基于脯氨酸相关指标动态监测玉米苗期盐碱胁迫伤害

Dynamic Monitoring Saline-alkali Stress Injury at the Maize Seedling Stage Based on Proline Related Indexes

以3份玉米单交种(郑单958、先玉335、吉单27)及其双亲(郑58/昌7-2、PH6WC/PH4CV、四-287/四-144)为试验材料,分别用200 mmol/L NaCl和100 mmol/L Na2CO3对其进行苗期盐、碱胁迫处理,并在10个时间点监测苗情和测定脯氨酸(Pro)含量、Δ1-吡咯啉-5-羧酸合成酶(P5CS)和脯氨酸脱氧酶(PDH)活性。通过方差分析和相关性分析,探究盐碱胁迫对玉米生长的影响,并筛选耐盐性评价指标和时间点,对材料进行耐盐性综合分级。结果表明,碱胁迫对植株伤害更严重。由于脯氨酸相关指标变化表现明显的阶段分化,将9个胁迫点划分为3个阶段,并将胁迫后1、3和5 d确立为玉米苗期耐盐碱鉴定适宜的胁迫时间点,P5CS活性被确立为评价指标。郑单958为高耐盐品种,吉单27为高耐碱品种,四-287、四-144和郑58为高耐盐/碱自交系。

Three maize hybrids(Zhengdan958,Xianyu335,Jidan 27)and their parental lines(Zheng 58/Chang7-2,PH6WC/PH4CV,Si-287/Si-144)were subjected to salt and alkali stress treatments at the seedling stage using 200 mmol/L NaCl and 100 mmol/L Na2CO3,respectively.Seedling growth was monitored,and the Pro content,P5CS,and PDH activities were measured at 10 different time points.Through variance analysis and correlation anal⁃ysis,the impact of salt-alkali stress on maize was explored,and salt tolerance evaluation indices and time points were selected for comprehensive classification of salt tolerance.The results showed that alkali stress inflicted more severe damage on the plants.Due to the significant phase differentiation in proline-related indicators,the nine stress points were artificially divided into three stages,and the 1st day,3rd day,and 5th day after stress application were identified as suitable time points for evaluating salt-alkali tolerance in maize seedlings.P5CS activity was es⁃tablished as the evaluation index.Zhengdan958 was identified as a high salt-tolerant variety,Jidan 27 as a high al⁃kali-tolerant variety,and Si-287,Si-144,and Zheng 58 were classified as high salt/alkali-tolerant inbred lines.This study provides technical support for dynamic monitoring and evaluation of salt-alkali stress damage in maize seedlings.