裸子植物种子发育过程及基因调控研究进展

种子是裸子植物和被子植物所特有的繁殖器官,是植物有性繁殖的最高形式.裸子植物的种子裸露,形态较为简单,由种皮、胚和胚乳三部分组成,胚乳一般由雌配子体直接发育而来,为单倍体.其发育过程中会有AB13、FUS3等转录因子和miR159、miR172等miRNA参与调控,同时,DNA甲基化及RBR、ATG5等基因对裸子植物种子发育也起到重要的调控作用.本文从结构特征和分子调控等方面对裸子植物种子发育过程进行综述.     

短梗五加种子萌发影响因子研究

短梗五加[Acanthopanax sessiliflorus(Rupr.et Maxim.)Seem]种子透水性良好,休眠后萌发不受其影响。果肉、种皮和胚乳中均存在抑制物质,胚乳中提取物质对白菜种子萌发的抑制效果最明显,果肉其次,种皮最弱。果实成熟种子自然脱落时,种胚尚未发育完全,处于心形胚阶段。种子萌发需要先暖温层积以完成胚的分化与生长,然后转入低温完成生理后熟。     

植物种子萌发的生物力学

植物生物力学是一个多学科领域。植物种子萌发是植物生活史中基于生物力学的一个阶段。种子萌发的生物力学研究关系到种子产业和农业作物的发展,有关机理的研究具有重要的理论和实践意义。文章首先介绍了生物学材料的特性,这是将种子作为生物材料研究其生物力学的基础。概述了种子萌发生物物理学、胚生长和胚乳弱化的生物力学及种子的机械传感,指出调控种子萌发的生物力学因素主要是种皮、胚乳弱化和胚生长潜力等。重点讨论了种子萌发过程中的生物力学和分子调控机制。     

马蔺种子休眠机理的研究

为进一步分析马蔺种子的体眠机理,对马蔺种子种皮透水性、种胚发育状况、萌发抑制物质以及暖层积(25℃)期间的一些相关指标进行了测定,结果表明:马蔺种子种皮及胚乳组织较致密,种子吸水缓慢,种皮携带萌发抑制物质;暖层积之后种子内的萌发促进物质GA<,3>含量上升,抑制物质ABA含量下降,种皮萌发抑制物质消失,发芽率显著提高.综合以上结果可以看出,马蔺种子属于综合休眠,种皮对种子萌发有限制作用,种胚存在生理休眠.     

植物胚对ABA和渗透势的生理学和分子学反应的研究进展

胚的发育过程开始于合子形成,直至胚成熟结束,整个发育过程不仅受胚本身的遗传信息的时序控制,而且还与胚周围的环境(种子环境和母体环境)条件密切相关。遗传和环境对胚发育过程的调节和影响主要通过两个生理调控因子,一个是生长调节剂ABA等,而另一个为渗透势(主要指胚周围的化学渗透环境)。许多研究结果表明,ABA和渗透势均具有促进胚发育成熟和抑制早萌的双重作用。本文以此为出发点,着重阐述植物胚发育对ABA和渗透势的生理学和分子学反应,旨在了解早萌(或胎萌)发生的生理和分子学机理。     

太子参种子特性及种胚离体诱导培养技术研究

采用解剖学观察和无菌诱导培养技术研究太子参种子特性并离体诱导培养种胚。结果表明:太子参种子由外种皮、内种皮、外胚乳和胚构成,胚由子叶、胚芽、下胚轴和胚根组成,其中胚芽非常细小;种子具休眠特性,需要后熟过程才能自然萌发;种子的外胚乳对胚的萌发有抑制作用,剥去种皮和外胚乳的裸胚在培养基MS+6 BA 1.0 mg/L+NAA 0.2mg/L中能很快被诱导萌发生长,萌发率78.3%。说明太子参种胚通过离体诱导培养,可有效解决种子的休眠现象,这为实现太子参无病毒种苗的工厂化育苗提供新途径及技术支持。     

两型豆种子发育的解剖学研究

两型豆为豆科野生物种,对大豆育种和植物发育生物学研究具有重要价值.试验采用石蜡切片法进行了两型豆种子发育的解剖学研究,结果表明:(1)胚珠在花后12 h完成受精;(2)花后2 d合子进行第1次分裂,第1次分裂为横分裂,花后4 d形成原胚;(3)花后24 d,原胚经过球形胚期、心形胚期、鱼雷胚期,发育为成熟胚;(4)胚乳发育为核型,成熟种子为无胚乳种子;(5)外珠被发育为种皮,种皮细胞呈栅栏状且外被角质层,是造成三籽两型豆地上种子硬实的重要原因之一.     

夏蜡梅种子形态结构和种子萌发研究

为了解夏蜡梅种子形态结构和萌发特性,以其种子为研究对象,用体视显微镜结合石蜡切片法观察夏蜡梅种子形态和种胚的解剖结构,用称重法测定不同处理种子吸水率,并统计不同贮藏种子萌发情况。结果表明,夏蜡梅种子呈不规则纺锤状或长圆形,由种皮和胚两部分组成,属双子叶无胚乳种子;外种皮致密坚硬,深褐色、有光泽,透水能力较差,通过刻伤种皮,可显著提高吸水率;内种皮薄膜状,浅褐色,紧贴种胚;种胚发育较为成熟,白色或淡黄色,胚细胞富含淀粉粒,子叶发育良好,两片子叶相互卷合,胚芽分化不明显;湿沙冬藏处理可缩短种子萌发时间并显著提高发芽率,高达(72.22±6.44)%;刻伤种皮处理,可显著提高吸水率,从而打破休眠,提高其发芽率。研究表明,水分冲破种皮对破除夏蜡梅种子休眠和促进萌发极为重要。     

蓖麻种子结构的解剖和显微观察

本文通过萌发法、分离法、石蜡切片法和显微观察技术,分别以番红固绿和希夫试剂染色,系统观察了蓖麻种皮、胚乳和胚的结构及其维管束分布。(1)蓖麻种子背侧基部的种孔并未被种阜所覆盖。(2)种皮包括外种皮、内种皮和种阜3部分,其中,外种皮由外至内分别为长柱状表皮层、海绵组织层和栅栏组织层,而内种皮则依次为马氏层、海绵组织层和内珠被内层,在种阜端由内种皮内层和外层共同围成气室,类似于鸡蛋的气室。(3)在外种皮和内种皮中均有维管束分布,其中外种皮的大型维管束仅分布在种子腹侧种脊的海绵组织层内,它从种脐延伸至种阜相对一端;而内种皮维管束也分布在海绵组织层中,通过维管束索,逐级分枝,止于种阜端气室边缘;内、外种皮的维管束通过合点端的连接点相连续,共同构成种皮维管系统。(4)种阜由表皮和薄壁组织构成,其中薄壁组织由外侧小型薄壁细胞和内侧大型薄壁细胞构成。种阜维管束仅2束,分布在种阜中部腹侧,独立构成种阜维管系统;在种阜中,还有种阜管道,其内端开口于内种皮的气室,外端为盲端。(5)胚乳由含大量糊粉粒的薄壁细胞构成,其中未见维管束分布。在胚中,维管束为外韧维管束,它们分化于胚轴,从胚轴顶端两侧分别进入2片子叶主脉,在主脉中由4个逐步减少为1个,在子叶中分枝变细,构成胚维管系统;子叶表皮和叶肉细胞中均含糊粉粒,但在胚芽、胚轴和胚根中未见糊粉粒;2片子叶近轴面分离,远轴面则通过粘液层与胚乳相连接;胚轴和胚根在空间上与胚乳分离。这些结果为全面掌握植物蓖麻种子的结构和研究种子发育和萌发过程及其物质运输提供了解剖学依据。     

南方红豆杉种子浸提液对油菜种子萌发与幼苗生长的影响研究

摘要：本文研究了南方红豆杉种子的种皮和胚乳（含胚）的不同浓度甲醇浸提液对油菜种子萌发和幼苗生长的影响。研究结果发现：种皮和胚乳不同浓度的提取液对油菜种子的萌发、幼苗的生长均存在一定的抑制作用。随着浸提液浓度的升高,油菜种子萌发率、幼苗的根长和茎长均逐渐下降。在相同的浓度中,油菜种子在胚乳浸提液中的萌发率比种皮浸提液低,油菜幼苗的根长在种皮浸提液中比胚乳浸提液中短。方差分析结果表明,不同处理组之间幼苗的根长存在显著的差异。结果表明红豆杉种皮和胚乳均有抑制物质存在,胚乳浸提液对油菜种子的萌发抑制作用较强,而种皮浸提液对油菜根长抑制作用强。     

Inheritance in seed size of alfalfa: Quantitative analysis and response to selection

Seed size in alfalfa (Medicago saliva L.) has been positively correlated with seedling vigour and early growth, but there were few published reports on inheritance or selection for this trait. The objective of this research was to estimate components of genetic variance for inheritance of alfalfa seed size and determine the most efficient selection method. Components of genetic variance were estimated on seed and pollen plants of ‘BIC-7-WH’ and their progeny arranged in a North Carolina Design II mating design under controlled environmental conditions. Three selection methods, differing in parental control and selection pressure, were used to determine selection response. The seed parent genotype had a major role in determining alfalfa seed size, but the genotype of the seed had no influence. For genetic studies, pollen and seed parent effects on seed size should be measured on seed harvested from progeny plants. Seed size was controlled by additive and non-additive components of genetic variance. Heritability for seed size was 41.3%. Selection for seed size was effective and a significant shift for larger and smaller seed was attained after one cycle of selection.     

籼型巨胚稻的发现及其遗传育种研究

以若干籼稻品种为材料,通过核辐射诱变于M3代获得巨胚品系。对巨胚性状作了遗传育种分析。结果表明,巨胚属隐性单基因遗传,种胚的大小直接由合子基因型决定,而与为胚发育提供营养的母株基因型、胚乳基因型及细胞质均无关系。因此,可在诱变的M2世代或杂交F2世代的种子上直接进行巨胚性状选择。巨胚稻糙米胚重比原来品种大     

Relationship between Seed Characters, Plant Growth and Yield Parameters of Phaseolus vulgaris

Legumes are an important component of the dietary pattern of the developing world. Thus optimal yields are a vital factor in agricultural production in these countries. Seed characters affect plant growth and yields of grain legumes. Due to the lack of similar studies in Phaseolus vulgaris (Frenchbeans), a study was carried out to determine the effect of seed characters on the growth cycle of frenchbean plants. Seed size was primarily determined by the size and weight of cotyledons and seed coat, as embryo size was similar in all seed classes. Seed size had no effect on seed viability, although larger seeds germinated earlier. There was a positive relationship between seed size and plant growth characters. Larger seeds developed plants with better growth and yield component parameters, resulting in higher yields. The importance of determining seed size in frenchbeans is presented.     

Genetic effects of embryo and endosperm for four malting quality traits of barley

Seed of seven cultivars of two-rowed barley (Hordeum Vulgare L.) and F2 seed from a half-diallel set of crosses among the cultivars were malted in two years to obtain data on diastatic power (DP), alpha-amylase activity (αAA), beta- amylase activity (βAA) and malt nitrogen (N) content. Embryo and endosperm genetic effects on the traits were studied by using a genetic model including genotype × environment interaction for malting quality characters. Variation of the four malting quality traits was affected by gentic effects and environmental interaction. Performance of DP and βAA was mainly controlled not only by endosperm dominance effects but also by embryo genotype × environment interaction and endosperm dominance × environment interaction. Variation of αAA and malt N content was controlled by both embryo and endosperm genetic effects, but the embryo dominance and endosperm additive effects contributed a major part to the total genetic effects. Significant interaction variances (embryo additive × environment and dominance × environment and endosperm dominance × environment) were also observed for αAA and malt N content. Diastatic power was related positively to βAA. Malt N content was associated positively with DP, largely because of the relationship between malt N and βAA. No obvious phenotype association between DP and αAA was found. General narrow-sense heritabilities of αAA and malt N content were 26.1% and 27.8%, respectively. This revised version was published online in July 2006 with corrections to the Cover Date.     

南方红豆杉种子不同溶剂提取液对白菜种子萌发及幼苗生长的化感效应

通过生物检测方法研究了南方红豆杉种子的种皮和胚乳的石油醚、甲醇、乙酸乙酯、乙醚以及水浸提液对白菜籽发芽率和幼苗生长的化感作用,结果表明,其浸提液对白菜发芽及生长均有抑制作用,且随浸提液浓度增大抑制作用增强。种皮和胚乳甲醇相抑制物质对种子的萌发及生长抑制活性最强,抑制率达100%,种皮的石油醚相、乙醚相和乙酸乙酯相对发芽率的抑制作用强于胚乳,胚乳水相的抑制作用强于种皮;对白菜苗高生长的抑制作用,水相中低浓度处理的种皮抑制作用大于胚乳,高浓度处理时则相反;种皮石油醚相和乙酸乙酯相对白菜根长生长抑制作用大于胚乳,而乙醚相和水相中则相反。胚乳中各相对白菜苗高生长的抑制作用由强到弱依次甲醇相、乙酸乙酯相、乙醚相、石油醚相、水相;对发芽率和根长生长抑制作用由大到小依次甲醇相、乙醚相、乙酸乙酯相、水相和石油醚相。种皮中各相对苗高和根长生长的抑制作用由强到弱依次甲醇相、石油醚相、乙酸乙酯相、乙醚相和水相,对白菜籽发芽率的抑制作用由大到小依次为：甲醇相、乙醚相、乙酸乙酯相、石油醚相和水相。     

紫椴种子萌发特性及休眠解除方法研究

为探明紫椴种子休眠原因并找到休眠解除方法,以紫椴种子为材料,对其透性、萌发特性及休眠解除方法进行了研究。种子透性试验结果表明,紫椴种子经浓硫酸处理后透性增加,吸水率显著提高。种子萌发特性试验显示,紫椴完整种子萌发率为0,去掉种皮后,保留完整胚乳的种子萌发率为4.0%,切除部分胚乳（根尖未露出）的种子萌发率为23.3%,剥除胚乳帽露出根尖的种子萌发率为84.7%,离体胚萌发率为100%,此结果表明紫椴种子存在休眠,但其种胚并不存在休眠,其休眠是由胚外因素导致,胚乳（尤其是胚乳帽）是造成紫椴种子休眠的主要原因。种子休眠解除方法试验结果表明,浓H₂SO₄处理15 min+500 mg/L GA₃溶液浸泡12 h+低温层积30天,可使紫椴种子发芽率达92.0%,可作为快速解除紫椴种子休眠的有效方法。综上,紫椴种子的种皮具有一定的透性障碍,但胚乳帽是造成其休眠的主要原因,使用浓H₂SO₄处理+GA₃浸泡+低温层积的综合处理方法可在30天内解除紫椴种子的休眠。     

Inheritance of Seed Coat Thickness in Chickpea (Cicer arietinum L.) and its Evolutionary Implications

The desi and kabuli chickpeas are characterized, among other things, by their seed coats being thicker in the desi than in the kabuli type. The inheritance of seed coat thickness, and its relation to flower colour and seed size, was studied. Seed coat thickness exhibits monogenic inheritance, the thin kabuli seed coat being the recessive character. Linkage was found between seed coat thickness and flower colour, the recombinant fraction being 0.19. No relationship was found between seed coat thickness and seed size. The role of these characters in the evolution of the chickpea is discussed.     

Transcriptomic analysis of developing seeds in a wheat (Triticum aestivum L.) mutant RSD32 with reduced seed dormancy

Seed dormancy, a major factor regulating pre-harvest sprouting, can severely hinder wheat cultivation. Reduced Seed Dormancy 32 (RSD32), a wheat (Triticum aestivum L.) mutant with reduced seed dormancy, is derived from the pre-harvest sprouting tolerant cultivar, ‘Norin61’. RSD32 is regulated by a single recessive gene and mutant phenotype expressed in a seed-specific manner. Gene expressions in embryos of ‘Norin61’ and RSD32 were compared using RNA sequencing (RNA-seq) analysis at different developmental stages of 20, 30, and 40 days after pollination (DAP). Numbers of up-regulated genes in RSD32 are equivalent in all developmental stages. However, down-regulated genes in RSD32 are more numerous on DAP20 and DAP30 than on DAP40. In central components affecting the circadian clock, homologues to the morning-expressed genes are expressed at lower levels in RSD32. However, higher expressions of homologues acting as evening-expressed genes are observed in RSD32. Homologues of Ca²⁺ signaling pathway related genes are specifically expressed on DAP20 in ‘Norin61’. Lower expression is shown in RSD32. These results suggest that RSD32 mutation expresses on DAP20 and earlier seed developmental stages and suggest that circadian clock regulation and Ca²⁺ signaling pathway are involved in the regulation of wheat seed dormancy.