摘要:为探讨红豆和白扁豆种子萌发及幼苗生长对盐胁迫的响应及其生理机制，以红豆品种‘渝红豆2号’和传统白扁豆品种为材料，分别用不同浓度NaCl（0 mmol·L-1、20 mmol·L-1、40 mmol·L-1、60 mmol·L-1、80 mmol·L-1、100 mmol·L-1）溶液处理种子，测定不同NaCl浓度胁迫下红豆和白扁豆种子的发芽指标及幼苗生长指标、叶片丙二醛（MDA）含量、超氧化物歧化酶（SOD）和过氧化物酶（POD）活性，分析NaCl胁迫对红豆和白扁豆种子萌发及幼苗生长的影响。结果表明：1）随NaCl浓度增加，红豆和白扁豆种子发芽率、发芽势、发芽指数和活力指数均呈下降趋势。当NaCl浓度为80 mmol·L-1时，白扁豆发芽势、发芽指数、活力指数降为0，红豆的发芽势、发芽指数、活力指数分别为20.00%、2.00、0.83；NaCl浓度为100 mmol·L-1时，红豆的发芽率为16.67%，但白扁豆为0，这表明在盐胁迫下红豆较白扁豆具有更高的萌发能力。2）红豆与白扁豆相对盐害率随NaCl浓度的增加而增加，当NaCl浓度为80 mmol·L-1和100 mmol·L-1时，白扁豆相对盐害率为96.58%和96.67%，红豆相对盐害率为47.05%和83.18%，说明红豆受盐害程度较低。3）红豆与白扁豆幼苗胚根、胚芽及鲜重均随NaCl浓度增加而下降。NaCl浓度为100 mmol·L-1时，白扁豆胚根长为0，红豆胚根长为0.23 cm。4）随NaCl浓度升高，红豆和白扁豆叶片的MDA含量均增加，造成细胞膜透性逐渐增大，但是红豆幼苗MDA积累量低于白扁豆，这表明红豆叶片细胞膜损伤较小。5）NaCl胁迫下，红豆与白扁豆SOD活性均显著升高，但红豆SOD活性显著高于白扁豆；NaCl胁迫下，POD活性显著升高，但白扁豆POD活性显著下降。研究发现红豆可通过提高SOD和POD活性以降低细胞膜氧化伤害，减少MDA积累量，进而提高种子萌发能力。在相同浓度NaCl胁迫下红豆较白扁豆有更高的耐盐性，能更好地适应盐胁迫环境。
关键词:盐胁迫/
耐盐性/
保护酶活性/
种子萌发/
红豆/
白扁豆
Abstract:Soil salinization has an important effect on seed germination of plants; however, little attention has given to the effect of salt stress on the seed germination of legumes. The Vigna angularis variety 'Yuhongdou 2' and traditional Dolichos lablab variety were used to determine the germination percentage, germination potential, germination index, vigor index, radicle length, embryo length, and fresh weight, malondialdehyde (MDA) content, and superoxide dismutase (SOD) and peroxidase (POD) activity under different NaCl concentrations (0 mmol·L-1, 20 mmol·L-1, 40 mmol·L-1, 60 mmol·L-1, 80 mmol·L-1, 100 mmol·L-1) in an artificial climate chest. The goal of this study was to investigate the relationship between osmotic regulators, stress resistance enzymes, and salt tolerance of leguminous plants under NaCl stress. The results were as follows:1) salinity stress inhibited the germination index of V. angularis. Then germination percentage, germination potential, germination index, and vigor index of V. angularis decreased with increasing NaCl stress and was significantly higher than that of D. lablab. 2) The relative salt damage rate of V. angularis and D. lablab increased with the increase in NaCl concentration. When the NaCl concentration was 80 mmol·L-1 and 100 mmol·L-1, the relative salt damage rate of D. lablab was 96.58% and 96.67%, whereas the relative salt damage rate of V. angularis was 47.05% and 83.18%, indicating that the salt damage to V. angularis was less intense. 3) The radicle length, embryo length, and fresh weight of V. angularis and D. lablab seedlings decreased with the increase of NaCl concentration. When NaCl concentration was 100 mmol·L-1, the radicle length of D. lablab was 0, and that of V. angularis was 0.23 cm. 4) With the increase of NaCl concentration, the content of MDA in the leaves of V. angularis and D. lablab increased, resulting in a gradual increase in cell membrane permeability, but the accumulation of MDA in V. angularis seedlings was lower than that in D. lablab, which indicated that the cell membrane of V. angularis leaves was less damaged. 5) Under NaCl stress, SOD activity of V. angularis and D. lablab increased significantly, but SOD activity of V. angularis was significantly higher than that of D. lablab. Under NaCl stress, POD activity of V. angularis increased significantly, but the POD activity of D. lablab decreased significantly. It was found that V. angularis could reduce the oxidative damage of the cell membrane and the accumulation of MDA by increasing SOD and POD activities, thus improving the germination ability of seeds. V. angularis was higher in salt tolerance than D. lablab under the same concentration of NaCl stress and can better adapt to a salt stress environment.
Key words:Salt stress/
Salt tolerance/
Protective enzyme activity/
Seed germination/
Vigna angularis/
Dolichos lablab
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