安祖花组织培养及其细胞和叶绿体发育过程的电镜观察

取安祖花的幼嫩叶片在添加适当浓度植物激素的ＭＳ培养基上,诱导愈伤组织并发化出试管苗,分别取疏松型和致密型的愈伤组织以及小苗幼嫩叶片进行电镜观察。结果显示,三者在细胞超微结构上有很显著的差异;疏松型愈伤组织的细胞细胞质稀薄,液泡大,细胞器的个烽少,观察不到典型的质体或前质体;而致密型愈伤组织细胞和幼嫩叶的细胞,细胞质浓,液泡小,并可清楚地观察到叶绿体和线粒体的内部结构及其发育过程。由此可以推断,经长     

甜菊愈伤组织生长、分化与甜菊糖苷积累的关系

耐菊（Steviarebaudiana）愈伤组织中甜菊糖苷的积累与愈伤组织的生长呈负相关、与愈伤组织细胞的组织化及转绿呈正相关。愈伤组织芽的分化并不是积累较高水平甜菊糖苷的必要前提。绿色、质地致密、生长缓慢的愈伤组织,不论有芽分化或无芽分化时,其甜菊糖苷含量均较高。在电镜下观察到,这两种愈伤组织细胞具有类似的超微结构特征：细胞高度液泡化;叶绿体发育成熟,光合膜系统结构发达,基质浓厚且含有质体小球;微体具有典型的晶格结构,常与叶绿体紧密相靠。黄色、质地致密、生长缓慢的愈伤组织中甜菊糖苷含量较低,其细胞内质体富含淀粉粒,只有少量分散的片层结构,有的质体甚至完全被淀粉粒所充塞。黄色、质地疏松、生长快速的愈伤组织中甜菊糖苷含量最低,其细胞内质体结构简单,片层稀少。质体的发育和液泡的分化与甜菊糖苷的积累密切相关。愈伤组织具有较高的甜菊糖苷含量在于愈伤组织细胞的组织化以及细胞的高度液泡化并具有发育成熟的叶绿体。     

甜菊愈伤组织生化,分化与甜菊糖苷积累的关系

甜菊愈伤组织中甜菊糖苷的积累与愈伤组织的生长呈负相关、与愈伤组织细胞的组织化及转绿呈正相关。愈伤组织芽的分化并不是积累较高水平甜菊糖苷的必要前提。绿色、质地致密、生长缓慢的愈伤组织,不论有芽分化或无芽分化时,其甜菊糖苷含量均较高。在电镜下观察到,这两种愈伤组织细胞具有类似的超微结构特征：细胞高度液泡化;叶绿体发育成熟,光合膜系统结构发达,基质浓厚且含有质体小球;微体具有典型的晶格结构,常与叶绿体紧     

甜菊组织培养物中叶绿体的超微结构与脱分代

含有叶绿体的甜菊（Ｓｔｅｖｉａｒｅｂａｕｄｉａｎａ）愈伤组织细胞转移至新鲜培养基后,导致光合片层的逐渐减少或消失,最后叶绿体脱分化形成原质体样的结构。超微结构观察表明,光合片层的减少或消失与降解及叶绿体分裂特别是不均等缢缩分裂而致基质组分和类囊体膜稀释有关。这一过程并不完全同步,一些质体含有少量正常的片展而另一些质体含有退化的片层甚至片展结构完全消失。细胞的一个明显特点是细胞器大多聚集在细胞核附近,细胞质增加并向细胞中央伸出细胞质丝。同时可观察到原质体。培养７ｄ后,许多细胞呈分生状态,细胞质富含细胞器,充满了细胞的大部分空间。此时细胞中的质体大多呈原质体状态。在细胞生长的稳定期,质体内膜组织成基质基粒片层,同时质体核糖体增加。文中讨论了高度液泡化细胞脱分化与细胞中叶绿体脱分化的关系。     

甜菊叶愈伤组织诱导过程中叶绿体的超微结构变化

观察了甜菊(Stevia rebaudiana Bertoni)叶外植体愈伤组织诱导过程中叶绿体的超微结构变化。结果表明,当叶外植体转移到培养基上培养后,叶绿体的片层结构逐渐退化。在叶绿体发生退化的过程中伴有叶绿体出芽和原质体的形成。推测新产生的原质体来自叶绿体产生的芽状体。而叶绿体本身最后完全解体消失。叶绿体超微结构的这种变化与高度液泡化的叶肉细胞脱分化至分生状态是平行的。随着培养的进行,分生状态的细胞发生液泡化变为薄壁细胞时,在愈伤组织表层的细胞中,质体重新形成片层结构,而内部细胞的质体则充满淀粉粒。     

黄槐叶片培养过程中器官发生的研究

以黄槐（ＣａｓｓｉａｓｕｒａｔｔｅｎｓｉｓＢｕｒｍ．ｆ．）幼嫩叶片为材料,接种于ＭＳ＋ＮＡＡ１ｐｐｍ＋２,４－Ｄ１ｐｐｍ＋６－ＢＡ２ｐｐｍ的培养基上,诱导形成两种形态的愈伤组织,即致密愈伤组织与雪花状愈伤组织．将愈伤组织转移到ＭＳ＋ＮＡＡ：１ｐｐｍ＋６－ＢＡ２ｐｐｍ的分化培养基上．仅致密型愈伤组织经过球状体至不定芽途径形成大量再生植株。扫描电镜及组织细胞学观察表明,致密愈伤组织表层细胞排列紧密,有许多分生细胞团,而雪花状愈伤组织表层细胞薄壁化,分裂能力很低。球状体起源于致密愈伤组织表层的分生细胞团,其细胞有极强的分生能力,顶端可以分化发育成不定芽原基,最后形成不定芽并发育成小植株。球状体可以看成是具有形成不定芽能力的繁殖单位．     

甜菊组织培养物中叶绿体的超微结构与脱分化

含有叶绿体的甜菊愈伤组织细胞转移至亲鲜培养基后,导致光合片层的逐渐减少或消失,最后叶绿体脱分化形成原体样的结构。超微结构观察表明,光合片层的减少或消失与降解及叶绿体分裂特别是不均等缢缩分裂而致基质组分和类囊体膜稀释有关,这一过程并不完全同步,一些质体含有少量正常的片支厕国一些质体有退化的片层对片导全消失。细胞的一个明显特点是细胞器大多聚细胞核附近,细胞质增加并向细胞中央伸出细胞质丝,同时可观察到质     

红花组织培养中细胞分化的超微结构研究

红花子叶脱分化及愈伤组织形成的超微结构研究揭示：处于脱分化过程中的细胞代谢极其活跃。贮藏的脂类在诱导的初期即被利用,伴随细胞脱分化的同时,叶绿体了同样经历一个脱分化的过程,内膜肿胀解体,同时质体分裂或出芽增殖。转移到分化培养基后,叶绿体细胞逐渐恢复,分化成熟,处于脱分化的细胞以及愈伤组织细胞中,常可以观察到处于质膜与细胞之间的所谓壁旁体的囊泡结构,对壁旁体可能的功能以及叶绿体脱分化的原因进行了讨论     

向日葵幼叶及其培养的愈伤组织细胞的超微结构研究

通过超微结构的观察,向日葵幼叶及其经培养后10天的愈伤组织细胞之间有明显区别。叶肉细胞的细胞质、细胞器及核的结构和发育都比较完整。当外植体组织发生变化和愈伤组织形成时,观察到线粒体相互连接成链状围绕在叶绿体周围,而叶绿体有的围绕在核的周围;线粒体的嵴和基质,叶绿体的基粒和片层结构常发生退化或解体,细胞质稀薄,核糖体和胞质凝成线状或网状,微体和高尔基体消失,液泡化程度高并含有较多的次生物质;而细胞核在后期才发生明显变化,轮廓不够清晰。     

油菜叶片及其脱分化和再分化中质体的电镜观察

我们用电镜观察了油菜叶片植株再生中质体的超微结构变化。在油菜叶肉细胞中,叶绿体的基粒,基质片层发育良好,偶尔有淀粉粒。在来自叶片的愈伤组织细胞中,质体体积变小,类囊体已经消失或部分消失,有的质体含有淀粉粒,但很少有质体小球。经培养分化后的愈伤组织,特别是在表层细胞中,质体数量急剧增多,形态变化很大,贮藏淀粉明显减少。基质内已有泡状或管状结构。有的质体已出现长的基质片层,但未见到基粒;质体中常有质体球。由此可见,质体是一个十分敏感的细胞器,它的变化与细胞分化有关,变化最大的部分是片层系统,贮藏淀粉,质体小球。片层系统中尤以基粒片层变化最为显著。     

LEAF ANATOMY OF TISSUE-CULTURED LIQUIDAMBAR STYRACIFLUA (HAMAMELIDACEAE) DURING ACCLIMATIZATION

Structural changes accompanying the acclimation process were observed in leaves of sweetgum, Liquidambar styraciflua, using light and transmission electron microscopy (TEM). Comparisons were made of leaves obtained from tissue culture, plantlets acclimated after transfer from the in vitro environment to soil, and field grown trees. Leaves of cultured plantlets lacked a differentiated palisade parenchyma and had spongy parenchyma interspersed with large air spaces. Field grown leaves showed distinct palisade and spongy tissues and a high cell density. New leaves from acclimated plantlets showed an elongation of the upper mesophyll with fewer intercellular spaces than cultured plants. Cells from leaves from in vitro plantlets had large vacuoles, limited cytoplasmic content and flattened chloroplast with an irregularly arranged internal membrane system. Acclimated and field leaf cells had a greater cytoplasmic content than cultured leaves, with the former having more dominate vacuoles. Chloroplasts had evident grana. Acclimated and field leaves had a well developed cuticle unlike leaves from culture.     

Ultrastructural study of the effect of TNT on callus cells and cells of intact plants of Yucca gloriosa L.

Intracellular distribution of assimilated 2,4,6-trinitrotoluene (TNT) in callus cells, flower buds, and leaves of intact Yucca gloriosa L. plants with the use of electron microscopy radioautography was carried out. The radiotracer was detected in vacuoles, plastids, mitochondria, endoplasmic reticulum, and cytoplasm. It was found that TNT incorporation in the vacuoles of dedifferentiated callus cells was higher compared to cells from intact plant. Therefore, the ultrastructural continuity of differentiated cells is less damaged.     

蚕豆叶片细胞中IAA的胶体金免疫电镜定位

利用胶体金免疫电镜技术对蚕豆(Vicia faba L.)叶片细胞中的IAA定位进行了研究。幼嫩叶片的叶肉细胞中金颗粒主要分布在细胞核和叶绿体中,细胞质及细胞壁也有金颗粒标记。成熟叶片的叶肉细胞中金颗粒主要分布在叶绿体和细胞质,细胞壁也有少量金颗粒标记,液泡中没有发现金颗粒标记。成熟叶片小叶脉的韧皮细胞发现有大量的金颗粒标记,金颗粒主要标记在传递细胞的细胞壁中。小叶脉的维管束鞘细胞中也有很多的金颗粒标记,金颗粒主要分布在叶绿体、细胞质及细胞壁中。幼嫩叶片组织不进行IAA的固定或用正常兔IgG代替IAA抗体染色的对照,很难发现金颗粒标记。对IAA在组织及亚细胞中的定位及其生理意义进行了讨论。     

花烛离体培养叶色变异株系的相关性状

以花烛（Anthurium andraeanum）间接器官发生途径中再生出的一株花叶变异植株为原始材料,进行增殖并对得到的3个叶色变异株系的叶色相关性状进行了初步研究。结果表明：通过愈伤组织器官发生途径和腋芽增殖途径对这一花叶苗进行增殖,均分离到3种变异株系,即花叶苗、黄化苗和天鹅绒绿色叶片苗;天鹅绒绿色苗叶片中的叶绿素含量比正常离体苗的含量低;叶片解剖结构表明,叶绿体在叶肉细胞中的分布与其叶片表现型相同,天鹅绒绿色叶片与正常叶片在解剖结构上无明显差异。花烛原套只具有1层细胞,无明显的L2层分生结构,因此叶肉的薄壁细胞完全由向各个方向分裂的原体细胞发育而来,这种组织结构导致花叶叶片中含有叶绿体的细胞和不含有叶绿体的薄壁细胞呈不规则分布。这种花叶株系可以作为育种材料或直接作为盆栽花烛进行推广。     

花烛离体培养叶色变异株系的相关性状

以花烛(Anthurium andraeanum)间接器官发生途径中再生出的一株花叶变异植株为原始材料, 进行增殖并对得到的3个叶色变异株系的叶色相关性状进行了初步研究。结果表明: 通过愈伤组织器官发生途径和腋芽增殖途径对这一花叶苗进行增殖, 均分离到3种变异株系, 即花叶苗、黄化苗和天鹅绒绿色叶片苗; 天鹅绒绿色苗叶片中的叶绿素含量比正常离体苗的含量低; 叶片解剖结构表明, 叶绿体在叶肉细胞中的分布与其叶片表现型相同, 天鹅绒绿色叶片与正常叶片在解剖结构上无明显差异。花烛原套只具有1层细胞, 无明显的L2层分生结构, 因此叶肉的薄壁细胞完全由向各个方向分裂的原体细胞发育而来, 这种组织结构导致花叶叶片中含有叶绿体的细胞和不含有叶绿体的薄壁细胞呈不规则分布。这种花叶株系可以作为育种材料或直接作为盆栽花烛进行推广。     

细叶黄芪叶肉原生质体植株再生

从细叶黄芪(Astragalus tenuis)外植体愈伤组织分化出的再生苗叶片分离原生质体。原生质体培养在改良 K8p 培养基中形成了愈伤组织。增殖后的愈伤组织转入分化培养基中分化出苗。幼苗在生根培养基中长出不定根,再生成为完整植株。再生苗叶肉原生质体在 AY培养基中,种子无菌苗叶肉原生质体在改良 K8p 或 AY 培养基中均不能形成愈伤组织。较低的2,4-D 浓度有利于原生质体愈伤组织的形成和分化,过高的2,4-D 浓度对愈伤组织的形成和分化有不利的影响。     

AN ULTRASTRUCTURAL STUDY OF CHLOROPLAST STRUCTURE AND DEDIFFERENTIATION IN TISSUE CULTURES OF STREPTANTHUS TORTUOSUS (CRUCIFERAE)

Cells of Streptanthus tortuosus callus tissue contain chloroplasts when cultured in a liquid medium in the light. Similar cells grown in the dark contain proplastids that fail to develop prolamellar bodies but do contain a complex of loosely-associated membranes. When green, light-grown cultures are cut into small pieces and subcultured to a fresh culture medium, they become bleached even though maintained under the same illumination. The fine structure of the chloroplasts and the chlorophyll content of the cells indicate a dedifferentiation of the chloroplasts to a proplastid state during the early culture period. The changes in the ultrastructure of the plastids are paralleled by a dedifferentiation of the vacuolate cells to a less differentiated, meristematic state. Subsequent growth in the light results in a re-formation of chloroplasts and an increase in the chlorophyll content of the cells. The period of chloroplast redevelopment is associated with the re-formation of large central vacuoles in the cultured cells. Invaginations of the inner membrane of the plastid envelope occur at all stages of plastid development and are not lost during the period of grana degeneration. The proplastids formed from the dedifferentiation of the chloroplasts contain a large number of these invaginations and the redevelopment of grana is associated with a change in the electron density of the invaginating membranes. The degradation of the chlorophyll-containing membranes of the grana occurs during a period of rapid cytoplasmic synthesis induced by the fresh supply of nutrients in the culture medium. These results suggest that the high levels of nutrients may act directly on the chloroplasts and cause their dedifferentiation or that the rapid cell growth induced by the nutrients may cause a degradation of the membrane proteins in the grana of the chloroplasts and an incorporation of the released amino acids into non-plastid components of the cytoplasm.     

Intracellular Localization of Lunularic Acid and Prelunularic Acid in Suspension Cultured Cells of Marchantia polymorpha

Intracellular localization of lunularic acid and prelunularic acid in suspension cultured cells of Marchantia polymorpha L. was studied. The sum of both compounds was determined as lunularic acid group (LNAs) because of the instability of prelunularic acid to convert into lunularic acid.

Mechanical disruption of the cells followed by differential centrifugation showed that LNAs was associated with the supernatant of 100,000g centrifugation. Protoplasts isolated from the cells were osmotically ruptured and the distribution of LNAs among the organelles was examined by discontinuous density gradient centrifugation of the protoplast contents. Successful isolation of intact chloroplasts, mitochondria and peroxisomes free from cytoplasm indicated that LNAs was not accumulated in these organelles. Flotation techniques resulted in an efficient isolation of pure vacuoles and revealed that LNAs was distributed almost equally in the vacuoles and cytoplasm.

     

Leaf Structure of Tobacco In Vitro Grown Plantlets as Affected by Saccharose and Irradiance

Tobacco plantlets were cultured in vitro under high (200 µmol m^–2 s^–1) or low (60 µmol m^–2 s^–1) irradiance with or without saccharose in the medium. Light microscopy and image analysis were used to evaluate the effect of these culture conditions on leaf anatomy. Addition of saccharose resulted in thicker leaves (all leaf layers) and larger mesophyll cells under both growth irradiances. Various irradiance affected leaf anatomy differently when plantlets had been cultivated in presence or absence of saccharose in the medium. While under high irradiance in presence of saccharose leaf thickness and number of chloroplasts per cell section were increased, plantlets grown under high irradiance in absence of saccharose had thinner leaves and less chloroplasts per cell section. The changes were more pronounced in palisade parenchyma layer.