NaHCO_(3)和Na_(2)CO_(3)胁迫对碱茅和披碱草种子萌发、幼苗生长和生理指标的影响

Effects of NaHCO_(3) and Na_(2)CO_(3) stress on seed germination,seedling growth,and physiological indexes of Puccinelia chinampoensis and Elymus dahuricus

盐碱化土壤限制植物的正常生长,明确禾本科草本植物对NaHCO_(3)和Na_(2)CO_(3)胁迫的适应机制对于盐碱土壤的开发利用以及作物的种植具有重要意义。以碱茅和披碱草为材料,用NaHCO_(3)和Na_(2)CO_(3)混合物胁迫处理,测定碱茅和披碱草的种子发芽率、幼苗干重、叶片细胞膜透性、光合气体交换参数、叶绿素荧光参数、叶片超氧化物歧化酶活性和丙二醛含量,以及叶片和根系Na^(+)、K^(+)离子含量。结果显示,胁迫处理降低碱茅和披碱草种子发芽率、幼苗干物质积累、叶片净光合速率和电子传递量子效率,并提高两种植物相对电导率和丙二醛含量。胁迫处理下碱茅叶片质膜的受损程度大于披碱草,叶片光合气体交换参数受影响更大,而披碱草更能维持SOD酶活性,相同混合物浓度处理时其叶片MDA含量低于碱茅。综上,NaHCO_(3)和Na_(2)CO_(3)混合处理抑制碱茅和披碱草的正常生长,但披碱草的抗逆性强于碱茅。本研究通过生理特性分析筛选出潜在的更具耐盐碱材料,能够为盐碱地区土壤的生物修复以及禾本科作物的种植提供理论依据。

Saline-alkali soil restricts the normal growth of plants.Understanding the adaptation mechanism of grasses to NaHCO_(3) and Na_(2)CO_(3) stress is important for the utilization of saline-alkali soil and the cultivation of crops.In this experiment,Puccinelia chinampoensis and Elymus dahuricus were treated with NaHCO_(3) and Na_(2)CO_(3) mixtures.The seed germination rate,seedling dry weight,a series of leaf physiological parameters,including cell membrane permeability,photosynthetic gas exchange parameters,chlorophyll fluorescence parameters,superoxide dismutase activity and malondialdehyde(MDA)content,as well as leaf and root Na^(+),K^(+) ion contents were measured.The results showed that stress treatment reduced the seed germination rate,dry matter accumulation of seedlings,leaf net photosynthetic rate and electron transfer quantum efficiency,and increased the relative conductivity and MDA content of the two plant species.Under stress,the damage of the leaf cell plasma membrane of P.chinampoensis was greater than that of E.dahuricus,and the photosynthetic gas exchange parameters were more affected.E.dahuricus maintained higher SOD enzyme activity and lower MDA content than P.chinampoensis under stress treatments.In conclusion,the mixed treatment of NaHCO_(3) and Na_(2)CO_(3) inhibited the normal growth of P.chinampoensis and E.dahuricus,but E.dahuricus was more resistant than P.chinampoensis.This study provides theoretical basis for soil bioremediation and planting of grasses in saline-alkali areas.