低温胁迫萌芽对青稞γ-氨基丁酸合成的调控作用研究

为探究低温胁迫萌芽对青稞γ-氨基丁酸（γ-aminobutyric acid，GABA）的富集情况及其调控机理，以柴青一号青稞为原料，考察浸泡时间、萌芽时间、培养温度3 个因素对青稞GABA 合成的影响，在单因素试验的基础上，采用响应面试验优化低温胁迫萌芽富集青稞GABA 的工艺条件，进一步研发低温胁迫萌芽对GABA 关键调控酶（谷氨酸脱羧酶、多胺氧化酶、二胺氧化酶）活性的影响，揭示其调控机制。结果表明：在浸泡时间8 h、萌芽时间16 h、培养温度0 ℃的工艺条件下，制得的萌芽青稞籽粒中GABA 质量分数为（78.70±1.73）mg/100 g，是青稞原料的1.74 倍，表明低温胁迫可以高效富集青稞GABA；谷氨酸脱羧酶对GABA 合成影响较明显，多胺氧化酶活性普遍较低，揭示GABA支路为低温胁迫青稞合成GABA 的主要途径。

Regulation of γ-Aminobutyric Acid Synthesis in Highland Barley by Low-temperature Stress Germination

To investigate the enrichment of γ-aminobutyric acid（GABA）and its regulatory mechanism in highland barley by low-temperature germination，this study investigated the effects of soaking time，germination time，and incubation temperature on GABA synthesis in highland barley using ''Chaiqing No.1'' barley as the raw material.Based on single-factor experiments，the process conditions for enriching barley GABA by lowtemperature germination were optimized using response surface experiments.Meanwhile，the effects of lowtemperature germination on the activities of key regulatory enzymes for GABA（glutamate decarboxylase，polyamine oxidase，and diamine oxidase）were studied to reveal their regulatory mechanisms.The results showed that under the process conditions of soaking for 8 h，germination for 16 h，and incubation temperature of 0 ℃，the mass fraction of GABA in the germinated barley grains was（78.70±1.73）mg/100 g，which was 1.74 times that of the highland barley raw material.This indicated that low-temperature germination could efficiently enrich GABA in highland barley.Glutamate decarboxylase had a more significant impact on GABA synthesis，while polyamine oxidase activity was generally low，indicating that the GABA pathway was the main route for GABA synthesis in barley under low-temperature germination.