NaCl和Na_2CO_3胁迫对四翅滨藜种子萌发及保护酶活性的影响

Effects of Activities of Protective Enzymes and Seed Germination in Atriplex canescens under NaCl and Na_2CO_3 Stress

土壤盐渍化是困扰人类的五大土壤问题之一（王春裕等,1997）。我国华北和滨海地区存在大量盐渍化土地,有些区域土壤含盐量达到1%以上（毛建华等,2005）,严重影响着当地种植业生产的持续发展,也给园林绿化带来很大困难。大量培育、引种、选择具有耐盐、耐旱特性植物,在干旱和盐渍化地区栽培,不仅能够改善干旱和盐渍化环境,而且能够带来经济效益,是未来园林绿化和林业发展的方向。

The seed germination rate,germination index,germination value,vigor index,growth of radical and hypocotyls and activities of protective enzymes of Atriplex canescens were investigated under NaC1 and Na2CO3 stresses.The results showed that：1） While low NaC1 concentration（0.05 mol.L-1） promoted the germination rate,germination index and germination value of Atriplex canescens seeds,high NaCl,as well as Na2CO3,inhibited these parameters,and the inhibition was aggravated with the increasing salinity.Under Na2CO3 stress,seeds were not able to germinate at 0.25 mol.L-1 Na ＋ concentration.The osmotic stresses were the dominant factor to inhibit those three parameters in seed germination period.2） The length and growth rate of hypocotyls and radical,and vigor index under NaCl treatment were 1-5 times higher than Na2CO3 treatment,which suggested that high pH value was the main factor to affect the seedling growth.3） At low concentrations of NaCl treatment（NaCl≤0.1 mol.L-1）,SOD and POD in Atriplex canescens seeds played the principal role,while at high concentrations of NaCl treatment（NaCl 0.1 mol.L-1）,the POD and CAT were the principal factor.The changes of protective enzymes of the seeds in low concentration Na2CO3 stress were to the same as that under low concentration NaCl stress.POD maintained a high activity only in high concentration of Na2CO3 treatment,however,POD activity started to decline when the Na ＋ concentration was higher than 0.2 mol.L-1.For all above factors the injuries imposed by Na2CO3 stress were greater than by NaCl stress.