银杏雌配子体发育过程中淀粉和蛋白质的积累与代谢

 以20年生银杏核用品种‘佛指’（Ginkgo biloba L.‘Fozhi’）为试材,通过树脂切片对雌配子体发育过程中淀粉和蛋白质形成与代谢进行显微和超微结构观察。结果表明：（1）雌配子体发育过程中,细胞内淀粉和蛋白质的积累呈现规律性变化。表现为受精作用发生前,套细胞、帐篷柱细胞和颈细胞内迅速积累大量淀粉粒,靠近颈卵器周围胚乳细胞中的淀粉粒逐渐被转移而减少。受精作用发生时,套细胞和帐篷柱细胞内淀粉粒代谢迅速,靠近颈卵器周围的胚乳细胞中淀粉粒全部消失,细胞壁呈现皱缩解体现象,颈细胞的细胞壁开始解体。受精作用完成后,套细胞、帐篷柱细胞、颈细胞和颈卵器周围胚乳组织出现相继解体现象;（2）雌配子体胚乳细胞内的淀粉和蛋白质积累可分为胚乳薄壁细胞增殖期、淀粉粒和蛋白质形成期、淀粉粒和蛋白质快速积累期和淀粉粒和蛋白质缓慢积累期;（3）淀粉体由造粉质体发育而来,每个造粉质体可含一到多个淀粉体,以芽孢或中间缢断的方式增殖。蛋白质体存在P1和P2两种形式,其中P1存在于内部的胚乳细胞中,P2存在于外围的糊粉层中。受精作用发生前套细胞、帐篷柱细胞内充满了大量的淀粉体和蛋白质体等营养物质,并分布有较多的线粒体、内质网和小泡等细胞器。     

黄瓜雌配子体与胚胎发育的初步研究

以长春密刺黄瓜为材料,采用石蜡切片法对黄瓜胚胎的发生发育过程进行了研究。解剖学观察表明:黄瓜从雌花显蕾到种子发育成熟需经历60d左右,其间雌配子体发育经历18～20d形成成熟蓼型胚囊,开花前10d进入单核胚囊期,开花前7d左右出现二核胚囊,开花前3d出现四核胚囊,开花前1～2d形成八核成熟胚囊。受精过程在授粉后第2～3天完成。胚胎的发育经历3个阶段,授粉后2～11d为原胚期,11～25d为胚器官剧烈分化期,25～40d为胚器官的进一步充实分化期。胚胎发育过程中胚乳被吸收,最终形成无胚乳种子。     

大车前胚乳与胚发育的细胞胚胎学研究

应用石蜡制片技术研究了大车前胚乳与胚发育过程的细胞胚胎学特征,为车前科胚胎学及分类地位的确立提供相关资料。结果表明：大车前成熟雌配子体为七细胞七核的蓼型。经双受精后形成合子与初生胚乳核。胚乳发育类型为细胞型,初生胚乳核第1次横分裂产生珠孔室与合点室胚乳细胞。珠孔室胚乳细胞经1次纵分裂或2次连续相交的纵分裂形成2个或4个胚乳细胞;进而同步进行横分裂形成2排,即4个或8个胚乳细胞;靠近珠孔的2个或4个胚乳细胞分化并发育成为单核的管状胚乳珠孔吸器;靠近合点室胚乳细胞的2个或4个细胞进行各个方向的分裂形成胚乳本体,并将合子分裂所形成的胚包围其中;与此同时,合点室胚乳细胞的细胞核进行1次核分裂但不伴随胞质分裂,在合子期便形成具有两个细胞核的胚乳合点吸器;胚乳吸器为胚乳本体的发育从珠被与合点吸收并转送营养物质。胚胎发生属于柳叶菜型,经原胚期、心胚期、鱼雷胚、子叶胚形成成熟种子。珠被绒毡层发达。对胚乳本体以及球胚的流式细胞仪细胞核DNA分析表明,胚的DNA含量为二倍体,而胚乳为三倍体。     

枇杷胚胎和胚乳发育的初步研究

枇杷原胚的发育方式,基本上属于十字花型(柳叶菜型)。因为合子横向分裂,形成由小的、合点端的顶细胞和大的、珠孔端的基细胞组成胚体的基础;基细胞进行一次横向分裂,结果形成四细胞的倒“T”型原胚。基细胞又经2～3次纵、横分裂,形成由4～8列细胞组成的胚柄,胚乳的发育方式属核型。珠形胚期,胚乳已开始由珠孔端的原胚周围逐渐移向合点端形成细胞壁。心形胚期,胚乳又从珠孔端原胚周围逐步移向合点端开始解体。当胚发育成具有双子叶典型胚时,胚乳及珠心冠原均被吸收殆尽。     

番茄花药发育中多糖和脂滴的分布特征

花药发育中的营养物质转运和转化规律很复杂。采用组织化学方法对番茄花药发育中的多糖和脂滴分布特征进行了分析。结果显示:造孢细胞时期仅花药药隔细胞中有较多淀粉分布。小孢子母细胞的胼胝质壁呈现明显多糖特征,药隔细胞中的淀粉减少。减数分裂后四分体时期的花药中营养物质没有明显变化。在游离小孢子发育早期,药隔细胞中淀粉数量又增多;游离小孢子的花粉壁局部呈现多糖特征。到小孢子发育晚期,液泡化小孢子中既没有淀粉也没有脂滴,仅在花粉壁部位仍显示了多糖特征;药隔细胞中的淀粉数量明显减少,此时绒毡层细胞变形、退化。小孢子分裂后,二胞花粉中先出现一些脂滴。伴随着花粉的发育成熟,又出现了大量的淀粉。开花时花药表皮细胞中也聚集了较多的脂滴。番茄花粉中先积累脂滴、后积累淀粉、以及成熟花粉中积累大量淀粉和脂滴的现象是其花粉发育中营养物质代谢的特征,呈现出不同植物的特异性。     

从胚乳培养再生三倍体柑桔植株

为了研究用胚乳培养获得无核水果和通过培养杂种胚乳探索作物育种新领域,我们研究了柑桔胚乳培养的条件。研究结果指出:(1)在MT培养基+2,4—D(2ppm)+BA(5ppm)+CH(1000ppm)上,可将发育到细胞时期的幼胚乳诱导成愈伤组织;(2)在2MT培养基+GA(2—15ppm)上,胚乳愈伤组织分化出各种发育阶段的胚状体,这些胚状体并能形成根、茎、叶和完整的小植株;(3)根尖染色体计数初步说明胚乳分化的根是三倍体(3n=27)。     

苹果蠹蛾卵成熟过程及卵巢发育分级研究

【目的】研究苹果蠹蛾卵的成熟过程和卵巢发育特征及其分级。【方法】采用常规解剖和石蜡切片方法,对苹果蠹蛾卵粒在卵巢管中的成熟过程进行观察,并对其卵巢发育及分级进行划分。【结果】苹果蠹蛾卵成熟过程根据卵粒大小、滋养细胞和滤泡细胞的形态变化以及卵黄沉积情况,分为卵黄发生前期、早期卵黄发生期、中期卵黄发生期、后期卵黄发生期和成熟期5个时期。卵巢发育根据有无卵室、卵黄沉积情况和卵巢形状划分为5个级别,即:发育初期(Ⅰ级)、卵黄沉积期(Ⅱ级)、成熟待产期(Ⅲ级)、卵盛期(Ⅳ级)和产卵末期(Ⅴ级)。【结论】明确了卵粒在成熟过程中的形态变化和苹果蠹蛾卵巢发育的分级特征,为准确进行该虫的预测预报和综合防治提供了科学依据。     

槜李雌蕊形态及早期胚胎发育研究

采用常规石蜡切片法对槜李雌蕊形态和早期胚胎发生发育进行了研究,以期从生殖生物学角度探讨影响槜李低产的原因。结果表明,槜李花柱实心,子房1室,横生胚珠,双珠被,厚珠心。雌蕊胚囊在盛花时仍处在2～4核期。观察的材料中,绝大部分胚囊在盛花后3d发育为成熟胚囊,胚囊蓼型。合子约休眠2～3d后开始分裂。胚乳在盛花7d后出现,八分体原胚出现在第12天。胚胎发生发育过程中有珠心珠被退化、成熟胚囊结构异常等现象。     

辣(甜)椒游离小孢子培养中的雄核发育和胚胎发生

对灯笼、牛角、羊角、线形和朝天椒等辣(甜)椒游离小孢子的培养与观察表明：在雄核发育过程中,分离后仍膨大的小孢子能够继续发育,皱缩的则死亡;小孢子最初的细胞分裂有均等和不均等两种分裂方式;脱分化的小孢子可经历胚胎发生和器官发生两种发育途径,二者之间可相互转换;胚胎发生过程与合子胚发育过程极相似,直到心形胚以前均可观察到胚柄的存在;成熟的胚状体能够萌发,但胚根端生长的能力远远比胚芽端强;观察到胚状体发生不同步及多种畸形发育样式;小孢子在分裂早期如果突破花粉壁会形成薄壁细胞团,继续发育为愈伤组织,进而转向器官发生途径;小孢子愈伤组织易形成不定根,可形成次生胚状体,未观察到不定芽的发生。不同类型辣(甜)椒游离小孢子的雄核发育与胚胎发生程序相同。     

叶籽银杏叶生胚珠的发育组织化学研究

 采用树脂半薄切片技术对叶籽银杏叶生胚珠生长发育各阶段进行观察及组织化学分析。结果表明：（1）叶生胚珠发端期在叶片上表现为“突起”状态,其结构主要为维管束、薄壁细胞和分泌腔;其内中央淀粉粒少,与叶缘结合处淀粉粒多,淀粉粒小且沿细胞壁分布。（2）叶生胚珠雌配子体的发育经历了游离核阶段和细胞化阶段;游离核阶段雌配子体呈液体状态;细胞化初期,雌配子体内是大的薄壁细胞,无淀粉粒、脂肪和蛋白质的分布;随后淀粉粒渐多;细胞化后期淀粉粒进一步增多,变大,且有黑色脂滴在细胞壁附近。（3）胚乳发育阶段,细胞中积累淀粉粒,蛋白质增多,营养物质中心密集,边缘稀疏。（4）雌配子体游离核阶段开始有外珠被和中珠被的分化;7月上旬叶生胚珠出现明显的内珠被。（5）中珠被与内珠被间中隐线上方有一“锥状”结构,外珠被和中珠被间有较多的淀粉粒。     

苹果果实发育过程中淀粉代谢和淀粉粒超微结构研究

苹果果实发育过程中,伴随果糖、葡萄糖和蔗糖的积累,淀粉含量经历了从低到高,又从高到低的变化。发育中后期,果实淀粉与可溶性糖呈现互为消长的变化。淀粉粒超微结构的变化表明,幼果期果肉细胞代谢旺盛,可观察到发育初期的造粉质体和大量的线粒体;发育中期是果实淀粉的主要累积期,整个造粉质体内充满淀粉;成熟期的果肉细胞呈现降解特征,淀粉粒大部分被降解,但淀粉粒表膜依然保持完整。还研究了淀粉代谢及淀粉粒超微结构变化与果实发育的关系。     

银杏成熟胚乳培养的细胞组织学观察

诱导银杏（GinkgobilobaL．）成熟胚乳产生愈伤组织时无需胚的存在。单独使用生长素或在细胞分裂素／生长素为0．5～0．9的范围内均能诱导部分胚乳切块产生愈伤组织。并且在White＋Kt2．7mg·l-1＋2,4－D1．0mg·l-1＋NAA2．0mg·l-1的培养基上,愈伤组织的诱导率最高,达到83．3％。胚乳细胞脱分化进行有丝分裂和无丝分裂,其中无丝分裂可以观察到劈裂和缢裂两种类型。愈伤组织起源于胚乳表皮及其下方2～3层细胞,且愈伤组织的形成需经历一个“假愈伤组织化”阶段。     

The isolation of early nuclear endosperm of <Emphasis Type="Italic">Oryza sativa</Emphasis> to facilitate gene expression analysis and screening imprinted genes

Background

Since the quality and yield of rice production depends on endosperm development, previous studies have focused on the molecular mechanism that regulates this developmental process. Recently, how this process is epigenetically regulated has become an important topic. However, the gene expression analysis and screening imprinted genes during early endosperm development remain challenging since the isolation of early endosperm has not been possible. Here, we report a procedure for the isolation of endosperm at 24 or 48 HAP (hours after pollination) during the free nuclear stage of endosperm development.

Results

This technique allows for rapid and convenient collection of pure free nuclear endosperm. Early endosperm RNA can then be extracted from the isolated endosperm cells using dynabeads. Our results showed that the quality of RNA is satisfactory for gene expression analysis and screening the parental-of-origin specific genes in early endosperm.

Conclusions

Thus, we offer a reliable method to overcome one of the major obstacles in the investigation of the molecular mechanisms of early endosperm development. Our approach can be used for accurate gene expression analysis and screening of imprinted genes, and facilitates the confirmation of endosperm-specific gene expression at the very early stages of endosperm development. This method could also be used in other species to collect early free nuclear endosperm.

     

Assessment of volatile and non-volatile organic compounds in the liquid endosperm of young ‘Nam Hom’ coconut (Cocos nucifera L.) at two stages of maturity

SUMMARY

Young coconut (Cocos nucifera L.) fruit collected 6–8 months after anthesis (MAA) contain a high volume of water [20% (w/w)] and can provide a refreshing drink. The present study investigated volatile organic compounds (VOCs), as aroma components, and physico-chemical changes in the liquid endosperm of young ‘Nam Hom’ coconut at two stages of maturity: the one-layer stage (6 MAA) and the two-layer stage (7.0–7.5 MAA) of the flesh. The liquid endosperm of coconut fruit becomes sweeter and more turbid late during maturation. Lauric acid (C_12:0) and myristic acid (C_14:0) were the main free fatty acids in the liquid endosperm of coconut. Short-chain fatty acid (C₁₀–C₁₂) concentrations increased slightly, and longer-chain fatty acid (C₁₄–C₁₈) concentrations declined when fruit matured from the one- to the two-layer stage of flesh. Solvent extractions showed a 1.4-fold increase in the total concentration of VOCs in the liquid endosperm during fruit development. This was related to a major increase in squalene and sterols, to 21.7% (w/w) of the total VOC and non-volatile organic compounds, whereas the concentrations of terpenes and esters remained stable. Although a series of alkanes existed in the liquid endosperm of coconut, the main aroma components were 2-methyl-1-butyl acetate and terpenes such as D-limonene, α-pinene, and 3-carene. We conclude that, when coconut fruit developed from the one- to the two-layered flesh stage, the liquid endosperm not only became sweeter and contained higher concentrations of aroma volatile and non-volatile components, but also became oily and less translucent.     

四倍体西瓜低稔性胚胎发育研究

试验以二倍体自交为主要对照，四倍体与二倍体正反交为辅助对照，研究了四倍体西瓜自交低稔性的胚胎发育。通过镜检观察表明：1．四倍体西瓜自交花粉萌发率低，花粉管在柱头与花柱中生长出现异常现象，在花柱中生长缓慢，授粉后12h到达花柱基部。2．四倍体西瓜有少数结构不正常胚囊，但所占比率低于10％，不是稔性低的主要原因。3．四倍体自交双受精过程正常，但花粉管进入的胚囊数少，受精率仅35．8％。4．四倍体自交只有少数胚能正常发育，形成有活力种胚；大部分胚由于游离核或细胞化胚乳的异常解体，在原胚或球形胚阶段败育；少数胚分化到心形胚、鱼雷胚后，由于细胞化胚乳过早解体，胚停止分化而败育。     

GA_3诱导枇杷无核的组织解剖学观察

为了阐明GA3处理枇杷导致无核的原因,以枇杷品种大五星为材料,采用石蜡切片法和花粉发芽试验等方法分别对花前经GA3处理枇杷花穗后的枇杷胚胎发育过程进行了研究。结果表明,1)枇杷的胚珠为倒生胚珠,双珠被,核型胚乳;2)花前用GA3处理枇杷导致无核的原因主要在于胚乳败育或者珠心退化导致胚退化,由于胚乳败育使胚发育所需要的营养不足,引起合子胚分裂异常,最终胚解体退化。但珠被在初期能够发育,所以形成败育种子(秕子)。     

Net primary productivity (NPP) dynamics and associated urbanization driving forces in metropolitan areas: a case study in Beijing City,China

Context

Eco-environmental effects of urbanization are a focus in landscape ecology.

Objective

The influences of population, economic and spatial development during the urbanization process in Beijing City, China on net primary productivity (NPP) were analyzed. The responding mechanism of NPP in different urbanization stages was also examined to develop advice about eco-environmental sustainability of urban development.

Methods

Using the Carnegie Ames Stanford Approach model, we estimated NPP. Using linear regression and polynomial regression analysis, we analyzed NPP responses to stages of urbanization.

Results

High NPP areas were located in northeast Yanqing, northwest Miyun, northern Huairou and Pinggu. The distribution of NPP generally occurred in the following order from high NPP to low NPP: outer suburbs, inner suburbs, encircled city center, and inner city. Because of the heat island effect in winter, the estimated NPP in the encircled city center and inner city was higher in 2009 than in 2001. There was a negative correlation between NPP and both economic and spatial urbanization, but an increase in population did not necessarily lead to an immediate decrease in NPP. An analysis of NPP dynamics in five kinds of urban development zones showed that urbanization resulted in a lasting and observable loss of NPP over time and space, although there was some promotion of NPP in highly urbanized zones.

Conclusion

There are three stages in the response of NPP to urbanization: damage stage, antagonistic stage, and coordination stage. The stage threshold depends on local eco-environmental management and urban planning interventions.

     

百合‘白天使’与山丹远缘杂交胚胎发育的细胞学研究

采用石蜡切片法对以亚洲百合品种‘白天使’为母本,野生种山丹为父本杂交后不同发育时期的胚珠进行制片观察,发现白天使×山丹远缘杂交受精和胚胎发育过程比较复杂,共有4种情况,即:不能完成受精,胚囊成员细胞最后解体;卵受精,只产生胚而无胚乳;极核受精,只产生胚乳而无胚;完成双受精,产生了胚和胚乳。百合杂种胚发育经过合子、原胚、球形胚、偏梨形胚、棒状胚阶段。偏梨形胚之前,胚的发育所需要的营养主要是通过胚柄从珠心和珠被中吸收。当胚体内部开始分化,外形呈棒状,胚柄解体。此后胚发育所需的营养则主要由胚乳细胞提供。百合胚乳发育为核型。杂种胚败育的可能原因是胚没有得到胚乳的哺育,这样的胚最多发育到球形胚阶段;其次是胚乳发育缓慢或停止,最后导致胚的夭折。该杂交组合授粉后45d,是进行胚抢救的最佳时期。