【作者】 谢祝捷；

【导师】 曹卫星；

【作者基本信息】 南京农业大学 ， 作物栽培学与耕作学， 2003， 博士

【摘要】 理解小麦籽粒品质形成的生理机制及调控原理对于深化小麦品质生理生态研究和指导专用小麦调优栽培具有重要的理论意义和应用前景。本论文以不同类型专用小麦品种为材料，综合研究了适宜土壤水分、干旱和渍水状况对小麦籽粒品质形成、光合特性、C／N物质运转和相关酶活性的影响，探讨了内、外源激素对小麦籽粒品质形成的调控机制，进一步明确了干旱和渍水条件下生长调节剂对小麦籽粒品质的调控作用。主要研究内容和结果如下： 在温室盆栽条件下，以黑小麦76、皖麦38、扬麦10、扬麦9四个籽粒蛋白质含量不同的小麦(Triticum aestivum L．)基因型为材料，研究了花后土壤干旱(SRWC=45％～50％)、渍水和适宜水分条件(SRWC=75％～80％)下小麦籽粒蛋白质和淀粉等主要品质特性。结果表明，干旱显著提高了各品种籽粒蛋白质含量、谷蛋白含量及谷蛋白／醇溶蛋白比值，并显著提高了籽粒湿面筋和干面筋含量。渍水显著降低了籽粒谷蛋白含量及谷蛋白／醇溶蛋白比值。干旱和渍水均显著降低了籽粒淀粉产量。干旱和渍水对各品种籽粒面筋指数、沉降值和降落值的影响较为复杂，对不同品种的影响并不一致。且与对照水分处理相比，干旱和渍水逆境下不同小麦品种的不同籽粒品质特性间的相关性很低，表明极端土壤水分状况使得小麦籽粒的各项品质特征指标与正常水分状况下差异明显，从而改变了各类专用小麦的籽粒品质。 在同一温室内盆栽控水试验中，研究了正常土壤水分供应、干旱和渍水条件下四个小麦品种旗叶净光合速率和叶绿素含量的动态变化，营养器官花前贮藏同化物再运转与花后同化物输入籽粒量，以及成熟期籽粒蛋白质与淀粉产量和含量的差异。结果表明，干旱和渍水均缩短了各品种花后旗叶的光合速率高值持续期(PAD)和叶绿素含量缓降期(RSP)，水分处理间的PAD和RSP变化趋势为对照＞渍水＞干旱。各品种处理间叶片、茎鞘、颖壳等营养器官花前贮藏同化物的运转率均为对照＞干旱＞渍水。而花后同化物输入籽粒量为对照＞渍水＞干旱，花后同化氮素输入籽粒量为对照＞干旱＞渍水。各品种蛋白质产量为对照最高，渍水最低，不同水分处理间的差异达到显著水平。干旱处理显著提高了各品种籽粒蛋白质含量，而渍水与对照间的差异均不显著。干旱和渍水均显著降低了淀粉产量，不同水分处理对淀粉含量的影响因品种不同有所差异。 在温室盆栽控水试验中，以两个冬小麦品种皖麦38和扬麦9号为材料，研究了花后土壤干旱、渍水和适宜水分状况对小麦源、库器官中与籽粒蛋白质和淀粉积聚相关的调控酶活性的影响。发现小麦旗叶和籽粒中与籽粒蛋白质和淀粉积聚相关的关键土壤水分胁迫对小麦籽粒品质形成的影响及激素调控研究调控酶活性变化趋势在两个品种间基本一致。与对照相比，干早和渍水均明显降低了花后旗叶中蔗糖含量和磷酸蔗糖合成酶(SPS)活性，而氨基酸含量和谷氨酞胺合成酶(GS)活性略有下降。干早和渍水均降低了籽粒库蔗糖合成酶(55)和结合态淀粉合成酶(GBSS)活性，可溶性淀粉合成酶(555)活性降低尤甚。其中干早状况下SS的下降比渍水更为明显。与对照相比，渍水明显降低了籽粒谷丙转氨酶(GPT)和GS活性，而干旱的影响较小。相关性分析结果表明，籽粒淀粉产量和含量与SPS，555和GBSS活性的关系比与55活性更为密切，籽粒蛋白质产量和含量与叶中GS和籽粒中GPT活性的关系比与籽粒中的GS活性更为密切。 在温室盆栽控水试验中，在花后10天(籽粒伸长阶段)和20天(籽粒灌浆阶段)，用酶联免疫法(E LISA)测定了四个品种小麦植株源库器官内源脱落酸(ABA)、赤霉素(GA卜3)、叫垛乙酸(IAA)和玉米素核糖昔(ZR)的含量水平。发现四个品种的内源激素水平变化模式相似。干旱和渍水条件下ABA水平明显高于对照。与对照相比，干旱和渍水状况下整株(根、叶和籽粒)GAI+3水平在花后10天变化较小，但在花后20天明显下降。干早和渍水状况下内源IAA水平的变化依器官和生长阶段不同，花后20天，整株(根、叶和籽粒)中IAA水平在干旱和渍水状况下明显下降。与对照相比，干旱和渍水状况下，花后10天和20天中根、叶和籽粒ZR水平均显著下降。 以温室盆栽的皖麦38、扬麦9号两个冬小麦品种为材料，在花后土壤干旱(RWC=45一50%)和渍水状况下，分别施用生长调节剂及自由基形成抑制剂和清除剂6一BA(0 .05~ol/L)，自由基OH.清除剂苯甲酸钠SBN(1~ol几)，光合磷酸化和光合速率促进剂NaHSO:(2 nlnlol几)，分析了不同生长调节物质对水分胁迫下小麦光合特性、不同器官中物质运转和籽粒蛋白质及淀粉品质的影响。发现三种生长调节物质均不同程度地减轻了花后逆境水分状况引起的小麦旗叶净光合速率和叶绿素含量的快速下降，并减轻了花后同化物和同化氮素输入籽粒量的显著下降，通过延缓花后光合功能和花后氮素同化功能的衰退，提高了花后同化物对籽粒重以及花后同化氮素对籽粒总氮的贡献率，改善了逆境水分状况下的小麦籽粒蛋白质和淀粉品质。 利用小麦穗离体培养手段，研究了外源激素ABA和CTK对小麦籽粒蛋白质积聚进程中光合特性、氮运转、相关氮素代谢酶和籽粒蛋白质含量和更多还原

【Abstract】 Elucidating the physiological mechanism and regulation principles for grain quality formation in wheat is of important significance for understanding grain quality physiology and guiding cultural management in wheat. With controlled water experiments, the present study characterized the photosynthesis, C/N assimilate translocation and regulatory enzyme activities in relation to formation of grain quality in different wheat varieties under varied soil water status, explored the regulation mechanisms of endogenous and exogenous hormones on wheat grain quality, and established the technical approaches to regulation of the wheat grain quality with plant growth regulators under soil drought and waterlogging.Four winter wheat (Triticum aestivum L.) genotypes differing in grain protein contents, Heixiaomai76, Wanmai38, YangmailO and Yangmai9, were used in pot culture experiment in greenhouse to investigate the effects of post-anthesis drought (SRWC=45%~50%), waterlogging and moderate soil water status (SRWC=75%~80%) on protein and starch contents and relative quality characters in wheat grains. The results indicated that grain protein content, glutenin content, ratio of Glu/Gli, dry gluten and wet gluten contents were increased significantly under drought. Glutenin content and ratio of Glu/Gli were reduced significantly under waterlogging. Under both drought and waterlogging, grain starch yields were reduced significantly, and amylose contents were elevated while amylpectin contents were lowered. So the ratios of amylose/amylpectin were depressed under both drought and waterlogging. Drought and waterlogging had differential effects on grain gluten index, sedimentation value and falling number in different varieties. Compared with CK, correlations among grain quality characters in different wheat varieties under drought and waterlogging were reduced. Thus, the distinct differences in grain quality characters between extreme and moderate soil water status would have impact on grain quality and utilization values of specialty wheats.With the four winter wheat varieties in the same experiment, investigations were made on the effects of post-anthesis drought, waterlogging and moderate soil water status on net photosynthesis and chlorophyll contents of flag leaves, remobilization of assimilates stored before anthesis, transportation of post-anthesis assimilates, and contents and yields of starch and protein in grain at maturity. It was found that the PAD and RSP of flag leaves in four wheat genotypes were shortened by both drought and waterlogging. As compared to CK, the values of PAD and RSP declined under waterlogging and drought. Theremobilization rate of pre-anthesis stored assimilates was the highest for CK, while the lowest for waterlogging. The amounts of post-anthesis assimilates and nitrogen transferred into grains were declined with CK>\vaterlogging>drought and CK>drought>waterlogging, respectively. The yield of grain protein significantly decreased at 5% level with the order of CK> drought > waterlogging in four wheat genotypes. The contents of grain protein increased significantly under drought, but had no significant differences between CK and waterlogging. Compared with CK, starch yield significantly decreased under drought and waterlogging in four wheat genotypes, but starch content varied among four wheat genotypes.In the same experiment, two winter wheat varieties, Wanmai 38 and Yangmai 9, were chosed to investigate the effects of drought, waterlogging and moderate water supply on the activities of key enzymes for grain starch and protein accumulation. The results showed that the changing patterns in the activities of enzymes in both leaves and grains were similar in the two varieties. Compared with CK, sucrose content and SPS activity declined more markedly than amino acid content and GS activity under drought and waterlogging. Both drought and waterlogging resulted in decreases in the activities of SS and GBSS, and especially in that of SSS. More marked decreases in the activity of SS occurred更多还原