盐胁迫下外源脯氨酸对油菜Na^(+)/K^(+)平衡、生长及抗氧化系统的影响

Effects of exogenous proline on Na+/K+balance,growth and antioxidant system of rapeseed under salt stress

为探究盐胁迫下外源脯氨酸对油菜生长发育的调控机制,以甘蓝型油菜为试验材料,在150 mmol/L盐胁迫下设置5个外源脯氨酸水平(0、0.25、0.5、1和2 mmol/L),探究外源脯氨酸对盐胁迫下抗氧化系统、渗透物质和离子含量的影响。结果显示:盐胁迫显著抑制油菜的生长,较低浓度(0.25 mmol/L和0.5 mmol/L)外源脯氨酸均可促进油菜的生长,相比0.25 mmol/L外源脯氨酸,施用0.5 mmol/L对油菜长势具有较好的促进作用,能够减少叶片Na^(+)积累,提高K^(+)含量,提高抗氧化酶的活性,并降低活性氧含量。另外,0.5 mmol/L外源脯氨酸还可以促进油菜叶片脯氨酸等渗透物质的积累。而施用较高浓度(1 mmol/L和2 mmol/L)外源脯氨酸不仅没有缓解盐胁迫,还对油菜叶片造成进一步的伤害。综上,盐胁迫会对油菜生长造成损伤,而施用适量外源脯氨酸能够激发抗氧化系统,有效缓解盐胁迫对油菜生长的抑制,提高油菜的耐盐性。

Five levels of exogenous proline including 0,0.25,0.5,1 and 2 m mol/L were set for Brassica napus under 150 mmol/L salt stress to study the regulatory mechanism of exogenous proline on the growth and development of rapeseed under salt stress.The effects of exogenous proline on the antioxi⁃dant systems,osmotic substances,and content of ion under salt stress were investigated.The results showed that salt stress significantly inhibited the growth of rapeseed.Low concentrations(0.25 mmol/L and 0.5 mmol/L)of exogenous proline promoted the growth of rapeseed.Compared to 0.25 mmol/L exog⁃enous proline,the application of 0.5 mmol/L had a better promoting effect on the growth of rapeseed,re⁃duced Na^(+)accumulation in leaves,increased the content of K^(+),improved the activity of antioxidant en⁃zyme,and reduced the content of reactive oxygen species.In addition,0.5 mmol/L exogenous proline pro⁃moted the accumulation of osmotic substances including proline in rapeseed leaves.The application of high concentrations(1 mmol/L and 2 mmol/L)of exogenous proline not only did not alleviate salt stress,but also caused further damage to rapeseed leaves.It is indicated that salt stress can cause damage to the growth of rapeseed.Applying an appropriate amount of exogenous proline can stimulate the antioxidant sys⁃tem,effectively alleviate the inhibition of salt stress on the growth of rapeseed,and improve its salt toler⁃ance.