Influence of Seasonality on Certain Leaf Characteristics in Rice Cultivars

Higher growth and grain yield in rice was obtained in February planting as compared to July and October plantings. This was achieved through favourable leaf characteristics. In all the three plantings, leaf number monitored the leaf area rather than ILS which showed minimal alterations by the seasonality. There was a considerable variation in the attainment of critical leaf area index (LAI) among cultivars in different seasons. Thus, attainment of critical LAI would be necessary to influence the sink strength positively.     

水稻淀粉合成相关基因对稻米RVA谱特征的影响

以优质粳型糯稻苏御糯为供体，品质较差的籼稻桂朝2号为轮回亲本，构建了BC₂F₄群体，通过发展分子标记，研究了淀粉合成相关基因Wx、Sbe1、Sbe3、Isa、Pul、SssⅠ等对稻米淀粉RVA谱特征的影响。结果表明Wx基因对RVA谱8个特征值的表现均起主要作     

水稻移栽后苗期茎叶光合产物运转与分配特性研究

采用³H核素示踪方法,研究了水稻移栽后苗期茎叶光合产物的运转分配特性。结果表明,栽后4 d标记的茎鞘3H同化物在标记后10 d,有7.6%~9.8%运往新根,6.7%~15.6%运往主茎新叶,6.9%~9.9%运往分蘖茎叶;标记后30 d,约12%分配至新根,10%~14%分配至分蘖茎叶。标记后10~30 d参与再分配的同化物主要来自主茎茎鞘,输入器官主要为分蘖和新根。移栽后20 d标记叶片的3H同化物在标记后10 d,19%~28%分配至主茎新叶,4.6%~13.4%分配至分蘖,3%~5%运往新根。3个品种中,冈优22茎、叶光合产物分配到主茎中的比例较高,K优047分配到分蘖的比例较高,Ⅱ优162输送到新叶中的比例最大。     

水稻丙酮酸激酶基因OsPK1的过表达转基因株系的获得与鉴定

利用农杆菌介导的转化方法研究OsPK1过表达对水稻的影响。将CaMV 35S启动子驱动的OsPK1的全长CDS序列导入到日本晴基因组中。选择3个过表达转基因系作为代表进行鉴定和分析。结果显示,过表达植株在株高、分蘖数、穗长和千粒重四方面接近野生型水稻,结实率略下降,但每穗饱满种子数明显增加。通过定量RT-PCR分析,发现有4个代谢酶在过表达植株嫩叶中表达存在着上调或下调。用GC-MS方法检测糖含量,显示OsPK1过表达株系中葡萄糖、果糖、半乳糖和蔗糖的含量与野生型差异不大。总之,对OsPK1过表达株系的鉴定,有助于更好了解OsPK1的功能,并且每穗饱满种子数明显增加具潜在的应用价值。     

早晚季水稻耐光氧化反应特性及其与品质稳定性的关系

以耐光氧化反应特性和品质性状具有明显差异的9个水稻品种为材料,研究在早、晚季不同温光栽培条件下,水稻品种的耐光氧化反应特性和品质性状表现及其相互关系。结果表明,水稻的耐光氧化反应特性与稻米品质的优劣不呈显著性相关,但与垩白米率,垩白度,精米率,整精米率,磨损率和直链淀粉含量等品质性状在早晚季的稳定性密切相关,即耐光氧化反应特性强的品种在不同季节栽培其米质稳定性较好。     

水稻逆转座子的研究现状

逆转座子是水稻转座因子的一个主要组成部分。本文介绍了水稻活性逆转座子的发现、分离以及到目前为止发现的活性最高的水稻逆转座子Tosl7的结构及其在遗传分析中的应用。同时概述了逆转座子对水稻进化的影响以及逆转座子研究中存在的问题和解决方法。     

水稻株高的遗传控制及其在育种上的应用

株高是水稻品种的重要农艺性状之一,矮秆水稻品种的选育和推广是20世纪水稻育种工作的重大成就,因此矮秆基因的发掘研究和利用备受重视。本文综述了水稻株高基因的遗传、定位、作用机理及其在水稻育种中的利用情况等方面的研究进展,分析了水稻株高基因在水稻育种应用中所存在的问题,并对其发展前景作了展望。     

水稻悬浮培养研究进展

悬浮细胞培养是现代植物生物技术和植物细胞的分子机理研究的最重要方法之一.其中水稻悬浮培养足近年来的研究热点.本文从水稻悬浮培养外植体的选取、基因型的选择、愈伤组织的诱导、悬浮培养方法的优化、悬浮细胞的彤态特征和生理生化变化以及其在生命科学研究中的应用等方面进行了概述,并提出了目前水稻悬浮培养中尚待加强研究的问题.     

美国水稻品种对稻瘟病小种IE-1k、IB-33、IB-49和IC-17的抗性遗传

1994年10月至1995年5月，在美国阿肯色大学水稻研究推广中心的温室，对5个美国水稻品种Katy、Lemont、L202、RA73和Bond、其F1、F2和部分组合的F3随机选系，用4个主要美国稻瘟病菌小种IE-1k、IB-33、IB-49和IC-17进行接种鉴定，通过完全双列杂交进行遗传分析的研究。结果表明：所有的亲本对IB-33感病；除RA73外，其他亲本对IE     

水稻花器官发育的分子机理

在水稻上,花器官发育是从营养生长转向生殖生长的重要阶段,也是繁衍后代的必然过程,因此是生物学研究的重点与热点。通过对拟南芥、金鱼草等植物的研究,人们了解了植物花器官发育的某些重要特征,克隆了许多相关基因。本文综述了植物花器官发育的ABCDE模型,较详细地总结了参与水稻花器官发育的MADS-box基因及其功能,并介绍了近年来报道的一些水稻花器官突变体及相关基因。     

一个水稻半矮秆突变体的鉴定与遗传分析

高黄矮材料是由黄矮与高秆材料杂交后代F2群体中分离得到的一个半矮秆突变体材料,株高在95 cm左右,比黄矮高约40 cm.该材料在苗期倒2叶叶尖开始出现黄化,分蘖期倒2叶叶尖仍然黄化,倒3叶近1/3叶面黄化干枯、破损现象比较明显.将该突变材料与不同高秆材料杂交,杂种F1表现为高亲本,F2群体株高数据符合3:1分离比例,结果表明该矮生性状受1对隐性基因控制,因其叶尖黄化性状与半矮秆性状共分离,故暂将该基因命名为dy(t)基因;同时将突变材料与其他不同基因型的半矮秆杂交,F2群体均符合9:3:3:1的分离比例,结果表明dy(t)基因与sdl、sdn、sdg基因均不等位,为一新的半矮秆基因.对不同株高材料的幼苗进行不同浓度外源赤霉素(GA3)叶面喷施处理后,结果表明dy(t)基因对该激素敏感.     

The Deterioration of Eating and Cooking Quality Caused by High Temperature During Grain Filling in Early-Season indica Rice Cultivars

The effect of temperature during grain filling on eating and cooking quality of early-season indica rice was investigated by using four cultivars with different amylose content. Starting from flowering stage until maturity, the plants of all cultivars were subjected to two temperature treatments, referred as optimum (mean daily air temperature, 22 °C) and high (32 °C) temperature regimes. The results showed that the effect of high temperature on apparent amylose content and gel consistency in milled rice was cultivar-dependent. Under high temperature, amylose content increased for cv. Jiayu353 and remained little changed for cv. Guangluai4, which had intrinsically higher amylose content, and decreased for cv. Zhefu49 and cv. Jiazao935, which had lower amylose content. By contrast, high temperature reduced or kept stable gel consistency values for cultivars with higher amylose content and increased gel consistency values for those with lower amylose content. Moreover, high temperature significantly increased the gelatinization temperature of all cultivars. Pasting profiles and X-ray diffraction pattern of rice were also affected by temperature. The results suggest that high temperature during grain filling change the component and crystalline structure of starch and result in deterioration of eating and cooking quality for early-season indica rice.     

Improvement of Appearance Traits of elite Rice Zhenshan 97B by Molecular Introgression of Targeted about 800 kb Interval from Indica Rice Jiafuzhan Genome

Rice appearance trait is mainly mean grain length (GL), grain width (GW), ratio of length and width (L/W), chalkiness (CH) and transparence (TR). Appearance is the first impression, and rice appearance traits effect significantly the value of commodity. Hybrid rice is relatively low quality, especially on rice appearance quality,which restricts partially its extend and badly export of hybrid seed and rice in China.Shanyou 63, the most famous hybrid rice combination of China, could not be also sustainable application because of its poor qualities. In this studies, We attempt to improve appearance quality of the elite rice maintainer of Zhenshan 97B by using molecular approach of genomic interval targeted introgression. Three F2 populations were constructed to study the classical and molecular genetic of rice appearance traits, at the same time, molecular marker-asisted toimprove the main maintainer line, Zhenshan 97B were performed. There some following results:Three F2 populations were constructed based on crosses of Guangluai 4×Jiafuzhan (GJ popu.), Minghui 86×Jiafuzhan (MJ popu.) and Zhenshan 97B×Jiafuzhan (ZJ popu.). ZJ popu and GJ popu were produced to reconstruct the linkage maps related with rice appearance traits based on BSA, and detect QTL of target traits based on IM.In ZJ popu, 9 QTLs of target traits were detected. The interval, RM169～RM516 on Chromosome 5, was genetic locus of GW, L/W, CH and BW, and the explained variances were 10.9%, 14.9%, 12.0% and 14.2%, respectively.RM214 on chromosome 7, RM339 on chromosome 8 were genetic loci if CH and BW, and the explained variances were 9.4%, 10.0%, 11.0% and 12.1%. besides there is a genetic locus, RM347, of G/W on chromosome 3, and the explained varance was 10.3%. In GJ popu, 5 QTLs of rice appearance traits were detected. The interval, RM169-RM516 on Chromosome 5, were also the genetic loci of GW, CH and BW, and the explained variances were 9.0%, 12.5%, and 13.6%, respectively. RM264～RM80 on chromosome 8 was the genetic loci of GW amd L/W,and the explained variances were 14.7% and 13.4%. The genotypes of all QTLs, except RM214, from Jiafuzhan contributed to improving riee appearance traits.The research was to improve the rice appearance quality of Zhenshan 97B by introgressing QTLs of rice appearance traits from Jiafuzhan, a donor parent, by means of MAS in the process of recurrent backcrossing, 4 SSR markers were used to detect the target genotypes from donor parent, and 70 SSR primers to identify the genetic background of recurrent parent. Consequently, there were 19 target individuals in BC3, in which the mean value of GL, GW, L/W, CH and BW were 6.06±0.04mm, 2.50±0.02mm, 2.43±0.02, 29.5±2.7 and 29.4±2.7%, respectively,and the mean homologous degree (HD) to recurrent parent is up to 98.22%. Compared to Zhenshan 97B, GL, CH and BW decreased 0.17 mm, 34.9% and 34.5% respectively and however L/W increased 0.19. which accounted separately for 25.37%, 54.79%, 54.57% and 10.50% of thedifference of every trait between two parents. It is very luckly to find a individual, 13BC2-3BC3 line, whose GL, GW, G/W, CH and BW were 6.04 mm, 2.43 mm, 2.49,2.5% and 2.5% separately, There is very important signification for it to be used in hybrid rice breeding improving appearance traits. In the research, MAS efficiency of 3 loci (with 4 markers ) was 5.68% and coincident degree was 73.08%.     

粳稻杂种劣势的遗传及表型特性分析

杂种优势是自然界的一种普遍现象,但在杂交水稻育种实践中也时常发现杂种劣势现象,为了更好地阐明杂交育种理论和揭示品种本质有必要对杂种劣势的遗传机理进行更深层次的研究。本研究旨在通过两个韩国粳稻品种(Aranghyangchalbyeo和Sanghaehyangheolua)及其正反交后代(F1,F2)特性的比较,解析水稻杂种劣势的表型、类别及其遗传模式。形态学分析表明,正反交F1植株的劣势表现均明显、稳定且不受环境影响,主要农艺性状的中亲劣势值均为负值,其中F1的株高、分蘖数和结实率与亲本相比显著降低(P<0.01);F1劣势表现从发芽后第5d开始,地下部的劣势表现比地上部更为明显。细胞组织结构观察表明,分蘖盛期F1劣势植株叶片发育正常,而其根部气腔发育较亲本迟缓,从而阻碍了地上部与地下部的通气情况,因此也影响了整个植株的正常生长。遗传学分析发现,该劣势组合成熟期F2群体中正常与劣势植株呈现7:9的分离,结合分蘖盛期该F2群体株高的分离模式,推断该杂种劣势的表型是由两个互补的显性基因控制。该研究结果为揭示杂种劣势的多样性及分子遗传机制提供了新思路。     

水稻航天衰老突变体基因psl2的表型和遗传分析

叶片是植物最主要的光合作用器官,是水稻的源器官。其生长、发育和衰老的分子机理的研究对水稻经济产量和生物产量具有重要的意义。2006年我单位在参加农业部实践8号卫星航天育种工程的空间辐射诱变籼稻(Oryza sativa L.indica)泸恢H103中得到一叶片早衰突变体。初步研究结果表明,该早衰叶突变体表现的特点是:抽穗期前心叶抽出时,先前抽出的倒4叶片就开始变黄衰老,抽穗初期时先前抽出的倒3叶表现衰老,抽穗后期先前抽出的倒2叶表现衰老,灌浆期剑叶表现衰老,完全成熟时剑叶完全衰老死亡。利用该突变体分别与其野生型泸恢H103、R527、R602杂交,获得F1及其衍生的F2群体,对早衰叶突变体进行遗传分析。遗传分析表明由一隐性核基因psl2控制。本研究为最终定位和克隆目标基因奠定了基础。     

水稻颖花退化机理与调控途径

水稻颖花退化现象在水稻生长发育中普遍存在,是限制产量进一步提高的重要因素。颖花退化既受内在的遗传和生理的调控,也受外在环境的影响。以往有研究曾用不同遗传作图群体定位了分布在第1至第11号染色体上的多个水稻颖花退化数量性状基因座（QTL）,但这些QTL对颖花退化的贡献率均不大;利用突变体材料确定了多个颖花退化候选基因,并克隆了其中的3个基因,但其分子机制仍不清楚。关于颖花退化的生理生化机制有很多假设,包括资源限制、自组织过程、化学调节等,但均缺乏有力证据。近年的研究表明,水稻穗分化期特别是减数分裂期内源油菜素甾醇（BRs）和多胺（PAs）水平较低、乙烯水平较高与颖花退化有密切的关系,提高BRs、PAs或PAs与乙烯的比值,可以减少颖花退化。水稻颖花退化的另一个重要原因是三磷酸腺苷（ATP）含量和能荷水平过低及活性氧（ROS）过度积累,使得膜脂过氧化伤害和小穗程序性细胞死亡,导致颖花退化。通过栽培措施适度提高减数分裂期植株含氮量或BRs含量可提高幼穗能荷水平,减少ROS积累,进而显著减少水稻颖花退化。今后需要从内在因素（遗传、生理生化）、植株整体水平、栽培调控和环境条件等方面深入研究水稻颖花退化的机理及其调控途径,破解水稻颖花退化的科学难题。     

低磷胁迫对不同水稻品种幼苗光合作用的影响

低磷胁迫下,水稻叶片的无机磷含量、光合速率、RuBP羧化酶活性下降.与低磷敏感品种沪占七相比，耐低磷品种大粒稻无机磷含量、RuBP羧化酶活性下降的幅度更小.在低磷胁迫初期(10 d)较低光强下，大粒稻与沪占七光合速率受低磷的影响相近，而较高光强下以及胁迫后期(20 d)大粒稻受低磷影响较小.叶绿素荧光参数测定表明，在低磷胁     

早稻-再生稻头季稻不同育秧方式秧苗素质及生理生化特性（Ⅰ） ——杂交水稻高产突破的生理生态与调控技术研究

通过对常规栽培模式湿润育秧苗与超高产栽培模式旱育秧苗的秧苗素质、根系性状、生理生化特性等的研究，探讨了不同栽培模式中育秧方式对水稻产量的影响，以揭示超高产栽培模式实现高产的生理原因。结果表明，超高产栽培模式下旱育秧苗的干物质积累和分蘖数比湿润育秧苗高22.78%、73.33%，而株高比对照矮14.91%，同时还表明，超高产栽培模式下旱育秧的根系还原力强、发根数多、发根能力强，硝酸还原酶、ATP酶、叶绿素及过氧化氢酶、过氧化物酶、超氧化物岐化酶等细胞保护酶含量增加，表现出强大的生理生化优势，而丙二醛含量比对照降低20.99%，可溶性糖和硝态氮含量增多，C/N适中，有利于提高旱育秧苗的抗逆性，是旱育壮秧形成的内在生理基础。     

水稻耐低磷机理的初步研究

以耐低磷品种大粒稻和汕优63、低磷敏感品种新三百粒和沪占七为材料.测定0.5 mg/L(P)和10 mg/L(P)两种磷水平下水稻根系形态、氧化力、呼吸速率、动力学参数、丙二醛含量、酸性磷酸酶活性(APA)的品种间差异.实验表明,0.5 mg/L(P)时,大粒稻和汕优63根长分别比CK(10 mg/L)下降了15.2%和22.0%,根体积分别下降了25.2%和22.2%,而沪     

水稻生育后期叶片早衰突变体的光合特性与叶绿体超微结构观察

以旗叶早衰的水稻突变体(psf)与其野生型对照(浙恢7954)为材料,对两者在水稻抽穗开花后旗叶衰老过程中的光合速率、叶绿素荧光和叶绿体超微结构比较分析表明,旗叶早衰突变后的每穗实粒数、结实率、千粒重和单株产量均不同程度降低,以对每穗实粒数和结实率的影响程度最明显; 在水稻灌浆期间,psf旗叶的叶绿素含量、叶绿素a/b值、净光合速率(P_n)、PSII潜在活性(F_v/F_o)和最大光化学效率(F_v/F_m)均比其野生型对照明显降低,且随着抽穗开花后天数的推移,供试材料间的差异幅度呈逐渐拉大趋势; psf叶肉细胞中的叶绿体排列、形态大小及其类囊体结构在水稻抽穗开花期基本正常,但随着叶片衰老过程的推进,psf叶肉细胞中的叶绿体相继会出现沿细胞壁周缘化、外部形态缩皱变形、嗜锇颗粒增多变大、类囊体膜系统退化、片层结构完全解体等变化。其中,叶绿体沿叶肉细胞壁排列的周缘化与外形结构的球状化表现,与叶绿体类囊体膜系统损伤和开始降解之前的净光合速率(P_n)下降有关,而由类囊体膜系统受损所带来的F_v/F_m和F_v/F_o下降过程,则相对滞后于P_n和叶绿素含量下降的起始时间。