedlings under Mixed Salt Alkali Stress

该研究以荻（Miscanthus sacchariflorus）幼苗为材料,模拟中国东北大庆盐碱地的低、中、高浓度盐碱土壤环境,考察不同盐碱处理浓度及其不同处理时间（0~25d）对荻幼苗各项生理指标的影响,以界定荻幼苗的复合盐碱耐受范围,为荻类能源植物的耐盐碱性筛选和在园林中的应用提供理论依据。结果表明：（1）随着复合盐碱胁迫时间的延长和胁迫程度加剧,荻幼苗叶绿素含量不断降低,根活力在低、中浓度处理下随时间不断升高,而在高浓度处理时先降低后上升再降低;同时,幼苗相对电导率和MDA含量则不断升高。（2）随着复合盐碱胁迫时间延长,荻幼苗SOD、POD、CAT、APX、GR活性和ASA、GSH含量一般在低浓度处理时缓慢升高,而高浓度处理时则呈先升高后降低的趋势。研究发现,荻幼苗能够通过调节自身保护酶系统活性和抗氧化物积累,清除体内过多活性氧和自由基,保护细胞结构,有效抵御外界低、中浓度的复合盐碱胁迫,但其对高浓度的复合盐碱胁迫基本没有抵抗能力。

Simulating the saline-alkali soil environment of Daqing in northeast of China which include low,middle and high concentration,we studied the effects of different concentrations and processing time（0~25d）on each physiological index of Miscanthus sacchariflorus seedlings which basically defined the complex salt-alkali tolerance range of M.sacchariflorus seedings and provided a theoretical basis for the screen of saline-alkali tolerant plants and applications in landscape of energy plants like M.sacchariflorus in the future.The results showed that：（1）with the increase of mixed saline-alkali stress intensity over time,the chlorophyll content of M.sacchariflorus seedlings was constantly drop.The root activity was rising with the treatments of low concentration and middle concentration over time.While it showed decreased first and then increased and decreased in the end with the treatments of high concentration.At the same time,the relative electrical conductivity and MDA content of M.sacchariflorus seedlings were also rising over time;（2）the SOD,POD,CAT,APX,GR activities,ASA and GSH contents were rising slowly in low concentration,but in the treatment of high concentration these indexes increased at first and then decreased with time passing by.The study found that M.sacchariflorus seedlings could remove excess reactive oxygen and free radicals and protect the cell structure by regulating the activities of the protective enzymes and the ac-cumulation of antioxidants.M.sacchariflorus seedlings could effectively resist saline-alkali stress of middle and low concentrations,while they have no resistance to high concentration.