混合盐碱胁迫对鹰嘴紫云英种子萌发及幼苗生理特性的影响

Effects of mixed saline-alkali stress on seedgermination and physiological characteristicsof Astragalus cicer

摘要:

以鹰嘴紫云英为材料,将中性盐NaCl、Na₂SO₄和碱性盐NaHCO₃、Na₂CO₃按不同比例混合,以碱性盐比例逐渐增加的趋势,模拟出18种天然盐碱生态条件(浓度20~120 mmol/L),在鹰嘴紫云英种子萌发期及幼苗期进行胁迫处理,通过对萌发期各项发芽指标及幼苗期相关生理指标的测定,分析鹰嘴紫云英各生理特性对混合盐碱胁迫的响应特点。结果表明:混合盐碱胁迫对鹰嘴紫云英种子萌发及幼苗生理特性均产生了明显的抑制作用。萌发期其发芽率、发芽势、幼芽和幼根长度均随盐浓度的增加呈下降趋势,苗期幼苗随着盐浓度的递增,鹰嘴紫云英的丙二醛(MDA)含量呈增加趋势,超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性表现为先上升后下降的趋势,抗坏血酸过氧化物酶(APX)活性随盐浓度的增加呈下降趋势。在A(无碱性盐)、B(碱性盐比例较低)、C(碱性盐比例较高)的混合盐碱胁迫中,鹰嘴紫云英在低度(20~40 mmol/L)的B组胁迫下生长表现最好,在低度(20~40 mmol/L)、中度(60~80 mmol/L)、重度(100~120 mmol/L)胁迫下A组具有较强的耐性。

Abstract:

The high-quality leguminous forage Astragalus cicer was used as the material,neutral salts (NaCl and Na₂SO₄) and alkaline salts (NaHCO₃ and Na₂CO₃) mixed in different concentrations to stimulate 18 natural saline-alkali ecological conditions (concentration ranged from 20 to 120 mmol/L) were used as saline-alkali stress factor to study the response of Astragalus cicer at germination and seedling stages to the stress.The results showed that mixed saline-alkali stress obviously inhibited the seed germination and seedling growth.The germination rate,germination potential,sprouts and root decreased along with the increase of salt concentration during germination.With the increase of salt concentration at seedling stage,the malondialdehyde content showed a rising trend.The activities of superoxide dismutase (SOD),peroxidase (POD),and catalase (CAT) showed a rising trend at first,and then began to decline after reaching the peak.The ascorbic acid peroxidase (APX) activity showed a decreasing trend with the increase of salt concentration.Among the three groups of mixed saline-alkali stress of A (alkaline-free salt),B (low proportion alkaline salt) and C (high proportion alkaline salt),A.cicer in group B (20~40 mmol/L) performed the best growth,and it performed stronger tolerance in group A under low-level (20~40 mmol/L),medium-level (60~80 mmol/L) and high-level (100~120 mmol/L) stress.