【作者】 蔡一霞；

【导师】 朱庆森； 杨建昌；

【作者基本信息】 扬州大学 ， 作物栽培学与耕作学， 2004， 博士

【摘要】 本研究通过严格控制土壤水分的盆栽及大田试验，采用大面积生产上应用的品种和反义Wx基因的不同转化系及受体亲本武运粳7号(9522)为材料，重点研明土壤水分对稻米品质形成的调控效应，探讨不同土壤水分状况下米质形成过程中淀粉(包括直链淀粉和支链淀粉)、蛋白质等的物质的积累变化动态及其合成过程中关键酶活性的动态变化规律；明确土壤水分对稻米淀粉粒结构、米粉RVA谱特征以及米饭质地的影响效应，并对低土水势下稻米垩白增加的原因进行分析，提出优质米生产的结实期间歇灌溉的低限土水势指标，为灌溉调(保)优技术(指标)的制定提供了科学依据；并观察了严重水分胁迫(旱种条件下)对不同基因型品种的主要米质性状指标的影响，为大面积生产筛选优质高产旱作稻品种提供依据，为旱种水稻的推广提供前提条件。本文的主要研究结果如下： 1，研明了结实期土壤水分(土水势)与稻米诸品质性状指标的关系及源库活性对米质的影响。水稻籽粒整个灌浆结实期间，当间歇灌溉的低限土水势为-15kPa时，整精米率提高，对垩白粒率和垩白度无显著影响，胶稠度变软，稻米品质有所改善；而当低限土壤水势≤-30kPa时，整精米率显著降低，垩白粒率和垩白度显著提高，而对粒形、直链淀粉含量和粗蛋白含量影响较小，处理间差异不显著；胶稠度与低限土水势的关系可用二次曲线进行拟合。在籽粒灌浆期，≤-30kPa低限土水势降低了灌浆中后期(花后25～35天)的源库活性，影响了米质形成期的光合生产和籽粒中淀粉的积累，最终导致米质变劣，整精米率显著下降，垩白粒率和垩白度显著增加。这一结果为调优灌溉技术的制订提供了科学依据。 2．明确了结实期土壤水分胁迫对水稻强、弱势粒稻米主要米质性状及其RVA谱特征的影响，探明了水分胁迫下淀粉粒结构和籽粒灌浆特征与米粒垩白形成的关系。强势粒和弱势粒达到最大粒重和最小垩白时的结实期处理土水势是相同的，均约为-20kPa，在此土水势下，强势粒和弱势粒加工品质和蒸煮品质无显著变化，改善了营养品质，米质相对较优；当土水势降到-60kPa时，强势粒和弱势粒粒重、整精米率及弱势粒的直链淀一一一一一一一竺鱿里二竺竺里塑鳗甚扭理.粉含量显著降低，胶稠度变硬，食味变差，米质变劣。强势粒米粉RVA谱土壤水分处理间差异较小，而弱势粒米粉RVA谱水分处理间差异明显;当土水势降到一60kPa时，武香粳9号弱势粒米粉R刀A谱的粘度值均小于水层处理。结实期土壤水分对胚乳淀粉粒的形状、大小、结构的影响因品种和米粒内部位置的不同而不同，汕优63强弱势粒横断面腹部和心部以及武香粳9号弱势粒横断面腹部淀粉粒结构易受土水势影响，外观上易形成腹白和心白。水分胁迫加快了强势粒灌浆，削弱了弱势粒对灌浆基质的转化能力，这种籽粒灌浆的进程异常和灌浆物质的分配变化易形成至白。 3.水种和旱种两种种植方式下稻米主要品质性状和米粉的粘滞性特征之间存在明显差异，并因品种而异。旱种下精米率和整精米率有所提高，部分供试品种显著提高:旱种籽粒的粒形表现瘦长(与水种相比)，釉稻品种的至白粒率和蟹白度减小，而粳稻品种的奎白粒率和坚白度略有增加。旱种下各品种胶稠度的变化比较复杂，无规律可循;旱种稻米的粗蛋白含量明显高于水种(三个旱稻除外)。直链淀粉含量和碱消值受种植方式的影响较小;旱种米粉RvA谱特征值与水种相比发生明显的变化。据品种在早种下(与水种相比)品质的变化情况可将供试材料分为3类:第一类品种是生产上可用于早种的品种，该类品种旱种下蒸煮和食味品质有变优的趋势，其他品质性状指标与水种下的相近，其中扬旱1号最为典型;第二类和第三类品种旱种下使得稻米的食味品质变差，部分品种的坚白显著增加，就稻米品质形成而言，这些品种不宜用于早种。 4.结实期水分胁迫对淀粉合成过程中关键酶酶活性变化、直支链淀粉含量积累动态及米粉的孙从谱特征和米饭质地有着明显的影响。以水层灌溉为对照，结实期水分胁迫下ADP一Gppase、GBsS和555三者表现趋势基本一致，在籽粒灌浆初期(花后5一10d)上述酶酶活性增强，但随着水分胁迫天数的延长，在籽粒灌浆盛期这些酶活性显著降低，到成熟期酶活性降低的速度也加快;催化支链淀粉中a一1，6糖昔键形成的Q酶活性于水分胁迫下明显降低，而去分支酶ISA和Pullulanase酶活性却显著增强。水分胁迫下籽粒中总淀粉的积累有所降低，但却提高了直链淀粉的含量和直链淀粉占总淀粉的相对比率，降低了支链淀粉的含量和支链淀粉占总淀粉的相对比率。GBSS最大活性与直链淀粉含量关系最为密切(产0.981”)，呈极显著的正相关关系，555、Q酶和DBE最大酶活性与总淀粉和支链淀粉含量之间不存在明显的相关性。水分胁迫下，供试的4个品系的主要品质性状指标发生着明显的变化，整精米率和至白粒率提高;粗蛋白含量明显降低:稻米1认!A谱特征发生着明显的变化，水分胁迫下崩解值明显低于水层灌溉处理，而最终粘度和消减值却明显高于水层灌溉处理;水分胁迫处理的米饭硬性增加，粘附性减小，蒸煮扬州大学溥士学位论文食味品质有着变劣的趋势。 5.研明了土壤水分胁迫与不同氮更多还原

【Abstract】 Based on the pot and field experiments by rigorously controlling soil water potential with tensionmeters for the cultivars applied in production and transgenic rice plants with anti-sense Wx gene and original variety WuyunjingJ (9522), the regulating effects of soil moisture on the development of rice quality were examined. The dynamic changes of starch (including amylose and amylopectim), protein and the activities of key enzyme involved in the synthesis under different soil water potentials were analyzed in this paper, and the effects of soil moisture on the structure of starch granule, the characteristics of RVA profile of rice flour and the texture of cooked rice and the reasons of the increase of chalkiness were studied. The index of intermittent irrigation for the production of high quality rice was brought out, which provided the scientific reference for the establishment of the technique regulating the high quality by irrigation. The effects of severe water stress (dry cultivation) on the main characters of grain quality were observed, which could offer the theoretically reference for the selection of the varieties with high quality in dry cultivation, and could supply the premise condition for the popularization of dry cultivation. The main results indicated:1. The relations of soil moisture (or soil water potential) with the character of rice quality during grain filling were defined, and the effect of the activities of source and sink on the grain quality were proved up. During the grain filling period, when the soil water potential (SWP) was reduced to -15kPa, head milled rice was significantly increased, gel consistency become soft and no obvious effects on the percentage of chalky grain and chalkiness were observed. While SWP was less than -SOkPa, head milled rice was significantly decreased, both the percentage of chalky grain and chalkiness were significantly increased. There was a conic relationship between gel consistency and SWP, and no significant difference among treatments in other quality indices, such as kernel shape, amylose and protein content, were found. There were obviously changes in leaf to spikelet ratio, chlorophyll content and grain water content during grain-filling period. If the low soil water potential was under -30kPa, the relative dispersion of leaf to spikelet ratio and chlorophyll content were presented negative effects during the 25-35 days after flowering, dehydration of kernel wasvery rapid, which had an effect on both the production of photoassimilates and the accumulation of starch and resulted in the reduce of head milled rice and the increase of chalkiness.2. Effects of soil water stress on the main characters of superior and inferior grains quality and the properties of RVA profile during grain-filling period were examined, and the morphological microstructure of starch granule and the parameters of grain filling subjected to water stress were analyzed. When the soil water potential (SWP) was at -20kPa, the grain weight of superior and inferior kernel in two cultivars was at its most, and the chalkiness was at its least. There was no obvious change in the milling and cooking quality and the nutrient quality was improved. The trend of high quality was observed. When the SWP was declined to -60kPa, the weight and head milled rice of superior grains (SG) and inferior grains (1G) and the amylose content of 1G were decreased significantly, stiffer gel consistency, bad taste quality and low rice quality was found. Effects of SWP on the RVA characteristics of the different grains in a panicle varied with the kernel position, there was no significant difference in the RVA profiles of SG between the treatments, but the obvious difference was observed in the RVA profiles of IG between the treatments, and especially when the SWP was decreased to -60kPa, the visible changes of the RVA characteristic value were detected, the viscosity under -60kPa was much less than that under well water. Effects of SWP on the shape, size, structure of starch granule in the grain transec更多还原