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【目的】小麦生育后期土壤渍水(WL)、高温(HT)是长江中下游和黄淮南部麦区的主要气象灾害之一,对小麦产量形成和品质性状影响较大。本研究旨在探明小麦在逆境及其复合胁迫下籽粒淀粉组成和品质的变化。【方法】2011—2013年度以小麦品种郑麦004为材料,采用盆栽方式研究小麦花后土壤渍水(WL,花后5—14 d全天进行)、高温(HT,花后5—14 d,每天10:00—16:00处理)及渍水+高温复合胁迫(WL+HT)对小麦产量、淀粉组成及其糊化特性的影响。【结果】WL、HT及WL+HT胁迫均导致小麦淀粉产量显著下降,其中2011—2012年分别下降28%、46%和52%,2012—2013年分别下降27%、43%和61%。WL对总淀粉及其组分的影响不显著,但使直链淀粉含量降低,支链淀粉含量增加,淀粉直/支比呈下降趋势。HT和WL+HT复合胁迫使直链淀粉和支链淀粉含量均下降,并显著降低总淀粉含量,其中2011—2012年度使总淀粉含量分别下降11.0%和10.8%,2012—2013年度分别下降8.2%和5.5%。WL对淀粉糊化特性的影响两年间存在差异:2011—2012年度WL使低谷黏度显著下降,但对其他黏度参数的影响不显著;而2012—2013年度WL使其峰值黏度、低谷黏度、终结黏度、稀懈值和回生值分别增加27.9%、39.2%、31.5%、21.9%和27.9%,均达显著水平。HT显著降低淀粉的峰值黏度、低谷黏度、终结黏度、稀懈值和糊化时间,2011—2012年度分别降低22.2%、22.0%、16.9%、22.5%和4.8%,2012—2013年度分别降低39.6%、62.0%、62.7%、28.0%和7.0%。WL+HT复合胁迫对糊化特性的影响两年度间存在差异:2011—2012年度WL+HT使其峰值黏度、低谷黏度、终结黏度和稀懈值分别显著降低20.9%、23.9%、10.4%和15.2%,而2012—2013年度使其分别显著增加15.4%、30.2%、7.1%和6.4%。相关分析表明,籽粒中总淀粉和支链淀粉含量与峰值黏度、低谷黏度、终结黏度和稀懈值呈显著或极显著的正相关,而直链淀粉含量与主要黏度参数相关多不显著。【结论】土壤渍水、高温使小麦淀粉产量显著下降,土壤渍水和高温复合胁迫明显加重了危害。逆境胁迫改变淀粉组分和淀粉直/支比,导致主要淀粉糊化参数变化。与土壤渍水相比,高温对淀粉糊化参数的影响更大,而复合胁迫未表现出加重影响的现象。
【Objective】 Soil waterlogging (WL) and high temperature (HT) were one of the major meteorological disasters in wheat fields in the middle and lower reaches of the Yangtze River and the southern Huanghuai region in late growth stage of wheat, which had a great impact on the yield formation and quality traits of wheat. The purpose of this study was to determine the changes in starch composition and quality of wheat under stress and its combined stress. 【Method】 Wheat varieties Zhengmai 004 were used as materials to study soil waterlogging after flowering (WL) in wheat from 5 days to 14 days post-anthesis, and high temperature (HT, 5-14 days after anthesis) , Daily treatment of 10: 00-16: 00) and waterlogging + high temperature combined stress (WL + HT) on wheat yield, starch composition and gelatinization characteristics. 【Result】 Starch production of wheat decreased significantly under WL, HT and WL + HT stress, with 28%, 46% and 52% decrease in wheat from 2011 to 2012 respectively and 27%, 43% and 61% decrease from 2012 to 2013 respectively. The effect of WL on total starch and its components was insignificant, but the content of amylose decreased, the content of amylopectin increased and the ratio of starch / branch decreased. Under the combined stress of HT and WL + HT, the content of amylose and amylopectin decreased, and the content of total starch was significantly reduced, of which the total starch content decreased by 11.0% and 10.8% respectively from 2011 to 2012 and from 8.2% to 8.2% in 2012-2013 % And 5.5%. The effect of WL on starch gelatinization characteristics was different in two years: WL decreased the viscosity of the valley significantly in 2011-2012, but had no significant effect on the other viscosity parameters; WL made the peak viscosity, valley viscosity and the final viscosity in 2012-2013 , And the scores of remission and reversion increased by 27.9%, 39.2%, 31.5%, 21.9% and 27.9% respectively, reaching significant levels. HT significantly decreased starch peak viscosity, trough viscosity, terminal viscosity, breakdown value and gelatinization time by 22.2%, 22.0%, 16.9%, 22.5% and 4.8% respectively in 2011-2012, and decreased by 39.6% in 2012-2013 %, 62.0%, 62.7%, 28.0% and 7.0%. The effect of WL + HT compounding on gelatinization characteristics was different in two years: WL + HT significantly decreased peak viscosity, trough viscosity, end viscosity and breakdown value by 20.9%, 23.9% and 10.4% respectively in 2011-2012 15.2% in 2012-2013, a significant increase of 15.4%, 30.2%, 7.1% and 6.4% respectively in 2012-2013. Correlation analysis showed that there was a significant positive correlation between total starch and amylopectin content in peak and peak viscosity, trough viscosity, final viscosity and breakdown value, while amylose content was not significantly correlated with the main viscosity parameters. 【Conclusion】 Soil waterlogging and high temperature significantly decreased the starch yield of wheat, and soil waterlogging and high temperature combined stress significantly aggravated the damage. Adverse stress changes the starch composition and starch straight / branch ratio, leading to changes in the main starch gelatinization parameters. Compared with soil waterlogging, high temperature had a greater influence on the starch gelatinization parameters, while the composite stress did not show any aggravating effect.