外源脱落酸对小麦幼苗抗镉胁迫能力的影响

以小麦(Triticum aestivum L.)为试材,采用水培法研究了100mg/L镉(Cd2+)胁迫条件下施用外源脱落酸(ABA)对小麦幼苗生长及某些生理生化指标的影响。结果表明:(1)100mg/L Cd2+胁迫下,小麦叶片膜脂过氧化产物丙二醛(MDA)含量显著提高,植株生长受到抑制;(2)外源ABA能够明显提高Cd2+胁迫小麦幼苗的根系活力,增加其叶片SOD、CAT和POD活性,促进其脯氨酸积累,降低MDA的含量,并以5.0μmol/L ABA的效果最明显;(3)1.0～5.0μmol/L外源ABA不同程度地缓解Cd2+胁迫对小麦幼苗生长的抑制作用,且5.0μmol/L时效果最明显,其株高、根长、总干重分别比单一Cd2+胁迫处理显著提高6.73%、149%和10.52%,而10.0μmol/LABA反而加重了Cd2+对小麦幼苗生长的伤害。因此,适宜浓度的外源ABA能够通过增加体内保护酶活性和脯氨酸含量来缓解Cd2+胁迫对小麦幼苗生长的抑制作用,增强小麦幼苗的抗Cd2+胁迫能力,并以5.0μmol/L ABA处理效果最好。

Effect of Exogenous Abscisic Acid on Tolerance of Wheat Seedlings to Cadmium Stress

Effects of exogenous abscisic acid(ABA) on the growth and some physio-biochemical signs in wheat(Triticum aestivum L.) seedlings under cadmium stress(100 mg/L) were studied with hydroponics.The results showed that:(1)The malondialdehyde(MDA) content in wheat seedlings was significantly increased(P<0.05),and the growth of wheat seedlings was also obviously inhibited by Cd2+ stress.(2)Exogenous ABA with the concentration of 5.0 μmol/L playing a noticeable role increased root activity and proline content,enhanced activities of SOD,POD and CAT,and decreased MDA content.(3)Exogenous 1.0-5.0 μmol/L ABA eased the negative effects of Cd2+ on the growth of wheat seedlings,and 5.0 μmol/L ABA worked best with shoot height,root length and total biomass of seedlings in 5.0 μmol/L ABA and Cd2+ stress had increased 6.73%,149% and 10.52%,respectively,compared with those under single Cd2+ stress.However,10.0 μmol/L ABA exacerbated the growth of wheat seedlings.On the whole,preference concentration of exogenous ABA could ease the inhibitory effects of Cd2+ stress on the growth of wheat seedlings and boost the tolerance of wheat seedlings to Cd2+ stress by increasing SOD,POD and CAT activities and proline content.Furthermore,the most suitable concentration of ABA was defined to be 5.0 μmol/L.