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。     

紫背天葵叶片培养体细胞胚状体发生的研究

SH液体培养基附加2,4－D（0．125mg/l),BA(0.25-0.5mg/l),CM(10%v/v)或CH（0．2%w/v),摇床培养,同一培养基中培养50天后,出现球形,心形,鱼雷,子叶胚,虽然胚状体和不定芽同样来源于叶片的表皮细胞,但它们之间有下列区别;体细胞胚状体发育有4个不同时期,而不定芽没有;球形胚形成后,能脱落分散在培养液中,芽始终和外植体连在一起;鱼雷－子叶胚有明显的苗端和根端之分,苗端有两片子叶,叶间是顶端分生组织,有原形成层结构,而不定芽仅有芽原基。     

紫背天葵叶片培养体细胞胚状体发生的研究

SH液体培养基附加2,4－D（0．125mg/l),BA(0.25-0.5mg/l),CM(10%v/v)或CH（0．2%w/v),摇床培养,同一培养基中培养50天后,出现球形,心形,鱼雷,子叶胚,虽然胚状体和不定芽同样来源于叶片的表皮细胞,但它们之间有下列区别;体细胞胚状体发育有4个不同时期,而不定芽没有;球形胚形成后,能脱落分散在培养液中,芽始终和外植体连在一起;鱼雷－子叶胚有明显的苗端和根端之分,苗端有两片子叶,叶间是顶端分生组织,有原形成层结构,而不定芽仅有芽原基。     

禿杉组织培养研究

本文详细报道了从秃杉(Taiwania flousiana Gaussen)离体胚诱导不定芽、不定根及从无菌苗茎端培养再生植株的过程。诱导不定芽要求较低的蔗糖浓度(以3％最好);同时BA是必须的,在附加0.1—3 mg/1 BA的White培养基上,从离体胚的子叶或胚轴上诱导了不定芽的发生(以1 mg/1最好);NAA与BA结合使用,对不定芽诱导无促进作用;适当提高光照有利于不定芽的诱导。在诱导不定芽的同时,在子叶表面还观察到有许多无结构的“不定突起”。不定芽起源于子叶表皮下1—2层细胞。IBA对诱导离体胚上产生不定根效果较好。在有或无生长素的培养基上,从生长1月龄的无菌苗茎端培养获得了不定根的产生,在加有细胞分裂索的培养基上,从无菌苗上产生了腋芽。     

结球白菜带柄子叶外植体不定芽离体再生能力的遗传分析

解析控制植物不定芽离体再生能力的遗传因素,有助于从根本上提高离体培养困难材料的不定芽再生能力,是植物基因工程遗传改良的基础.本研究以结球白菜4个纯合亲本及其杂交后代的带柄子叶为外植体,建立了高频率离体不定芽再生技术.据此我们还对白菜不定芽再生能力进行遗传分析,并开展亲本与后代杂种的离体培养及反应研究,包括对培养基的激素需求,不定芽形成频率,不定芽形成数量,芽形态等系列特征.研究结果表明,杂种与亲本在培养基的激素浓度上有类似需求;杂交后代的不定芽再生率均至少高于一方亲本,在一些组合中可以高于双亲;在适宜的杂交组合及培养条件下,结球白菜带柄子叶外植体的不定芽再生率可以达100%,每一外植体上的不定芽数达3～7个.方差分析表明,结球白菜的不定芽离体再生能力存在基因的加性效应.     

橡胶树未成苗体细胞胚的茎芽分化及利用

以橡胶树未成苗体细胞胚为试材,选取未成苗双子叶胚、连体胚、多子叶胚、单子叶胚和子叶愈伤化胚作为外植体,研究不同体细胞胚类型的外植体分化茎芽的情况,并利用其进行幼态微型芽条的培育研究。结果表明:在植株诱导培养基中培养80d后,未成苗双子叶胚、连体胚、多子叶胚、单子叶胚、子叶愈伤化胚均能分化出芽,双子叶胚分化率最高(达90%),单子叶胚最低(20%),多子叶胚和连体胚最多可分化出芽3个,双子叶胚2个。幼态微型芽条增殖的最优培养基为MS+6-BA2mg·L-1或MS+6-BA2mg·L-1+KT1mg·L-1,而添加NAA对芽的伸长有抑制作用;适宜幼态微型芽条伸长培养的基本培养基为MS。     

酸枣叶片不定梢形成及玻璃化的影响因素

以酸枣无菌苗叶片为外植体,研究了培养条件对不定梢再生及不定梢玻璃化的影响.结果表明,叶片在加有细胞分裂素TDZ的诱导培养基(培养基Ⅰ)上连续培养,可诱导不定芽形成,但不能进一步发育成不定梢;而在诱导培养基Ⅰ上培养2周后转移到不加TDZ的培养基Ⅱ上,可获得不定芽伸长的不定梢.培养基Ⅱ的基本培养基组成影响不定芽(梢)的玻璃化症状:MS培养基产生玻璃化的不定芽(梢),而WPM培养基产生正常不定芽梢;光培养条件的变化对玻璃化症状的发生没有影响.不定芽(梢)玻璃化的发生可能与培养基中铵或硝酸铵的浓度有关,在不定芽伸长发育阶段,培养基中高浓度的铵导致了玻璃化苗的发生.     

影响辣椒离体再生芽伸长因素研究

以辣椒子叶为外植体,比较不同浓度BA和IAA激素组合对辣椒再生芽诱导的差异,利用筛选出的高效芽诱导培养基为基础,研究了赤霉素、芽诱导时间、培养基有机成分、不同激素组合和品种等因素对辣椒不定芽伸长的影响。结果表明:不同基因型辣椒子叶再生能力不同,BA3.0mg.L-1 IAA0.5mg.L-1的激素配比对不定芽诱导频率最高;不定芽的伸长百分率随着GA3浓度的增加而增加,GA3的适合浓度为1.0～2.0mg.L-1;不定芽诱导时间对不定芽的伸长有一定的影响,诱导21d的不定芽,其伸长频率明显高于诱导14d的不定芽;B5有机成分在辣椒不定芽的伸长中效果优于MS有机成分;激素组合对不定芽伸长有一定的影响,Zeatin GA3激素组合对伸长效果最好,BA IAA GA3伸长效果较好,BA PAA(苯乙酸,phenylaceticacid) GA3伸长效果次之;不同品种辣椒不定芽的伸长能力有一定差异,楚风和苏椒五号再生芽伸长能力最佳。与IAA和NAA相比,IBA对再生芽生根效果较好。     

简单快捷建立高频黄瓜子叶离体再生体系

以１０种我国市场上常见的黄瓜品种为材料,建立了一个简单高效的黄瓜子叶离体再生系统。从种子萌发到获得再生植株仅需６周。子叶外植体在ＭＳ＝０．５ｍｇ／Ｌ ＢＡ培养基上不经愈伤组织诱导阶段而直接走器官发生途径。４～５天的子叶外 植体的不定芽发生能力最强。供试１０种基因型中,“碧春”和“甜翠绿”的再生率高达１００％。待不定芽长度超过１．０ｍｃ时,直接将不定芽转移到ＭＳ培养基生根成苗,幼苗移栽温室后正常结实     

泰山酸枣离体叶片再生体系的建立

以泰山酸枣叶片为外植体,以WPM为基本培养基,研究了植物生长调节剂种类、浓度及培养方法等因素对离体叶片不定芽再生的影响,结果表明:不定芽启动的最佳培养基激素组合为1.0 mg·L-1 TDZ+0.5 mg·L-1 IAA;不定芽诱导伸长最佳培养基的激素组合为0.1 mg·L-1 IAA+0.5 mg·L-1 GA3.暗培养是不定芽再生的必需条件,在最适宜的不定芽再生培养基上,叶片连续光培养,不定芽不能再生;叶片先进行暗培养3周后转入光下培养,叶片不定芽再生效果最好,再生率最高可达100%.     

In vitro studies on the anatomy and morphology of bud regeneration in melon cotyledons

Summary The anatomy and morphology of bud regeneration were investigated in melon (Cucumis melo L.) cv. Galia, which regenerates in vitro only by direct organogenesis from the cotyledon explant. Explants were cut from the cotyledon proximal to the apex from 3-d-old in vitro seedlings. After 3 d on Murashige and Skoog medium with N⁶-benzyladenine, cell division can be observed in the epidermal layer on the adaxial side in the center of the explant, near the most proximal (wounded) cut edge. Over the next week, the area of the meristem increases laterally. Additional cell layers are added to the meristematic area by cell division in the epidermis. In places the epidermis remains active in cell division. Alongside those active areas there are zones where the epidermis has become inactive, although the subepidermal layers continue to divide. In transverse section, the explant now has small protuberances on the adaxial surface. After 10 d on cytokinin-containing medium, the first signs of development are visible on the adaxial surface adjacent to the proximal cut edge. The protuberances observed after 10 d are neither primordia nor buds, although some meristematic bulges are observed. The first regenerated shoot buds are observed histologically after 15 d, by which time the surface has many protuberances and some small leaves. The first shoot is found by histology after 22 d. By this time the surface is covered with protrusions and leaves, mostly without accompanying buds. The leaves may be produced from the protrusions initially visible after 10 d.     

以叶盘为外植体的白桦的再生

从不同的激素组成(BA, K T, 2, 4~D, NAA, GA₃)、基本培养基(MS, WP)、外植体放置的方向性进行了实验, 建立了以白桦叶盘为外植体的再生系统。当叶盘向轴面朝下放置在培养基上时, 三周后, 从叶盘边缘生出不定芽。不定芽的诱导率为64%, 平均每片叶盘可生出6 个不定芽。叶盘再生系统的建立为白桦的遗传转化提供了前提。     

De novo organogenesis and plant regeneration in <Emphasis Type="Italic">Pongamia pinnata</Emphasis>, oil producing tree legume

Role of Thidiazuron (TDZ) in inducing adventitious organogenesis in Pongamia was studied. TDZ at different concentrations (0, 0.45, 2.27, 4.54, 6.71, 9.08, 11.35, 13.12 and 22.71 μM) were used for induction of caulogenic bud formation in deembryonated cotyledon explants. Each cotyledon was cut into three segments and identified as proximal, middle and distal. Duration of TDZ exposure, influence of the segment and orientation of the explant were studied. TDZ at 11.35 μM concentration was optimum for the induction of shoots and rapid elongation. Shoots induced at higher concentration elongated after several passages in growth regulator free medium, thereby extending the period of differentiation. Exposure of the explant for 20 days yielded more number of buds than 10 days. Proximal segment of the cotyledon was more responsive. Contact of abaxial surface in the medium was more effective and generated more buds than the adaxial side. Buds differentiated and elongated on transfer to MS basal medium for 8–12 passages of 15 days each. Rooting and elongation of shoots was achieved in charcoal supplemented half-strength MS medium. Rooted plantlets survived on transfer to sand soil mixture. The plants were hardened and transferred to green house. This is the first report on in vitro regeneration of Pongamia pinnata via adventitious organogenesis using TDZ. This protocol may find application in studies in genetic transformation, isolation of somaclonal variants and in induction of mutants. It also provides a system to study the inhibitory role of TDZ on shoot differentiation.     

Rapid adventitious shoot regeneration from leaf explants of European birch

The goal of this research was to develop a rapid and efficient system for regenerating shoots from leaf explants of European birch, Betula pendula Roth. Single-node stem explants were established in culture, and microshoots were subcultured every 4 weeks through 12 subcultures. Leaves from glasshouse plants or subcultured shoots were excised from stems, cut into approximately 35-mm² pieces, and placed on Woody Plant Medium (WPM) containing different combinations of naphthaleneacetic acid (NAA) (0, 3, 6 or 9 M) and benzyladenine (BA) (0, 7.5, 15 or 22.5 M) in a 4×4 factorial design. The percentage of leaf pieces forming shoots and the number of shoots regenerated per explant were recorded after 4 weeks. Only media containing BA without NAA stimulated shoot formation on leaf explants. Fifteen micromolar BA induced the most shoots to form on leaf explants compared to 30, 45 or 60 M of this cytokinin. In addition, shoot regeneration was enhanced up to four-fold between the first and eleventh subculture. Over 90% of the leaf explants regenerated shoots with an average of 18 buds formed per explant for the eleventh subculture. Almost twice as many explants formed shoots if their adaxial side was in contact with the medium rather than oriented away from it. The ability to regenerate shoots from leaves varied among plants, regardless of stock plant age. This reliable shoot regeneration system can be used for rapid shoot proliferation and potentially for genetic engineering of European birch.     

Phenylacetic acid improves bud elongation and in vitro plant regeneration efficiency in Capsicum annuum L.

 A highly efficient three-stage protocol for the regeneration of chilli pepper (Capsicum annuum L.) from cotyledon explants was developed. This protocol used PAA in both the shoot-bud induction medium and the medium for elongation of the shoot buds. A superior medium for the induction of buds from the cotyledons was MS medium supplemented with BA (5 or 7 mg/l) + PAA (2 mg/l). Buds were elongated during the second stage on medium containing BA (2 or 5 mg/l) + PAA (2 mg/l). On this medium most of the buds elongated, and their number also increased due to the formation of new buds; bud elongation was achieved in 100% of the cultures provided the buds were induced in the primary stage on a medium supplemented with BA+PAA. The shoots that elongated in the second-stage rooted at 100% frequency on a medium supplemented with NAA (1 mg/l). The complete plantlets with well-developed root and shoot systems were transferred to field conditions where they grew to maturity, flowered and fruited normally. While shoot-bud induction from the cultured cotyledons was also observed on media supplemented with BA (5 or 7 mg/l) alone or in combination with IAA (0.2–2 mg/l), buds induced on these media were often distorted, with most not developing into normal shoots in the second-stage subculturing; a rosette of buds was seen in the second stage subculturing. On the other hand, PAA in combination with BA in the primary induction medium and second-stage medium promoted normal development and the elongation of shoot buds. Received: 28 July 1998 / Revision received: 22 December 1998 / Accepted: 19 February 1999     

Histo-Cytological Observations on Callus and Bud Formation in Cultures of Nicotiana tabacum L.

Leaf explants of tobacco were cultured on MS medium supplemented with 2 mg/ l NAA and 0.5 mg/l BA for induction of callus formation, or supplemented with 2 mg/l BA for bud formation. Histocytological observations on callus and bud formation were carried out. Three days after cultivation, mesophyll cells enlarged, the nuclei became more apparent and dark stained, and starch accumulated in the cells. Cell divisions began in the mesophyll cells at the cut ends, in the palisade cells near the vascular bundles and in the vascular parenchyma. Mitotic activity then spreaded over tbc explants, and was most active at the edges of leaf explants. Regular rows of cells appeared as a result of series of transverse divisions in the palisade. The number of chloroplast in the mesophyll cells decreased and degenerated gradually. A number of meristemoids ware initiated in the cultured leaf explants after 7 days of cultivation. They were originated from two kinds of tissues, the mesophyll and vascular bundle, including the phloem parenchyma and vascular sheath. On the medium with NAA and BA, callus formation was induced with vigorous divisions, whereas bud primordia were differentiated from the meristomoids on the medimn with 2 mg/l BA. The buds were developed from both the superficial meristemoids and the meristematic regions deep within the callused leaf explants. The accumulated starch in the cells gradually disappeared as bud formation proceeded.     

杉木再生系统的比较研究

通过对杉木(Cunninghamia lanceolata Hook)再生系统的比较研究,建立了子叶、下胚轴、茎段和针叶等四个再生体系。子叶在附含1mg/L BA和0.1mg/L NAA的DCR培养基中再生频率为93.7%±0.45%,平均芽数为3.76±0.25;下胚轴在附含2mg/L BA和0.2mg/L NAA的DCR培养基中再生频率为96.2%±0.35%,平均芽数为17.4±0.18;茎段在附含1mg/L BA和0.1mg/L NAA的DCR培养基中再生频率达100%,平均芽数为3.28±0.11;针叶在附含1.5mg/L BA和0.1mg/L NAA的DCR培养基中再生频率达84.5%±0.45%,平均芽数仅为1.42±0.08。不定芽在附含0.2mg/L BA和0.02mg/L NAA的DCR培养基中有效伸长。芽苗经预处理后在附含0.3mg/L IBA的1/2 DCR培养基中生根效果最佳。     

Histological study of in vitro development of adventitious buds on leaf explants of oriental beech (Fagus orientalis lipsky)

Summary Adventitious shoots were induced on the proximal portion of leaves excised from Fagus orientalis shoot cultures derived from a 2-mo.-old or a 4-yr-old seedling. Up to 90% of the explants formed between 13 and 19 buds after culture on Woody Plant Medium containing 2.9 μM indole-3-acetic acid and 4.5 μM thidiazuron. Adventitious buds developed mostly on petiole stub callus, but also on the midvein. The histological events leading to shoot organogenesis were examined. Some shoots developed directly from subepidermis or epidermis, but most originated indirectly from cell file proliferation produced by periclinally dividing cells subadjacent to the epidermis. Some cells in the outermost layers of these files became meristematic and divided extensively, resulting in the formation of meristemoids after 16 d of culture. Dedifferentiation into meristematic cells, which exhibited a large, prominent nucleus, densely-stained cytoplasm, and a high nucleus-to-cell area ratio, was generally associated with anticlinal divisions in cells previously originated by periclinal division. Subepidermal cell proliferation occurred mainly in the abaxial surface of the explant, which initially formed a diffuse cambium and later evolved to a phellogenic cambium. Some meristemoids were also differentiated by lenticel phellogen. Organized cell divisions in meristemoids gave rise to bud primordia that emerged from the explant surface and differentiated a protoderm. The progressive structural differentiation of the apical meristem, leaf primordia, and procambial strands led, after about 28 d of culture, to shoots with vascular connections with treachery elements previously differentiated in adjacent tissues.     

Anatomical and ultrastructural analyses of in vitro organogenesis from root explants of commercial passion fruit (Passiflora edulis Sims)

This study aimed to characterize the anatomical events and ultrastructural aspects of direct and indirect in vitro organogenesis in Passiflora edulis. Root explants were cultured on induction medium, supplemented with 4.44 μM 6-benzyladenine. Roots at different stages of development were collected and processed for observation by light microscopy and scanning and transmission electron microscopy. Patterns of direct and indirect regeneration were observed in the explants. During direct organogenesis, the organogenic buds and nodules, formed from meristemoids, originated from the pericycle regions distant from the cut surface. Completely differentiated buds were observed after 20 days of culture. During indirect organogenesis, bud formation occurred via meristemoids at the periphery of the calli, which differentiated from the cortical region of the initial explant. Regardless of the regeneration pattern, the meristemoids had similar ultrastructural characteristics; however, differences were reported in the nuclear shape of the cells of the meristemoids formed directly and indirectly. This study provides important information for enhancing the understanding and characterization of the organogenic process in non-meristematic explants and provides information on the use of roots as explants in genetic transformation protocols for this important tropical species.     

Source, etiolation and orientation of explants affect in vitro regeneration of Venus fly-trap (Dionaea muscipula)

In vitro culture of Venus fly-trap (Dionaea muscipula) was initiated using flower stalk explants. Activated charcoal was required for bud initiation, but omitted in the subculture of regenerated plantlets. Regenerated plants were subsequently used as explant source for investigations concerning effects of source of tissue, etiolation, orientation and illumination of leaf explants on plant regeneration. Etiolation of source plantlets increased the rate of regeneration from explants and decreased explant failure. Generally, adventitious buds developed at the adaxial side and proximal end of an explant. However, when explants were incubated in the dark, 20–30% of bud initiation occurred at the distal end. The site of shoot regeneration on a leaf explant was affected by both illumination and orientation of explants. Placing an explant adaxial side up resulted in the highest rate of regeneration. The most effective condition for plantlet regeneration was found with etiolated petioles incubated with the adaxial side facing the light. Received: 18 March 1998 / Revision received: 12 August 1998 / Accepted: 7 September 1998