外源亚精胺对盐胁迫下甜高粱(Sorghum bicolor)幼苗的影响

Effects of Exogenous Spermidine on Sorghum bicolor Seedlings under Salt Stress

为探究外源亚精胺(spermidine,Spd)对盐胁迫下甜高粱幼苗生长及生理生化的影响,以‘辽甜1号’甜高粱为试验材料,采用不同浓度(0.5 mmol/L,1.0 mmol/L,1.5 mmol/L)的Spd喷施处理165 mmol/L NaCl胁迫下的甜高粱幼苗,测定处理7 d和15 d后甜高粱幼苗的叶绿素、可溶性糖、可溶性蛋白、脯氨酸(Pro)、丙二醛(MDA)含量和净光合速率(Net photosynthetic rate,Pn)、气孔导度(stomatal conductance,Gs)、胞间CO2浓度(intercellular CO2 concentration,Ci)、蒸腾速率(transpiration rate,Tr)以及超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)、过氧化氢酶(catalase,CAT)和抗坏血酸过氧化物酶(ascorbate peroxidase,APX)活性等生理生化指标,测定处理15 d后甜高粱幼苗的株高、鲜重、干重及幼苗相对含水量。结果表明,盐胁迫显著抑制了甜高粱幼苗的生长及生理生化指标,喷施不同浓度Spd可提高盐胁迫下甜高粱幼苗叶片叶绿素含量、Pn、Gs、Tr,降低Ci,提高可溶性糖、可溶性蛋白和Pro含量,降低MDA含量,提高SOD、POD、CAT和APX活性。说明在盐胁迫下外源喷施Spd能够增强甜高粱幼苗的光合作用,促进幼苗生长,同时增加渗透调节物质含量,提高抗氧化物酶活性以稳定细胞内环境,从而增强甜高粱幼苗的耐盐性,其中1.0 mmol/L的Spd处理效果最佳。本研究为利用外源Spd缓解植物盐胁迫伤害提供科学依据,为提高甜高粱幼苗的耐盐性提供一种新的手段。

In order to investigate the effects of exogenous spermidine(Spd)on the growth,physiological and biochemical characteristics of sweet sorghum seedlings under salt stress,the'Liaotian 1'sweet sorghum was used as the experimental material,and Spd with different concentrations(0.5 mmol/L,1.0 mmol/L,1.5 mmol/L)was used.The sorghum seedlings under 165 mmol/L NaCl stress were treated.The physiological and biochemical indexes such as chlorophyll,soluble sugar,soluble protein,proline(Pro),malondialdehyde(MDA)content,net photosynthetic rate Net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO2 concentration(Ci),transpiration rate(Tr),and superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),and ascorbate peroxidase(APX)of sweet sorghum seedlings were measured after 7~15 d treatment.The plant height,fresh weight,dry weight and relative water content of seedlings of sweet sorghum seedlings were determined after 15 days.The results showed that salt stress significantly inhibited the growth and physiological and biochemical indexes of sweet sorghum seedlings.Spraying different concentrations of Spd could increase the chlorophyll content,Pn,Gs,Tr,decrease Ci,and increase soluble sugar and soluble protein of sweet sorghum seedlings under salt stress.And Pro content,reduce MDA content,increase SOD,POD,CAT and APX activity.Under salt stress,exogenous Spd can enhance the photosynthesis of sweet sorghum seedlings,promote seedling growth,increase the content of osmotic adjustment substances,increase the activity of antioxidant enzymes to stabilize the intracellular environment,and enhance the salt tolerance of sweet sorghum seedlings.Among them,1.0 mmol/L Spd has the best treatment effect.This study provides a scientific basis for the use of exogenous Spd to alleviate salt damage in plants,and provides a new means for improving the salt tolerance of sweet sorghum seedlings.