【作者】 刘正辉；

【导师】 张国平； 程方民；

【作者基本信息】 浙江大学 ， 作物学， 2004， 博士

【摘要】 水稻种子发育过程中，以C、N和P的代谢最为活跃，它们深刻地影响着产量与品质的形成。C代谢将来自叶片的光合产物合成淀粉并储存在胚乳组织的淀粉体中；N代谢和P代谢的产物主要是蛋白质和植酸。成熟的水稻种子内，淀粉约占其干重的90％，蛋白质约占8％，植酸约占0.8％。种子内局部C代谢发生障碍将导致该区淀粉积累不完全，淀粉粒堆积松散，在外观上表现为不透明的白色区域，即垩白。因此，垩白、蛋白质和植酸含量是种子发育过程中C、N和P代谢的最终体现，研究不同品种这些成份的差异及其对环境的反应以及与这3种代谢之间关系，有助于阐明水稻品质的形成规律。 本文研究了粳稻种子中植酸、垩白和蛋白质等3种品质性状的基因型差异及其它们的粒位效应。首先测定分析了江浙地区当前一些主栽粳稻品种(品系)种子中的3种理化性状，明确了粳稻品质现状，并分析了3种理化性状之间的关系；在此基础上，以3种性状差异明显的基因型为材料，研究了种子垩白、植酸和蛋白质的粒位效应，明确了这3种性状在穗内不同粒位之间的变异规律以及它们相互间的关系。 主要研究结果如下： 1 粳稻种子植酸含量的基因型差异与环境效应 杭州种植条件下，72份源自江浙不同地区的粳稻品种(品系)种子植酸含量变动于0.685％-1.034％，均值0.873％，变异系数8.35％。可见所征集的粳稻品种种子植酸含量的差异较小，极差在2倍以内。相关分析表明，种子植酸含量和总磷含量之间呈极显著的正相关(r=0.7824)，表明在粳稻低植酸含量育种上，可以通过对种子总磷含量这一相对容易检测的指标间接地估算植酸含量，从而简化测定程序。24个品种在4个地区种植的种子植酸含量方差分析结果表明，品种、地点及两者的互作效应均达显著水平，其中以地点效应最大；品种和地点之间互作显著显示，比较与评价水稻种质的植酸含量时应充分考虑环境(地区)的影响。 2 粳稻种子蛋白含量的基因型差异及其与粒重、植酸含量之间的关系杭州种植条件下，72份试验品种的总蛋白、清蛋白、球蛋白、醇溶蛋白和谷蛋白含量的平均值依次为8.72％、0.352％、0.352％、1.021％和6.99％。在4种蛋白质组分中，醇溶蛋白的变异系数最小，为7.89%，谷蛋白的变异系数最高，为巧.07%;清蛋白、球蛋白和总蛋白的变异系数较为接近，分别为12.39%、12.12%和11.89%。4种蛋白质组分之间，仅清蛋白和球蛋白之间相关显著(r二0.4609**)，粒重与谷蛋白和总蛋白之间呈显著的负相关。种子植酸含量与4种蛋白质组分、总蛋白和粒重之间均无显著的相关关系;总蛋白含量和植酸含量之间无显著相关，启示出选育高蛋白低植酸水稻品种的可能性。3粳稻至白发生的基因型差异与粒位效应 依奎白米中心白米/腹白米的比率，可将48份试验品种分为两类:其一，以心白为主(心白型)，心白米/腹白米值大于l，共有22份;其二，以腹白为主(腹白型)，心白米/腹白米值小于1，共有26份。心白型品种心白米率平均值为37.25%，变异系数76.84%，有7个品种仅有心白发生，它们是:SH25、SH02、秀水52、167、9944、NJ09和9915。腹白型品种腹白米率平均值为50.01%，变异系数42.60%，，有2个品种仅有腹白发生，它们是K45和淮9140。以上结果显示，目前我国江浙地区粳稻奎白的发生在奎白类型、组合及坐白米率等方面呈现出较大的基因型差异。 上部、中部和下部枝梗及一级和二级枝梗这两类粒位对至白发生的影响均达显著水平。一般而言，奎白米率在不同粒位之间的规律如下:上部枝梗>中部枝梗>下部枝梗;一级枝梗>二级枝梗。两类粒位的互作对心白米率、腹白米率和至:白米率也有重要的影响，且其显著性依品种而定。这样，穗内不同粒位之间在心白米率、腹白米率和奎白米率的高低顺序上呈现多种变化，启示出穗内不同粒位种子在发育过程上的差异性。同一粒位上心白和腹白发生的相对可能性为:二级枝梗或上部枝梗心白发生的可能性较腹白大，一级枝梗或下部枝梗腹白发生的可能性较大。4粳稻种子植酸和蛋白含量的粒位效应 以种子植酸和蛋白含量差异明显的6个基因型为材料，研究了种子植酸和蛋白质含量在上部、中部和下部枝梗及一级枝梗和二级枝梗之间的变异规律，并探讨了它们在稻穗内的关系。研究结果显示，粳稻种子植酸和4种蛋白质组分含量粒位间差异很大，但植酸的变异系数相对较小。一般而言，二级枝梗上的种子清蛋白、球蛋白和醇溶蛋白含量要高于一级枝梗;蛋白含量较低的3个基因型，即丙98110、SH24和秀水217，一级枝梗的种子谷蛋白和总蛋白含量显著高于二级枝梗;但蛋白质含量较高的3个基因型，一级枝梗和二级枝梗之间种子总蛋白含量无显著差异。 对穗内种子植酸、蛋白质含量和粒重之间进行了相关分析，结果表明，粒重和清蛋白含量(r=一0.8797*)、球蛋白含量(r=一0.9449”)、清蛋白和球蛋白含量(r=o.8983’)以及谷蛋白和总蛋白含量(r=0.9846*’)之间的相关系数在低植酸和低蛋白含量的3个品种中达显著水平。而在3份高植酸、高蛋白含量的品种中，仅见谷蛋白和总蛋白之间的相关达到显著水平(r=o.9846更多还原

【Abstract】 Carbon, nitrogen and prosperous metabolisms are most active during seed development in rice, which are closely related to the formation of yield and quality. In C metabolism, the assimilates transported from the leaves and stems are used for starch synthesis and deposited in the amyloplast of the starchy endosperm through carbon metabolism. The most nitrogen and phosphorus taken up from soil and stored in the shoots before flowering are assimilated, and accumulated in the form of protein and phytic acid. In a matured rice grain, carbohydrates, mainly starch is predominant, occupying about 90% of dry matter, followed by protein content, being about 8%, and phytic acid content is only around 0.8%. The bulk of proteins are deposited in protein bodies of the starchy endosperm, and phytic acid is also found in protein bodies, but it is mainly located in the aleurone layer and embryo. Chalkiness is the untranslucent part of rice grain, and was supposed to be the result of uncompleted accumulation of starch during grain development. Thus, chalkiness, phytic acid and protein content in rice grain is actually final demonstration of C, N, and P metabolism during grain development.The present research investigated the effect of genotype and grain position within a panicle on chalkiness, phytic acid and protein contents in japonica rice. Firstly, 72 cultivars from different locations of China were evaluated on chalkiness, phytic acid and protein contents, to determine the situation of rice quality in this area in terms of phytic acid and protein content, and the relationships among the three characters. Secondly, some genotypes with contrast performance in both phytic acid and protein contents would be used to study the effect of grain position on the three characters and determine their variation among grains within a panicle. The main results are shown as follows:1 The genotypic and environmental variation of grain phytic acid content in japonica ricePhytic acid and total phosphorus contents in grains of japonica rice cultivars, collected from different areas of China were assayed in this study. Meanwhile, a multi-location trial was conducted to determine phytic acid content of 24 cultivars grown at 4 locations with wide difference in ecological conditions. It was found that phytic acid content ranged from 0.685% for SH22 to 1.034% for Huai9746 among 72 genotypes, with a mean of 0.873%, and total phosphorus content ranged from 0.231% for SH22 to 0.388% for SH15, with a mean of 0.324%. There was highly significant correlation between grain phytic acid and total phosphorus content (r=0.7824**), indicating that total phosphorus, which is more easily measured, can be used as an alternative for phytic acid determination in low phytic acid rice breeding. The effects of cultivars, environments (locations) and their interactions on phytic acid content were all highly significant, with the location having the largest effect. The highly significant interaction between cultivars and environments suggests that the correct evaluation of rice germplasm in phytic acid content should be conducted under multi-environments.2 Genotypic differences in rice grain protein content and its relation to grain weight and phytic acid contentAveraged over 72 genotypes grown in Hangzhou, grain toatal protein, albumin, globulin, prolamin, and glutelin content were 8.72%, 0.352%, 0.352%, 1.021%, and 6.99%, respectively, with prolamin and glutelin having the least and largest CV, 7.89% and 15.07%, respectively. There were significantly positive correlation between albumin and globulin(r=0.4609**), and significantly negative correlation among grain weight and glutelin content(r=-0.2410*) and total protein content (r=-0.2480*). There was no significant correlation between grain phytic acid and protein content, suggesting the possibility to breed the japonica rice cultivars with low phytic acid and high protein content.3 Effect of genotype and grain position within a panicle on the occurrence of chalkinessAccording to the rati更多还原