镧对NaCl胁迫下黑麦草幼苗根系生理特性的影响

Effects of Lanthanum on Physiological Characteristics in Ryegrass Seedling Roots under NaCl Stress

采用水培法研究NaCl胁迫下黑麦草幼苗根系活性氧代谢和渗透调节物质含量的变化及La(NO3)3对其变化的影响,结果表明:随着NaCl浓度的增加,黑麦草幼苗根中丙二醛(MDA)、超氧阴离子(O2.-)和过氧化氢(H2O2)含量增大,过氧化氢酶(CAT)、过氧化物酶(POD)和抗坏血酸过氧化物酶(APX)活性及抗坏血酸(ASA)、谷胱甘肽(GSH)、可溶性蛋白质和脯氨酸含量先升后降,超氧化物歧化酶(SOD)活性和可溶性糖、Na+含量不断提高,K+含量和质膜H+-ATP酶活性持续下降。添加20 mg/L La(NO3)3处理提高了NaCl胁迫下幼苗根中SOD、CAT和H+-ATP酶的活性及ASA、GSH、可溶性蛋白质、可溶性糖和K+的含量,降低了APX活性及O2.-、H2O2、MDA、脯氨酸和Na+的含量,POD活性在低浓度NaCl(50 mmol/L、100 mmol/L)时下降,高浓度(200 mmol/L、300 mmol/L)时升高。表明适宜浓度的La(NO3)3可通过提高盐胁迫下根系清除活性氧和渗透调节的能力,降低植株的膜脂过氧化,从而增强黑麦草的耐盐性。

The changes in the metabolism of active oxygen and the contents of osmoticum from root tips of perennial ryegrass（Lolium perenne L.） seedling under NaCl stress were investigated by a hydro culture method in the presence or absence of La（NO3）3.The results indicated that under NaCl stress,the contents of malondialdehyde（MDA）,O2.-and H2O2 in ryegrass roots increased gradually with increasing NaCl concentration,the activities of catelase（CAT）,guaiacol peroxidase（POD）,ascorbate peroxidase（APX） and the contents of ascorbic acid（ASA）,reduced glutathione（GSH）,soluble protein and proline increased and then decreased,superoxide dismutase（SOD） activity and the contents of soluble sugar,Na＋ increased,while K＋ content and plasma membrane H＋-ATPase activity decreased unceasingly;compared with the NaCl stress treatment the addition of exogenous 20mg/L La（NO3）3 increased the activities of SOD,CAT and plasma membrane H＋-ATPase and the contents of ASA,GSH,soluble protein,soluble sugar and K＋,but decreased the APX activity and the contents of O2.-,H2O2,MDA,proline and Na＋ in the root tips of ryegrass seedling;POD activity decreased at low concentration（50 and 100mmol/L NaCl） while increased at high concentration（200mmol/L,300mmol/L）.These findings suggested that appropriate concentration of La（NO3）3 could decrease the lipid peroxidation caused by salt in ryegrass roots via increasing the ability of scavenging reactive oxygen and osmotic adjustment,thus improves salt resistance of the ryegrass plants.