3种盐胁迫对蓟幼苗生长及生理生化的影响

采用盆栽试验研究不同浓度(0.1%、0.2%、0.3%、0.4%、0.5%、0.6%)的NaCl、Na_2SO_4、Na_2CO_3对蓟(Cirsium japonicum)幼苗苗高、叶片相对含水量、丙二醛(MDA)、抗氧化酶(POD、SOD、CAT)以及渗透调节物质(可溶性糖、游离脯氨酸)的影响。结果表明,除0.1%NaCl处理蓟苗高和叶片相对含水量高于无盐胁迫(CK)外,其余处理均低于CK,且随盐浓度增加而降低,其中,0.3%NaCl、0.4%Na_2SO_4和0.1%Na_2CO_3处理下苗高依次为CK的62.15%、58.00%和45.77%,而0.5%Na_2CO_3处理幼苗死亡;随盐处理浓度增加和处理时间延长,叶片中丙二醛含量均呈上升趋势;POD、SOD、CAT活性随盐浓度、时间变化的趋势不尽一致,3种酶活性均出现了阈值,POD出现在0.3%NaCl、0.3%Na_2SO_4、0.4%Na_2CO_3胁迫5d,SOD出现在0.3%NaCl处理3d、0.5%Na_2SO_4处理1d、0.4%Na_2CO_3处理3d,CAT出现在0.3%NaCl、0.2%Na_2SO_4、0.1%Na_2CO_3胁迫3d;相同处理时间下,随盐浓度的增加,除NaCl胁迫下游离脯氨酸(Pro)含量先增后减外,Na_2SO_4和Na_2CO_3胁迫下游离脯氨酸含量,以及3种盐胁迫下可溶性糖(SS)含量均逐渐增加。综上认为,蓟对NaCl、Na_2SO_4、Na2CO4这3种盐均具有一定的耐性,可以在低于0.3%NaCl、0.4%Na_2SO_4和0.1%Na_2CO_3条件下生存和生长。

Effects of three salt stresses on growth,physiology,and biochemistry of Cirsium japonicum

The effects of three salt stresses (NaCl,Na2 SO4 ,Na2 CO3 )at different concentrations (0.1%, 0.2%,0.3%,0.4%,0.5%,and 0.6%)on seedling height,relative water content,malondialdehyde (MDA), antioxidase activity (POD,SOD,and CAT),and osmotic regulation substances (soluble sugar and free proline contents)in leaves of Cirsium japonicum were studied in pot experiments.The results showed that seedling heights and relative water contents were reduced compared to the control (CK)in all salt stress treatments ex-cept 0.1% NaCl treatment and that the effects increased with increasing salt concentrations.Seedling heights in the 0.3% NaCl,0.4% Na2SO4,and 0.1% Na2CO3 treatments were 62.15%,58.00%,and 45.77%,respective-ly,of the CK level;seedlings in the 0.5% Na2 CO3 treatment died.Increasing salt concentrations and length of treatment caused an increase in MDA contents in leaves.The POD,SOD and CAT activities of leaves varied with changes in salt concentration and treatment time.A significant activity threshold was observed for POD on the fifth day of the 0.3% NaCl treatment,0.3% Na2 SO4 treatment,and 0.4% Na2 CO3 treatment.Significant activity of SOD was first detected on the third day with 0.3% NaCl treatment,on the first day of 0.5% Na2 SO4 treatment,and on the third day with 0.4% Na2 CO3 treatment.Significant CAT activity was first observed on the third day with 0.3% NaCl treatment,0.2% Na2 SO4 treatment,and 0.1% Na2 CO3 treatment.At the same process times,the proline contents increased at first and then decreased in the NaCl treatments;in the Na2 SO4 and Na2 CO3 treatments,the soluble sugar content increased gradually with the increase in salt concentration.In conclusion,C.japonicum shows some tolerance to NaCl,Na2 SO4 ,and Na2 CO3 stress,and can survive and grow under conditions of less than 0.3% NaCl,0.4% Na2 SO4 ,or 0.1% Na2 CO3 .