【作者】 卢红芳；

【导师】 王晨阳；

【作者基本信息】 河南农业大学 ， 作物栽培学与耕作学， 2013， 博士

【摘要】 本文以两个不同品质类型小麦品种（郑麦366和豫农949）为材料，连续2年采用盆栽方式与人工气候室模拟高温相结合的方法，研究了灌浆期不同时段（前期和中期）高温、干旱及其复合胁迫对小麦籽粒淀粉粒度分布、谷蛋白大聚合体（Glutenin macropolymer, GMP）粒度分布及籽粒氮代谢关键酶活性的影响，分析不同逆境胁迫下小麦淀粉组成与特性、蛋白质含量与组成和产量的变化，旨在探讨逆境胁迫影响小麦籽粒淀粉和蛋白质品质的内在机制与范围，为小麦抗逆调优高产栽培提供理论依据。其主要研究结果如下：一、小麦籽粒淀粉粒度分析结果表明，淀粉粒数目分布表现为单峰曲线，而体积和表面积均表现为双峰分布。逆境胁迫主要影响小麦籽粒淀粉粒体积和表面积分布，对淀粉粒数目分布的影响较小。在高温、干旱及其复合胁迫下，强筋小麦品种郑麦366的>9.9μm淀粉粒（A型）体积百分比显著下降，<2.8μm的淀粉粒表面积百分比显著下降，而2.8-5.8μm和5.8-9.9μm的淀粉粒体积百分比显著升高。中筋小麦豫农949的>9.9μm（A型）淀粉粒体积和表面积百分比显著升高，2.8-5.8μm和5.8-9.9μm的淀粉粒体积百分比显著降低。两品种比较，强筋小麦郑麦366籽粒淀粉粒体积分布受逆境胁迫的影响较大。不同处理比较，前期高温干旱复合胁迫（HT1+DS）>前期高温胁迫（花后8~11d，HT1）>干旱胁迫（DS）>中期高温胁迫（花后18~21d，HT2）>中期高温干旱复合胁迫（HT2+DS）。结合电镜扫描观察发现，前期高温干旱复合胁迫下淀粉粒明显变形、体积减小。二、灌浆期高温、干旱及其复合胁迫显著影响小麦籽粒淀粉含量、组成和淀粉特性：使籽粒直链淀粉、支链淀粉及总淀粉含量均下降，但对直链淀粉的影响较小，因此使直/支比升高。不同胁迫处理对淀粉糊化特性参数（峰值粘度、低谷粘度、终结粘度、稀懈值和回生值）及膨胀势的影响存在差异：干旱胁迫使强筋小麦郑麦366的糊化特性参数显著升高、膨胀势降低，而使中筋小麦豫农949的糊化特性参数显著降低，膨胀势升高；但高温处理和高温干旱复合胁迫下，两品种的糊化特性参数及膨胀势均降低。两品种比较，中筋小麦豫农949淀粉含量及淀粉特性更易受逆境胁迫的影响。不同处理相比，高温胁迫的影响明显大于干旱处理，高温干旱复合胁迫具有明显的叠加效应。从不同时期高温处理看，前期影响大于中期。三、籽粒淀粉粒度分布与淀粉含量的相关分析结果表明，总淀粉、直链和支链淀粉含量与>9.9μm（A型）淀粉粒体积和表面积分布均呈极显著的负相关，与2.8-5.8μm的淀粉粒体积和表面积百分比呈极显著的正相关。表明淀粉粒体积和表面积分布对淀粉含量及其组分的影响较大，淀粉粒数目百分比主要影响直链淀粉含量。籽粒淀粉粒度分布与淀粉糊化特性也有一定的相关性，其中淀粉粒数目分布与糊化特性的关系较密切。研究结果还表明，膨胀势、糊化特性参数（峰值粘度、终结粘度、稀懈值和回生值）与支链淀粉和总淀粉含量极显著或显著正相关，但与直/支比极显著或显著负相关。上述结果表明，逆境胁迫通过改变籽粒淀粉粒度分布发生改变，影响支链淀粉和总淀粉含量，改变淀粉直/支比，进而影响了淀粉品质特性。四、灌浆期高温、干旱及其复合胁迫均使两品种总蛋白质含量显著提高，灌浆前期高温、高温干旱复合胁迫和干旱胁迫均导致谷/醇比显著下降，而中期高温及高温干旱复合胁迫使谷/醇比显著升高。籽粒蛋白质含量及组成对面粉色泽有重要影响，L*与总蛋白质含量、球蛋白和谷蛋白含量极显著或显著负相关，与谷/醇比显著正相关。a*与总蛋白质和谷蛋白含量均极显著正相关，b*与总蛋白质和球蛋白、谷蛋白含量显著或极显著正相关，与谷/醇比显著负相关。可见逆境胁迫下，总蛋白质含量升高及组成变化，影响面粉L*、a*和b*值，并最终影响面粉色泽。五、灌浆期高温、干旱及其复合胁迫使两品种籽粒谷氨酰胺合成酶（GS）和谷丙转氨酶（GPT）活性升高。相关分析表明，籽粒GS和GPT活性与醇溶蛋白含量呈极显著正相关，籽粒GPT活性与总蛋白含量呈极显著正相关，籽粒GS活性与谷/醇比显著负相关。表明高温、干旱及其复合胁迫下，籽粒GS和GPT活性变化影响醇溶蛋白含量及谷/醇比，从而影响蛋白质含量。六、灌浆期高温、干旱及其复合胁迫影响小麦籽粒谷蛋白大聚合体（GMP）积累，使成熟期籽粒GMP含量升高。不同胁迫对GMP粒度分布的影响存在品种间差异：强筋小麦郑麦366GMP小颗粒（<10μm）所占比例（体积、表面积）降低，大颗粒（>100μm）所占比例升高；而中筋小麦豫农949则相反。高温、干旱及其复合胁迫对两品种籽粒GMP数目分布的影响均较小。相关分析结果表明，GMP含量、蛋白质含量与<10μm的GMP颗粒体积、表面积百分比及<100μm的GMP颗粒表面积百分比呈极显著或显著负相关，与10-100μm和>100μm的GMP颗粒表面积百分比呈极显著或显著的正相关。说明逆境胁迫主要通过影响GMP大小颗粒体积、表面积分布，从而影响GMP含量和蛋白质含量。七、高温、干旱及其复合胁迫使小麦灌浆速率降低，从而降低千粒重、穗粒重和产量。高温干旱复合胁迫下，籽粒灌浆期缩短6d，对产量的影响较单一因子胁迫严重，表现出明显的叠加效应。同时，逆境胁迫亦导致小麦籽粒蛋白质和淀粉产量下降。其中郑麦366更易受高温胁迫的影响，豫农949受干旱胁迫的影响较大。蛋白质和淀粉是小麦产量的主要组成部分，对产量形成有重要影响。穗粒数、穗粒重、千粒重和盆产量与淀粉含量、淀粉产量及蛋白质产量均极显著正相关，与蛋白质含量极显著负相关。因此，高温、干旱及其复合胁迫下，淀粉和蛋白质积累受抑制是造成粒重和产量下降的重要原因。更多还原

【Abstract】 To understand effects of post-anthesis high temperature (HT) and drought stress(DS) on wheat grain quality and yield, the present studies, two different wheatcultivars with strong-and mid-gluten (Zhengmai366and Yunong949) used,combined pot culture with climate-controlled greenhouse simulating high temperature,were carried out to characterize effects of HT, DS and their combination on the starchgranule distribution, glutenin macropolymer particle size distribution and keyenzymes relating to N metabolism in wheat grains, and analyse the variation in starchcomponents, characteristics and protein concentration, components as well as thegrain yield. This aimed to investigate the internal mechanisms and scope that stressinfluenced on the starch and protein quality in wheat grains, and make a theoryevidence for the wheat production of high yield and high quality resisting the stress.The main results are as follows:1. The present results showed that the number distribution showed one-peakcurve, while the volume and surface area distribution all showed two-peak curve indifferent treatments. High temperature, drought stress and the combination of thesestressors during grain filling stage mainly influenced the starch volume and surfacearea distribution, but had less effect on the number distribution. High temperature,drought stress and their combination all led to a significant reduction in the volumeproportion of A-type starch granules (>9.9μm) and the surface area proportion ofgranules <2.8μm, and a significant increase in the volume proportion of granules2.8-5.8μm and5.8-9.9μm in Zhengmai366with strong-gluten. Whereas, in Yunong949with mid-gluten, HT, DS and their combination all led to a significant increase inthe volume and surface area proportion of A-type starch granules, yet a significantdecrease in the volume proportion of granules2.8-5.8μm and5.8-9.9μm. The starchgranule distribution of Zhengmai366with strong-glutenin was more sensitive tostress than Yunong949. The degree of different stress influencing the starch volume distribution showed that the combination of HT and DS at early stage of grain fillingwas greater than other stresses, following were HT applied at early stage, DS, HTapplied at mid-stage of grain filling, and the last was the combination of HT and DSat mid-stage. The starch granules were notably distorted and volume reduced by HTand DS in scanning electron microscope.2. High temperature, drought stress and its combination significantly affected thestarch concentration and its components as well as the starch characteristics in wheatgrains. The concentrations of amylose, amylopectin and total starch all decreasedunder stress treatments, yet the amylose was less sensitive to stress than amylopectinand total starch, which led to the increase in ratio of amylose to amylopectin. Thepasting characteristics of peak viscosity, hold through, final viscosity, breakdown andsetback all significantly increased in Zhengmai366and decreased in Yunong949under DS, while, that significantly declined in Zhengmai366and Yunong949underHT and the combination of HT and DS. The swelling power declined in Zhengmai366and increased in Yunong949under DS, whereas, that decreased in the two wheatcultivars under HT and the combination of HT and DS. The starch concentration andstarch characteristics in Yunong949with mid-gluten were more sensitive to stresstreatments than Zhengmai366. The HT treatments had a greater effect on the starchquality than DS, and there was a notable additive effects between HT and DS. The HTapplied at early stage of grain filling stage had greater effects than that at mid-stage.3. The correlation analysis of starch granule distribution with starchconcentration in wheat grains showed that a negative correlation existed in A-typestarch volume and surface area distribution with concentrations of total starch,amylose and amylopectin in extremely significant level, yet a positive correlationexisted in starch volume and surface area distribution in diameter of2.8-5.8μm withthat. Which indicated that starch volume and surface area distribution were moreclosely related to starch concentrations, yet starch number distribution mainly affectedamylose concentration. Starch granule distribution also had a correlation with starchcharacteristics and starch number distribution was more closely correlated with thatthan others. The correlation analysis of starch characteristics with starch concentrationshowed that swelling power, peak viscosity, final viscosity, breakdown and setbackpositively correlated with concentrations of amylopectin and total starch, and negatively correlated with ratio of amylose to amylopectin in extremely significant orsignificant level. This indicated that starch granule distribution varied with the stresstreatments and influenced concentrations of amylopectin and total starch, leading tothe variation of the ratio of amylose to amylopectin, thus affected starchcharacteristics.4. High temperature, DS and its combination all notably enhanced the totalprotein concentration. Drought stress, high temperature and their combinationtreatments at early stage of grain filling all led to a reduction in ratio of glutenin togliadin. Whereas, HT and combination of HT and DS treatments at mid-filling stagesignificantly increased the ratio of glutenin to gliadin. Protein concentration andcomponents played an important role in flour color. The value of L*was negativelycorrelated with concentrations of total protein, globulin and glutenin in extremely orsignificant level, yet positively correlated with ratio of glutenin to gliadin insignificant level. The value of a*was positively correlated with concentrations oftotal protein and glutenin in extremely significant level. The value of b*waspositively correlated with concentrations of total protein, globulin and glutenin insignificant or extremely significant level, yet negatively correlated with ratio ofglutenin to gliadin in significant level. There were differences in effects on the valueof L*, a*and b*by stress. Under stress, total protein concentration increased andprotein components changed, thus influenced the value of c and L*, a*and b*leadingto the variation of flour color.5. The activities of Glutamine synthetase (GS) and Glutamic pyruvictransaminase (GPT) of wheat grain in two wheat cultivars were all enhanced in themass by DS, HT and their combination. The correlation analysis showed that theactivities of GS and GPT in wheat grains positively correlated with gliadinconcentration and that of GPT positively correlated with total protein concentration inextremely significant level, yet GS activity in wheat grain negatively correlated withratio of glutenin to gliadin in significant level. It indicated that the activities of GS andGPT were changed by HT, DS and its combination, and then mainly influencedgliadin concentration and ratio of glutenin to gliadin, thus led to protein concentrationchanged. 6. The accumulation of glutenin macropolymer (GMP) was affected by HT, DSand its combination during grain filling stage leading to a increase of GMPconcentration at maturity in wheat grains. There were differences of GMP particledistribution by stress in different wheat cultivars. The volume and surface areaproportion of small GMP particle (<10μm) in Zhengmai366with strong-glutendeclined, while that of large particle (>100μm) increased under stress treatments.Whereas, the volume and surface area proportion of small GMP particle (<10μm) inYunong949with mid-gluten increased, still that of large particle (>100μm)decreased under stress treatments. The number distribution of GMP particle was lesssensitive to stress than others. Which indicated that the change of GMP particledistribution under stress mainly due to the variation of GMP volume and surface areaproportion, but not the change of number proportion. The correlation analysis showedthat concentrations of GMP and protein negatively correlated with the volume andsurface area proportion of GMP particle <10μm and with the surface area proportionof that <100μm in extremely significant or significant level, yet positively correlatedwith the surface area proportion of GMP particle10-100μm and>100μm. Itindicated that the concentrations of GMP and protein were influenced mainly due tothe volume and surface area proportion of GMP particle changes under stress.7. High temperature, DS and its combination all reduced the rate of grain filling,leading to the grain weight per spike, thousand grains weight and gain yield alldeclined. The duration of grain filling was shortened by6days under the combinationof HT and DS, which had greater effect on the grain yield than HT or DS. Thisindicated that there was notable superimposed effect between HT and DS. The stressalso led to a reduction in yields of protein and starch. The yield of Zhengmai366wasmore sensitive to HT, yet Yunong949was more sensitive to DS. The yields of starchand protein, main components of grain yield, played an important role in grain yield.It showed that spikes per plant, grains per spike, grain weight per spike, thousandgrains weight and grain yield per pot were all positively correlated with starchconcentration, starch yield and protein yield in extremely significant level, yetnegatively correlated with protein concentration. So it was mostly attributed to theaccumulation of starch and protein disturbed by HT, DS and its combination that thegrain yield declined.更多还原