金线莲种子培养的研究

金线莲种子在培养基1/2MS 6-BAl.0 mg/L NAA1.0 mg/L上萌发后形成原球茎,原球茎可以直接发育成幼苗,也可以由原球茎产生愈伤组织,再由愈伤组织发育成类原球茎而分化成幼苗.通过类原球茎可以实现大量增殖,在Ms 6-BA1.0 mg/L NAA0.1 mg/L上培养60 d的增殖倍数达到6.7倍.在培养基MS IBA0.3mg/L上,金线莲的生根率可达到96.0%.     

金线莲种子培养的研究

金线莲种子在培养基1／2MS＋6-BA1．0mg／L＋NAA1．0mg／L上萌发后形成原球茎,原球茎可以直接发育成幼苗,也可以由原球茎产生愈伤组织,再由愈伤组织发育成类原球茎而分化成幼苗。通过类原球茎可以实现大量增殖,在MS＋6-BA1．0mg／L＋NAA0．1mg／L上培养60d的增殖倍数达到6．7倍。在培养基MS＋IBA0．3mg／L上,金线莲的生根率可达到96．0％。     

白芨胚发育与种子萌发的关系

随着白芨胚龄增大,胚成熟度不断增加,有胚率和萌发率逐渐提高,种子萌发时间逐渐变短。胚龄为20周后采收最好,有胚率最高,萌发率为100%,萌发时间只需1周。种子萌发时胚先发育成原球茎,原球茎再分化出叶片和根系,形成完整的小植株;花宝一号1g/L+花宝二号2g/L+10%椰子汁培养基可促进种子萌发及幼苗生长,比常用的基本培养基加生长调节剂更简捷,幼苗生长健壮。     

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。     

油橄榄(Olea europaea L.)组织培养的细胞组织学研究 Ⅱ.组织分化和器官发生

油橄榄愈伤组织转入分化培养基进行继代培养后,在它外围部分的局部表面可以由愈伤形成层发生周皮。同时在它内部有星散的管胞和维管束分化,这些维管组织并不构成维管系统,与器官发生无任何联系。此外,愈伤组织内有由薄壁细胞不规则地发生胚性细胞,它具有分生细胞的性质,以它不同的细胞分裂形式,产生两种分生组织的结构,即分生细胞团和分生组织结节。分生组织结节形成生长中心而无任何分化,但可分化为维管组织结节,它有以形成层状细胞围绕着许多管胞的结构,在它具有单向极性时,从它发育成根原基,而芽原基则由愈伤组织近表面的分生细胞团分化形成。并初步观察到在愈伤组织中有再次胱分化的过程。对维管组织结节在构造上的差异和根与芽的起源问题,根据观察结果作了简要的讨论。     

茴香组织培养中体细胞胚胎发生的组织细胞学研究

将茴香幼茎或叶柄的愈伤组织转入附加6-BA和低浓度2,4-D的MS培养基以后,愈伤组织逐步由松软状转变成为颗粒状的胚性愈伤组织,胚状体起源于胚性愈伤组织中的单个细胞或胚性细胞团。在含NAA和6-BA的培养基中,胚状体发育成熟,并再生小植株。茴香的胚状体主要以单细胞内起源方式发生。首先由胚状体单个原始细胞分裂形成2-细胞原胚,2-细胞原胚以三种方式进行分裂:1.T- 形分裂;2.直线形分裂;3.田字形分裂。不同的分裂方式决定了胚柄的有无。茴香胚状体的发育过程与合子胚基本相同。由原胚发育成为球形胚,依次经过心形胚和鱼雷胚阶段,形成成熟的子叶胚。在胚状体发育的每一个阶段,都有其分生组织的活动中心。球形胚期,两团分生组织位于胚体中部对应的两点;心形胚期,位于两侧和中部;鱼雷胚期,分生组织的分布在子叶形成区域呈倒“U”形,在下胚轴部位呈中空的梭形。到子叶期,分生组织从两片子叶伸向胚根,呈“Y”形分布。两子叶间产生茎生长点,由生长点分化出叶原基。胚状体最终发育成为完整植株。     

小麦组织培养中体细胞胚胎发生的细胞胚胎学及淀粉消长动态的研究

小麦幼胚在附加2,4-D 2 mg/L+KT0.5 mg/L+LH 300 mg/L+3%蔗糖的MS 培养基上诱导出愈伤组织,继代2—3次后,降低2,4-D 的浓度,该愈伤组织约以60%的频率转变为胚性愈伤组织,继而形成不同发育期的体细胞胚。这些体细胞胚是起源于愈伤组织表层或近表层的单个胚性细胞,体细胞胚经球形胚、梨形胚、盾片胚、成熟胚而成再生植株。在胚性细胞内淀粉粒大最积累,淀粉颗粒大而密集。随着胚性细胞的分裂,淀粉逐渐被消耗,到多细胞原胚期,胚体细胞内淀粉粒趋于消失。球形胚期淀粉粒又开始积累,但到成熟胚期,淀粉积累只限于生长点区域,尔后随着胚体萌发,淀粉含量又趋于减少。这一消长动态过程与小麦合子胚发生中淀粉代谢动态基本一致。     

文冠果的体细胞胚胎发生

文冠果种子在MS 6-BA 1.0 mg·L-1 2,4-D 1.0 mg·L-1 NAA 1.0 mg·L-1 3%蔗糖的固体培养基上暗培养,形成愈伤组织,愈伤组织在B5 6-BA0.5mg·L-1 NAA0.5mg·L-1 2%蔗糖的培养基中弱光悬浮培养形成体细胞胚.在蔗糖为1%时,子叶状胚萌发形成完整小植株.细胞学观察表明,文冠果体细胞胚源于胚性愈伤组织的外层细胞,此区域细胞富含淀粉粒.     

NaCl胁迫对豫棉112种子萌发,幼苗生长及愈伤组织产生的影响

系统研究了ＮａＣｌ胁迫对豫棉１１２种子萌发,幼苗生长和不同外植体愈伤组织形成的影响。结果表明：ＮａＣｌ对种子萌发,幼苗生长有抑制作用,浓度愈高,抑制作用愈显著;低浓度ＮａＣｌ对子叶,胚轴愈伤组织诱导率没有影响,浓度升高,诱导率明显下降。     

天麻种子与兰小菇共生萌发过程中超微结构变化研究

天麻Ｇａｓｔｒｏｄｉａｅｌａｔａ种子与兰小菇Ｍｙｃｅｎａｏｒｃｈｉｄｉｃｏｌａ的共生萌发试验表明兰小菇可与天麻种子共生促进天麻种子萌发并形成原球茎。菌丝自胚柄端的柄状细胞侵入天麻种子原胚,其分布被限制在天麻原球茎基部的柄状细胞、外皮层细胞和内皮层细胞内,均被电子透明物质和原球茎细胞质膜包围而与原球茎细胞质相隔离。菌丝在外皮层细胞中形成菌丝结,在内皮层细胞中则被消化,形成扁化、衰败的菌丝或菌丝四块。含有衰败菌丝的原球茎细胞可被菌丝重新定殖,新近定殖的菌丝又被原球茎细胞消化。     

Regulation of starch and protein accumulation in alfalfa (Medicago sativa L.) somatic embryos

Compared to seeds, somatic embryos accumulated relatively low levels and different types of storage carbohydrates. The regulation of starch accumulation was studied to determine its effects on desiccation tolerance and vigor of dry somatic embryos. Somatic embryos of Medicago sativa are routinely matured through three phases: 7 days of development; 10 days of phase I maturation, a rapid growth phase; and 10 days of phase II maturation, a phase leading to the acquisition of desiccation tolerance. The control of starch deposition was investigated in alfalfa somatic embryos by manipulating the composition of the phase I maturation medium with different levels of sucrose, abscisic acid, glutamine and different types of carbohydrates and amino acids. After phase II maturation, mature somatic embryos were collected for desiccation and subsequent conversion, or for biochemical analyses. Starch deposition occurred primarily during phase I maturation, and variations in the composition of this medium influenced embryo quality, storage protein and starch accumulation. A factorial experiment with two levels of glutamine × three levels of sucrose showed that increasing the sucrose concentration from 30 to 80 g/l increased embryo size and starch content, but had minimal effect on accumulation of storage proteins; glutamine also increased embryo size, but decreased starch content and increased accumulation of the high salt soluble S-2 (medicagin) storage proteins. ABA did not influence any of the parameters tested when included in phase I maturation at concentration up to 10 μM. Replicating sucrose with maltose, glucose, or glucose and fructose did not alter embryo size or starch accumulation (mg/g fresh weight), but replacement with fructose alone reduced embryo size, and replacement with glucose alone reduced germination. Suplementation with the amino acids, asparagine, aspartic acid and glutamine increased seedling vigor, but decreased the starch content of embryos. The data indicate that starch accumulation in somatic embryos is regulated by the relative availability of carbon versus nitrogen nutrients in the maturation medium. The quality of mature somatic embryos, determined by the rate of seedling development (conversion and vigor), correlated with embryo size, storage protein and free amino acid but not with starch. Therefore, further improvements in the quality of somatic embryo may be achieved through manipulation of the maturation medium in order to increase storage protein, but not starch deposition.     

高粱体胚发生的组织细胞学观察

以Sb33高粱非胚性、胚性愈伤组织和体胚为材料,用传统石蜡切片法对各组织材料进行组织化学染色,对高粱胚性与非胚性愈伤组织以及体胚进行组织细胞学观察。结果表明：高粱非胚性愈伤组织无淀粉粒积累,高粱胚性愈伤组织淀粉粒积累较多,而与胚性愈伤组织相比,高粱体胚淀粉粒积累更多,这说明淀粉粒的积累与高粱体细胞的胚胎发生密切相关。此外,高粱可通过鱼雷胚基部产生球形胚的方式实现体胚的增殖,高粱离体再生途径以体细胞胚发生为主,并同时存在少量器官发生途径。在高粱体细胞胚胎发生中,外起源和内起源同时存在。本研究为高粱体细胞胚胎发生提供细胞学理论基础。     

a—吡啶羧酸和致病毒素对水稻离体培养与幼苗生长的影响

比较了a—吡啶羧酸和稻瘟病菌粗毒素滤液对水稻种胚离体培养和幼苗生长的影响。结果表明,a—吡啶羧酸处理水稻种胚,其发芽率与愈伤组织诱导率明显降低,随a—吡啶羧酸处理浓度的提高,有逐步下降的趋势,感病品种(系)较抗病品种(系)更为敏感。a—吡啶羧酸处理不同抗病类型水稻的萌动种子,幼苗生长受到明显抑制,受抑制程度与处理浓度和品种感病性呈正相关。a—吡啶羧酸和病原菌粗毒素对水稻种胚离体培养与幼苗生长的影响基本一致。     

胚乳和蔗糖对大麦成熟胚无菌苗生长和叶片切段愈伤组织诱导及分化的影响

大麦无菌苗的苗高。苗干重和单位长度、叶片切段的干重均依胚培养时所带胚乳的增多而递增。但叶片切段培养时的愈伤组织诱导率和再分化率并不与胚乳多少正相关。成熟胚培养时蔗糖的供应明显影响叶片切段培养时的愈伤组织诱导率。培养带1/2胚乳的胚,用萌发率高的新鲜种子培养无菌苗时,以不供给蔗糖的有较高的叶段愈伤组织诱导率,用萌发率显著降低的陈种子时,则以育苗时供给6％蔗糖为好。     

Embryo rescue and plant regeneration in banana (<Emphasis Type="Italic">Musa</Emphasis> spp.)

An efficient regeneration protocol for zygotic embryos at varying maturity stages was developed for wild banana (Pisang Jajee (AA)). Embryo ontogeny was studied to determine the best maturity stage for embryo rescue, suitable media and culture conditions (light and dark) for germination and regeneration. The conversion of endosperm from transparent fluid into a semi-solid state was followed by visible embryo development, which commenced only after 70% embryo maturity. Zygotic embryos of Pisang Jajee at different maturity levels were excised and cultured on medium fortified with different concentrations of 6-benzyl adenine (BA) and indole acetic acid (IAA). Zygotic embryos produced callus or plantlets 25 days after initiation. The frequency of callus induction was greater in immature embryos irrespective of the media composition and decreased with increasing maturity. Fully matured embryos regenerated directly into plantlets without producing callus. Immature embryos required medium supplemented with plant growth regulators (PGRs) for successful regeneration. Although the culture conditions had no influence, dark conditions favoured callus induction and plant regeneration.     

Starch deposition and amylase accumulation during somatic embryogenesis in bamboo (Dendrocalamus hamiltonii)

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.     

ULTRASTRUCTURE OF NON-ARTICULATED LATICIFERS IN MATURE EMBRYOS AND SEEDLINGS OF ASCLEPIAS SYRIACA L. (ASCLEPIADACEAE)

The protoplast of the non-articulated branched laticifer in the embryo and seedling of Asclepias syriaca L. was studied at the ultrastructural level and was found to differ from that of adjacent cell types. Embryonal laticifers possess numerous vesicles with electron-dense contents, but lack a large organized central vacuole. Plastids have few lamellae, possess phytoferritin, and accumulate small amounts of starch. Other organelles and membrane systems are similar to those in other cells. After germination, laticifers develop numerous elongated vacuoles by dilation of endoplasmic reticulum. Nuclei in laticifers within the hypocotyl of seedlings are highly lobed and possess dilated perinuclear spaces. Plastids and other organelles are similar to those observed in the protoplast of laticifers in the embryo. The latex or rubber component of the laticifer is not apparent in mature embryos of 72-hr seedlings.     

Patterns of storage protein and triacylglycerol accumulation during loblolly pine somatic embryo maturation

Conifer somatic embryo germination and early seedling growth are fundamentally different than in their zygotic counterparts in that the living maternal megagametophyte tissue surrounding the embryo is absent. The megagametophyte contains the majority of the seed storage reserves in loblolly pine and the lack of the megagametophyte tissue poses a significant challenge to somatic embryo germination and growth. We investigated the differences in seed storage reserves between loblolly pine mature zygotic embryos and somatic embryos that were capable of germination and early seedling growth. Somatic embryos utilized in this study contained significantly lower levels of triacylglycerol and higher levels of storage proteins relative to zygotic embryos. A shift in the ratio of soluble to insoluble protein present was also observed. Mature zygotic embryos had roughly a 3:2 ratio of soluble to insoluble protein whereas the somatic embryos contained over 5-fold more soluble protein compared to insoluble protein. This indicates that the somatic embryos are not only producing more protein overall, but that this protein is biased more heavily towards soluble protein, indicating possible differences in metabolic activity at the time of desiccation.     

Somatic embryogenesis from callus cultures of <Emphasis Type="Italic">Terminalia chebula</Emphasis> Retz.: an important medicinal tree

Somatic embryogenesis was obtained from cotyledon and mature zygotic embryo callus cultures of Terminalia chebula Retz. Callus cultures of cotyledon and mature zygotic embryo were initiated on induction medium containing Murashige and Skoog (MS) nutrients with 1.0 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D) either 0.01 or 0.1 mg/l Kinetin and 30 g/l sucrose. Induction of somatic embryogenesis, proliferation and development was obtained through different culture passages. Embryogenic cotyledon callus with globular somatic embryos was obtained on MS basal medium supplemented with 50 g/l sucrose. Globular somatic embryos were observed from mature zygotic embryo callus on induction medium. Different stages of somatic embryo development from cotyledon and mature zygotic embryo calluses were observed on MS basal medium supplemented with 50 g/l sucrose after 4 weeks of culture. Histological studies have revealed the developmental stages of somatic embryos. A maximum of 40.3±1.45 cotyledonary somatic embryos/callus was obtained from mature zygotic embryo compared to 7.70±0.37 cotyledonary somatic embryos/callus initiated from cotyledons. Germination of somatic embryos and conversion to plants were achieved. Highest frequency of germination (46.66±0.88) of somatic embryos was obtained on MS basal medium containing benzyladenine (0.5 mg/l) with 30 g/l sucrose.