模拟盐渍化对甜瓜种子萌发和幼苗生理特性的影响

为了解盐渍化对甜瓜种子萌发的影响,本研究以甜瓜品种’新银辉’为材料,采用NaCl和NaHCO3单独处理和复合处理模拟盐渍化,观测不同处理下甜瓜种子萌发情况以及生理生化指标的变化。结果表明:NaCl、NaHCO3、NaCl和NaHCO3复合处理模拟的盐渍化几乎都对甜瓜种子萌发产生了抑制作用,胁迫浓度越高,抑制作用越明显;仅低浓度(50 mmol/L)的NaCl表现出一定的促进作用。NaCl和NaHCO3复合处理后甜瓜种子萌发过程中超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性随着处理时间增加,呈升-降-升的趋势;过氧化物酶(POD)活性先上升后下降;脯氨酸(Pro)含量持续上升;可溶性糖含量持续下降;丙二醛(MDA)含量始终显著高于蒸馏水对照;淀粉含量随着处理时间增加呈下降的趋势,α-淀粉酶活性和β-淀粉酶活性均呈先下降、后上升的趋势。模拟盐渍化明显抑制甜瓜种子的萌发和幼苗生长,保护酶活性、淀粉代谢在应对胁迫中起到了明显作用,研究结果有助于为甜瓜耐盐机制和设施栽培提供有益的参考。

Effects of Simulated Salinization on Seed Germination and Physiological Characteristics of Muskmelon Seedlings

Using muskmelon cultivar ‘Xinyinhui’ as the material, the effects of salinization on the germination of muskmelon seeds were observed after treated by NaCl and NaHCO₃ alone and combined. At the same time, some physiological and biochemical indexes related to saline-alkali stress were measured. The results showed that the simulated salinization of NaCl, NaHCO₃, NaCl and NaHCO₃ could inhibit seed germination. The inhibition increased with the increase of stress concentration and the extension of stress time. Only low concentration (50 mmol/L) of NaCl showed a certain promoting effect. The activities of superoxide dismutase (SOD) and catalase (CAT) first increased, then decreased, and then turned to an upward trend during the germination of muskmelon seeds treated with NaCl and NaHCO₃. Peroxidase (POD) activity increased first and then decreased. Proline (Pro) content continued to rise, while soluble sugar content continued to decline. Malondialdehyde (MDA) content was always significantly higher than that of the control group treated with distilled water. Starch content decreased with the extension of treatment time. The activity of α-amylase and β-amylase decreased first and then increased. Generally speaking, simulated salinization significantly inhibited the seed germination and seedling growth of muskmelon, and protective enzymes and starch metabolism significantly participated in the response to salt-alkali stress. The results would help to reveal the response mechanism of muskmelon seeds to salinization stress during germination, and provide theoretical and practical references for facility seedling raising and plant cultivation in saline-alkali environment.