南林‘895’杂交杨组培苗对NaCl胁迫的生理响应

Physiological response of Populus delotides × P.euramericana cv.’Nanlin895’ tissue culture seedlings to NaCl stress

以南林‘895’杂交杨(Populus delotides×P.euramericana cv.‘Nanlin895’)组培苗为试验材料,采用CK、25、50、75和100 mmol·L-1 5种盐处理,研究盐胁迫对于‘895’杨叶片生理特性的影响。结果表明:(1)25 mmol·L-1盐处理可以促进‘895’杨的生长,100 mmol·L-1盐处理抑制了‘895’杨的生长。(2)盐处理增加了过氧化氢(H2O2)与丙二醛(MDA)含量,在100 mmol·L-1时处理20 d时最为显著。(3)随着盐浓度的升高,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物(APX)呈先增加后下降的趋势,APX的峰值出现在25 mmol·L-1盐处理时,SOD、POD及CAT的峰值出现在50 mmol·L-1盐处理时。在100 mmol·L-1盐处理时,SOD、POD、CAT和APX活性显著低于对照。(4)随着盐浓度的升高,谷胱甘肽还原酶(GR)活性、还原型抗坏血酸(As A)含量呈增加的趋势,100 mmol·L-1盐处理时,GR活性、AsA含量显著高于对照。谷胱甘肽(GSH)含量在1 d与10 d处理时随着盐浓度的上升而增加,20 d处理时,GSH含量在100 mmol·L-1盐处理较75 mmol·L-1盐处理微微下降。(5)根长、茎长和MDA、H2O2、GSH和AsA呈负相关关系;MDA、H2O2与SOD、CAT、APX呈负相关关系,与POD、GR呈正相关关系;SOD、CAT、APX3种酶互为正相关关系,POD与GR、SOD、CAT呈正相关关系。由此可见,低盐浓度(25 mmol·L-1)处理刺激了‘895’杨的生长,其通过提升抗氧化酶活性与抗氧化物质含量来维持活性氧平衡,避免受到毒害;高盐浓度(100 mmol·L-1)处理抑制了抗氧化酶与非酶抗氧化物质的作用,‘895’杂交杨受到了伤害;APX是‘895’杂交杨叶片内抵御膜脂过氧化最为关键的酶。

The antioxidant of Populus ’Nanlin895’ seedlings were studied under salt stress of 0,25,50,75 and 100 mmol·L-1,respectively.The results were as follows:(1)Salt treatment at the concentration of 25 mmol·L-1 promoted the growth of ’Nanlin895’ poplar,while which inhibited its growth at 100 mmol·L-1.(2)The contents of H2O2 and MDA increased under the salt treatment,which were most significant when treated with 100 mmol·L-1 salt for 20days.(3)With the increase of salt concentration,the peak value of APX appeared under 25 mmol·L-1 salt treatment,while the peak values of SOD,POD and CAT appeared under 50 mmol·L-1 salt treatment.The activities of these enzymes with 100 mmol·L-1 salt treatment were significantly lower than those in the control.(4)With the increase of salt concentration,the activity of GR and the content of AsA increased,which were significantly higher under 100mmol·L-1 salt treatment than those in the control.The content of GSH increased with the increase of salt concentration on the 1st and 10th day of the treatment,and it decreased slightly on the 20th day under 100 mmol·L-1 salt treatment compared with 75 mmol·L-1 salt treatment.(5)The root length,stem length and MDA,H2O2,GSH,AsA were negatively correlated;MDA and H2O2 were negatively correlated with SOD,CAT and APX;SOD,CAT and APX were positively correlated with each other.It was concluded that salt treatment at low concentration(25mmol·L-1)stimulated the growth of poplar ’Nanlin 895’;APX was the key enzyme to defense membrane lipid peroxidation in leaves of ’Nanlin895’;salt treatment at high concentration(100 mmol·L-1) inhibited the effects of antioxidant enzymes,antioxidant substances and damaged the cells.