【作者】 陈二影；

【导师】 王振林；

【作者基本信息】 山东农业大学 ， 作物栽培学与耕作学， 2012， 博士

【摘要】 我国黄淮冬麦区在小麦开花后常受阴雨寡照的影响，且小麦生产中存在群体过大，小麦生育后期群体内光照不足等问题，严重影响了小麦的产量和籽粒的品质。因此，本研究选用不同穗型和筋型的两品种，通过设置花后不同时期遮光、不同强度遮光和氮肥调节措施从农艺、生理和生化性状上系统研究花后弱光对小麦籽粒产量和蛋白质品质的影响及其生理基础。进一步明确花后弱光下，小麦生长发育的生理生化的变化，阐明了通过调节氮肥施用时期缓解这种不利影响的作用途径及生理、生化机制。主要研究结果如下：1花后不同时期遮光下小麦籽粒蛋白质品质变化的研究小麦籽粒花后不同时期遮光均提高了两不同筋型小麦品种籽粒蛋白质及各组分的含量。在两小麦品种中，小麦籽粒灌浆前期遮光对醇溶蛋白的影响更为显著，降低了麦谷蛋白和醇溶蛋白的比值；籽粒灌浆中期遮光对麦谷蛋白的影响更为显著，提高了麦谷蛋白和醇溶蛋白的比值。这与小麦籽粒醇溶蛋白在籽粒灌浆前期形成，而麦谷蛋白在籽粒灌浆中后期形成有关。两筋型小麦品种谷蛋白大聚合体（GMP）的含量在籽粒灌浆期内均呈先降低后增加的趋势，在花后21天达到最低值。在小麦两生长季内，强筋小麦品种济南17(JN17) GMP的含量在整个籽粒灌浆期内均高于中筋小麦品种泰农18(TN18)。说明强筋小麦品种JN17的优质特性与其较高的GMP含量有关。小麦花后各时期遮光处理均显著提高了籽粒GMP的含量。在小麦花后0-21天，籽粒灌浆前期遮光处理对GMP含量的影响更为显著，而花后21-35天，灌浆中期和后期遮光处理的作用更为显著，两品种表现相同的趋势。小麦籽粒灌浆期不同时期遮对GMP的粒度分布有着显著的影响。小麦籽粒灌浆前期遮光显著提高了籽粒小粒径的GMP颗粒所占的体积、数目和表面积百分比，降低了大粒径GMP颗粒所占的比例，而籽粒灌浆中期和后期遮光则表现出相反的趋势。说明GMP颗粒的形成对籽粒灌浆前期的弱光非常敏感，而在籽粒灌浆中期和后期短期的弱光处理则有助于加速大粒径GMP颗粒形成的超聚合过程，促进大粒径的GMP颗粒的形成。两筋型小麦品种各亚基均在花后14天开始积累，小麦籽粒灌浆各阶段遮光处理对各亚基的起始形成时间无显著影响，但均显著提高了籽粒各亚基的含量，且在籽粒灌浆后期差异更为显著。小麦花后不同时期遮光处理均提高了0-21天以前小麦籽粒总亚基及各亚基的积累量，但降低了花后21-35天以后籽粒总亚基的积累量，两品种表现趋势一致。两小麦品种Glu-A1、Glu-B1和Glu-D1位点上的各亚基含量和积累量均随小麦籽粒灌浆进程呈逐渐增加的趋势，在花后35天时达最大值。强筋小麦品种JN17的Glu-A1位点上1亚基的含量在整个籽粒灌浆期内均高于中筋小麦品种TN18的1亚基含量。小麦籽粒中HMW-GS的含量与粒径﹤10m和﹤100m的GMP颗粒的体积百分比呈显著的负相关，与粒径﹥100m的GMP颗粒呈显著的正相关。在遮光条件下，大粒径GMP颗粒的体积形成提高了籽粒中HMW-GS的含量。2花后不同强度遮光下小麦生长发育及机理的研究小麦花后轻度遮光通过小麦自身的补偿机制提高了两穗型小麦品种的籽粒产量，而中度和重度遮光均则显著降低了籽粒产量。在遮光条件下，小麦植株的补偿效应随着遮光强度的增强而逐渐降低，且多穗型品种JN17的补偿效应要高于大穗型品种TN18。小麦花后不同强度遮光均显著降低了两穗型小麦品种籽粒的最大灌浆速率，但推迟了两小麦品种最大籽粒灌浆速率形成的时间。小麦花后各强度遮光提高了多穗型品种JN17籽粒灌浆持续期，但降低了大穗型品种TN18籽粒灌浆持续期。小麦花后不同强度遮光均显著降低了花后干物质的积累，且随遮光强度的提高，花后干物质降低的幅度增大，两品种表现趋势一致。小麦花后中度和重度遮光均显著提高了花前同化物质向籽粒中的转运及对籽粒的贡献，而小麦花后轻度遮光处理则提高了花后小麦花后同化物质的积累及对籽粒的贡献。小麦花后轻度遮光处理显著提高了两小麦品种的上三叶的单叶净光合速率，而重度遮光处理均显著降低了两小麦品种上三叶单叶的净光合速率。小麦花后中度遮光处理显著降低了小麦旗叶的单叶净光合速率，但提高了倒二和倒三叶的光合速率。小麦花后不同强度遮光均降低了籽粒灌浆前期的叶面积指数，但提高了籽粒灌浆后期叶面积指数，两穗型小麦品种表现趋势一致。小麦花后重度遮光均提前了两穗型小麦品种的最大叶面积指数的形成时间。小麦花后轻度遮光提高了多穗型小麦品种JN17的冠层底部和大穗型品种TN18冠层上部叶面积所占的比例，而花后中度和重度遮光处理则均提高了两品种冠层上部叶面积所占的比例。在小麦花后各遮光条件下，多穗型小麦品种JN17的整个冠层和大穗型品种TN18的底部冠层的光能传递系数均显著提高。花后轻度遮光提高了上三叶光系统Ⅱ的Fv/Fo、 PS和ETR,降低了NPQ值，而重度遮光则显著降低了光系统Ⅱ的活性和光能的利用效率。表明花后轻度遮光提高了两穗型品种的光能的传递、吸收和利用的效率，从而提高了叶片的光合速率。在籽粒灌浆前期，小麦花后各强度遮光处理均降低了小麦上三叶片游离氨基酸的含量和GS活性，但提高了籽粒灌浆后期游离氨基酸的含量和GS活性。小麦花后遮光显著降低了籽粒灌浆前期上三叶中蛋白质的降解，延缓其衰老过程，提高了籽粒灌浆后期上三叶蛋白质降解酶的活性，提高营养器官中氮素的再转运及向籽粒中的分配和转运。3遮光条件下氮肥施用时期对小麦生长发育及机理的研究在小麦生产中增加小麦生育期氮肥的基追比例能显著提高小麦的单穗粒数和籽粒产量，但对单位面积的穗数无显著影响。说明通过提高小麦生育期氮肥的基追比例，特别是在孕穗期追施氮肥均显著提高小麦单穗的粒数和籽粒产量，缓解遮光对小麦籽粒产量的不利影响。在花后弱光条件下，推迟小麦氮肥追施时期及增加小麦中后期追肥比例，均能显著提高小麦品种JN17上三叶片的单叶净光合速率，且对倒二和倒三叶的影响更为显著。小麦品种JN17上三叶的最大光化学活性（Fv/Fm）在不同氮肥施用时期处理间均无显著性差异。而小麦上三叶的潜在光化学活性（Fv/Fo）、电子的传递速率（ETR）和实际光化学效率（PS）随着追肥时期的后移均呈逐渐提高的趋势，以拔节期和孕穗期追施氮肥处理最高，各施肥时期处理间的差异在倒二和倒三叶中更为显著。在遮光条件下，推迟施肥时期及追施比例均显著降低了其NPQ值。表明在花后弱光的条件下，推迟施肥时期及提高追施比例均能有效提高小麦上三叶片吸收光能的利用效率从而提高叶片的光合速率，增加干物质的积累。在遮光条件下，施肥时期后移及后期追施比例的增加均显著降低了小麦品种JN17上三叶籽粒灌浆前期谷氨酰胺合成酶和蛋白质降解酶的活性，但提高了在籽粒灌浆后期的活性。上三叶游离氨基酸的含量在籽粒灌浆前期随着施肥时期的后移及追施比例的增加而降低，而在籽粒灌浆后期则显著提高。表明在花后遮光条件下，推迟氮肥的施用时期及提高氮肥的追施比例能显著降低了籽粒灌浆前期上三叶叶片蛋白质的降解，延缓其衰老，提高了籽粒灌浆后期上三叶蛋白质降解酶的活性，加速了营养器官中氮素的再转运及向籽粒中的分配。更多还原

【Abstract】 Shading after anthesis as a result of cloudy or rainy days and big population density oftenoccurs in the the Huang-Huai-Hai plain of China, and has negative influence on wheat grainyield and quality. In the present study, two different gluten winter wheat cultivars withdifferent subunit compositions, and two different spike-types cultivars were used to evaluatethe effect of shading at different grain filling stages, different shading intensities and nitrogenregulatory measures on changes in wheat grain yield and quality at agronomy, physiology andbiochemistry levels. Information obtained will help to determine the physiology andbiochemistry changes in wheat growth and development and how to alleviate the negativeeffect of shading on wheat development from adjusting the nitrogen application times, whichwill provide a theoretical basis for obtaining higher grain yield and superior grain quality inwheat. The main results were as follows:1The study of changes of wheat grain protein quality at different grain filling stagesShading at different grain filling stage increased the protein content and its componentsat the maturity. The gliadin are more sensitive to shading at early grain filling stage thanshading at other grain filling stages, the content of glutenin increases most to the shading atmiddle shading grain filling stage for two cultivars. The ratio of glutenin to gliadin wasincreased by shading at the early grain filling stage and decreased by shading at the middlegrain filling. This could be explained that the gliadin protein was formed at early grain fillingstages, while the glutenin protein was formed at middle and late grain filling stages.The changes of GMP content during the grain filling showed the “V” model with thelowest content at21DAA for the two cultivars. This may be caused by the lower proteinaccumulation rate than the starch accumulation rate which had dilution effect on the GMPcontent. For the comparison of the two cultivars in the two seasons, the GMP content inJinan17was higher than that in Tainong18in different treatments during the grain filling,especially at the maturity. Shading at different grain filling stages all increased the GMPcontent during the grain filling. The GMP content under shading at early grain filling stagewas higher than shading at middle grain filling stages before and in21DAA and then was lower than shading at middle and late grain filling stages. The proportion (by volume, numberand surface area) of larger granules in GMP was decreased by shading at early grain fillingstage and increased by shading at middle and late grain filling stages. In general, the presentresult suggested that the formation of larger GMP particles was more sensitive to shading atearly grain filling stage and short-term dim light at the middle and late grain filling stageswere helpful to accelerate the hyper-aggregation process and promote the formation of largerGMP granules.HMW-GS accumulation in grain started at about14DAA in Jinan17and Tainong18, theinitial formation time of individual subunits was not influenced by shading at different grainfilling stages, however the content of each it was increased by shading at different grainfilling stages, especially at middle grain filling stage, though the amount per grain of eachindividual subunit was decreased by shading which was due to the decreased grain weight atmaturity. The content and accumulation amount of Glu-A1、Glu-B1and Glu-D1subunitsshowed the increasing trend during the grain filling stages and attained the maximum valuesat the35DAA. The content of Glu-A1subunits of stronger gluten cultivars JN17were higherthan that of TN18during the whole grain filling stages. The present result indicated thatshading during grain filling had no effect on the origination formation time of HMW-GS, butincreased the HMW-GS content and decreased the HMW-GS amount per grain in wheat grainat maturity.The HMW-GS content was negatively correlated with the volume proportion of granules<10and <100m and positively correlated with the volume proportions of GMPgranules>100m, while the total HMW-GS content was not significantly correlated with theproportion by volume of GMP granules10-100m, which indicated that the correlationbetween larger GMP granules and HMW-GS content may account for a positive relationshipbetween GMP and HMW-GS. The present result showed that an increase in the totalHMW-GS content enhanced the volume proportion of larger GMP granules induced byshading.2The study of wheat growth and development mechanism at different shading intens-itiesLow-intensity shading increased grain yield by9.9%and6.6%in Jinan17and Tainong18respectively, while the grain yield was reduced significantly by mid and serious shading afteranthesis in both Jinan17(multiple-spikes cultivar) and Tainong18(Larger-spikes cultivar) inthe present study. There had compensation effect on grain yield under shading, and the compensation effect decreased with the increasing shading intensity. In addition, thecompensation was higher in the multiple-spikes cultivar (Jinan17) than the larger-spikescultivar (Tainong18) under low shading. The different shading intensities treatmentssignificantly decreased the maximum grain filling rates and postponed the time of themaximum grain filling rates. The grain filling duration times in JN17were increased byshading after anthesis, while it was decreased by shading after anthesis in TN18.The different shading intensities treatments especially serious shading treatment alldecreased the dry matter accumulation after anthesis, the two cultivars showed the sametrends. The mid and serious shading increased the redistribution of stored dry matter fromvegetative organs into grains, while low shading increased the contribution of dry matteraccumulated from anthesis to maturity to the grain. In addition, under all shading treatments,the multiple-spike cultivar Jinan17could remobilize more dry matter stored in vegetativeorgans into grains than the larger-spike cultivar Tainong18to compensate the loss ofphotosynthesis after anthesis ascribed to shading.In the present study, we found that serious shading decreased photosynthesis of top threeleaves during the whole grain filling stages for both cultivars, while under low shading,photosynthesis of the top three leaves in both cultivars all increased during the whole grainfilling stages compared with control. In addition, mid shading reduced Pn of flag leaf andincreased Pn of penultimate and third leaves in both cultivars. Shading reduced the leaf areaindex at the early grain filling stages, however, LAI was increased at the late grain fillingstages for both cultivars by shading. In addition, serious shading brought forward theformation of the maximum LAI for the both cultivars. Low shading increased the fraction ofbottom leaf area in Jinan17and the fraction of top leaf area in Tainong18respectively, whilemid and serious shading all increased the fraction of top leaf area in both cultivars. However,better light transmission was found in the whole canopy in Jinan17and bottom layer of wheatcanopy in Tainong18under shading than the control. The PS system centre was found not tobe essentially damaged by shading, and inversely low shading increased Fv/Fm, PS andETR, and decreased NPQ in the top three leaves. However serious shading damaged PS system activity of top three leaves including decreasing Fv/Fo, PS and ETR, andincreasing the light energy which was dispersed via heat. This indicated that low shadingincreased the light absorption and use efficiency, and then increased the photosynthesis.The different shading intensities treatments decreased the free amino acid content andglutamate synthetase activity of top three leaves in JN17during the early grain filling stages, however increased them at late grain filling stages. This indicated that shading after anthesissignificantly decreased the protein degradation and postponed senescence of top three leavesduring the early grain filling stages. While during the late grain filling stages, shading afteranthesis increased remobilization of accumulated protein in leaves and it’s contribution tograin.3The study of effect of nitrogen application times on wheat growth and developmentmechanism under shadingThe increased ratio of nitrogen application at late grain filling could significantlyincrease the kernels per spike and grain yield, while had no effect on spikes per area. Thisindicated that increasing ratio of nitrogen application at late grain filling, especially at headingstages could increase the grain yield from augmenting the kernels per spike to alleviate theharmful effect of shading on wheat grain yield.Under shading, the increased ratio of nitrogen application at late grain filling couldsignificantly increase the photosynthesis of top three leaves in JN17, especially at thepenultimate and third leaves. Increasing ratio of nitrogen application at late grain fillingsignificantly increase the Fv/F0, ETR and PS, while had no effect on Fv/Fm. NPQ was alsodecreased by increasing ratio of nitrogen application at late grain filling stages. This indicatedthat increasing ratio of nitrogen application at late grain filling stages increased the lightabsorption and use efficiency, and then increased the photosynthesis.Increasing the ratio of nitrogen application at late grain filling stages decreased thedegradative enzymet and glutamate synthetase activity of top three leaves in JN17during theearly grain filling stages, however increased them at late grain filling stages. Free amino acidcontent of top three leaves showed increasing trend with increasing the ratio of nitrogenapplication at late grain filling stages. This indicated that increasing the ratio of nitrogenapplication at late grain filling stages significantly decreased the protein degradation andpostponed senescence of top three leaves during the early grain filling stages. While duringthe late grain filling stages, increasing the ratio of nitrogen application at late grain fillingstages under shading increased remobilization of accumulated protein in leaves and it’scontribution to grain.更多还原