【作者】 顾锋；

【导师】 王振林；

【作者基本信息】 山东农业大学 ， 农业生态学， 2009， 博士

【摘要】 本研究选用12个不同类型小麦品种(系),研究了小麦籽粒淀粉的粒度分布特征、完熟期籽粒提取淀粉的糊化特性及其发育过程中直支链淀粉积累特点、淀粉合成关键酶活性变化,并针对不同品质类型小麦品种设计3个氮肥水平,研究了氮素水平对小麦籽粒淀粉的粒度分布、直支链淀粉积累、糊化特性的影响,初步探讨了小麦籽粒淀粉组成与其糊化特性之间的关系。研究结果表明:1小麦籽粒淀粉粒度分布特征及其对氮素水平的响应小麦籽粒中淀粉粒的数目分布呈单峰或双峰曲线变化,仅个别品种呈3峰曲线变化;体积和表面积分布呈双峰曲线变化,仅个别品种呈3峰曲线变化。B型淀粉粒的数目和表面积比例显著高于A型淀粉粒的,A型淀粉粒的体积比例一般高于B型淀粉粒的。不同类型小麦籽粒中淀粉粒度分布存在差异。糯小麦籽粒中B型淀粉粒的比例显著高于普通小麦,强筋小麦籽粒中B型淀粉粒的比例明显高于弱筋小麦。氮素水平对不同品质类型小麦籽粒中的淀粉粒度分布均存在显著影响,且影响的趋势因品种类型而异。强筋小麦随氮肥用量的增加,B型淀粉粒的比例呈下降趋势,平均径和中位径显著增大,体积和表面积分布的B型淀粉粒峰值粒径显著增大。中筋小麦随氮肥用量的增加,籽粒中B型淀粉粒的比例呈一定程度的增大趋势,平均径和中位径呈降低趋势。弱筋小麦增施氮肥后,籽粒中B型淀粉粒的比例显著提高,且以低氮处理的为最大,低氮处理的平均径和中位径均低于对照。2不同类型小麦品种淀粉积累的差异及其酶学机制籽粒灌浆过程中糯小麦、部分糯小麦和非糯小麦淀粉含量、积累量变化存在显著差异。非糯小麦和部分糯小麦籽粒中总淀粉和支链淀粉含量快速提高的时间较糯小麦早,前两者为花后6天,后者为花后10天;支链淀粉快速增长终止时间方面,糯小麦相对较早。花后10天至成熟期的大部分籽粒灌浆过程中,糯小麦和部分糯小麦的淀粉含量一般高于非糯小麦;糯小麦支链淀粉含量显著高于非糯小麦和部分糯小麦;糯小麦直链淀粉快速积累的时间显著短于部分糯小麦和非糯小麦,其直链淀粉含量极低,显著低于部分糯小麦和非糯小麦。不同类型小麦籽粒灌浆过程中直支淀粉比的变化趋势显著不同,糯小麦直支淀粉比显著低于部分糯小麦和非糯小麦。籽粒灌浆初期(花后6天前),糯小麦的蔗糖合酶活性较高,降解蔗糖的能力较强,表现为蔗糖含量较低,同时此期UGPP和AGPP活性较高,说明淀粉合成所需底物的供应能力较强。尽管此期糯小麦的SSS、GBSS和SBE活性低于非糯小麦和部分糯小麦,但其支链淀粉和总淀粉含量高于后两者。糯小麦、部分糯小麦和非糯小麦籽粒灌浆过程中AGPP活性的变化趋势存在显著不同。非糯小麦和部分糯小麦开花后籽粒中的AGPP活性持续提高,花后20天左右达峰值,之后降低;糯小麦的AGPP活性花后6天前略有降低,花后6-25天快速提高,于花后25天左右达峰值,之后降低。整个籽粒灌浆过程中,非糯小麦和部分糯小麦籽粒中GBSS活性显著高于糯小麦。与非糯小麦和部分糯小麦相比,糯小麦籽粒灌浆后期UGPP、AGPP、SBE和DBE活性较高是其支链淀粉含量较高、持续时间较长的重要生理原因。3氮素水平对小麦籽粒灌浆过程中淀粉含量和积累量的变化存在显著影响增施氮肥降低灌浆过程中小麦籽粒中直链淀粉的含量。低氮处理提高小麦籽粒中总淀粉含量,但高氮处理对其影响不大,甚至降低。支链淀粉含量变化趋势与总淀粉含量大致相同。增施氮肥降低灌浆过程中小麦籽粒中直链淀粉的积累量。低氮处理提高强筋小麦豫麦47籽粒中支链淀粉积累量,但高氮处理使其降低;低氮处理提高中筋小麦山农8355籽粒灌浆过程中的支链淀粉积累量,但高氮处理使其支链淀粉积累量的增幅降低;增施氮肥降低弱筋小麦豫麦50籽粒中灌浆前期的支链淀粉积累量,灌浆后期低氮处理的支链淀粉积累量迅速增长,高出对照2%,而高氮处理虽有所提高但始终低于对照。强筋小麦豫麦47高氮处理显著降低总淀粉积累量;中筋小麦山农8355籽粒淀粉积累量在灌浆过程中,随氮肥增施,低氮处理大部分时间显著高于对照;高氮处理仅在灌浆前期下降显著;弱筋小麦豫麦50籽粒淀粉积累量在灌浆前期,低氮处理和高氮处理均下降显著,降幅超过5%,有时甚至超过10%。4小麦籽粒提取淀粉糊化特性及其对氮素水平的响应非糯小麦和部分糯小麦的高峰粘度、最终粘度明显高于糯小麦,而低谷粘度明显低于糯小麦,从而造成非糯小麦和部分糯小麦的稀懈值、反弹值显著高于糯小麦;糯小麦的糊化温度和峰值时间显著高于非糯小麦和部分糯小麦。强筋小麦的高峰粘度、稀懈值显著高于中筋小麦和弱筋小麦,其低谷粘度、最终粘度、反弹值、峰值时间、糊化温度显著低于后两者。强筋品种增施氮肥后,低谷粘度、最终粘度和反弹值提高;低氮处理的糊化温度提高,到达峰值的时间延长,高峰粘度、稀懈值降低;高氮处理的糊化温度降低,峰值时间缩短,高峰粘度、稀懈值提高。中筋品种增施氮肥后高峰粘度、低谷粘度、最终粘度和稀懈值呈增大趋势;低氮处理的糊化温度降低,峰值时间提前,而高氮处理的糊化温度增大,峰值时间拖后。弱筋品种增施氮肥后淀粉糊化参数均降低,且低氮处理降低的幅度较高氮处理大。5小麦籽粒淀粉组成与糊化特性的相关性分析相关性分析结果表明,淀粉的直、支链淀粉组成和粒度分布与其糊化特性间存在一定相关性。B型淀粉粒的数目、体积和表面积比例与高峰粘度和稀懈值存在显著正相关;与低谷粘度、最终粘度和反弹值存在显著负相关;与峰值时间呈一定程度负相关,但未达显著水平。籽粒中直链淀粉含量、支链淀粉含量和总淀粉含量与高峰粘度、稀懈值呈显著负相关,与低谷粘度、最终粘度、反弹值和峰值时间呈一定程度正相关。更多还原

【Abstract】 In this study,we selected twelve different type wheat cultivars to study starch granule size distribution,isolated starch pasting properties,accumulation characteristics of amylose and amylopectin,dynamic changes of the activities of key enzymes related to starch biosynthesis.At the same time,we selected different quality-type wheat cultivars and set three nitrogen fertilizer rates to study effects of nitrogen application rates on starch granule size distribution,composition of amylose and amylopectin,and starch pasting properties.The realtionship between wheat starch composition and pasting properties was also analyzed.The main results were as follows:1 The granule size distribution characteristics of wheat grain starch and its response to nitrogen application ratesMost of wheat endosperms had a unimodal or bimodal curve in starch granule number distribution,and a bimodal curve in starch guanule volume or surface area distribution.Few cultivars in our study showed a trimodal curve in starch granule number distribution and a trimodal curve in starch guanule volume or surface area distribution.The number and surface area ratioes of B-type starch granules were much higher than those of A-Type starch granule in wheat grains.But the volume ratioes of A-Type starch granules were commonly higher than those of B-type starch granules.There exised obvious difference in the starch granule distribution among different type wheat cultivars.The ratioes of B-type starch granules in waxy wheat grains were much higher than those in nonwaxy wheat grains.The ratioes of B-type starch granules in strong-gluten wheat grains were much higher than those in weak-gluten wheat grains.The nitrogen rates influenced the distribution of starch granules in different quality-type wheat grains significantly,and the influencing trend varied with genotypes.Increasing nitrogen fertility amount decreased the ratioes of B-type starch granules and augmented the average diameter and the middle diameter markedly in the endosperm of strong-gluten wheat.The peak diameters of B-type starch granules in the volume and surface area distribution enhanced markedly in the endosperm of strong-gluten wheat with the increasing of nitrogen rates.The B-type starch granule ratioes in the medium-gluten wheat enhanced with a reasonable nitrogen rate,at the same time,the average diameter and the middle diameter decreased.The B-type starch granule ratioes in the weak-gluten wheat enhanced significantly by increasing nitrogen rates,and the B-type starch granule ratioes of low nitrogen rate(LN) were the highest among those of three treatments.The average diameter and the middle diameter of LN in the weak-gluten wheat were lower than those of CK.2 The difference of starch accumulation and the enzymatic mechanism of starch biosynthesis in different type wheat cultivarsDuring wheat grain filling,the dynamic changes of starch content and accumulation were significantly different among waxy,nonwaxy and partial waxy wheat cultivars.The starch and amylopectin(AP) content began to increase quickly in nonwaxy and partial waxy wheat grains at 6 days after anthesis(DAA),and that was at 10 DAA in waxy wheat grains.The time of AP content stopped increasing quickly in waxy wheat grains was earlier than that in nonwaxy and partial waxy wheat grains.The starch contents in waxy and partial waxy wheat were commonly higher than those in nonwaxy wheat during grain filling after 10 DAA.The AP content in waxy wheat was much higher than those in nonwaxy and partial waxy wheat.The time of amylase(AM) accumulation increasing quickly in waxy wheat was much shorter than those in nonwaxy and partial waxy wheat.It resulted in the low AM content in waxy wheat.The AM content in waxy wheat was much lower than those in nonwaxy and partial waxy wheat.The dynamic changes of the ratio of AM to AP were significantly different during different type wheat grain filling stage.The ratio of AM to AP in waxy wheat was much lower than those of nonwaxy and partial waxy wheat.At initial grain filling stage (before 6 DAA),the activity of SS in waxy wheat was higher,the ability of degradation of sucrose was stronger,which appeared as the sucrose content was lower in waxy wheat.At the same time,the activities of UGPP and AGPP were higher,which suggested that the supplying ability of substrates to synthesize starch in waxy wheat was stronger.The activities of SSS,GBSS and SBE in waxy wheat were lower than those in nonwaxy and partial waxy wheat at initial grain filling stage,but the starch and AP contents in waxy wheat were higher than the two latters’.The dynamic changes of activity of AGPP were obvious difference in waxy,nonwaxy and partial waxy wheat during grain filling.The activity of AGPP continually increased in nonwaxy and partial waxy wheat grains after anthesis,which reached peak at about 20 DAA and then decreased.The activity of AGPP slightly decreased in waxy wheat grains before 6 DAA,increased quickly from 6-25 DAA,reached peak at about 25 DAA and then decreased.The activity of GBSS in nonwaxy and partial waxy wheat was much higher than that in waxy wheat during grain filling.The activities of UGPP,AGPP,SBE and DBE in waxy wheat were higher than those in nonwaxy and partial waxy wheat during the later grain filling stage,which was the important physiological reason for the higher and continual longer of AP content.3 Nitrogen rate affected the dynamic changes of starch content and accumulation during wheat grain filling markedlyIncreasing nitrogen fertility could decrease the AM content in wheat grain during grain filling.Increasing nitrogen fertility appropriately could heighten the starch content in wheat grain,but as the amount of nitrogen continued to increase,grain starch content might decrease.The changing trend of AP content was similar to that of starch content.Increasing nitrogen fertility could decrease the AM accumulation in wheat grain during grain filling.Increasing nitrogen fertility appropriately could heighten the AP accumulation in strong-gluten wheat cultivar YM47,but as the amount of nitrogen continued to increase,the AP accumulation decreased.Increasing nitrogen fertility appropriately could heighten the AP accumulation in medium-gluten wheat cultivar SN8355,but as the amount of nitrogen continued to increase,the increasing percent of AP accumulation decreased.Increasing nitrogen fertility could decrease the AP accumulation in weak-gluten wheat cultivar YM50 in the early stage of grain filling.During the later grain filling stage,the AP accumulation of LN increased quickly in weak-gluten wheat YM50,which was higher 2% than CK,but the AP accumulation of HN increased slightly and was lower than CK all the time.Increasing nitrogen fertility excessively could decrease markedly the starch accumulation in strong-gluten wheat cultivar YM47.Increasing nitrogen fertility appropriately, the starch accumulation of LN was mostly much higher than that of CK in medium-gluten wheatcultivar SN8355 during grain filling.As the amount of nitrogen continued to increase,he starch accumulation decreased markedly in the early stage of grain filling.The starch accumulations of LN and HN decreased markedly in weak-gluten wheat cultivar YM50 in the early stage of grain filling,the decreasing range was higher than 5% and it was higher than 10% sometimes.4 The pasting properties of isolated wheat starch and its response to nitrogen application rateThe peak viscosity (PV) and final viscosity (FV) of isolated starch from nonwaxy and partial waxy wheat were much higher than those of isolated starch from waxy wheat.The through viscosity (TV) of nonwaxy and partial waxy wheat was much lower than that of waxy wheat.It resulted in that the breakdown (BD) and setback (SB) of nonwaxy and partial waxy wheat were much higher than those of waxy wheat.The pasting temperature (PM) and peak time (PT) of waxy wheat were much higher than those of nonwaxy and partial waxy wheat. The PV and BD of strong-gluten wheat were much higher than those of medium-gluten and weak-gluten wheat,but its TV,FV,SB,PT and PM were much lower than those of the two latters.In strong-gluten wheat, increasing nitrogen fertility properly could increase the TV,FV,SB,PM and PT,but decrease PV and BD.As the amount of nitrogen increasing to 300kg/hm2,the PM and PT decreased,and thePV,TV,BD,FV and SB increased.In medium-gluten wheat,increasing nitrogen fertility properly could increased the PV,TV,FV and BD,but decreasing PM and PT.As the amount of nitrogen increasing to 300kg/hm2,the PV,TV,FV,BD, PM and PT increased.The RVA parameters of isolated starches from weak-gluten wheat declined after using more nitrogen fertility,and the decreasing range of LN was higher than that of HN.5 Relationships of wheat grain starch composition and starch pasting propertiesThe correlative analysis results indicated that there were close correlations between wheat starch composition,which included AM or AP content and granule size distribution,and starch pasting properties.The number, volume and surface area ratioes of B-type starch granules were significantly positively correlated with PV and BD,and were negatively correlated with TV,FV and SB significantly,and were negatively correlated with PT,but the former did not reach significant level.The AM, AP and starch contents of wheat grains were significantly negatively correlated with PV and BD,and were positively correlated with TV,FV,SB and PT.更多还原