苗期干旱胁迫条件下外源ABA对甘薯膜透性和抗氧化酶系统的影响（英文）

Effects of Exogenous Abscisic Acid on Membrane Permeability and Antioxidant System of Sweetpotato at Seedling Stage under Drought Stress

为了研究外源ABA对提高甘薯苗期抗旱性的影响,以抗旱品种济薯21和不抗旱品种济紫薯1号为试验材料,研究了苗期干旱胁迫条件下,外源ABA对甘薯渗透调节和抗氧化酶系统的影响。结果表明,胁迫处理12 d以后(AW),干旱胁迫处理(PEGW)的叶片相对电导率、叶片和根系的MDA含量均显著高于对照,根系活力则显著低于对照,抗旱品种和不抗旱品种表现相同的趋势;抗旱品种济薯21干旱胁迫处理(JS21-PEGW)的叶片和根系的SOD、POD和APX活性均显著高于对照(JS21-C),而不抗旱品种济紫薯1号(JZ1-PEGW)的叶片GR和根系APX活性则显著低于对照(JZ1-C);抗旱品种济薯21干旱胁迫处理(JS21-PEGW)的叶片和根系的抗氧化酶活性以及根系活力均显著高于不抗旱品种济紫薯1号(JZ1-PEGW),而叶片和根系MDA含量则显著低于济紫薯1号。胁迫处理12 d以后(AW),外源ABA显著降低了叶片相对电导率,抑制了叶片和根系中MDA的积累,提高了根系活力,提高了叶片和根系中SOD、POD、CAT、APX和GR的活性。因此,外源ABA在提高甘薯苗期抗旱性方面起着重要的作用,通过降低叶片相对电导率和MDA的积累而缓解膜的损伤,通过提高根系活力而提高根系的吸收能力,通过提高抗氧化酶活性而提高苗期叶片和根系的抗氧化酶系统的防御能力。

In order to investigate the effects of exogenous ABA on the resistance to drought stress at seedling stage in sweetpotato,two sweetpotato cultivars(JS21,a drought-tolerant cultivar,and JZ1,a drought-sensitive cultivar)were used to investigate the effects of exogenous abscisic acid(ABA)on protection against drought damage as well as on membrane permeability and antioxidant defense systems of sweetpotato at seedlings stage under drought stress.The results showed that after 12 days drought stress(AW),the relative electrical conductivity in leaves and the malondialdehyde(MDA)content in leaves and roots of drought stress treatment(PEGW)were higher than those of the control for both JZ1 and JS21,while the root activities were lower than those of the control.The activities of superoxide dismutase(SOD),peroxidase(POD)and ascorbate peroxidase(APX)in leaves and roots in JS21(JS21-PEGW)were significantly higher than those of the control(JS21-C),while glutathione reductase(GR)in leaves and ascorbate peroxidase(APX)in roots in JZ1(JZ1-PEGW)were lower than those of the control(JZ1-C).The antioxidant enzymes activities in leaves and roots and the root activities in drought-tolerant cultivar JS21(JS21-PEGW)were significantly higher than those of drought-sensitive cultivar JZ1(JZ1-PEGW),while the MDA content in leaves and roots were significantly lower than those of JZ1(JZ1-PEGW).After 12 days drought stress(AW),application of exogenous ABA significantly inhibited the relative electrical conductivity in the leaves of seedlings,reduced the accumulation of MDA in leaves and roots.Additionally,exogenous ABA significantly increased root activity and caused significant increases in SOD,POD,CAT,APX and GR activities in leaves and roots in both cultivars under drought stress.In conclusion,the results suggested that ABA played an important role in the tolerance of sweetpotato against drought stress resulted from the alleviation of membrane damage as indicated by decreases of the relative electrical conductivity and MDA content,enhanced root absorption through increases of root activity,as well as through ROS scavenging due to increase antioxidant defense systems capacity.