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1.
石刁柏及党参体细胞胚发生中的淀粉代谢动态   总被引:8,自引:0,他引:8  
以石刁柏(Asparagusofficinalis)无菌苗的嫩茎和党参(Codonopsispilosula)的地下嫩茎为外植体,诱导体细胞胚发生。用PAS法研究体细胞胚发育过程中淀粉代谢的动态变化情况,实验结果表明,二种材料的体细胞胚发育中,淀粉动态情况基本相同,后期胚性细胞和器官原基分化之前出现二次淀粉积累高峰  相似文献   

2.
乔琦  肖娅萍 《广西植物》2008,28(1):113-116
采用石蜡切片和半薄切片法研究组织培养中防风体细胞胚发生和发育的形态和结构特征,以了解体细胞再生形成胚胎结构的细胞分化和形态发生特征。结果表明:(1)胚性细胞内含有丰富的淀粉体,随细胞分裂和分化逐渐减少;(2)体细胞胚的发生发育经历了类似合子胚的各阶段;(3)多细胞原胚形成的分裂方式以平周分裂为主,并由此表现出有序生长;(4)在体细胞胚迅速发育过程中,不同阶段的体细胞胚始终与周围细胞存在明显界限;(5)胚柄发育不明显;(6)畸形胚常见,其中连体胚是胚性细胞发生密度过高造成的,而次生胚则在原来胚的基础上又产生新的胚的发生中心。  相似文献   

3.
三七为五加科的重要药用植物。以三七的种胚为材料接种于MS 补加2,4-D、IAA、NAA 各1 mg/L的培养基上。接种后约二个月,在MS 补加IAA 或NAA 的培养基上可以产生体细胞胚;在MS 加2,4-D 的培养基上只产生愈伤组织而无器官分化。体细胞胚在MS+IAA 0.5 mg/L+GA_3 1 mg/L 培养基上可发育成小植株。体细胞胚用4%海藻酸钠和2%氯化钙进行人工种皮包埋后,在无菌条件下,人工种子可转换成苗,转换率达89.7%。三七的体细胞胚起源于愈伤组织内或近表层的单个胚性细胞。体细胞胚经球形、心型、鱼雷形及子叶期等诸阶段发育成植株。通过PAS 法染色发现,胚性细胞、球形胚、早心形胚阶段有明显地淀粉积累,淀粉颗粒大而密集;到晚心形胚及子叶期体胚,淀粉颗粒小而少或消失。淀粉消长变化的规律与体细胞胚的发育有着密切的关系。  相似文献   

4.
香果树体细胞胚胎发生过程中4种同工酶的研究   总被引:5,自引:1,他引:4  
用非变性聚丙烯凝胶电泳技术对香果树体细胞胚胎发生及形态建成过程中过氧化物酶(POD)、酯酶(EST)、淀粉酶(AMY)和超氧化物歧化酶(SOD)4种同工酶进行分析.结果表明:香果树体细胞胚胎发生及形态建成过程中,POD、EST、AMY和SOD活性变化与胚性愈伤组织的诱导及体细胞胚的发生发育密切相关.非胚性愈伤组织和胚性愈伤组织酶谱差异明显,胚性愈伤组织中EST和AMY同工酶酶带多且活性高,非胚性愈伤组织中缺乏EST和AMY同工酶表达,AMY同工酶可作为胚性细胞分化和发育的重要标志.香果树体细胞胚形态建成过程中,球形胚时期的AMY、POD、EST同_T酶活性最强,表明这一时期生理代谢旺盛,是体细胞胚形态建成的关键时期;POD、AMY和SOD 3种同工酶的酶谱及表达强弱在形态建成的不同时期呈现有规律的变化,可作为香果树体细胞胚发生发育特定时期的参考标记. 与胚性愈伤组织的诱导及体细胞胚的发生发育密切相关.非胚性愈伤组织和胚性愈伤组织酶谱差异明显,胚性愈伤组织中EST和AMY同工酶酶带多且活性高,非胚性愈伤组织中缺乏EST和AMY同工酶表达,AMY同工酶町作为胚性细胞分化和发育的重要标志.香果树体细胞胚形态建成过程 ,球形胚时期的AMY、POD、EST同_T酶活性最强,表明这一时期生理代谢旺盛,是体细胞胚形态建成的关键时期;POD、AMY和SOD 3种同工酶的酶谱及表达强弱在形态建成的不同时期呈现有规律的变化,可作为香果树体细胞胚发生发育特定时期的参考标记. 与胚性愈伤组织的诱导及体细胞胚的发生发育密切相关.非胚性愈伤组织和胚性愈伤组织  相似文献   

5.
松杉类植物体细胞胚发育机理的研究进展   总被引:3,自引:0,他引:3  
植物体细胞胚胎发生不仅可作为其繁育的重要手段,而且也是研究胚胎发育过程的一种重要模式系统.体细胞胚在形态和生理上的成熟,直接影响到植株的萌发和再生频率.本文综述了近年来国内外有关裸子植物中几种松杉类植物体细胞胚发育过程的研究报道,其中主要涉及培养基成分和脱落酸(ABA)对体细胞胚发育的影响,以及体细胞胚发育在细胞学、细胞程序性死亡、相关基因和蛋白质组学等方面的研究进展,并进一步讨论了松杉类植物体细胞胚的发育机理,以及体细胞胚在遗传转化系统中的作用.  相似文献   

6.
植物体细胞胚发生的细胞生物学研究进展   总被引:2,自引:0,他引:2  
体细胞胚发生是植物界的一个普遍现象,本文从组织细胞学、超微结构、电镜细胞化学、分子生物学等方面对体细胞胚发生发育过程中的形态建成和细胞结构,Ca2 和ATPase的动态变化,淀粉和蛋白质代谢,核糖体、线粒体等对极性变化的影响,畸形胚的发生和体胚同步化的诱导调控,基因调控等方面进行了综述,为进一步深入了解体细胞胚的发生发育规律及基因调控机制以及植物高效再生体系的建立提供参考。  相似文献   

7.
以北五味子不同发育阶段的体细胞胚为材料,利用高效液相色谱法(HPLC)对其内源吲哚乙酸(IAA)、脱落酸(ABA)和赤霉素(GA3)含量进行了测定,探讨内源激素在体细胞胚正常发育过程中所具有的作用。在北五味子体细胞胚发生过程中,IAA和GA3含量均呈现先增加后降低趋势,ABA含量表现为先降低后增加趋势。IAA和ABA含量分别在球形胚阶段达到最大值和最小值,而GA3含量在心形胚阶段达到最大值。与正常体细胞胚相比,畸形胚中IAA和GA3含量高于各时期的正常胚状体,而ABA含量则显著低于其他各时期的正常胚状体。高水平的IAA在北五味子体细胞胚的发生阶段起重要的作用,而ABA在体细胞胚的成熟过程中起关键作用,GA3则与其体细胞胚的生长发育过程密切相关。但过高水平的IAA和GA3,以及过低水平的ABA会使体胚无法正常发育成熟,可能是引起畸形胚数量增加的主要原因之一。  相似文献   

8.
白杄体细胞胚胎发生的细胞组织学和淀粉积累动态的研究   总被引:4,自引:0,他引:4  
以白木千(PiceameyeriRehd.etWils.)的成熟种胚为外植体,诱导体细胞胚胎发生。整体染色封片和组织切片的观察结果表明,白木千体细胞胚起源于胚性愈伤组织的单个细胞。胚性细胞经过一次不均等分裂产生两个细胞,即胚细胞和胚柄细胞。然后依次经过胚性胚柄团、球形胚、心形胚及鱼雷形胚阶段,最后发育成具有子叶的成熟胚。通过PAS反应研究后发现,在体细胞胚发育过程中,淀粉粒在胚性胚柄团时期开始积累,至心形胚时期达到积累高峰,且淀粉粒的分布主要集中于胚柄细胞、分裂旺盛的胚细胞、器官原基及其附近细胞。据此结果推测淀粉的消长与体细胞胚发生的能量供应有关。  相似文献   

9.
云南大叶茶体细胞胚发生及体细胞胚苗形成体系的建立   总被引:9,自引:0,他引:9  
利用云南大叶茶(Camellia sinensis var.assamica Kitamura)胚性细胞系(CL_1)中悬浮培养物,建立了高频率同步化体细胞胚发生及体胚苗形成体系。以改良的MS为基本培养基,将CL_1中培养物由液体保持培养基(0.1mg/L 2,4-D 0.5mg/L 6-BA)继代转入液体诱导培养基(0.05mg/L 2,4-D 0.50mg/L6-BA),暗培养诱导28d,转入不含任何激素的液体分化培养基中再培养28d,获得了不同发育时期的体细胞胚,其发生频率为81.5%。不同发育时期的体细胞胚用不同目的细胞筛收集,在液体生长培养基(1/2 MS 1.0mg/L GA_3 0.5mg/L 6-BA)中培养发育成熟。ABA有利于高质量体细胞胚的形成。20~70月大小的体细胞胚在固体生长培养基中成苗转换率为75%。在液体悬浮培养条件下观察记录了体细胞胚发育过程,证实其过程与合子胚的形态发生过程相似。  相似文献   

10.
本文报告了黑穗醋栗(Ribes nigrum L.)三个栽培品种中的薄皮黑豆未受精胚珠(花粉发育到单核晚期)在MS基本培养基附加植物激素BA,2.4-D和GA_3中形成了体细胞胚状体。长度约为0.5—1.0cm大小的胚状体在生根培养基中可以形成完整的再生植株。经过筛选得到了体细胞胚性愈伤组织无性系,继代培养二年多仍能保持胚状体形成能力。试验结果表明:诱导体细胞胚胎发生受品种和接种时期的影响,适宜的接种时期为花粉发育到单核晚期。培养基中的BA为诱导胚胎发生和保持胚性愈伤组织无性系所必需。  相似文献   

11.
Somatic embryogenesis requires auxin and establishment of the shoot apical meristem (SAM). WUSCHEL ( WUS ) is critical for stem cell fate determination in the SAM of higher plants. However, regulation of WUS expression by auxin during somatic embryogenesis is poorly understood. Here, we show that expression of several regulatory genes important in zygotic embryogenesis were up-regulated during somatic embryogenesis of Arabidopsis. Interestingly, WUS expression was induced within the embryonic callus at a time when somatic embryos could not be identified morphologically or molecularly. Correct WUS expression, regulated by a defined critical level of exogenous auxin, is essential for somatic embryo induction. Furthermore, it was found that auxin gradients were established in specific regions that could then give rise to somatic embryos. The establishment of auxin gradients was correlated with the induced WUS expression. Moreover, the auxin gradients appear to activate PIN1 polar localization within the embryonic callus. Polarized PIN1 is probably responsible for the observed polar auxin transport and auxin accumulation in the SAM and somatic embryo. Suppression of WUS and PIN1 indicated that both genes are necessary for embryo induction through their regulation of downstream gene expression. Our results reveal that establishment of auxin gradients and PIN1-mediated polar auxin transport are essential for WUS induction and somatic embryogenesis. This study sheds new light on how auxin regulates stem cell formation during somatic embryogenesis.  相似文献   

12.
以欧石楠茎段为外植体,研究其体细胞胚胎发生和植株再生。对影响茎段不定芽分化及胚性愈伤组织诱导的主导因子进行比较分析,并研究其体胚萌发、生根及移栽;同时,采用树脂切片法对茎段脱分化产生胚性愈伤组织及体胚发育过程进行组织细胞学观察。结果表明,接种在1/2WPM基本培养基上的茎段,胚性愈伤组织诱导率为88.7%,显著高于其他处理,不定芽诱导率可达90.6%,平均分化倍数为3.6个,平均分化苗高3.82cm;体细胞经过成熟培养后。在添加1.0mg·L-1 ZT和0.3mg·L-1 IBA的1/2WPM培养基上萌发,萌发的体胚在I/2WPM附加0.2mg·L-1 NAA和0.3mg·L-1 IBA的培养基上形成完整的体胚苗植株,体胚苗生根率达到87.4%,经炼苗后移栽到蛭石:珍珠岩=3:1(V/V)的栽培基质中,成活率可达63.7%。在显微镜下可观察到球形胚、心形胚、鱼雷形胚和子叶形胚;体细胞胚以间接方式发生,表现为愈伤组织外层细胞直接发生和愈伤组织组织内部细胞发生。  相似文献   

13.
In monocots, the zygotic embryo is protected and nourished by an endosperm. In the present study starch deposition and amylase accumulation was noticed during somatic embryogenesis in stem callus of a bamboo, Dendrocalamus hamiltonii. SEM studies revealed that starch grains were clearly visible in the scutellum during the maturation stage of the somatic embryo. As the somatic embryo developed further, the scutellum got reduced with corresponding increase in amylase. The amylase activity was tested periodically at different developmental stages of embryos. The role of scutellum in somatic embryos for starch deposition and amylase accumulation is discussed.  相似文献   

14.
Plant regeneration via somatic embryogenesis in cotton   总被引:6,自引:0,他引:6  
An efficient in vitro plant regeneration system characterized by rapid and continuous production of somatic embryos using leaf and stem explants of abnormal seedling as an explant have been developed in Gossypium hirsutum L. Embryogenic callus and somatic embryos have been obtained directly from the explants of cotton abnormal seedlings. Plant growth regulators influenced the induction of cotton somatic embryogenesis. The optimal medium for direct somatic embryogenesis was modified MS medium supplemented with 0.1 mg l-1 ZT and 2 g l-1 activated carbon. On this medium, an average of 28.0 and 28.1 matured somatic embryos formed from per leaf and stem explants respectively. The highest frequency of somatic embryogenesis was 100%. The somatic embryos were converted into normal plantlets when cultured on modified MS medium supplemented with 0.1 mg l-1 ZT. Upon transfer to soil, plants grew well and appeared normal. Plants could be regenerated within 60–80 days. The system of cotton somatic embryogenesis and plant regeneration described here will facilitate the application of plant tissue culture and genetic engineering on cotton genetic improvement. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

15.
The WUSCHEL gene promotes vegetative-to-embryonic transition in Arabidopsis   总被引:23,自引:0,他引:23  
Formation of somatic embryos in plants is known to require high concentrations of auxin or 2,4-dichlorophenoxyacetic acid (2,4-D), which presumably acts to trigger a signalling cascade. However, very little is known about the molecular mechanism that mediates the vegetative-to-embryogenic transition. We have employed a genetic approach to dissect the signal transduction pathway during somatic embryogenesis. In a functional screen using a chemical-inducible activation-tagging system, we identified two alleles of Arabidopsis gene PGA6 whose induced overexpression caused high-frequency somatic embryo formation in all tissues and organs tested, without any external plant hormones. Upon inducer withdrawal, all these somatic embryos were able to germinate directly, without any further treatment, and to develop into fertile adult plants. PGA6 was found to be identical to WUSCHEL (WUS), a homeodomain protein previously shown to be involved in specifying stem cell fate in shoot and floral meristems. Transgenic plants carrying an estradiol-inducible XVE-WUS transgene can phenocopy pga6-1 and pga6-2. Our results suggest that WUS/PGA6 also plays a key role during embryogenesis, presumably by promoting the vegetative-to-embryogenic transition and/or maintaining the identity of the embryonic stem cells.  相似文献   

16.
The genetic basis of stem cell specification in somatic embryogenesis and organogenesis is still obscure. SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK) genes are involved in embryogenesis and organogenesis in numerous species. In vitro culture of Cyclamen persicum immature ovules provides a system for investigating stem cell formation and maintenance, because lines forming either organs or embryos or callus without organs/embryos are available for the same cultivar and plant growth regulator conditions. The present aim was to exploit this property of cyclamen cultures to understand the role of SERK(s) in stem cell formation and maintenance in somatic embryogenesis and organogenesis in vitro, in comparison with expression in planta. CpSERK1 and CpSERK2 were isolated from embryogenic callus. CpSERK1 and CpSERK2 levels by RT-PCR showed that expression is high in embryogenic, moderate in organogenic, and null in recalcitrant calli. in situ hybridizations showed that the expression of both genes started in clumps of pluripotent stem cells, from which both pre-embryogenic aggregates and organ meristemoids derived, and continued in their trans-amplifying, meristem-like, derivatives. Expression declined in organ meristemoids, in parallel with a partial loss of meristematization. In mature somatic embryos, and in shoot and root primordia, CpSERK1 and CpSERK2 were expressed in meristems, and similar patterns occurred in zygotic embryo and primary meristems in planta. The results point to SERK1 and SERK2 as markers of pluripotency in cyclamen. It is proposed that the high expression of these genes in the trans-amplifying derivatives of the stem cells maintains a pluripotent condition leading to totipotency and, consequently, somatic embryogenesis.  相似文献   

17.
 The report describes a system for somatic embryogenesis and direct plant regeneration from the embryos of Manihot glaziovii. Somatic embryos were obtained by culturing young leaf lobes (3–6 mm long) adjacent to the apex in Murashige and Skoog medium containing 18 μm 2,4-dichlorophenoxy acetic acid for 20 days and then transferring them to a maturation medium with 0.5 μm 6-benzylaminopurine. Secondary embryogenesis was induced from cotyledonary segments of somatic embryos by using the same protocol as that for primary embryogenesis. For regeneration, somatic embryos were cultured in medium supplemented with 10−4m kinetin and 53.4% of them developed into plantlets. Linamarin and linamarase were not detected in calli or in somatic embryos. Linamarin content was found to be highest in leaves of regenerated plantlets, followed by stem and root tissues. Levels of linamarase activity were almost the same in leaves and stem tissues and very low in roots. Received: 19 April 1999 / Revision received: 11 August 1999 / Accepted: 17 August 1999  相似文献   

18.
Somatic embryogenesis in palm trees is, in general, a slow and highly complex process, with a predominance of the indirect route and, consequently, a lack of knowledge about the direct route. We present new knowledge related to the morphological, histochemical and ultrastructural aspects of the transition from somatic to embryogenic cells and direct formation of somatic embryos from mature zygotic embryos of Syagrus oleracea, a palm tree. The results support the general concept that 2,4-dichlorophenoxyacetic acid plays a critical role for the formation of somatic embryos of direct and multicellular origin. Seven days in medium with auxin were enough for the identification of embryogenic cells. These cells had a set of characteristics corresponding to totipotent stem cells. At 14 days on induction medium, nodular formations were observed in the distal region of inoculated embryos, which evolved into globular somatic embryos. At 120 days on induction medium, the quality of the somatic embryos was compromised. The dynamics of the mobilization of reserve compounds was also demonstrated, with emphasis on starch and protein as energy sources required for the embryogenic process. This study shows for the first time the anatomical and ultrastructural events involved in direct somatic embryogenesis in a palm tree and incites the scientific community to return to the discussion of classical concepts related to direct somatic embryogenesis, especially regarding the characteristics and location of determined pre-embryogenic cells.  相似文献   

19.
Somatic embryos of Vitis vinifera (cv. Grenache noir) develop normally up to the torpedo stage, but they germinate precociously and form viable plantlets with very low frequency. Because a peak in abscisic acid (ABA) in mid‐embryogenesis could be one factor preventing precocious germination during normal seed development, we followed the development of ABA content concurrent with that of the somatic embryos. Additionally, we measured changes in indoleacetic acid (IAA) levels. We also compared the levels of both hormones during precocious germination of somatic embryos and during normal germination of their zygotic counterparts. Somatic embryos were able to accumulate ABA and IAA throughout their development but no peak in ABA concentration was detected during embryogenesis. This suggests that the switch from mid‐ to late‐embryogenesis is not triggered. Furthermore, during precocious germination, i.e. from the torpedo stage onwards, the concentrations of ABA and IAA in somatic embryos were much lower than during normal germination of zygotic embryos. Thus, it is likely that when precocious germination occurs, grape somatic embryos do not accumulate ABA and/or IAA in sufficient concentrations to support normal plantlet development. Therefore, for grape somatic embryos we propose that prevention of precocious germination, i.e. triggering late‐embryogenesis, is attainable by an ABA treatment followed by slow desiccation, as already shown for conifer somatic embryos. Our results also suggest that the role of ABA and IAA for improving normal germination after imposed quiescence should be investigated.  相似文献   

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