【作者】 谭维娜；

【导师】 姜东；

【作者基本信息】 南京农业大学 ， 作物栽培学与耕作学， 2008， 硕士

【摘要】 渍水是我国小麦生产的主要自然灾害之一,生育中后期渍害显著影响了小麦产量品质的形成。明确花后渍水对小麦籽粒产量和品质形成的影响及其生理机制对于深化小麦产量品质生理生态研究和指导小麦抗逆调优栽培具有重要的理论意义和应用前景。本研究在盆栽条件下,以蛋白质含量不同的小麦品种扬麦9号(低蛋白)、豫麦34(高蛋白)为研究材料,设置对照(相当于田间持水量的70～80%)和渍水(保持1～2cm的水层)两个水分处理,研究花后渍水对小麦旗叶光合和衰老特性,碳氮代谢,根系衰老特性及产量品质形成的影响,进一步明确花后渍水对小麦籽粒产量品质形成的影响及其生理机制。主要研究结果如下:1.花后渍水对小麦旗叶光合、衰老特性及干物质转运的影响。渍水显著降低了旗叶叶绿素含量、气孔导度、蒸腾速率和旗叶净光合速率,且豫麦34较扬麦9号下降幅度大。最大光化学效率、PSⅡ潜在活性、实际光化学效率及光化学猝灭在渍水下显著下降,同时初始荧光强度和非光化学猝灭显著上升,表明PSⅡ光反应中心遭到破坏。超氧化物歧化酶、过氧化物酶及豫麦34过氧化氢酶(POD)活性在溃水下显著降低,而扬麦9号POD活性则呈主要上升趋势。渍水条件下,花后植株干物质积累量降低以及籽粒灌浆速率的下降,使籽粒干物质积累量减少。2.花后渍水对小麦氮素吸收转运的影响。渍水降低了两小麦品种叶片、茎鞘、全株及籽粒氮含量和积累量;增加了营养器官成熟期氮素分配量,降低了籽粒氮素分配。扬麦9号营养器官花前贮藏氮素运转量和豫麦34营养器官花前贮藏氮素运转率显著降低,花后氮素积累量均显著下降。3.花后渍水对小麦根系衰老特性的影响。花后渍水显著降低了小麦根系生物重及根系活力。渍水下根系质膜相对透性增大,MDA含量显著增加,保护酶CAT、SOD活性下降,而POD活性则显著提高。相关性分析结果表明,根活力、根干重、过氧化氢酶CAT及MDA含量均与碳氮代谢指标及产量呈一定的显著相关。4.花后渍水对小麦籽粒产量和品质的影响。渍水显著降低了籽粒千粒重,影响籽粒产量形成;增加了直链淀粉、醇溶蛋白含量,同时蛋白质含量、支/直比及谷/醇比降低;小麦干湿面筋含量有所增加,面筋指数、沉降值、降落值均下降。综上所述,花后渍水加快小麦旗叶和根系衰老进程,影响小麦氮素吸收、干物质积累及其转运,是导致渍水下小麦籽粒产量、蛋白质含量及淀粉含量差异的主要原因,渍水下小麦旗叶和根系抗氧化酶CAT、SOD和POD活性、根系活力及旗叶光合特性的下降是影响小麦产量品质形成的主要生理基础。更多还原

【Abstract】 Soil waterlogging is major natural adversity in wheat production in China, and waterlogging during mid to late growth stage is a major factor of limiting grain yield and quality formation. Elucidating the physiological mechanism and regulation principles for grain yield and quality formation in wheat is of important significance for understanding grain yield and quality physiology and guiding cultural management in wheat under post-antheais waterlogging. The effects of waterlogging on grain yield and quality of two wheat varieties (Triticum aestivum L) differring in grain protein content including Yangmai 9 with low protein content and Yumai 34 with high protein content were studied in a pot culture experiment. Two water treatments were established from anthesis to maturity, i.e. soil relative water content maintaining at 70-80% as control, and maintaining 1-2 cm water layer above the soil as waterlogging treatment. The effects of post-anthesis waterlogging on photosynthesis and senescense of flag leaf, carbon and nitrogen metabolize, root characteristics and senescence, grain yield and quality formation in different wheat varieties. Here are the main results.1. Effects of post-anthesis waterlogging on photosynthesis, senescense of flag leaf and matter redistribution in wheatWaterlogging significantly reduced chlorophyll content, stomatal conductance, transpitation rates and photosynthetic rate, and Yumai 34 decreased much faster than Yangmai 9. Ratios of variable to maximum and variable to initial fluorescence, actual photosynthetic efficiency, and photochemical quenching were much lower, while initial fluorescence and non-photochemical quenching were much higher under waterlogging than in control, indicating damage to photosystemⅡ. Waterlogging decreased activities of superoxide dismutase and catalase in both cultivars, and activity of peroxidase (POD) in Yumai 34, while POD activity in Yangmai 9 was mostly increased. The obvious decrease in the amount of post-anthesis accumulated dry matter and kernel filling rate which was redistributed to grains, also contributed to the grain dry matter loss under Waterlogging.2. Effects of post-anthesis waterlogging on nitrogen assimilation and translocation in wheatWaterlogging reduced nitrogen content and accumulation of leaf, grain, plant, stem and sheath. Compared with CK, waterlogging increased distribution of nitrogen in vegetative organs, while reduced distribution of nitrogen in grain. Nitrogen translocation amount of pre-anthesis assimilate in Yangmai 9, nitrogen translocation rate of pre-anthesis assimilate in Yumai 34 and nitrogen post-anthesis assimilates accumulation in two wheat were significantly reduced under post-anthesis waterlogging.3. Effects of post-anthesis waterlogging on wheat root characteristics and senescencePost-anthesis waterlogging significantly reduced root weight and root activity. Compared with CK, waterlogging reduced the activities of protective enzymes as superoxide dismutase (SOD) and catalase (CAT) in root, while increased the content of malondiadhyde (MDA) and the activity of peroxidase (POD), thus enhanced root membrane lipid peroxidation. In addition, significant relativities between root activity, root weight, catalase (CAT), the content of malondiadhyde (MDA) and index of carbon and nitrogen metabolize, grain quality were observed.4. Effects of post-waterlogging on grain yield and quality in wheatWaterlogging significantly reduced grain 1000-kernel weight, grain yield, protein content, ratios of amylopectin to amylose content and glutelin to gliadin content, while increased amylose and protein content. Compared with CK, waterlogging increased grain flour wet and dry gluten, reduced gluten index, sedimentation volume and falling number.In conclusion, enhanced root and flag leaf senescence, decreased in nitrogen assimilate translocation and dry matter accumulation translocation were involved in the depressed grain yield, protein and starch content in wheat under waterlogging. Further studies revealed that depressed anti-oxidative enzyme activities, root activity and flag leaf photosynthetic characteristics were key physiological mechanisms in affecting the grain yield and quality formation under post-anthesis waterlogging.更多还原