PEG和NaCl胁迫对草木樨种子萌发和幼苗生长的影响

Effects of PEG and NaCl stress on seed germination,seedling growth of Melilotus accession

以筛选出的5份优异草木樨(Melilotus)种质PI595335、MO-LX04、PI595388、Ames19257和PI593234为材料,分别用不同渗透势的PEG(0、-0.3、-0.6、-0.9、^(-1).2、^(-1).5 MPa)及不同浓度的NaCl溶液(0、50、100、150、200、300mmol·L^(-1))模拟干旱和盐碱胁迫条件,采用纸上发芽法进行种子萌发试验,测定发芽率、发芽势、胚根幼苗长、发芽指数、活力指数等指标,并综合比较不同种质的抗旱及耐盐能力。结果表明,1)高渗透势(≥-0.3 MPa)的条件能不同程度地促进5份种质的萌发,对PI595335、MO-LX04、PI595388胚根和幼苗的生长有一定抑制作用,对Ames19257、PI593234胚根和幼苗的生长有显著的(P<0.05)促进作用;而较低渗透势(≤-0.9 MPa)则显著抑制(P<0.05)所有种子的萌发与幼苗生长。2)不同浓度的NaCl溶液对5份种质草木樨幼苗的生长均有显著的(P<0.05)抑制作用,而低浓度的NaCl(≤100mmol·L^(-1))溶液能促进草木樨种子的萌发。3)用模糊数学隶属法综合评价结果显示,5份草木樨种质在种子萌发期抗旱性强弱为Ames19257>PI593234>MO-LX04>PI595335>PI595388,耐盐性强弱为PI593234>Ames19257>PI595388>MO-LX04>PI595335。其中Ames19257和PI593234在抗旱性和耐盐模拟试验中的表现均明显优于其它3份草木樨种质,更适于为今后杂交创制新种质提供遗传材料或在西北干旱、盐碱地区种植。

In this study,five high performing Melilotus accessions were evaluated seed germination and seedling growth under different PEG and NaCl treatment,by determination germination percentage,germination energy,the radicle and seedling length,germination index,vigor index.The analysis of Fuzzy Mathematics Based Comprehensive Evaluation method is used to investigate drought and salt tolerance differences among accessions.The results shows that：1）High osmotic potential（≥-0.3MPa）significantly（P〈0.05）increased seed germination in all accessions compared to the control.In addition,the radicle and seedling growth of PI595335,MO-LX04,PI595388 was significantly reduced but significantly（P〈0.05）increased for Ames19257 and PI593234at high osmotic potential（≥-0.3MPa）.At low osmotic potential（≤-0.9MPa）,all seeds germination and seedling growth were significantly（P〈0.05）reduced.2）Seedling growth was significantly influenced under different levels of NaCl treatment on all accessions.Seed germination was significantly（P〈0.05）increased at low concertation of NaCl（≤100 mmol·L^-1）.3）The analysis using Fuzzy Mathematics Based Comprehensive Evaluation showed that：the drought tolerance of five Melilotus accessions in seed germination period as follows：Ames19257PI593234MO-LX04PI595335PI595388,salt resistance is PI593234Ames19257PI595388MO-LX04PI595335.The performance of Ames19257 and PI593234were significantly better than the other three Melilotus accessions in the drought and salt tolerance test,and therefore they are good genetic materials for the future breedingprograms in the northwest of China.