低温对不同基因型棉种萌发过程中酶活性及激素含量的影响

Effects of low temperature on enzyme activity and hormone content in germination of different genotypes of cotton seeds

为探讨低温胁迫对不同基因型棉种萌发阶段的酶活性、渗透调节物质及激素含量的变化,以不同基因型棉花品种(‘新陆早65’和‘新海35’)为试验材料,设3个温度处理:1215oC、1821oC以及2528oC,测定了棉花种子萌发期不同阶段超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性和可溶性蛋白(SP)、可溶性糖(SS)、游离脯氨酸(FP)、丙二醛(MDA)和过氧化氢(H2O2)含量,以及赤霉素(GA3)、脱落酸(ABA)、生长素(IAA)和玉米核甘素(ZR) 4种内源激素的含量。结果表明,随温度的下降,棉种的发芽率、发芽势、发芽指数均呈显著性差异,且‘新海35’表现出更强的发芽能力;棉种抗氧化酶活性,渗透调节物质含量等均升高,而内源激素含量则呈现降低的变化趋势,其中‘新海35’的SOD、POD、CAT活性和SP、SS、ABA、GA3、IAA、ZR含量及GA3/ABA、IAA/ABA值在低温胁迫下分别比‘新陆早65’高42.34%、9.53%、27.53%、27.40%、10.42%、29.51%、91.01%、37.38%、39.31%、25.02%、6.53%,而‘新陆早65’的MDA含量及ZR/ABA值分别比‘新海35’高16.09%、23.68%。相关性分析发现抗氧化酶活性、渗透调节物质含量与内源激素含量存在显著或极显著关系,与激素比值存在显著或极显著的负相关;主成分分析发现ABA和SS是影响棉种萌发的主要因素。因此,海岛棉通过增强抗氧化酶活性,增加渗透调节物质和内源激素含量,减少MDA含量,降低活性氧的积累,从而加快物质代谢与转换,表现出更强的耐寒性。

In order to investigate the changes of enzyme activity, osmotic adjustment substance and hormone content in different genotypes of cotton genotypes during low temperature stress, this study used different genotype cotton varieties(‘Xinluzao 65’ and ‘Xinhai 35’) as experimental materials. Three temperature treatments were set: 12–15 oC, 18–21 oC and 25–28 oC. Physiological and biochemical methods were used to determine the superoxide dismutase(SOD), peroxidase(POD) and other stages of cotton seed germination. Catalase(CAT) activity, soluble protein(SP), soluble sugar(SS), free proline(FP), malondialdehyde(MDA) and hydrogen peroxide(H2 O2), and gibberellin(GA3) The contents of four endogenous hormones, abscisic acid(ABA), auxin(IAA) and corn ribose(ZR), were analyzed and compared. The results showed that with the decrease of temperature, the germination rate, germination potential and germination index of cotton varieties showed significant differences, and ‘Xinhai 35’ showed stronger germination ability;with the decrease of temperature, The activities of antioxidant enzymes and osmotic adjustment substances in cotton varieties increased, while the content of endogenous hormones showed a decreasing trend. The activities of SOD, POD and CAT of ‘Xinhai 35’ and SP, SS, ABA, GA3, IAA, ZR contents and GA3/ABA, IAA/ABA values were higher at ‘Xingluzao 65’ 42.34%, 9.53%, 27.53%, 27.40%, 10.42%, 29.51%, 91.01%, 37.38%, 39.31%, 25.02%, 6.53%, respectively, under low temperature stress. The MDA content and ZR/ABA values of ‘Xinluzao 65’ were respectively higher than ‘Xinhai 35’ 16.09%, 23.68%. Correlation analysis showed that there was a significant or extremely significant relationship between antioxidant enzyme activity, osmotic adjustment substance content and endogenous hormone content, and there was a significant or extremely significant negative correlation with hormone ratio. Principal component analysis found that ABA and SS were involved in cotton seed germination major factor. Therefore, Sea Island Cotton enhances the activity of antioxidant enzymes, increases the content of osmotic adjustment substances and endogenous hormones, reduces MDA content, reduces the accumulation of reactive oxygen species, thereby accelerating the metabolism and conversion of substances, and exhibits stronger cold resistance.