【作者】 范雪梅；

【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， 2004， 硕士

【摘要】 土壤水分逆境是限制小麦籽粒品质形成的重要生态因子，明确土壤水分逆境下小麦籽粒品质形成的生理机制及调优技术途径对于深化小麦品质生理生态研究和指导小麦调优栽培具有重要的理论意义和应用前景。本研究在池栽试验条件下，以蛋白质含量不同的小麦品种为材料，设置渍水、干旱（相当于田间持水量的45％～50％）和对照（相当于田间持水量的70～80％）三个水分处理，每个水分处理下设置两个施氮水平：120kg·ha^-1和240kg·ha^-1，综合研究适宜土壤水分、干旱和渍水状况下氮素供应对小麦籽粒品质形成、碳代谢与淀粉积累和氮代谢与蛋白质积累的影响，进一步明确干旱和渍水条件下氮素对小麦籽粒品质的调控的作用。主要研究结果如下： 1．花后渍水和干旱逆境下氮素营养对小麦籽粒产量和品质性状的影响。花后渍水和干旱处理显著降低了小麦籽粒产量以及蛋白质和淀粉产量。在适宜水分和干旱条件下，增施氮肥增加了小麦籽粒产量，而在渍水条件下，增施氮肥降低了产量。干旱处理提高了蛋白质含量，干、湿面筋含量，沉降值和降落值，而渍水处理则降低了小麦籽粒蛋白质含量和干、湿面筋含量。同一水分处理下，增施氮肥提高了蛋白质含量，谷蛋白／醇溶蛋白比，支链淀粉含量和支／直链淀粉比。此外，在小麦籽粒主要品质性状上存在显著的水氮互作效应，且水分、氮肥及水氮互作效应对小麦籽粒产量和品质的影响因品种的不同而异。 2．花后土壤干旱和渍水逆境下氮素水平对小麦旗叶衰老、物质运转、淀粉相关酶的活性以及籽粒淀粉积累的影响。干旱和渍水处理加重了旗叶膜脂过氧化程度，使渗透调节物质脯氨酸含量上升。水分逆境下增施氮肥可以提高旗叶SOD活性、可溶性蛋白含量和脯氨酸含量，减少MDA的积累。土壤水分适宜或亏缺条件下增施氮肥可以提高旗叶CAT活性，渍水处理下则相反。花后渍水和干旱处理显著降低小麦旗叶净光合速率和SPAD值，干物质积累量下降。干旱处理下，增施氮肥提高旗叶光合速率和SPAD值，渍水处理下则相反。水分逆境明显降低籽粒可溶性总糖含量，且渍水处理下增施氮肥降低小麦叶片和籽粒可溶性总糖含量，干旱状态下规律相反。花后渍水和干旱处理降低小麦营养器官花前贮藏物质再运转量和再运转率，降低了籽粒重。水分逆境下增施氮肥可以提高小麦叶和颖壳花前贮藏物质再运转量和运转率，茎鞘花前贮藏物质再运转量和运转率。在对照和干旱下增施氮肥提高了营养器官花前贮藏物质总运转量和运转率以及籽粒重和花后同化物输入籽粒量，而渍水下增施氮肥趋花后干早和渍水下氮素对小麦籽粒品质形成的影响及其生理机制势相反.水分逆境下增施氮肥可以提高旗叶磷酸蔗糖合成酶（SPS）活性。水分逆境降低了小麦籽粒蔗糖合成酶（Ss）活性.土壤水分适宜或亏缺条件下增施氮肥可以提高籽粒sS活性，而渍水下增施氮肥不利于提高籽粒SS活性。水分逆境下增施氮肥可以提高籽粒可溶性淀粉合成酶（555）和结合态淀粉合成酶（GBSS）活性.干旱和渍水处理均降低了籽粒灌浆速率和粒重，增施氮肥可以提高水分适宜或亏缺条件下籽粒灌浆速率，增加粒重，而渍水下施氮过多降低灌浆速率和粒重.渍水处理下增施氮肥降低淀粉积累速率。干早处理可以提高直链淀粉积累速率，而渍水使其降低。土壤千旱和渍水下增施氮肥降低了直链淀粉和支链淀粉积累速率。 3.花后土壤干旱和渍水逆境下氮素水平对小麦氮代谢、氮素运转、蛋白质相关酶的活性以及籽粗蛋白质积累的影响.研究结果表明，花后干旱和渍水均降低旗叶硝酸还原酶（NR.）活性、叶片总氮含量和游离氨基酸含量。干旱处理提高了茎鞘总氮与游离氨基酸含量，而渍水处理则使其降低。水分逆境下增施氮肥提高旗叶NR活性、叶片与茎鞘总氮和游离氨基酸含量。水分逆境降低了小麦各营养器官花前贮藏氮素再运转量和再运转率，降低了小麦籽粒氮积累量。在对照和干旱下增施氮肥提高了小麦叶片的花前贮藏氮素运转量和运转率，茎鞘的贮藏氮素运转量，营养器官花前贮藏氮素总运转量和运转率，籽粒氮积累量以及花前氮素对籽粒总氮贡献率，而渍水下增施氮肥趋势相反.研究结果表明，与对照相比，花后干旱和渍水均降低旗叶谷氛酞胺合成酶（Gs）和谷丙转氛酶（GPT）的活性，而水分逆境下增施氮肥可以提高旗叶GS和GPT活性.水分逆境降低了小麦籽拉GS活性，而干旱提高了籽粒GPT活性，渍水使其降低。水分逆境下增施氮肥可以提高籽拉GS和GPT活性.干旱处理可以提高蛋白质含量，而渍水使其降低.水分逆境下增施氮肥提高籽粒游离氛基酸和蛋白质含量.适宜水分或亏缺条件下增施氮肥可以提高籽粒蛋白质积累量，而渍水下增施氮肥不利于蛋白质的积累。 综上所述，花后干旱和渍水下氮素对小麦光合衰老特性、碳氮代谢及物质运转和分配的影响是导致不同处理下籽粒蛋白质、淀粉产量和含量差异的主要原因。调控籽杜淀粉生产和积聚的叶中SPS及籽粒中ss、555和GBSS、调控籽粒蛋白质生产和积聚的的籽粒和叶中的GS和GPT，是花后干旱和渍水下氮素影响籽粒淀粉和蛋白质产量和含量的主要酶学基拙.关键词:小麦;籽粒品质;千旱;渍水;氮素;淀粉积累;蛋白质积累更多还原

【Abstract】 Soil water stress is major ecological factor of limiting grain quality formation in wheat. 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. The effects of nitrogen rates on grain yield and quality of two wheat varieties {Triticum aestivum L) differing in grain protein content grown under drought and waterlogging stress from anthesis to maturity were studied in a cement pool culture experiment. Three water treatments were established from anthesis to maturity, i.e. waterlogging, drought (SRWC=45%~50%) and moderate water supply (SRWC=70%~80%), and under each water treatment, two nitrogen levels of 120 and 240 kg’ha’1 were implemented. The effects of nitrogen rates on grain quality formation, carbon metabolism and starch accumulation, and nitrogen metabolism and protein accumulation in two wheat varieties under drought and waterlogging stress from anthesis to maturity were studied. And it was established the function to regulation of the wheat grain quality with nitrogen under drought and waterlogging. The main results were as follows:1. Both drought and waterlogging significantly reduced grain yield, yields of grain protein and starch in wheat, compared with CK. Under CK and drought, nitrogen increased grain yield, and reduced yield under waterlogging. Compared with CK, drought increased the contents of protein, dry gluten and wet gluten, and SDS-sedimentation volume and falling number, while waterlogging reduced the contents of grain protein, dry and wet gluten. Under the same water treatment, nitrogen increased protein content, ratio of glutenin to gliadin, amylopectin content and ratio of amylopectin to amylose. In addition, significant interactions between water and nitrogen on major grain quality traits were observed. The effects of water, nitrogen and their interaction on grain yield and quality varied with different wheat cultivars.2. Effects of nitrogen rates on flag leaf senescence, photosynthetic characteristics andassimilate translocation, the activities of key enzymes for grain starch accumulation and grain starch accumulation in two wheat varieties differing in grain protein content under soil drought and waterlogging from anthesis to maturity were investigated in a cement pool culture experiment. Compared with CK, drought and waterlogging enhanced leaf membrane lipid peroxidation, while content of proline, the osmotic substance increased. Under drought and waterlogging nitrogen increased superoxide dismutase (SOD) activity, contents of soluble protein and proline, while reduced the content of malondiadehyde (MDA) in flag leaf. Under CK and drought, nitrogen increased catalase (CAT) activity in flag leaf while reduced under waterlogging.Compared with CK, drought and waterlogging reduced flag leaf photosynthesis (Pn) and SPAD value, and dry matter accumulation. Nitrogen supply increased under drought while reduced under waterlogging flag leaf Pn and SPAD value. Both drought and waterlogging reduced total soluble sugar concentration in grains. Total soluble sugar contents in leaf and grain decreased under waterlogging while increased under drought. Compared with CK, drought and waterlogging reduced the amounts and remobilization rate of pre-anthesis stored assimilates and grain weight. Under drought and waterlogging nitrogen increased amounts and remobilization rate of pre-anthesis stored assimilates in leaves, hull and rachis, stem and shell. Under CK and drought nitrogen increased total amounts and remobilization rate of pre-anthesis stored assimilates, grain weight and the amounts of pre-anthesis assimilates transferred into grains, while nitrogen reduced them under waterlogging. Nitrogen increased sucrose phosphate synthase (SPS) activities in flag leaf under drought and waterlogging. Drought and waterlogging reduced sucrose synthase (SS) activities in grain. Under CK and drought, nitrogen increased SS activity in grain while nitrogen redu更多还原