复杂盐碱条件对星星草种子萌发的影响

将2种中性盐NaCl、Na2SO4及2种碱性盐Na2CO3、NaHCO3按不同比例混合。模拟出24种盐度和碱度各不相同的复杂盐碱条件,并用以处理星星草种子,测定其发芽率、发芽势。结果表明,不同碱度的盐分组成对星星草种子萌发的影响基本一致,即均随着盐浓度的增高发芽延迟,发芽率降低,而且均在盐浓度超过300 mmol/L时发芽率降至零。对各胁迫因素与发芽率之间进行统计学分析,结果表明,盐浓度是影响星星草种子萌发的决定性因素,其他因素的作用很小。本实验结果表明,吸水是决定星星草种子萌动与否的关键,由于盐浓度决定水势进而决定种子吸水,所以盐浓度表现为影响种子萌发的关键因素。由于pH值、缓冲量等代表碱度的指标与水势没有直接关系,所以对星星草种子萌动阶段没有决定性影响。

Effects of complex salt and alkali conditions on the germination of seeds of Puccinellia tenuiflora

The stress conditions of salt-alkalinized soil were simulated to investigate the effects of alkali-saline mixed stress on the germination of seeds of Puccinellia tenuiflora.The features of salt-alkalinized soil in northeast China were simulated using 24 kinds of alkali-saline conditions with different salinities and pH obtained by mixing two neutral salts(NaCl and Na_2SO_4) and two alkalie salts(NaHCO_3 and Na_2CO_3) in various proportions.The seeds of P.tenuiflora were treated with the mixed salts and their germination rate and germination energy were investigated.The effects on germination of P.tenuiflora seeds of various mixed salts with different alkalinities were similar.Seed germination was delayed,and the germination rate,and speed of sprouting decreased as the salinity increased.The seeds did not sprout when the salinity was over 300 mmol/L.Statistical analysis showed that salinity was the dominant stress factor which inhibited the seed sprouting.At the stage of seed germination,water absorption was the key factor that determined whether the seeds did or did not sprout.Since salinity determined water absorption,it was a decisive factor while other indices,such as pH and buffer capacity were irrelevant to the water potential,as they had no decisive effect on germination.