影响香根草体细胞胚胎发生和植株再生因素初探

为了探索提高香根草(Vetiveriazizanioides)遗传种质改良效率的有效途径,初步研究了影响香根草体细胞胚胎发生和植株再生的若干因素。以MS培养基为基本培养基,附加不同配比的生长素和细胞分裂素,对香根草的腋芽及无菌不定芽进行离体培养。结果表明,2,4-D是诱导体细胞胚胎发生的关键因素,当培养基中只含2,4-D而不含或少含细胞分裂素(6-BA)时,外植体经由体细胞胚胎发生途径形成再生植株。愈伤组织诱导频率在有的品种之间差异显著,最高的达到96.7%(cv.Zomba),最低的不到30%(cv.Malaysia);而有的品种之间差异不显著(例如cv.Kandy和cv.Sunshine)。胚性愈伤组织的再生能力可以长期保持,从未经继代培养的到持续继代第23代的胚性愈伤组织,再生频率都在80%以上,而且再生植株的生长良好。在3-7℃的低温下进行分化培养时,仍然有40.5%-50.0%不同世代的胚性愈伤组织还保持着再生能力。     

几种生长素对木薯体细胞胚发生和植株再生的作用

木薯（ＭａｎｉｈｏｔｅｓｃｕｌｅｎｔａＣｒａｎｔｚ）嫩叶外植体在含２,４－Ｄ（１－１６ｍｇＬ－１）或ＮＡＡ（４０ｍｇＬ－１）的诱导培养基上能直接诱导初生体细胞胚胎发生,而低活性的生长素ＩＢＡ或ＩＡＡ（４０ｍｇＬ－１）或低浓度的２,４－Ｄ（０．１ｍｇＬ－１）则不能。而以木薯初生体细胞胚切段为外植体时,次生体细胞胚的诱导对生长素的活性或浓度的要求降低。降低生长素浓度或活性能缩短体细胞胚诱导时间并促进根的形成,有利于提高体细胞胚的再生频率。体细胞胚外植体在诱导培养基上的培养时间对下一步体细胞胚胎发生的诱导产生影响。通过石腊切片观察,在含２,４－Ｄ诱导培养基上,木薯体细胞胚不能形成芽分生组织。结果表明,２,４－Ｄ等生长素类物质对诱导木薯体细胞胚胎发生是关键因子,但对体细胞胚的进一步发育和植株再生起抑制作用。     

金花茶子叶在离体培养中胚状体的发生和小植株的形成

研究了金花茶(Camellia chrysantha(Hu)Tuyama)子叶在离体培养中体细胞胚状体发生的条件。在MS基本培养基中附加苄基嘌呤(BA)或苄基嘌呤与萘乙酸(NAA)组合,诱导了胚状体发生。组织学观察表明,胚状体起源于子叶的表皮细胞。在增添细胞分裂素和生长素的MS或改良B_5液体培养基里振荡培养,明显地促进了胚状体根的生长和茎的发育。胚状体在继代培养中能保持旺盛的再生能力。已得到两个繁殖率较高的胚状体无性系。在合适的条件下,胚状体能长成正常的小植株。     

组织与原生质体培养

921834木夏体细胞胚胎发生〔会,英刀Barve,D。M.…广In Vitro一1992,2了(3),Pt.2。一i4iA巨译自DBA,1991,10(16),91一09291〕 利用大量木豆(Ca了a,us caja幻基因型子叶培养物获得了体细胞胚胎发生。此体细胞胚形成取决于特定的细胞分裂素和矿物营养浓度。在高浓度细胞分裂素培养基上,分离子叶的远端迅速膨胀、变绿、体细胞胚胎发生。低浓度细胞分裂素有利于胚状体成熟。不用细胞分裂素而加少量植物生长素时有效地诱导了体细胞胚萌发。用此法可获得高度胚胎发生,故可用之产生抗病无性系。(李思经)921台3弓再生菠莱植株的雌雄性变化〔会,…     

香根草不同处植体诿导体细胞胚胎发生和器官发生

以禾本科植物香根草（Ｖｅｔｉｖｅｒｉａ ｚｉｚａｎｉｏｉｄｅｓ）的嫩叶鞘基部切段为外植体,再取其试管苗的基部切段诱导体细胞胚胎发生和芽的器官发生。结果表明生长素是诱导外植体脱分化和形成体细胞胚的关键因子,而芽的形成则源于体细胞胚的萌发,它们是由ＮＡＡ或低浓度的２,４－Ｄ所诱导的。通过研究建立了有效的香根草循环诱导再生体系和试管苗繁殖体系,为进一步研究香根草的生物技术奠定了良好的基础。     

蔷薇科植物体细胞胚胎发生及影响因素研究进展

总结了近30年来蔷薇科植物体细胞胚胎发生及影响因素的研究进展。蔷薇科植物体胚发生多数是直接发生途径和间接发生途径同时存在,但以间接发生途径为主。合子胚作为外植体明显好于营养器官作为外植体。诱导体胚发生的植物生长素类调节剂以NAA、2,4-D为主,细胞分裂素类调节剂以6-BA为主,少数植物种类的体胚诱导需要添加KT。冷处理对蔷薇科植物的体胚分化有效。光照对蔷薇科植物的体胚发生没有显著的影响,有时光照会抑制体胚发生。今后应逐步开展对蔷薇科植物体细胞胚胎发生的生理、生化及分子机理的研究,这在蔷薇科植物的新品种培育、遗传改良、优良单株的离体扩殖等具有重要意义。     

植物的微体繁殖

植物微体繁殖是植物在离体的条件下,以其组织、器官或细胞作为外植体,在一定的培养基中和培养条件下,经过形态发生的不同时期与细胞的生长、发育和分化,形成再生植株的过程。1902年哈布兰特(Haberlandt)提出植物细胞全能性理论,1958年斯蒂沃德(Steward)从胡萝卜根的悬浮细胞诱导分化,形成完整的再生小植株,首次证实了细胞全能性,至今,植     

芸芥体细胞胚胎发生及植株再生体系的建立

以芸芥子叶为外植体,诱导芸芥体细胞胚胎发生并建立植株再生体系.结果表明:基因型及植物生长调节剂对芸芥体细胞胚胎发生均有一定的影响,其中以含有1.0mg·L-12,4-D的MS培养基诱导芸芥体细胞胚胎发生的效果最优.在MS 0.2mg·L-12,4-D培养基上,胚性愈伤组织可大量增殖.对芸芥体细胞胚胎成熟的研究表明,体胚在N6培养基上成熟最佳,且45.2%的成熟体胚可在1/2MS 0.1mg·L-1IBA培养基上萌发生长.     

糜子离体体细胞胚胎发生的组织学研究

利用组织学连续石腊切片的研究方法,观察了糜子组织培养中植株再生的过程,从而证明了植株再生是通过体细胞胚胎发生途径的。结果表明:(1) 糜子成熟胚培养首先从下胚轴及胚根区愈伤组织化;(2) 体细胞胚起源于下胚轴及胚根维管束周围愈伤组织中单个离散的胚性细胞;(3) 糜子离体体细胞胚有与典型禾谷类作物合子胚大致相似的发育过程。     

禾谷类作物细胞培养：体细胞胚性潜力的诱导与表达

体细胞胚胎发生已成为禾谷类作物细胞培养研究中的一个重要方面。本文参照近几年来发表的主要文献并结合本实验室的研究工作,对禾谷类作物的体细胞胚胎发生做了综合评述。就培养基,植物激素,氮源,渗透压,外植体来源及发育时期,起始材料的状态,培养时间等各种因素对禾谷类作物胚性愈伤组织的诱导和保持,胚性悬浮细胞系的建立以及体细胞胚胎发生与植株再生的影响进行了分析。并对长期继代培养物再生能力丧失（或胚性潜力难以充     

Influence relative de la BAP et de l'IBA sur la néoformation de bourgeons et de racines sur les plantules du Biota orientalis (Cupressacées)

Relative influence of BAP and IBA on the induction of adventitious buds and roots on plantelts of Biota orientalis (Cupressaceae)
Both cytokinin (BAP) and auxin (IBA) have an influence upon the intensity of adventitious bud induction in vitro on hypocotyls of Biota orientalis .
Increase in either the concentration or the length of contact with cytokinin enhances the mean number of neoformed buds per explant, while that of auxin results in an increase of the mean number of reactive explants as well as in the nature of neoformations. Auxin contributes to a restoration of the induction when the length of contact with cytokinin is too short. However, this synergism is only observed when the contract with IBA is simultaneous or follows that with contract with BAP.
Rhizogenesis is also influenced by the auxin-cytokinin balance. An increase in the duration of contact with IBA is always followed by an increased in the mean number of explants forming roots. This organogenesis may be partially or completely inhibited if the duration of contact with cytokinin – before, simultaneously or after that with auxin- exceeds two weeks.     

Culture of Mesophyll Protoplasts and Stem Segments of Antirrhinum majus (Snapdragon): Growth and Organization of Embryoids

Protoplasts isolated enzymatically from the leaves of Antirrhinummajus L. were cultured on a synthetic medium and their growthand development were followed in vitro. Cultured protoplastsincreased in size, regenerated cell walls, divided and formedsmall colonies and embryoids. Cell wall formation and cell divisionrequired both auxin and cytokinin in the medium. Isolated stemsegments of the same species, when cu1tured on a synthetic mediumwith an added auxin, yielded rapidly growing callus tissuesin which differentiation of embryoids occurred.     

Isolation of <Emphasis Type="Italic">HAG1</Emphasis> and its regulation by plant hormones during in vitro floral organogenesis in <Emphasis Type="Italic">Hyacinthus orientalis</Emphasis> L.

Floral organs have been successfully induced from the regenerated floral buds of Hyacinthus orientalis L. by precisely controlling exogenous hormones in the medium. Under high concentrations of cytokinin and auxin, the regenerated floral bud produces only tepals. However, at reduced levels of the hormones, the regenerated floral bud can produce stamens and/or carpels with ovules. To understand the molecular mechanism of hormone-regulated flower development, a MADS-box gene, HAG1, which is homologous to AGAMOUS (AG) in Arabidopsis, was isolated from the floral tissues of Hyacinthus. Overexpression of HAG1 in Arabidopsis created flower phenotypes resembling those of the apetala2 mutant and AG transgenic Arabidopsis plants. Furthermore, the HAG1 expression pattern was similar to that of AG, confirming that HAG1 is the ortholog of AG in Hyacinthus. HAG1 mRNA was first detected in cultured explants at day 5 in the medium containing high levels of cytokinin and auxin, which could induce floral regeneration in vitro. However, no HAG1 mRNA was detected in the cultured explants until day 10 in media with low or no hormones. Further, HAG1 mRNA was detected in the stamens and carpels of regenerated floral buds, but not in the tepals. Our data support the hypothesis that hormone-regulated HAG1 activity is required for the induction of floral buds and the determination of floral organ types during the regeneration of floral buds.     

Plant regeneration from shoot tips and callus of papaya

Summary Two methods of in vitro culture were employed to regenerate papaya plants. One involved regeneration of plants from callus and the other, production of multiple plants from single shoot-tip explants. Callus was induced from stem sections of papaya seedlings in a medium containing 1 mg per 1 NAA and 0.1 mg per 1 kinetin. The callus regenerated shoots and/or embryoids when transferred to a medium of lower auxin, 0 to 0.05 mg per 1 IAA, and higher cytokinin, 1 to 2 mg per 1 kinetin Multiple shoots were produced when the excised shoot-tip explants were cultured in a medium supplemented with 0.05 mg per 1 IAA and either 5 mg per 1 kinetin or 0.5 to 1.0 mg per 1 benzyladenine. Root formation of the shoots or embryoids that derived from callus or shoot tips occurred in a medium containing 5 mg per 1 IAA and in a light intensity of 3000 to 4000 Ix. The rooted plants could be established in soil and under standard greenhouse conditions after they had been acclimated by initially growing them in moist vermiculite contained in polyethylene-covered pots. This research was supported by the National Science Council, Republic of China.     

In vitro propagation and cryopreservation of Romanian endemic and rare Hypericum species

Efficient micropropagation and cryopreservation of Hypericum richeri ssp. transsilvanicum, an endemic species in Romania, and Hypericum umbellatum, a rare and endangered Daco-Balkan species, was achieved. The effects of type of explant and cytokinin on in vitro plant regeneration were investigated. Shoot organogenesis was achieved in all explants, but stem nodes regenerated best. Organogenesis from nodal segments was promoted by incubating these explants on Murashige and Skoog (MS) medium in the presence of cytokinins (6-benzyladenine, thidiazuron, kinetin or 6-??,??-dimethylallylaminopurine), each tested at four concentrations. The best morphogenic response for both Hypericum species (number of shoots per explant, shoot length, axillary branching of shoot, and frequency of shoot organogenesis) was observed when explants were incubated on MS medium containing 0.44 or 1.11???M 6-benzyladenine. Root induction was achieved only when regenerated shoots were transferred to fresh medium with or without auxin. Maximum rooting was recorded on MS medium supplemented with 2.45???M indole-3-butyric acid. Plantlets grown in vitro were successfully acclimatized in the greenhouse and showed normal development. Shoot tips and axillary buds excised from the in vitro regenerated plants were successfully cryopreserved in liquid nitrogen by the droplet-vitrification method. Following preculture in 0.25?M sucrose, dehydration and cryopreservation, the highest regeneration rates were obtained in both species by using axillary buds (68?% for H. richeri ssp. transsilvanicum and 71?% for H. umbellatum).     

Micropropagation ofLarix decidua Mill. andpinus sylvestris L.

Shoot multiplication of Larixdecidua was achieved using axillary and adventitious buds. The formation of axillary buds was stimulated on shoot tips soaked in a cytokinin solution (BAP 10-50 mg 1⁻¹ for 2–4 h. Adventitious buds were induced on cotyledons, needles and vegetative buds cultured on WPM or QL medium supplemented with cytokinin (BAP 1–3 mg 1⁻¹). The shoot formation from induced axillary and adventitious buds was promoted on WPM or QL medium containing a low concentration of auxin (IBA 0.1 mg 1⁻¹). Shoot multiplication of Pinussylvestris was stimulated on WPM, MS, and QL media supplemented with a low concentration of cytokinin (BAP 0.2 mg 1⁻¹) and auxin (IBA 0.1 mg 1⁻¹). Shoot segments produced 2–5 new axillary shoots within 4–5 weeks. Root initiation was stimulated on larch and pine shoots cultured first on WPM supplemented with auxins (NAA and IBA) and later transferred to auxin-free medium.     

TDZ诱导花生幼叶的不定芽和体细胞胚发生的组织学观察

花生实生苗幼叶接种于MS TDZ 0.2mg/L NAA0.4mg/L诱导培养基上经诱导培养,继而转移到无激素培养基MS可获得不定芽和体细胞胚。组织学观察表明,花生不定芽和体细胞胚均起源于愈伤组织表层,不定芽为多细胞起源,而体细胞胚起源于单个胚性原始细胞。体细胞胚的发育经历多细胞原胚、球形胚、心形胚、鱼雷胚和子叶胚等时期发育成小植株。     

The influence of thidiazuron on shoot regeneration from leaf explants of fifteen cultivars of Rhododendron

The influence of cytokinin thidiazuron (TDZ) and auxin indole-3-acetic acid (IAA) on in vitro shoot organogenesis of fifteen Rhododendron genotypes was investigated and a protocol for high frequency adventitious shoot regeneration from leaf explants was developed. High genotypic variation was observed and regeneration frequencies ranged from 0 to 100 %. Genotype Ovation had the highest number of shoots (26.4 per explant) after 12 weeks on medium with 0.57 μM IAA and 1.20 μM TDZ, but only 65 % of explants regenerated. Catawbiense Grandiflorum had 17.7 shoots per explant and 75 % regeneration on medium with 5.70 μM IAA and 0.45 μM TDZ and Van Werden Poelman had 14.3 shoots per explant and 100 % regeneration on medium with 0 57 μM IAA and 0.45 μM TDZ.     

Influence of growth regulators on plant regeneration from epicotyl and hypocotyl cultures of two groundnut (Arachis hypogaea L.) cultivars

This study was designed to evaluate the effect of phytohormones on plant regeneration from epicotyl and hypocotyl explants of two groundnut (Arachis hypogaea) cultivars. Explants cultured on media with auxins and in combination with cytokinin produced high frequency of callus. After four weeks, callus from these cultures was transferred to medium with cytokinin and reduced auxin, shoot buds regenerated from the cultures. A high rate of shoot bud regeneration was observed on medium supplemented with 2.0 mg/L BAP and 0.5 mg/L NAA. Among the different auxins tested, NAA was found to be most effective, producing the highest frequency of shoot buds per responding cultures. Of the two explants tested, epicotyl was found to be best for high frequency shoot bud regeneration. Multiple shoots arose on MS medium supplemented with BAP or kinetin (1.0–5.0 mg/L) plus IBA (1.0 mg/L), with maximum production occurring at 5.0 mg/L. The elongated shoots developed rootsin vitro upon transfer to MS medium supplemented with NAA or IBA (0.5–2.0 mg/L) and kinetin (0.5 mg/L) for 15 days.In vitro produced plantlets, were transferred to soil and placed in a glasshouse developed successfully, matured, and set seeds.     

大果良种沙棘愈伤组织诱导及植株再生的研究

大果良种沙棘的幼嫩茎尖,茎段外植体接种在MS,1／2MS附加不同浓度配比的IAA,IBA,BA,NAA培养基上可诱导茎尖及腋芽生长,将诱导产生的无性系芽接种在MS或1／2MS附加BA0．3－0．5mg/L,NAA0．05mg/L的培养基上可形成丛生芽,同时在小叶片和嫩茎上诱导产生愈伤组织,继续培养愈伤组织表面形成大量的绿色突起,进一步分化成不定芽,在相同培养基上,不定芽上可直接产生不定芽,从而形成多达数百个的不定芽族,不定芽长至3cm时切下转至1／2MS附加IAA或IBA 0．2mg/L的培养基上可生根而形成完整 的再生植株。