特种稻品种籽粒灌浆特性的初步研究

应用Ｒｉｃｈａｒｄｓ方程配合，研究了紫香糯、乌贡１号、黑珍米３个特种稻品种的籽粒灌浆特性，结果表明：３个特种稻品种所配合的Ｒｉｃｈａｒｄｓ方程的参数Ｎ的值均大于１，生长速率曲线右偏；乌贡１号前、中期的灌浆速率较平稳。紫香糯含水率峰值高于乌贡１号、黑珍米；籽粒含水率峰值出现的时间比灌浆速率峰值出现的时间要早；乌贡１号、黑珍米灌浆的临界含水率为２７％左右，而紫香糯为３３％     

Is barley yield in the UK sink limited?: I. Post-anthesis radiation interception,radiation-use efficiency and source–sink balance

Source or sink limitation of grain filling in cereals is often inferred from experiments in which the source:sink ratio is manipulated by shading, defoliation or grain removal. However, interpretation of this type of experiment is usually qualitative rather than quantitative in nature and the extent of any imbalance between the source and sink is not known. The objectives of the current work were: (1) to provide a detailed analysis of radiation interception, radiation-use efficiency (RUE) and carbohydrate storage reserves in winter barley in order to quantify the potential supply of photosynthates for grain filling; (2) to estimate the variation in source–sink balance between environments. Field experiments were conducted on cv Pearl at six sites in the UK and over 3 years. Crops were grown under a comparable husbandry regime at each site and received a full fertilizer and crop protection programme. When the cumulative interception of post-anthesis photosynthetically active radiation (PAR) was plotted against the increase in biomass to determine RUE, the pattern of response differed between sites and years; for some site/years the response was linear, for others it was non-linear where RUE decreased during the latter stages of grain filling. The extent and statistical significance of non-linearity was determined from the quadratic term of fitted 2nd order polynomials. There was no significant association between climatic variables, such as temperature, radiation or rainfall, and the value of the quadratic term of RUE. Neither could non-linearity of RUE be explained in terms of the shedding of leaf tissue during canopy senescence. There were weak associations (r² < 0.3) between the extent of non-linearity and green area index (GAI), above-ground biomass, and specific leaf N, at ear emergence (Zadoks GS 59). A much stronger relationship (r² = 0.63) was found between the source:sink ratio (green area per grain) at GS 59 and non-linearity of RUE. These results suggest that a major factor leading to the reduction in RUE during the second half of grain filling at some sites was feedback inhibition from a limited sink capacity. This conclusion is supported by a fairly strong positive association between RUE non-linearity and the apparent contribution of stem carbohydrate reserves to grain yield (r² = 0.47). The potential assimilate supply for grain filling was estimated as (maximum post-anthesis RUE × PAR intercepted) + stem soluble carbohydrate reserves at GS 59. The potential supply exceeded the measured yield at all sites except one implying that crops were predominantly sink limited. The size of the excess, which is a measure of the relative source–sink balance during grain filling, differed widely between site/years.     

籼粳交超级稻甬优538的穗部特征及籽粒灌浆特性

以籼粳交超级稻甬优538为试材,常规粳稻镇稻18和杂交籼稻中浙优1号为对照,将穗部分成上部一次枝粳籽粒(UP)、上部二次枝粳籽粒(US)、中部一次枝粳籽粒(MP)、中部二次枝粳籽粒(MS)、下部一次枝粳籽粒(LP)、下部二次枝粳籽粒(LS)6个部分,比较不同类型品种的穗部特征和籽粒灌浆特性。结果表明:(1)两年中甬优538平均产量为12.5 t hm–2,较中浙优1号和镇稻18分别高17.6%和15.2%;每穗粒数和群体颖花量以甬优538最高。(2)单穗重和着粒密度以甬优538最高;甬优538穗部6个部位的籽粒数均显著高于对照品种,且以上部二次枝粳籽粒和中部二次枝粳籽粒数增加最为明显。(3)甬优538中,UP与MP、MS与US、LP与LS为同步灌浆,但两两之间为异步灌浆。中浙优1号和镇稻18中,UP、US和MP为同步灌浆,而UP、US、MP与LP、LS为异步灌浆。品种类型间,穗部6个部位米粒终极生长量的平均值以镇稻18最高,最大灌浆速率和平均灌浆速率的平均值为中浙优1号镇稻18甬优538,有效灌浆时间为甬优538镇稻18中浙优1号。     

水分胁迫对贪青水稻籽粒充实及其淀粉合成关键酶活性的影响

以两个灌浆速率差异较大的杂交稻组合(汕优63，Pc311/早献党)为材料，设置出穗后高氮(HN)和正常氮(NN)两个水平，以正常灌水为对照(WW)，研究适度水分胁迫(WS)对水稻籽粒灌浆速率与籽粒中淀粉合成关键酶活性的影响。结果表明， HN导致水稻贪青迟熟，主要表现为淀粉积累速率和积累量显著下降，造成粒重和产量降低。适度水分胁迫处理能有效改善贪青稻株的籽粒充实状况。施高氮导致水稻籽粒中蔗糖合成酶(SuSy)、腺苷二磷酸葡萄糖焦磷酸化酶(ADP-Gppase)、颗粒结合淀粉合成酶(GBSS)、可溶性淀粉合成酶(SSS)和淀粉分支酶(SBE)活性降低，是贪青稻株籽粒淀粉积累速率下降和充实不良的内在生理原因。适度水分胁迫处理能诱导籽粒中SuSy、ADP-Gppase、SSS和SBE活性上升，进而增加籽粒淀粉积累和粒重。而正常施氮下，水分胁迫导致稻株籽粒灌浆后期同化物供应不足和淀粉合成代谢酶活性下降过快，是其籽粒淀粉积累总量减少、粒重降低的主要原因。     

不同温度下灌浆期水稻籽粒内源激素含量的动态变化

利用人工气候箱设置高温(日均温度32℃)和适温(日均温度22℃)2个处理，对籽粒灌浆过程中4种主要内源激素（IAA、ZR、GA₃和ABA）含量差异及其动态变化作了比较分析。结果表明，高温对籽粒灌浆的影响主要表现为加速早期灌浆和缩短持续时间。在水稻灌浆初期，高温处理下籽粒IAA、ZR、GA₃含量明显低于适温处理，而灌浆中、后期的处理间差异较小；温度处理对籽粒ABA含量的影响尤为显著，整个灌浆期均呈高温处理明显高于适温处理的基本趋势；2个供试品种在不同温度处理下的4种内源激素含量变化存在着一定差异，其变化与品种的灌浆动态有关。高温下灌浆前期籽粒中IAA、ZR、GA₃含量的降低，尤其是ABA含量的剧增，可能是其早期灌浆加速及灌浆持续时间缩短的主要原因。     

粳稻根系与叶片早衰的关系及其对籽粒灌浆的影响

以衰老程度不同的品种为试材,对根系和叶片衰老的生理机制、根系与叶片衰老的关系、根系和叶片衰老对籽粒灌浆结实的影响进行了研究.结果表明:(1)抽穗后根系和叶片MDA含量持续上升,而SOD活性却先上升然后再持续下降,说明MDA含量上升最初并不是由SOD活性下降引起的.(2)根系和叶片衰老受ZRs和ABA平衡关系的调控,ZRs含量的下降和     

播期对水稻粒位间籽粒灌浆动态的影响

[目的]为北方水稻良种的选育和高产优质栽培提供理论与实践依据。[方法]应用Logistic模型研究了播种期对稻米品质迥异的2个品种、不同粒位间籽粒灌浆特性的影响。[结果j播期推迟1个月均对2个品种的籽粒灌浆特性有明显影响。品质较差的大穗型粳稻品种丰优2000的千粒重下降较为明显，但品质有所改善，主要表现在强势粒灌浆速度快，有效灌浆持续时间短，弱势粒启动较慢，有效灌浆时间延长，灌浆高峰期延后。品质较好的沈农265强势粒受播期影响不大，而中部二次粒和下部二次粒受显著影响。[结论]播期对品质较差的品种改善较大，其中以垩白度和食味值最为显著。播种期不仅影响起始灌浆量、灌浆速率和有效灌浆时间等灌浆参数，而且还影响品种间、强弱势粒间的灌浆进程。     

燕麦抽穗期和灌浆期配合力的分析

燕麦的抽穗前天数及灌浆持续期是和生育期密切相关的两个性状。本文通过５个亲本双列杂交的１０个Ｆ＿１［１／２ｐ（ｐ－１）］对它们的配合力进行分析，结果表明，两性状的一般及特殊配合力方差均达显著或极显著水平，当一个亲本（或组合）在抽穗前天数上有较高配合力时，其灌浆持续期的配合力就相应较低。     

氮肥运筹对大穗型水稻品种金恢809灌浆期叶片蛋白质表达的影响

籽粒灌浆期叶片的代谢情况对水稻最终产量的形成具有重要的意义。本文运用双向电泳技术探讨了两种不同氮肥施用比例下,籽粒灌浆不同时期叶片蛋白的差异表达情况。共检测到32个出现差异表达的蛋白,其中27个在后期适当增加氮肥施用比例的处理下上调表达,5个下调表达。依据蛋白功能可以将鉴定到的蛋白分为5大类即光合代谢(12个)、抗逆反应(5个)、激素合成及信号转导(5个)、细胞生长和分化(5个)、假想蛋白(5个)。为了进一步明确氮肥调控对灌浆期叶片的影响,本文考察了叶片光合以及保护酶相关指标。结果显示,增加水稻生育后期的氮肥施用比例,延缓了叶片中叶绿素以及可溶性蛋白在籽粒灌浆期的降解,延长了叶片光合作用时间,提高了SOD、POD和CAT在灌浆后期的活性,降低了膜脂过氧化程度。生理指标结果进一步证明了差异蛋白组学结果的可靠性,说明后期增加氮素的供应确能有效地促进叶片灌浆期正常的生理代谢。本研究在蛋白水平和生理指标水平,为进一步揭示氮肥调控措施对水稻灌浆代谢机理的影响提供了理论依据。     

Study on the Relationship of the Characteristics of Vascular Bundles in the First Internode and Grain-filling of Heavy Panicle Type Hybrid Rice

The characteristics of vascular bundle in the first internode from top and grain-filling of heavy panicle type hybrid rice(HPTHR) were studied. The results were as follows: The HPTHR had more vascular bundles and a much bigger area of single vascular bundle, all vascular bundle, all phloem and all xylem in the first inter-node than Shanyou63. The vascular bundles had the similar load of spikelet number and sink capacity between the HPTHR and Shanyou63. The HPTHR had not only a larger sink but also normal grain-filling and sink-filling, high seed-setting rate and heavier panicle. Those characteristics of vascular bundle were the biological bases for the larger and heavier panicle of HPTHR. The results also indicated that the breeding model of HPTHR was an effective measure for the super high-yielding rice breeding.