八角莲组织培养的器官发生途径研究

为探究小檗科植物八角莲组织培养的器官发生方式,该研究以八角莲离体叶片、叶柄在MS培养基上诱导产生的愈伤组织、不定芽、不定根为对象,用连续石蜡切片技术分析八角莲组织培养的器官发生途径。结果表明:八角莲愈伤组织形成的解剖学特征是靠近表皮的薄壁细胞经激素刺激恢复分裂能力,继续培养形成拟分生组织。拟分生组织可形成许多分化中心。通过对八角莲组织培养产生的不定芽细胞组织学观察发现芽原基起源于愈伤组织外侧的几层薄壁细胞,芽原基背离愈伤组织中央生长形成不定芽,故八角莲脱分化形成的芽起源方式为外起源。而八角莲的根原基起源于组织深处髓部薄壁细胞和部分维管形成层细胞,进而形成类似球形或楔形并朝韧皮部突起的根原基轮廓,根原基继续发育会突破表皮生成不定根,起源方式为内起源。八角莲离体再生途径为器官发生型,在组培苗生长过程中先诱导形成不定芽,再诱导形成不定根,在愈伤组织上形成维管组织将不定芽和不定根连接成完整植株。     

兔眼蓝莓离体叶片再生组织细胞学观察

离体叶片再生是兔眼蓝莓离体快繁和遗传转化的重要途径。为了探明兔眼蓝莓离体叶片再生途径,以兔眼蓝莓杰兔品种的试管苗叶片为外植体,对离体叶片再生途径进行细胞学观察。结果表明,离体叶片不定芽在30 d内基本完成其发生、发育和形成的全过程。离体叶片以直接再生途径发生不定芽,且属于多起源,其分生组织起源于离体叶片切口附近与维管束相邻的上表皮细胞、维管组织薄壁细胞及周围薄壁细胞,通过细胞分裂和分化形成分生细胞团,直接形成芽,再发育成苗。此外,兔眼蓝莓离体叶片不定芽的形成具有特定的时空特性,多个不定芽先后在离体叶片上形成单芽或丛生芽。     

亚麻植株的再生及诱导因素的研究

亚麻根、下胚轴、茎和叶外植体在适宜培养基上可产生愈伤组织和不定芽。愈伤组织在分化培养基上产生幼芽。在生根培养基上小苗生根长大。组织细胞学观察表明,下胚轴表皮、皮层和韧皮部细胞都能产生小分生细胞团,后者形成不定芽和愈伤组织。愈伤组织边缘区域分化芽原基,内部产生大量的分生组织结节和维管组织结节。根原基起源于维管组织结节的形成层状细胞。不同器官外植体再生植株的潜力不同,对诱导条件的反应有差别,其中茎和下胚轴切段易兼生不定芽和愈伤组织,再生植株频率高。外源激素、基本培养基和损伤刺激明显影响植株再生。     

结球甘兰下胚轴组织培养形态发生的组织学研究

结球甘兰离体下胚轴培养,近切口的中柱薄壁细胞首先启动分生,中柱外的内皮层,皮层,表皮细胞随后也启动分生。随着愈伤组织的生长和愈伤形成层的建成,维管组织与分生组织产生。组织培养中出现的多倍性细胞团和单倍性细胞,不会引起原二倍体物种的遗传性变异和性状变化。在愈伤组织中,芽多为外起源。由原体原始细胞和原套原始细胞发育成芽原基,进一步形成不定芽。另外,不定芽还可由外植体皮层内薄壁组织直接产生。不定根为内起     

盾叶薯蓣类原球茎发育的形态解剖学观察

为探讨盾叶薯蓣类原球茎形态建成的发育机理及植株移栽成活率高的原因,对盾叶薯蓣离体培养条件下形成类原球茎的形态发生过程进行形态学和石蜡切片组织学观察,并与不定芽的发生进行比较。结果表明：类原球茎是由愈伤组织中致密的卵圆形胚性细胞团分化出芽原基和鳞片叶,随后出现初生增厚分生组织和原形成层（维管束原）,其类原球茎形态建成。不定根的发生为内起源,其维管组织与类原球茎的维管组织相连接,故移栽成活率高。而不定芽为愈伤组织表面的胚性细胞分裂产生的分生细胞团分化而来,其不定根通常发生在茎基部形成的愈伤组织表面,故不易成活。     

甜瓜子叶离体培养直接再生不定芽的形态学和解剖学观察

对甜瓜品种“西莫洛托”子叶离体培养直接再生不定芽过程进行了形态学和解剖学观察,结果表明：以子叶远轴面接触培养基培养能直接再生不定芽,以子叶近轴面接触培养基培养只能得到无序组织块;不定芽再生过程中,培养4d时,子叶变绿,但还不见有细胞分裂,约6d时,在子叶外植体的形态学下端切口处的近轴面到有局部的表皮细胞和亚表皮细胞分裂活跃,初步形成了拟分生组织,7－9d时,这些拟分生组织形成了肉眼可见的小突起,10－14d时,这些突起变得狭长,发育成幼叶或叶状体,它们在外植体上成族存在,但此时还没有典型的“芽”结构出现,15－20d时,成族突起形成幼叶丛,一些幼叶和叶状体的近轴面的基部出现叶腋分生组织,这些将外植体转入伸长培养基,3－5d后,幼叶充分展开,成丛叶状,多个叶腋分生组织同时发育成芽,再过2－7d,相继有不定芽从丛叶外植体上伸长,将伸长的不定芽切下,可促使外 植体上的其它不定芽伸长。     

油菜花序轴、叶片组织培养中形态发生的细胞组织学研究

油菜花序轴、叶片在MS培养基上经诱导可产生愈伤组织并形成再生植株。愈伤组织形成可分3个时期:细胞启动期、分裂期和分化期。实验证明:花序轴启动部位多发生在皮层薄壁细胞、髓部薄壁细胞、韧皮薄壁细胞和木薄壁细胞。叶片主要是叶肉细胞、叶脉薄壁细胞和表皮细胞启动。细胞分裂期的特点是启动细胞反复增殖,形成连续的分生细胞层。细胞分化期的特点是一部分细胞保持分裂能力,一部分细胞分化形成薄壁细胞和输导分子。观察了愈伤组织中器官发生的部位和方式。实验证明,根的发生多为内起源,芽的发生多为外起源。     

番茄离体培养过程中器官发生的细胞组织学观察

对番茄下胚轴、子叶、茎段、叶片、叶柄不同类型外植体离体培养中有关细胞启动、分裂、分化以及器官发生作了细胞组织学观察。研究结果表明番茄不同类型外植体在同样的培养条件下,愈伤组织生长表现出明显差异,其中下胚轴、子叶诱导产生愈伤组织时,细胞启动最早,生长最快,其分裂方式基本为无丝分裂,未见有丝分裂,因此我们认为以不定芽方式获得转基因植株时,植株的所有性状变化,是否纯属目的基因所为,应该反复考察,不能忽视不定芽产生过程中的种种变化;下胚轴诱导愈伤组织形成时,细胞不规则的无丝分裂少于子叶,故下胚轴离体培养得到的正常芽的比例高于子叶的;番茄离体培养中不定芽通常发生在愈伤组织的周边区,也可起源于维管组织结节周围的形成层状细胞。不定根则由茎中柱鞘处发生。     

莲的根茎构造,伸长与增粗

莲 (Nelumbo nucifera)种苗的茎短而直立,叶互生。幼苗期茎延伸成横卧根茎,其上生有营养芽及混合芽。腋生鳞片为叶的衍生部分,形如叶鞘状,包着预芽。年苗上的冬芽内全为混合芽。根茎内的维管束分散排列,无导管及形成层存在。节间延长通过肋状分生组织及节间内的薄壁组织细胞分裂与增长来完成。根茎可由初生加厚分生组织,维管束细胞,皮层薄壁细胞等的细胞分裂,使层次增加,但增粗主要是由皮层薄壁细胞体积显著增大而引起的。     

番茄离体培养过程中器官发生的细胞组织观察

对番茄下胚轴、子叶、茎段、叶片、叶柄不同类型外植体离体培养中有关细胞启动、分裂、分化以及器官发生作了细胞组织学观察。研究结果表明：番茄不同类型外植体在同样的培养条件下,愈伤组织生长表现出明显差异,其中下胚轴、子叶诱导产生愈伤组织时,细胞启动最早,生长最快,其分裂方式基本为无丝分裂,未见有丝分裂,因此我们认为以不定芽方式获得转基因植株时,植株的所有性状变化,是否纯属目的基因所为,应该反复考察,不能忽视不定芽产生过程中的种种变化;下胚轴诱导愈伤组织形成时,细胞不规则的无丝分裂少于子叶,故下胚轴离体培养得到的正常芽的比例高于子叶的;蕃茴离体培养中不定芽通常发生在愈伤组织的周边区,也可起源于维管组织结节周围的形成层状细胞。不定根则由茎中柱鞘处发生。     

Morpho-Histological Investigation of Plantlet Formation In Vitro in Taiwania flousiana Gaussen

Histological events during adventitious shoot formation in cultured shoot apex of 10–12-day-old seedlings and adventitious root formation in the elongated shoot of Taiwania floudana Gaussen were examined. Ceils of the peripheral subsurface layers of the shoot apex responded to cytokinin and divided into meristematic cells from which the shoot primordia were proliferated. A few bud primordia also originated from the epidermis and hypodermis of the adaxial surface of the cotyledon. The parenchyma of leaf gap of the shoots cultured in rooting medium dedifferentiated to regain the capacity of division and form adventitious root. Besides, cells that had relatively low potential of differentiation, such as the cortex parenchyma, pith ray, phloem parenchyma and cambium zone, albeit initiated to divide, but seldom formed root primordium. The origin of the adventitious roots in the leaf gap facilitated the establishment of the vascular connection between the shoot and root.     

Histological analysis of somatic embryogenesis and adventitious shoot formation from root explants of <Emphasis Type="Italic">Centaurium erythreae</Emphasis> Gillib

Direct somatic embryogenesis and adventitious shoot formation were successfully achieved from root explants of Centaurium erythrea Gillib. cultured on Murashige and Skoog medium with half-strength macronutrients, full-strength micronutrients and vitamins, 3 % sucrose, 0.7 % agar, 100 mg dm⁻³ myo-inositol and without growth regulators. Histological studies revealed that somatic embryos were formed directly from epidermal cells and adventitious buds were developed from meristematic cells in root cortex tissues. Somatic embryos as well as adventitious shoots developed into whole plantlets.     

DEVELOPMENTAL ANATOMY OF DIRECT SHOOT ORGANOGENESIS FROM LEAF PETIOLES OF VITIS VINIFERA (VITACEAE)

The anatomy of direct shoot organogenesis from leaf petioles of Vitis vinifera cv. French Colombard cultured in vitro was studied by light microscopy. Regenerating petiole stubs were fixed at 2- or 3-day intervals and sectioned longitudinally. By day 3 on regeneration medium, new cell divisions were observed. After 6 days, three distinct regions of meristematic activity were apparent within the expanding petiole stub: the wound-response, organogenic, and vascularization regions. In the organogenic region, rapid periclinal divisions of vacuolate outer cortical cells formed nodular bumps, many of which developed vascular strands and marginal meristems and formed adventitious leaves. Promeristems with small, densely staining cells and a distinct tunica layer also originated in the organogenic region, by cell division in the epidermal and subepidermal cell layers. With vascularization and the formation of leaf primordia, many promeristems became adventitious shoot meristems. Adventitious leaves and promeristems were initiated continuously from day 10 until day 33. Promeristems were often initiated near or upon adventitious leaves but could form either before or after the adventitious leaf developed. Adventitious leaves and shoot meristems developed vascular connections with the vascular bundles of the original expiant. The implication of this pattern of regeneration for Agrobacterium-mediated transformation of Vitis is discussed.     

Morphogenesis in dormant embryonic shoots of Picea abies: Influence of the crown and cold treatment

Retention of the crown, a plate of homogeneously thickened collenchymatous cells at the base of the embryonic shoot of Picea abies (L.) Karst., has marked effects on the induction of adventitious buds from the needle primordia. These effects were observed on embryonic shoots of three clones which were cold-treated at 4 ± 1°C for nil, two, four and six months; and then excised either with or without the crown, before subculturing either directly on a medium lacking plant growth regulators or after application of 125 μM benzyladenine (BA) as a 3-h pulse. Embryonic shoots retaining the crown and treated with BA responded reproducibly better than those lacking it. This was true both for the number of shoots that produced adventitious buds and for the numbers of adventitious buds per shoot. Differentiation of as many as five adventitious buds in a single needle primordium was observed, with development occurring nearly twice as early (7 as compared with 12 weeks) in the presence as in the absence of the crown. The response decreased progressively with increasing exposure to cold treatment.
A number of anatomical changes occurred during culture in vitro. After 3 to 4 weeks a band of sclerenchymatous cells commenced differentiation at the centre of the crown. In embryonic shoots without the crown, a tissue which was identified as a wound periderm formed at the excision surface. Vascular unions were observed between the tissues of the newly — formed shoots induced from the needle primordia and those of the original shoot explants.     

栝楼不定根尖分化不定芽过程中的细胞组织学研究

将栝楼（Trichosanthes kirilowii)长约0.5-1cm不定根尖（连同原外植体茎段或根段一起,或不连）培养在MS附加6－BA5mg/L的培养基上光照培养15d,可在根尖分化出大量不定芽。不定根尖培养过程中每隔2－3d取材,用FAA固定液固定1次,通过石蜡切片观察,将栝楼的不定根尖端分化不定芽的细胞组织学变化分为4个时期。1．启动期（0-3d),根尖分生组织细胞、中柱鞘细胞起动分裂。2“根茎转变区”原形成层形成期（4－6d0。起动细胞分裂后形成2－3层体积小、核大、质浓、近似扁平形的细胞层,组成“杯形”的“根茎转变区”原形成层。3．“根茎转变区”形成期（7－10d)。原形成层不同部位加速分裂使根尖膨大成半球形、球形或梭形,并在膨大区进行维管组织的转变。4．芽分化形成期（11－15d)。原形成层在不同部位向外形成“突起”即分生细胞团,每个“突起”发育为1个芽原基。作者还讨论了栝楼与其它植物根芽产生的异同。     

Organogenesis from internode-derived nodules of Humulus lupulus var. Nugget (Cannabinaceae): histological studies and changes in the starch content

The sequence of histological and histochemical events occurring during organogenesis from Humulus lupulus var. Nugget internode-derived nodules was studied. Sections were made and studies were carried out from the start of culture treatment until the development of shoot buds. Cell division was observed in both cambial and cortical regions during the first week of culture establishment. Cell division in cortical cells led to the formation of an incipient callus tissue. From the calluses prenodular structures of cambial origin appeared and gave rise to nodules from which shoot buds formed. Nodules kept separating into "daughter nodules" from which arose an increasing number of shoot buds. Iodide staining showed a strong starch accumulation in callus tissue and in prenodular structures. During shoot-bud primordia formation starch content decreased in nodules. Some starch was also noted in control explants (cultured on basal medium), however at a lower level than that observed in explants cultured on media with growth regulators. Shoot-bud regeneration was not observed in control explants.     

杨树叶薄层培养中不定芽形态发生的细胞组织学研究

将杂种杨树(Populus nigra var.betulifolia×P.trichocarpe)NE299叶主脉用振动切片机横切成400μm或800μm的薄切片,培养在附加0.2mg/L BA和0.01mg/L NAA的木本植物培养基上。培养后,位于主脉维管束两侧中上部的维管束鞘薄壁细胞首先启动分裂。几乎同时,与其邻接的一些栅栏组织细胞也分裂,并很快形成胚性分生细胞团。主脉的愈伤组织主要由维管束鞘薄壁细胞,以及与其邻接的一些栅栏组织细胞和韧皮部的薄壁细胞分裂而来。不定芽通常发生在愈伤组织的周边区,也可以起源于维管组织结节(vascular nodules)周围的形成层状细胞。侧脉的维管束鞘细胞分裂活动很强,可不经愈伤组织直接长成不定芽。杨树叶主脉处的维管束鞘薄壁细胞在与叶肉组织相邻接的细胞中,通常含有少量较小的叶绿体,而位于背腹面的细胞中含有贮藏的淀粉。对形态发生的特定部位及其细胞进行了讨论。     

ADVENTIVE ORGANOGENESIS FROM SOMATIC TISSUE CULTURES OF SOLANUM CAROLINENSE: ORIGIN AND DEVELOPMENT OF REGENERATED PLANTS

The development of adventitious shoot formation from cultured somatic tissues of Solanum carolinense was studied using light microscopy. For purposes of comparison, callus initiation and proliferation were also followed. When stem segments of this plant were cultured on medium supplemented with 6 mg/l benzyladenine (BA), cell division was first observed after 48 hr in the external phloem and inner cortex of the segments. This division activity gave rise to meristematic zones which subsequently formed shoot primordia within 6 days of culture. While organogenic potential appears to be limited to specific regions, all tissues of the explant were capable of callus formation when cultured on medium containing 3 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D). In conjunction with a previous study, it appears that unlike somatic embryogenesis in this species, organogenesis does not require an intermediate callus phase for differentiation to occur.     

细枝木麻黄离体培养过程中愈伤组织和再生芽的细胞组织学观察

为探讨细枝木麻黄(Casuarina cunninghamianaMiq.)愈伤组织分化过程的细胞组织学,对离体培养条件下的愈伤组织进行扫描电子显微镜和石蜡切片观察,分析愈伤组织的细胞分裂、分化以及芽再生的发生过程。结果表明,新鲜外植体培养于愈伤组织诱导培养基上,伤口处的薄壁细胞开始脱分化,培养1周后形成明显的愈伤组织;继续培养2周后,胚性愈伤组织形成,且表层细胞启动分化形成芽原基;培养4周,可肉眼观察到胚性芽原基,数量增多并逐渐分化形成不定芽;培养至第6周,生成不定芽,并大量增殖和分化。因此,细枝木麻黄是通过愈伤组织分化形成胚状体的途径进行植株再生的,为建立细枝木麻黄组织培养高效再生体系提供了理论依据。