低温胁迫对谷物种子萌发影响的红外光谱研究

Effects of Low-Temperature Stress on Grain Seeds Germination by Infrared Spectroscopy

种子萌发作为植物生命历程的开端,直接影响作物的最终产量。种子萌发常遭遇低温的影响,严重威胁粮食生产安全。利用傅里叶变换红外光谱结合曲线拟合研究低温对谷物种子(藜麦、青稞、水稻和小麦)萌发的影响。研究结果显示,4种谷物种子的发芽势、发芽率和发芽指数都随温度的降低而下降,青稞种子在4℃低温下的发芽率和发芽指数仍然较高,表明青稞种子的耐低温能力更强。红外光谱结果显示,低温胁迫下的谷物种子原始红外光谱整体特征相似,主要由多糖、脂肪和蛋白质的特征吸收峰组成。对低温胁迫下的谷物种子多糖(1200~950 cm^(-1))和酰胺Ⅰ带(1700~1600 cm^(-1))进行曲线拟合,结果显示:藜麦种子的多糖含量上升,蛋白质含量下降;青稞种子的多糖和蛋白质含量均呈先升后降的趋势;水稻种子的多糖含量下降,蛋白质含量上升;小麦种子的多糖含量呈先升后降的趋势,蛋白质含量呈先降后升的趋势。另外,在低温胁迫下,藜麦、青稞、水稻和小麦种子中都有不同比例的蛋白质二级结构从无序转向有序。因此,傅里叶变换红外光谱结合曲线拟合是一种研究低温胁迫对种子萌发影响的有效方法。

As the beginning of the plant life process,seed germination directly affects the final crop yield.Lowtemperature frequently inhibit seed germination,posing a serious threat to food production safety.The effects of lowtemperature on the germination of grain seeds(quinoa,highland barley,rice,and wheat)were investigated in this paper using Fourier transform infrared spectroscopy combined with curve-fitting.The results showed that the germination potential,germination rate,and germination index of the four grain seeds decreased as the temperature decreased,but the germination rate and germination index of highland barley seeds remained high at 4℃,indicating that highland barley seeds had stronger low-temperature tolerance.The results of infrared spectrum demonstrated that the original infrared spectra of grain seeds under low-temperature were similar,mainly composed of the characteristic absorption peaks of polysaccharide,fat,and protein.Under low-temperature stress,the curve fitting analysis for polysaccharide(1200-950 cm^(-1))and amide Ⅰ band(1700-1600 cm^(-1))in quinoa seeds revealed that polysaccharide content increased while protein content decreased.The polysaccharide and protein content of highland barley seeds increased at first,then decreased.The content of polysaccharide in rice seed decreased,while the content of protein increased.The polysaccharide content of wheat seeds increased first and then decreased,while the protein content decreased first and then increased.Furthermore,under lowtemperature stress,different proportions of protein secondary structures in quinoa,highland barley,rice,and wheat seeds changed from disorder to order.As a result,Fourier transforms infrared spectroscopy combined with curve fitting is an efficient method for investigating the effect of low-temperature stress on seed germination.