自由空气CO2浓度升高和储藏对水稻籽粒中不同形态多胺组分和含量的影响

以籼稻品种IR24和粳稻品种Asominori 为材料,比较分析了自由空气CO2浓度升高（free air CO2 enrichment, FACE）和储藏1年,对籽粒内游离态、结合态和束缚态3种类型多胺及其组分、含量的影响。在正常空气条件下,籼、粳稻籽粒中的多胺总量不存在显著差异;FACE处理降低了Asominori 籽粒多胺总量,但对IR24 影响不明显,因此FACE条件下IR24籽粒的多胺总量高于Asominori。储藏1年后,籽粒多胺总量呈下降趋势,其中正常空气条件下生长的IR24籽粒多胺总量显著下降。两水稻品种籽粒中的束缚态多胺总量明显高于游离态和结合态多胺,占总量的50%以上,而在束缚态多胺组分中,亚精胺（Spd）所占比例最大。 FACE处理降低了籽粒中的束缚态Spd含量,增加了结合态Spd含量,而这些FACE效应经籽粒储藏后消失。     

植酸形成与水稻籽粒充实的关系

研究了6个水稻品种（组合）的籽粒灌浆特征及植酸合成过程中相关生化成分变化与籽粒充实的关系。籽粒充实度好的亚杂1号(ISHR1)、亚杂2号（ISHR2）、R198和JW21,强、弱势粒灌浆不表现两段灌浆现象,而籽粒充实度差的亚杂3号（ISHR3）和559两段灌浆现象则十分明显。孕穗期至开花期,籽粒充实度好的品种其植酸、肌醇含量显著高于籽粒充实度差的品种;灌浆期,籽粒充实度差的品种无机磷含量明显高于籽粒充实度好的品种。相关分析表明,在孕穗期至开花期籽粒中植酸、肌醇含量与起始灌浆势（P0）、平均灌浆速率（RA）和籽粒充实率（GFP）均呈极显著正相关;灌浆期,无机磷含量与P0、RA和GFP呈极显著负相关,肌醇含量与P0、RA和GFP无明显相关性。提出了提高水稻籽粒充实度的有效途径。     

多胺与乙烯对水稻籽粒灌浆、粒重和品质的调控作用

研究水稻产量与品质特性对水稻优质高产育种和栽培具有重要意义。多胺与乙烯作为两类重要的内源植物生长调节物质,对水稻籽粒灌浆充实、粒重和品质形成具有重要的调控作用。本文分别介绍了水稻籽粒多胺与乙烯、灌浆充实、粒重和品质特性,简述了灌浆与粒重和品质形成的关系,重点综述了水稻灌浆期籽粒多胺与乙烯对灌浆充实、粒重和品质(稻米加工、外观和营养品质及籽粒淀粉品质)的调控作用及其生理机制,讨论了存在的问题和今后的研究方向。     

高温对水稻灌浆期籽粒氮代谢关键酶活性及蛋白质含量的影响

 选用粳稻品种越光与籼稻品种IR72为材料,研究了高温对水稻灌浆期籽粒谷氨酰胺合成酶（GS）、谷氨酸合酶（GOGAT）、谷氨酸 草酰乙酸转氨酶（GOT）、谷氨酸 丙酮酸转氨酶（GPT）的活性及蛋白质与氨基酸含量的影响。结果表明,灌浆期高温下水稻籽粒GOGAT、GOT与GPT活性显著或极显著升高,但籽粒GS活性显著或极显著降低;籽粒蛋白质及氨基酸各组分含量极显著增加。高温下籽粒GS活性显著降低并未影响籽粒蛋白质的合成,认为籽粒GS不是限制水稻蛋白质合成的关键酶。     

水分胁迫下外源多胺对水稻叶片光合速率与籽粒充实的影响

 以汕优63和PC311/早献党18为材料,研究了不同程度土壤干旱胁迫下水稻叶片中多胺含量变化以及外源多胺对籽粒充实和粒重的影响。在水分胁迫条件下,叶片中腐胺含量和腐胺与亚精胺以及精胺的比值提高。无论在土壤水分充足或水分胁迫条件下,抽穗期施用低浓度Spd和Spm后,叶片中的腐胺和MDA含量降低,而亚精胺和精胺、光合作用速率和籽粒的胚乳细胞数,饱满籽粒百分率以及千粒重显著增加。     

水稻灌浆期高温对天冬氨酸代谢酶活性及其家族氨基酸含量的影响

 选用粳稻越光和籼稻IR72为材料,研究了灌浆期高温对水稻籽粒中天冬氨酸转氨酶（AAT）、天冬氨酸激酶（AK）活性以及稻米蛋白质组分与天冬氨酸族氨基酸组分含量的影响。结果表明,水稻灌浆期高温下籽粒中AAT和AK活性、天冬氨酸、赖氨酸、苏氨酸、蛋氨酸和异亮氨酸相对含量均显著提高,籽粒中AAT和AK活性与天冬氨酸家族总氨基酸含量分别呈显著和极显著正相关,说明水稻籽粒中AAT和AK对于高温下稻米天冬氨酸家族氨基酸含量的提高具有重要作用。高温有利于稻米中蛋白质组分与天冬氨酸族氨基酸组分相对含量的提高,有利于单粒稻米中谷蛋白与天冬氨酸家族氨基酸组分的积累以及粗蛋白中部分氨基酸比例的改善,但高温降低了每穗稻米中蛋白质组分与部分氨基酸组分的含量。     

外源多胺调节剂对渗透胁迫下水稻胚芽鞘和幼根生长以及多胺含量的影响

以抗旱性不同的籼稻品种湘早籼32号、嘉早935和旱116为材料,研究了渗透胁迫下外源多胺调节剂对水稻胚芽鞘和幼根生长及多胺含量的影响。结果表明:渗透胁迫下,水稻胚芽鞘和幼根生长受到抑制,胚芽鞘和幼根中腐胺(Put)、亚精胺(Spd)和精胺(Spm)的含量上升,抗旱性强的嘉早935和旱116的上升幅度大于抗旱性弱的湘早籼32号;外源D-精氨酸(D-Arg)和鸟嘌呤腙(MGBG)抑制水稻胚芽鞘和幼根中Put、Spd和Spm含量的上升,加剧渗透胁迫下水稻胚芽鞘和幼根生长的受抑制程度;外源Spd能提高水稻胚芽鞘和幼根中Put,Spd和Spm含量,缓解渗透胁迫下水稻胚芽鞘生长的受抑制程度,但加剧了渗透胁迫对幼根的伤害程度。     

多光谱与热红外数据融合在冬小麦产量估测中的应用

为了解多光谱与热红外数据融合对冬小麦产量估测精度的影响,以30个黄淮麦区冬小麦品种为材料,利用三种灌溉处理（处理1、处理2和处理3灌水量分别为240、190和145 mm）下冬小麦拔节期、挑旗期、抽穗期与灌浆期的无人机多光谱和热红外动态数据,构造了多个光谱指数,以支持向量机构建冬小麦产量估测模型,并验证其精度。结果表明,植被指数与籽粒产量的相关性受溉水量影响,处理1下植被指数与籽粒产量均呈正相关,处理2下植被指数除土壤调整植被指数（SAVI）和转化叶绿素吸收反射指数（TCARI）外均与籽粒产量呈正相关,处理3下植被指数与籽粒产量均呈负相关。通过多光谱和热红外数据融合构建的冬小麦产量估测模型的预测精度比仅使用多光谱数据构建的模型提高8%。不同灌溉条件下,通过多光谱与热红外数据融合构建的模型的预测精度存在差异,在处理1、处理2和处理3下拔节期、挑旗期、抽穗期和灌浆期验证决定系数（R）最高值分别为0.63、0.68和0.56,均方根误差（RMSE）最低值分别为0.60、0.24和0.41 t·hm^-2,且在三种灌溉条件下灌浆期预测效果均最佳。因此,利用无人机光谱对小麦品种产量估测时应将多光谱与热红外数据融合,用支持向量机（SVM）算法构建产量估测模型,且模型在灌浆期具有较高预测  精度。     

蔗糖减缓水稻灌浆期高温对同化物转运抑制作用的原因分析

以早籼稻浙辐802及其近等基因系fgl为材料,采用盆栽试验,于籽粒灌浆期在人工气候箱进行高温处理10 d(40℃/30℃,昼夜),研究高温下喷施蔗糖溶液对水稻结实率、千粒重和干物质积累及分配的影响。结果表明,籽粒灌浆期高温胁迫对结实率的影响较小,但千粒重显著下降,其中,浙辐802下降的幅度显著高于fgl。蔗糖在一定程度上可减轻高温胁迫对水稻粒重及同化物转运的抑制作用。高温下,蔗糖处理的千粒重显著高于对照,籽粒面积、周长及长度均高于对照。高温下,蔗糖对水稻植株同化物积累影响不大,但显著提高同化物在穗部的比例,即高温下蔗糖处理穗部干物质积累比例显著高于对照。鉴于此,笔者认为,蔗糖减轻籽粒灌浆期高温胁迫抑制的作用,主要在于影响同化物转运而不在于干物质积累。     

ABA对水分胁迫下水稻籽粒灌浆的调节

 利用水平分根系统研究了水稻抽穗后水分胁迫条件下ABA对水稻品种汕优63叶片光合特性、糖代谢和籽粒灌浆过程的调节。当一半根系受干旱胁迫时，叶片的水势和相对含量变化很小，但叶片和籽粒内ABA的含量显著增加。整个根系受干旱胁迫时，叶片的水势和相对含水量随着胁迫的增加而显著地降低，ABA含量则显著增加。半干和全干处理的水稻叶片的光合速率和RuBP羧化酶／氧化酶（Rubisco）的活性显著下降。叶片内蔗糖和淀粉的积累和代谢与叶片内ABA的含量和水分状况存在密切的关系，低浓度的ABA和高的叶水势与高的蔗糖积累和蔗糖磷酸合成酶活性相一致，但当叶片ABA的浓度增加时，即使叶片的水势与对照相似，叶片的蔗糖和淀粉积累以及蔗糖磷酸合成酶的活性则显著地下降，叶片的α－和β－淀粉酶活性似与ABA和水分状况关系不密切。ABA对籽粒灌浆有显著的抑制作用，ABA对籽粒灌浆的抑制作用至少部分与其对催化水稻籽粒内蔗糖代谢和淀粉积累的关键酶蔗糖合成酶的抑制有关。另外，干旱处理对叶片光合速率和蔗糖与淀粉积累的抑制程度显著高于半干旱处理，说明干旱本身也对这些过程有直接的效应。根据这些结果，作者认为，当水稻遇到干旱胁迫时，ABA对其光合作用、糖代谢以及籽粒的发育过程都有极其显著的调节作用。还就ABA对这些生理过程调节的可能性进行了讨论     

Effects of Polyamines Synthesis Inhibitors Sprayed after Heading on Contents and Components of Polyamines in Rice Grains at the Ripening Stage

With a higher polyamine rice （indica variety Jinlingxiang） as experimental material, the changes in contents and components of polyamines （PAs） in rice grains after harvesting were investigated under the treatments by spraying the panicles and flag leaves of rice with PAs synthesis inhibitors, D-Arg （0.5, 1.0, 1.5 and 2.0 mmol/L）, methylglyoxal bis-guanylhydrazone （MGBG） （0.1, 0.5, 1.0 and 1.5 mmol/L） and cyclohexylamine （CHA） （1.0, 5.0, 10.0, 15.0 and 20.0 mmol/L）, at the heading, flowering and grain filling stages. The inhibition of D-Arg on the contents of free and bound PAs and its total amounts in rice grains was significant, especially treated at the flowering and grain filling stages. Treatments with MGBG and CHA affected mainly the components of PAs, and their effects on the total amounts of PAs were not significant except MGBG at the flowering stage and CHA at both heading and flowering stages.     

水稻强弱势籽粒核酸和蛋白质代谢差异

以两系杂交稻两优培九和培两优500为试验材料,对强弱势粒核酸和蛋白质含量进行了测定。水稻抽穗当天,强势粒单位质量子房中总RNA、mRNA含量都高于弱势粒,蛋白质含量却低于弱势粒。抽穗后第5天,强势粒单位质量子房中总RNA含量仍然高于弱势粒,mRNA含量两者差异不大,蛋白质含量依然低于弱势粒。不论是强势粒还是弱势粒,从抽穗到开花后第5天,其总RNA、mRNA和蛋白质单粒含量都有显著的增加,且各时期强势粒都高于弱势粒。抽穗当天强势粒有两条特异蛋白质带出现,而弱势粒没有,抽穗后第5天弱势粒才出现其中的一条。这说明强势粒与籽粒灌浆有关的基因表达比弱势粒早,强度高。     

Pre-anthesis non-structural carbohydrate reserve in the stem enhances the sink strength of inferior spikelets during grain filling of rice

Sink strength plays an important role in grain filling of cereals but how it is related to the pre-anthesis non-structural carbohydrate (NSC) reserves is not clear. This study investigated if and how an increase in NSC reserves could enhance sink strength, and consequently improve grain filling of later-flowering inferior spikelets (in contrast to the earlier flowering superior spikelets) for rice varieties with large panicles. Two “super” rice varieties (the recently bred high-yielding rice) and two New Plant Type (NPT, named in IRRI for the extra-large panicle) rice lines were compared with two elite inbred varieties under field-grown conditions. Three nitrogen (N) treatments, applied at the stages of panicle initiation, spikelet differentiation or both, were adopted with no N application during the mid-season as control. Both super rice and NPT rice showed a greater yield capacity as a result of a larger panicle than the elite inbred rice. However, a lower percentage of filled grains limited the realization of higher yield potential in super rice and especially in NPT rice, due to their lower grain filling rate and the smaller grain weight of their inferior spikelets. The low grain filling rate and small grain weight of inferior spikelets are mainly attributed to a poor sink strength as a result of small sink size (small number of endosperm cells) and low sink activity, e.g. low activities of sucrose synthase (SuSase) and adenosine diphosphoglucose pyrophosphorylase (AGPase). The amounts of NSC in the stem and NSC per spikelet at the heading time are significantly and positively correlated with sink strength (number of endosperm cells and activities of SuSase and AGPase), grain filling rate, and grain weight of inferior spikelets. Nitrogen application at the spikelet differentiation stage significantly increased, whereas N application at the panicle initiation or at both panicle initiation and spikelet differentiation stages, significantly reduced, NSC per spikelet at the heading time, sink strength, grain filling rate, and grain weight of inferior spikelets in super rice. The results suggest that pre-anthesis NSC reserves in the stem are closely associated with the sink strength during grain filling of rice, and N application at the spikelet differentiation stage would be a good practice to increase pre-anthesis NSC reserves, and consequently to enhance sink strength for rice varieties with large panicles, such as super rice varieties.     

灌浆成熟期粳稻抗倒伏性和茎鞘化学成分含量的动态变化

分析了不同抗倒类型的粳稻品种灌浆成熟过程中茎鞘抗倒伏性和化学成分含量的动态变化。结果表明,不同抗倒类型品种茎鞘的钾、硅和可溶性糖等总量差异很大,与钾和可溶性糖总量相比,硅总量的差异较大。随着籽粒灌浆进程,不同抗倒类型品种的茎秆物理强度和最大承载量均逐渐变小,到成熟期为最小,尤其是茎秆物理强度到蜡熟期开始迅速变小,但茎的钾、硅含量和总量及叶鞘的硅含量逐渐增加,出现沉积现象,而叶鞘的钾含量和总量及硅总量逐渐减少,呈输出迹象。除齐穗期茎的钾总量外,灌浆不同时期茎秆物理强度与茎的钾总量和硅总量均呈极显著正相关;茎秆物理强度与齐穗期和乳熟期茎的可溶性糖总量,与齐穗期叶鞘的硅总量和可溶性糖总量,与齐穗期和乳熟期的钾总量呈极显著或显著正相关,灌浆各时期穗部最大承载量与茎秆物理强度均呈极显著正相关。说明提高灌浆前期的茎鞘可溶性糖总量,以及通过追施硅肥增加植株硅总量有利于提高水稻抗倒伏能力。     

Relationship of milled grain percentages and flowering-related traits in rice

The economic value of harvested rice is determined by the grain yield and the percentages of head rice (at least 3/4 the length of a head or kernel) and total milled rice. This study was conducted to determine the effects of flowering-related traits such as duration of flowering, rate of flowering, heading, and duration from heading to maturity on head rice and total milling percentages of rice. Flowering data, gathered for two years from 105 long grain rice genotypes grown in Beaumont, Texas were analyzed for their effects on and relationship with milling traits. A positive linear relationship was obtained for rate of flowering and the duration from heading to maturity but negative for duration of flowering and days to heading. Genotypes with early heading had relatively shorter flowering durations, and genotypes with shorter flowering duration had higher head rice and total milled rice. A faster rate in attaining 100% flowering and more days from heading to maturity were favorable in increasing head rice and total milled grains. The duration from the start of flowering to heading or to 100% flowering can be used in the evaluation and selection for high head rice and total milled rice percentages in rice.     

结实期低温胁迫对水稻强、弱势粒淀粉形成与积累的影响

【目的】研究结实期低温胁迫对水稻强、弱势粒淀粉组分含量、积累速率及关键酶活性的影响，明确淀粉合成关键酶活性变化对淀粉积累速率的调控效应，探究强、弱势粒淀粉形成积累差异对水稻产量的影响。【方法】以耐冷型品种东农428和冷敏型品种松粳10为试验材料，设置1个常温处理(白天温度28℃，14h/夜间温度22℃，10 h，7 d)和4个低温处理(17℃，低温处理时间分别为1、3、5、7 d)，分析了结实期低温胁迫对强、弱势粒淀粉组分积累、合成关键酶活性、水稻产量及构成因素的影响，并探讨了灌浆期各阶段淀粉积累差异与酶活性变化的关系。【结果】与对照相比，结实期低温胁迫降低了两个品种水稻强、弱势粒中腺苷二磷酸葡萄糖焦磷酸化酶(AGPase)、可溶性淀粉合成酶(SSS)、淀粉分支酶(SBE)的峰值活性以及支链淀粉和总淀粉含量，提高了齐穗后28~38 d 低温处理3、5、7 d的颗粒结合型淀粉合成酶(GBSS)活性和直链淀粉含量。与对照相比，各低温处理酶活性最高和淀粉积累最快的时间均有不同程度的推迟，低温处理7 d的影响最大，强、弱势粒低温处理7 d的支链淀粉和总淀粉含量分别在齐穗后13、18 d降幅最大，直链淀粉含量在28 d增幅最大。相关分析表明，强、弱势粒直链淀粉含量及强势粒支链淀粉、总淀粉含量与其最大积累速率呈极显著正相关，弱势粒支链淀粉、总淀粉含量还受到其最大积累速率出现时间的影响。AGPase、GBSS、SSS、SBE活性变化与淀粉积累速率和积累时间早晚密切相关，对淀粉及淀粉组分含量的变化有着明显的影响。同时，结实期低温胁迫显著降低了水稻的千粒重、结实率和产量，且随低温处理天数的增加降幅逐渐增大。结实期低温胁迫对弱势粒中淀粉合成关键酶活性变化影响大于强势粒，弱势粒淀粉合成积累减慢，含量降低，导致水稻千粒重显著下降，产量降低。【结论】就品种而言，耐冷型东农428具有较高的淀粉合成关键酶活性，淀粉及其组分含量较高，在低温胁迫下产量能维持在较高的水平。因此，强、弱势粒淀粉合成关键酶活性对淀粉合成起着非常关键的调控作用，淀粉组分和含量及其变化对产量有着十分重要的影响。     

三角形强化栽培技术对水稻光合生理特性及产量形成的影响

以杂交水稻冈优527为材料,研究了水稻在三角形强化栽培、正方形强化栽培、抛秧栽培和常规高产栽培等不同栽培方式下的生理指标、灌浆特性及产量。结果表明,在三角形强化栽培技术体系下适宜密度的水稻群体具有独特的优势:在关键生育时期叶面积指数(LAI)较大,齐穗后剑叶衰老减缓,光合速率较高,能够充分发挥个体生长优势,贮存积累并向穗部转运较多的光合同化产物,不仅保证了强势粒的灌浆,而且弱势粒灌浆也较为顺畅,产量构成因素得到优化配置,从而获得高产。     

Variations in Carbohydrate and Protein Accumulation among Spikelets at Different Positions Within a Panicle During Rice Grain Filling

The accumulation dynamics of kernel components for spikelets at different positions within a rice panicle were investigated during grain filling to understand the physiological reasons for the variation of grain quality.Two rice cultivars,Yangdao 6 (indica) and Yangjing 9538 (japonica),were field-grown,and the grain filling characters and contents of starch,soluble sugar,and protein of the spikelets at different positions were studied.There were significant differences in matter accumulation among spikelets at different positions during grain filling.The early-flowering spikelets presented dominance over the late-flowering spikelets in initial time and initial rate of accumulation.At the initial and mid filling stages,the contents and the rates of starch and amylose accumulation in spikelets decreased with the flowering sequence,but soluble sugar content (SSC) exhibited the opposite trend.The difference in SSC among the spikelets of Yangjing 9538 was greater than that of Yangdao 6,but amylose content in mature spikelets showed no obvious relationship to their flowering sequence.The crude protein content (CPC) of early-flowering spikelets decreased more rapidly than that of late-flowering ones at the initial filling stage,and CPC in the spikelets on the secondary branch was higher than that on the primary branch,but CPC in early-flowering ones was lower than that in late-flowering across the whole grain filling period.Grain water content (GWC) of early-flowering spikelets decreased more rapidly than that of late-flowering spikelets on the same branch at the initial and mid filling stages,especially for the top grain on each primary branch.The results suggested that poor grain filling of late-flowering spikelets may be attributed to their low biological activity rather than carbohydrate supply limitation.     

氮肥对水稻胚乳淀粉品质、相关酶活性及基因表达量的影响

【目的】旨在为阐明灌浆成熟期氮素营养对水稻淀粉品质影响机理以及建立优质高产水稻栽培技术提供理论依据。【方法】选用4个籽粒直链淀粉含量差异显著的粳稻品种,通过盆栽试验研究氮素营养对稻米淀粉组分和蛋白质含量及稻米蛋白质水解对淀粉黏滞特性的影响,并分析氮素营养对灌浆过程中籽粒蔗糖合酶(SuSy)、蔗糖磷酸合酶(SPS)、蔗糖酸性转化酶(AI)活性及OsGBSSⅠ、OsISAⅠ、OsSBEⅠ、OsSBEⅡ基因转录表达量的影响。【结果】结果表明,籽粒支链淀粉含量对氮素营养很敏感,灌浆成熟期氮素营养能改变籽粒淀粉组分含量;施氮条件下,高直链淀粉含量品种蒸煮食味品质下降更加明显,去除稻米蛋白质可明显提高稻米黏滞特性,蛋白质对淀粉黏滞特性的影响很大;增加灌浆成熟期氮素营养能显著或极显著提高籽粒SuSy和AI活性,显著抑制籽粒SPS活性;灌浆成熟期氮素营养能改变灌浆不同时期籽粒OsGBSSⅠ、OsISAⅠ和OsSBEⅡ基因转录表达量,以致灌浆过程中这些基因的转录表达量变化动态发生改变,但OsSBEⅠ基因转录表达量不因氮素营养而发生改变;受氮素营养的影响,灌浆起始期籽粒OsGBSSⅠ基因表达量明显上调,而灌浆中后期明显下调;氮素营养明显抑制灌浆成熟期籽粒OsISAⅠ基因和灌浆中后期的OsSBEⅠ基因转录表达,显著提高灌浆前期和中期的籽粒OsSBEⅠ基因转录表达量;氮素营养能抑制灌浆起始期籽粒OsSBEⅡ基因的转录表达,而提高灌浆中后期的基因转录表达。【结论】灌浆成熟期氮素营养除了通过蛋白质含量对淀粉品质产生影响外,还通过调控淀粉合成相关的酶活性和基因表达量等生理环节对淀粉含量和精细结构起作用,最终改变稻米黏滞特性和食味品质。