黑松合子胚和体细胞胚发育阶段的形态特征比较

为掌握黑松合子胚和体细胞胚发育进程,以未成熟合子胚为外植体,建立了黑松体细胞胚胎发生体系。对合子胚和体细胞胚发育阶段的形态特征进行观察和比较,结果表明,合子胚和体细胞胚的发育进程均可划分为8个阶段,两者同一阶段的形态特征大致相同,只有第2阶段和第4阶段有细微差别。     

花楸树体细胞胚与合子胚的发生发育

利用花楸树人工控制授粉后的未成熟合子胚进行体细胞胚的诱导培养,通过石蜡切片、扫描电镜和透射电镜对合子胚和体细胞胚的发生发育过程进行组织、细胞观察。结果表明:1)体细胞胚发生进程与合子胚相似,均经历了球形期、心形期、鱼雷形期,最终发育成成熟胚;2)直接发生和间接发生在愈伤组织表面的体细胞胚均为单细胞起源,间接发生在愈伤组织内部的体细胞胚存在单细胞起源,同时还存在可能的多细胞起源;3)子叶和愈伤组织表面发生的体细胞胚在发育早期均具明显的胚柄,鱼雷形胚期胚柄退化;4)愈伤组织内部发生的体细胞胚没有胚柄;5)与合子不同,胚性细胞的第1次分裂为均等分裂;6)多细胞原胚周围降解的细胞具有细胞程序性死亡的形态特征。     

水曲柳体细胞胚与合子胚发生的细胞学研究

水曲柳(Fraxinus mandshurica)属木犀科(Oleaceae)白蜡树属,是我国东北重要珍贵硬阔树种之一,主要分布于小兴安岭、长白山、辽宁东部山地等地区, 以材质优良而著称.由于长期不合理的采伐利用,目前可利用的资源急剧减少,已被列为国家三级保护植物(傅立国,1992).进行水曲柳体细胞胚胎发生的研究,在资源保护、树种快繁和基因工程育种上有其重要的现实意义.     

杉木成熟合子胚器官发生和体胚发生

以杉木成熟合子胚为起始外植体,研究基本培养基、不同种类的细胞分裂素及生长素对杉木器官发生和体胚发生及不定芽生根的影响,并用石蜡切片法观察不定芽和体胚的发生和发育过程.结果表明:DCR 6-BA 1.0mg·L-1 TDZ 0.002 mg·L-1 NAA 0.1 mg·L-1对成熟合子胚诱导不定芽最有效;DCR 6-BA 1.0 mg·L-1 TDZ 0.003mg·L-1 NAA 0.1 mg·L-1是成熟合子胚诱导体胚的最佳培养基;不定芽在DCR基本培养基中可有效伸长;1/4MS IBA 0.2 mg·L-1 NAA 0.1 mg·L-1对不定芽生根最有效.石蜡切片观察表明:不定芽有2种发生方式,一种是表皮及表皮下的3～4层细胞分生组织化发育而成,另一种是外植体内部的小维管束脱分化发育而成.2种发生方式均为直接器官发生途径.     

火炬松成熟合子胚体胚发生与成熟试验

以火炬松成熟合子胚为外植体,开展成熟合子胚体胚诱导、胚性胚柄细胞团(ESM)维持与增殖培养及体胚成熟试验。结果表明:火炬松成熟合子胚体胚诱导率为3%,远远低于未成熟合子胚;诱导获得的多数ESM在连续的增殖培养中难以生存;不同胚性细胞系体胚发育和成熟能力不同,胚性细胞系AL-225经无植物生长调节剂培养基预培养后转入AL+ABA 50 mg·L-1+15%PEG8000培养基,体胚进一步发育,但未能获得完全成熟体胚。     

‘冷白玉’枣果实发育过程中内源激素变化与胚败育的关系

【目的】生长素、赤霉素、脱落酸等植物内源激素在促进胚胎发育过程中起着重要的作用。本研究通过分析‘冷白玉’枣4个重要发育阶段胚胎和果肉中生长素(IAA)、赤霉素(GA4)、顺式脱落酸(c ABA)和反式脱落酸(t ABA)的动态变化,探究枣胚败育与果实发育过程中内源激素变化的相互关系,为阐明枣胚败育机理提供证据,为败育胚的挽救提供理论支撑。【方法】以处于原胚、小球形胚、球形胚、鱼雷形胚4个时期的‘冷白玉’枣为试材,监测幼果和幼胚发育状况,采用液相色谱-质谱检测枣果发育过程中正常胚、败育胚、胚正常果肉、胚败育果肉中IAA、GA4、c ABA、t ABA 4种内源激素含量的变化。【结果】1)胚中IAA的含量显著高于果肉。在胚中,正常胚中IAA含量呈逐渐升高趋势,而在败育胚中IAA含量呈逐渐下降趋势。胚正常果肉中IAA含量变化呈倒V字形,而胚败育果肉中呈正V字形。2)胚中GA4的含量明显低于果肉,并一直处于较低水平。正常胚中GA4含量低于败育胚。胚发育正常果肉和胚败育果肉中GA4含量均表现为先升高后降低的趋势。3) c ABA在果肉和胚发育过程中均表现为逐渐降低趋势。在正常胚中,c ABA含量大于果肉中的含量;败育胚中,c ABA含量小于果肉中的含量。4)胚中t ABA的含量高于果肉。在胚中,正常胚中t ABA的含量呈逐渐下降趋势,而在败育胚中t ABA呈逐渐上升趋势,并在后期高于正常胚。在果肉中,胚正常果肉和胚败育果肉中的t ABA含量均呈先下降后缓慢升高趋势。5)胚中低水平的GA4且较高水平的IAA,及后期低含量的t ABA、c ABA和较高的IAA/GA4比值有利于幼胚的正常发育。胚中IAA下降和t ABA增加及(GA4+IAA)/ABA比值下降是导致胚败育的重要因素。【结论】在枣幼胚发育前期,需要较高的生长类激素促进生长,而在发育后期胚中t ABA含量的增加可引起胚败育。     

红松成熟合子胚愈伤组织诱导的研究

以红松(Pinus koraiensis Sieb.et Zucc.)成熟合子胚为基准试验材料,对红松愈伤组织诱导的影响因素进行了初步研究。结果表明,不同的培养基对有效愈伤组织的诱导效果不同,初始诱导应选用LM培养基使外植体完全脱分化,反复继代后可以产生有效愈伤组织,供试的其他培养基继代后则极少产生有效愈伤组织;不同的激素组合和浓度配比对有效愈伤组织的诱导率影响不同,2,4-D是愈伤组织启动的不可或缺的植物生长调节剂,其作用远远大于NAA。在LM+2mg.L-1 2,4-D+0.5mg.L-16-BA的诱导培养基中加入0.5mg.L-1 KT或0.5mg.L-1 TDZ,可明显提高有效愈伤组织的诱导率(可达75.7%)。     

香樟未成熟合子胚体胚发生及植株再生研究

以香樟的未成熟幼胚为外植体进行诱导体胚发生影响因素的研究.成功地从香樟幼胚中诱导出胚状体并获得再生植株,MS为基本培养基,蔗糖是最佳的碳源.经2年对初生胚的继代培养,获得胚性愈伤组织;胚性愈伤组织经体胚诱导、体胚成熟、体胚萌发3个过程的诱导后能够获得再生植株.     

果树胚败育研究概述

胚败育是限制果树杂交育种工作的一个关键问题。本文从细胞学、矿质营养元素和激素角度对胚败育机理的研究进行了综述,并进一步阐述了胚培养、生长调节剂、矿质营养元素和授粉、受精条件在克服胚败育中的作用。     

红松成熟合子胚愈伤组织诱导的适宜培养条件

为了探索以红松成熟合子胚为外植体诱导愈伤组织的适宜培养条件,以GD、DCR、LM、MS等为基本培养基,以2,4-D和6-BA组成不同浓度激素组合,进行愈伤组织诱导试验。结果表明,1供试培养基均可诱导红松成熟合子胚产生愈伤组织,但DCR培养基上诱导的愈伤组织出现最早,出愈率显著高于其他培养基,达93.3%;2在DCR培养基中添加2,4-D与6-BA的各种组合均获得了较好的愈伤组织发生,但以2,4-D 2 mg/L+6-BA 0.5 mg/L和2,4-D6 mg/L+6-BA 1 mg/L的出愈率最高,达96.7%。综上所述,红松成熟合子胚外植体诱导愈伤组织时,适宜基本培养基为DCR,适宜激素组合为2,4-D 2 mg/L+6-BA 0.5 mg/L。     

Effects of a nitric oxide donor and nitric oxide scavengers on Sorbus pohuashanensis embryo germination

The effects of an exogenous nitric oxide donor(sodium nitroprusside, SNP), a NO scavenger 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxode(PTIO) and carboxy-PTIO potassium salt(c PTIO) on the embryo germination of Sorbus pohuashanensis were studied in a petri dish test. SNP at 0.5–5 mmol L-1 increased germination percentage, mean time to germination, germination index and germination energy compared with the control to different degrees. Treatment with 2 mmol L-1 SNP improved germination most significantly; embryo germination percentage for mother tree 1(91.11%) and mother tree 2(64.44%) were much higher than the control. In addition,excessive SNP levels did not enhance embryo germination.Combined treatment with SNP and an NO scavenger delayed embryo germination. Treatment with c PTIO inhibited embryo germination; germination percentage was 42.22% and was lower than that of the control. These results show that low concentrations of exogenous NO can enhance the embryo germination of S. pohuashanensis,providing a simple, effective way for promoting germination of S. pohuashanensis.     

楸树不同类型胚性和非胚性愈伤组织的细胞学观察

以楸树幼嫩茎段为外植体,接种在诱导培养基上诱导初始愈伤组织,以初始愈伤组织诱导胚性和非胚性愈伤组织,分别利用扫描电镜和透射电镜对愈伤组织进行了观察。结果表明:不同类型愈伤组织在形态学和细胞学特性方面存在显著差异。III型白色愈伤组织I、V型褐色愈伤组织为非胚性愈伤组织;I型绿色愈伤组织、II型紫色愈伤组织可能为楸树胚性愈伤组织。为楸树体细胞胚胎发生提供了理论基础。     

Morphological and anatomical differences in Aleppo pine seeds from serotinous and non-serotinous cones

Mediterranean communities have been historically conditioned by fire and have therefore developed adaptive traits. Serotiny is a strategy that increases fire resilience by storing seeds in the canopy, protecting them from heat and delaying their dispersion. Aleppo pine is an important serotinous tree species in the low altitude, near-coastal Mediterranean Basin. Differences in serotinous and non-serotinous cones have been detected previously but in order to resolve a gap in the knowledge on seed adaptation to fire, we focused this study on two fire-prone habitats in southern Italy. Several cones were sampled and opened in an oven at two different temperatures in order to group seeds according to provenance and cone type (serotinous or non-serotinous). The sampled seeds were weighed and their coats were removed. Seed size, embryo diameter and nutritive tissue thickness were recorded. We found that seeds with greater weight and size came from the more humid site and from non-serotinous cones. Also, we observed wax and cutine cells formed a thicker seed coat in seeds from the more humid site using a scanning electron microscope. The scanning electron microscopy/energy dispersive X-ray spectroscopy showed higher Si and Ca concentrations in the covers of serotinous seeds. Seeds from different provenance and cone types have anatomic and morphological differences that confer different properties against heating. This knowledge can improve post-fire management and promote restoration tools.     

Interaction between reactive oxygen species and hormones during the breaking of embryo dormancy in Sorbus pohuashanensis by exogenous nitric oxide

The breaking of dormancy mediated by reac-tive nitrogen species (RNS) is related to the accumulation of reactive oxygen species (ROS) in germinating embryos but...     

Identification and quantitative analysis of stage-specific carbohydrates in loblolly pine (Pinus taeda) zygotic embryo and female gametophyte tissues

Stage-specific analyses of starch and 18 sugars, including pentoses, hexoses, disaccharides, trisaccharides, oligosaccharides and sugar alcohols, were made throughout seed development for zygotic embryo and female gametophyte (FG) tissues of loblolly pine (Pinus taeda L.). Tissue was most often analyzed in triplicate from two open-pollinated families grown in different locations and sampled in different years. Carbohydrates were analyzed by enzymatic assay, high performance liquid chromatography or gas chromatography/mass spectrometry. For all carbohydrates quantified, peak concentrations were higher in embryo tissue than in FG tissue. Significant changes in starch and sugar concentrations occurred over time, with both seed collections showing similar trends in temporal changes. Although concentrations were not always similar, embryo and FG tissues generally showed similar patterns of change in starch and sugar concentrations over time. Total starch concentration was highest during early seed development and decreased as development progressed. The major sugars contributing to osmotic potential during early seed development were D-pinitol, sucrose, fructose and glucose. During mid-seed development, D-pinitol, sucrose, fructose, glucose, melibiose and raffinose provided major contributions to the osmotic environment. During late seed development, sucrose, raffinose, melibiose, stachyose and fructose were the major contributors to osmotic potential. These data suggest stage-specific media composition for each step in the somatic embryogenesis protocol.     

马来西亚巨草竹属天然林的形态与解剖特征

对马来西亚2年和4年生巨草竹属天然林分的形态与解剖特征进行了研究。形态特征随着竹秆的年龄和高度发生变化。4年生薄壁组织和纤维的细胞壁厚度比2年生竹薄壁组织和纤维的细胞壁厚。在两个年龄组中,底部和上部的维管束的频率比中部频率大,在秆壁中部,2年和4年竹秆的导管直径没有区别。竹子的解剖结构与含水率和基本密度密切相关。     

基因型及胚发育对百合远缘杂交胚拯救的影响

以亚洲百合、铁炮百合、东方百合及喇叭百合远缘杂交子代为材料,进行了不同基因型、不同胚状态、不同胚龄的胚拯救试验.结果表明:不同基因型间胚囊(胚)获得率及萌发率均存在较大差异;成熟胚萌发率在85%以上,成熟胚囊萌发率在10%～59%,幼嫩胚囊萌发率很低,大多在20%以下;成熟胚囊、幼嫩胚囊、成熟胚组培苗生长时非正常苗出现情况亦各不相同;所有基因型最适宜的胚拯救胚龄为39～90天,不同基因型随着胚龄的不同其胚囊(胚)获得率呈现不同的变化规律.     

红缨海棠茎段快速繁殖技术及组织解剖观察

以红缨海棠当年生新枝为起始外植体建立了离体再生体系,并进行了不定芽及不定根分化的细胞组织学研究.结果表明:在添加6-BA 1.0 mg/L和NAA 0.05 mg/L的N6培养基中培养30天,丛生芽分化效果最佳,其分化率达100%.在添加6-BA 0.5 mg/L和NAA 0.05 mg/L的N6培养基中,丛生芽增殖效果最好.伸长的不定芽接种在附加NAA和IBA共0.5 mg/L(两者质量比为1:1)的1/2N6生根培养基中,先经6天暗培养,再经过24天培养后生根率可达100%,平均不定根数量达8条/株,平均不定根长0.3 cm,最长达1.0 cm.生根苗移栽至混有珍珠岩、蛭石和草炭土配比为1:1:1(V:V:V)的基质中,60天后成活率约为80.0%.而细胞组织学研究表明,带顶芽茎段在NAA 1.0 mg/L和6-BA 0.05 mg/L共同作用下,不定芽起源形式既有内起源,又有外起源.而不定根起源于茎维管形成层细胞,属内起源.     

西伯利亚花楸试管苗保存技术

以西伯利亚花楸幼嫩茎段为外植体,0.1%(m/v)升汞消毒6 m in,在MS+6BA 0.8 mg/L+NAA 0.08 mg/L+KT 0.4 mg/L+IBA 0.04 mg/L的增殖培养基上,成功地建立了西伯利亚花楸试管苗增殖体系。研究了不同保存条件和培养基对试管苗保存效果的影响,结果表明:试管苗在(2±2)℃的冰箱冷藏室,可有效保存240天以上,在MS+琼脂7 g/L+蔗糖50 g/L的培养基上,试管苗的生长得到明显的抑制。保存后的试管苗增殖、生根、驯化效果良好,生长正常。