盐胁迫对2种冷季型草坪草幼苗生长和生理特性的影响

Effects of NaCl stress on seedling growth andphysiological responses of Achnatheruminebrians and Festuca arundinacea

摘要:

探讨单盐NaCl对带菌(E+)醉马草(Achnatherum inebrians)、不带菌(E-)醉马草、高羊茅品种侠客岛(Festuca arundinacea cv.Island)和猎狗6号(F.arundinacea cv.Hound 6)幼苗生长及生理特性的影响,明确单盐NaCl对幼苗苗长、根长、根冠比、抗氧化酶、渗透调节物质和丙二醛(MDA)的影响。以E+醉马草(A1)、E-醉马草(A2)、高羊茅-侠客岛(A3)和高羊茅-猎狗6号(A4)为试验材料,分别采用质量分数为0.1%、0.3%、0.5%、0.7%和0.9%的NaCl溶液处理幼苗,测定苗长、根长、根冠比、脯氨酸(proline)和丙二醛(MDA)含量、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性,结合模糊隶属函数评价4种种质的耐盐性,采用主成分分析明确种质幼苗耐盐性的主要评价指标,并以种质幼苗相对胚根长为因变量,NaCl浓度为自变量进行曲线回归分析,确定4种种质的耐NaCl阈值。结果表明:与对照组相比,幼苗苗长、根长随盐浓度的升高而降低,且重度盐胁迫(0.7%和0.9%)显著抑制幼苗生长(P＜0.05);0.1%和0.3% NaCl盐胁迫可显著增加幼苗Na+/K+(P＜0.05);幼苗体内Pro含量、POD和SOD活性随着盐胁迫程度增加呈现出先上升后下降的趋势,且重度盐胁迫(=0.7%)下3者较对照组呈现显著上升的趋势。幼苗体内MDA含量随盐浓度上升而上升,与对照组相比重度盐胁迫下MDA含量显著增加(P＜0.05)。综合耐盐性从大到小依次为A1＞A2＞A4＞A3,POD和SOD活性、根长、proline含量为幼苗耐盐综合评价的主要指标。

Abstract:

This study aimed to investigate the effects of NaCl salt on the growth and physiological responses of endophyte infected (E+) Achnatherum inebrians (A1),endophyte non-infected (E-) Achnatherum inebrians (A2),Festuca arundinacea cv.Island (A3) and Festuca arundinacea cv.Hound 6 (A4).Five NaCl concentrations (0.1%,0.3%,0.5%,0.7% and 0.9%) were imposed.Shoot length,root length,shoot-root ratio,proline,malondialdehyde (MDA),superoxide dismutase (SOD),peroxidase (POD) were analysed.The comprehensive principal component analysis was used to determine the NaCl tolerance of those four germplasm.The results indicated that shoot length and root length of seedlings decreased with the increasing NaCl concentration compared with the control;and severe salt stress (0.7% and 0.9%) significantly inhibited seedling growth (P＜0.05).The Na+/K+ ratio was significantly increased (P＜0.05) under mild NaCl stress.The proline content and the activity of POD and SOD initially increased followed by a decrease along with the increasing NaCl stress;the values were significantly higher under severe salt stress (0.7%) compared with the CK.MDA content increased with the increasing NaCl concentration,and significantly increased under severe salt stress compared with the control group (P＜0.05).The salt tolerance followed the order of A1＞A2＞A3＞A4,and POD,SOD,root length and proline were the main indicators for the comprehensive evaluation of salt tolerance of seedlings.