摘要：

为探究水杨酸(SA)对盐碱胁迫下红芸豆幼苗的生理调控作用,并为山西典型盐碱区红芸豆抗逆栽培提供依据,以红芸豆为试材,采用NaCl、Na₂SO₄、NaHCO₃、Na₂CO₃配比为1∶9∶9∶1的复合盐碱体系模拟盐碱胁迫,设置0 (CK),20,40,60,80 mmol/L共5个盐碱浓度梯度对红芸豆进行盐碱胁迫处理,以筛选最佳盐碱胁迫处理浓度。然后,基于筛选出的盐碱浓度进行胁迫处理的同时施加20,40,60 μmol/L 3个浓度的SA处理,以研究SA对盐碱胁迫下红芸豆幼苗的缓解效应。结果表明,40 mmol/L盐碱胁迫下,红芸豆生长受到显著的抑制,但未达到致死性重度胁迫水平,为最佳盐碱胁迫浓度,该浓度胁迫可诱发红芸豆早期幼苗氧化损伤,抑制养分吸收和转运,并提高精氨酸脱羧酶(ADC)和鸟氨酸脱羧酶(ODC)活性,导致腐胺(Put)过量积累。在40 mmol/L盐碱胁迫下,外源施加40 μmol/L的SA后,红芸豆幼苗叶片和根系的丙二醛(MDA)含量分别降低37.63%,39.76%;过氧化氢(H₂O₂)含量分别降低38.71%,21.13%;超氧阴离子(O₂^-)含量分别降低40.00%,52.17%;根系活力提高56.14%。幼苗叶片和根系的Na含量均显著降低,而K、Cu、Ca、Fe元素含量均显著增加。此外,外源施加40 μmol/L SA还可降低盐碱胁迫下红芸豆幼苗的ADC与ODC活性,增加S-腺苷蛋氨酸脱羧酶(SAMDC)活性,并促进Put向Spd和Spm转化,进而增强植株的抗氧化能力与离子稳态调控能力。综上,外源水杨酸可通过激活抗氧化系统、优化多胺代谢、促进矿质元素吸收与分配,有效缓解复合盐碱胁迫对红芸豆幼苗的生理伤害。

关键词: 红芸豆, 水杨酸, 多胺, 复合盐碱胁迫, 幼苗生长

Abstract:

To investigate the physiological regulatory role of salicylic acid(SA)in alleviating saline-alkali stress in kidney bean seedlings and to provide a basis for stress-resistant cultivation of kidney beans in typical saline-alkali areas of Shanxi Province,kidney beans were used as the test material.A composite saline-alkali stress system with a ratio of NaCl,Na₂SO₄,NaHCO₃,and Na₂CO₃ of 1∶9∶9∶1 was used to simulate saline-alkali stress.Five concentration gradients of 0(CK),20,40,60,and 80 mmol/L were set to screen for the optimal concentration of salt-alkali stress treatment.Subsequently,based on the selected concentration,three SA concentrations(20,40,and 60 μmol/L)were applied simultaneously to study the mitigating effect of SA on kidney bean seedlings under saline-alkali stress.The results indicated that under 40 mmol/L salt-alkali stress,the growth of red kidney beans was significantly inhibited but did not reach lethal or severe stress levels,making it the optimal salt-alkali stress concentration.Stress at this concentration induced oxidative damage in early seedlings,inhibited nutrient absorption and translocation,increased the activities of arginine decarboxylase(ADC)and ornithine decarboxylase(ODC),and led to excessive accumulation of putrescine(Put).Under 40 mmol/L saline-alkali stress,exogenous application of 40 μmol/L SA reduced malondialdehyde(MDA)content in leaves and roots by 37.63% and 39.76%,respectively;hydrogen peroxide(H₂O₂)content by 38.71% and 21.13%,respectively;and superoxide anion(O₂^-)content by 40.00% and 52.17%,respectively.Root activity increased by 56.14%.The Na content in both leaves and roots significantly decreased,while the contents of K,Cu,Ca,and Fe significantly increased.Furthermore,exogenous application of 40 μmol/L SA reduced the activities of ADC and ODC,increased the activity of S-adenosylmethionine decarboxylase(SAMDC),and promoted the conversion of Put to spermidine(Spd)and spermine(Spm),thereby enhancing the plant's antioxidant capacity and ion homeostasis regulation.In conclusion,exogenous salicylic acid can effectively alleviate the physiological damage caused by composite saline-alkali stress in kidney bean seedlings by activating the antioxidant system,optimizing polyamine metabolism,and promoting the absorption and distribution of mineral elements.

Key words: Red kidney bean, Salicylic acid, Polyamines, Combined saline and alkaline stress, Seedling growth

中图分类号: 

• Q945植物生理学

• S643.1