H2O2胁迫下豌豆初生根及抗氧化酶系统对外源 Ca2＋的响应

摘要

In order to explore methodology for improving the resistance of pea primary roots to H2 O2 stress, physiological characteristics of pea primary roots were studied using a pea variety “Longwan 1 ”treated with Ca2 + under H2 O2 stress.Several physiological indexes like the curvature rate and root activity of pea primary roots were measured using physiological and biochemical methods.Some other indexes like the relative mem-brane permeability of primary roots,the concentration of malondialdehyde (MDA)in primary roots,the activi-ties of superoxide dismutase (SOD),peroxidase (POD),catalase (CAT)and ascorbate peroxidase (APX)en-zymes were also measured.The normal growth of pea primary roots under 80 mmol/L H2 O2 stress was obvi-ously inhibited.However,the inhibitory effect on root growth was reduced and the root activity was restored after treating with Ca2 + .The MDA content decreased 37.32% compared to controls after treatment with 10 mmol/L exogenous Ca2 + .The activities of four enzymes including POD,SOD,CAT and APX were enhanced and reached 51.946 U/(mg·min),865.174 U/g FW,1.9739 mmol/(L·g·min)and 2.569 μmol/(L·g· min),respectively.In summary,Ca2 + (10 mmol/L)significantly alleviated the damage to pea primary root cell membranes caused by H2 O2 stress,reduced membrane permeability and promoted the antioxidant capacity of pea primary roots for stress resistance.%以豌豆品种“陇豌一号”为材料，通过对豌豆种子萌发初期初生根生理特性的研究，探索提高豌豆初生根外源H2 O2胁迫条件下抗性能力的途径。运用生理生化方法，测定 H2 O2胁迫下豌豆初生根在外源 Ca2＋处理后的弯曲率和根系活力，并对豌豆初生根内的丙二醛（MDA）含量、相对膜透性、超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）活性进行测定。结果显示，80 mmol／L 的 H2 O2处理下的豌豆初生根正常生长受到显著抑制，但是经过 Ca2＋处理后，根系生长抑制作用得到缓解，根系活力得以恢复。外施10 mmol／L Ca2＋初生根 MDA 值较 CK1降低了37．32％，并显著地提高了 POD，SOD，CAT 和 APX 的活性，其值分别为51．946 U／（mg·min），865．174 U／g FW，1．9739 mmol／（L·g·min）和2．569μmol／（L·g·min）。总之，外源施加 Ca2＋能够有效降低 H2 O2造成的氧化胁迫，缓解对初生根细胞膜的伤害，降低质膜透性，增强初生根系抗氧化酶活性，达到抵抗逆境胁迫的目的。