光质、光照时间和振荡对‘紫叶’酢浆草叶感夜性运动的影响

为探究光质、光照时间和振荡对‘紫叶’酢浆草(Oxalis triangularis ‘Purpurea’)叶片感夜性运动的影响,在人工气候室中调控光质、光照时间,利用振荡器进行振荡处理,并用摄像机记录叶片的运动状态。结果表明,波长越长,叶片展开越快;波长越短,叶片闭合越慢。持续3 d光照,除红光下叶片仅在18:00时有开闭的变化外,其他5种光质下叶片均不会闭合;12 h/12 h (光照/黑暗)光周期持续3 d,早上叶片展开需45～61 min,夜晚叶片完全闭合需85～120 min,且除白光外的5种光质下,叶片在早上8:00光照前已展开;持续黑暗叶片仍可以每天展开3～5h。振荡可以改变夜间运动方式,300r/min振荡0.5～6 h,叶片在振荡时不会完全闭合,只闭合至60°左右;振荡时间越长,停止振荡后叶片闭合速率越快,但振荡2 h后停止振荡,叶片则不闭合,所以植物对于外界应力的适应能力存在一定的范围。在园林中应用‘紫叶’酢浆草时,可以利用短波长光照,延长叶片的展开时间,增加其观赏效果,以及在中午时段避免暴晒。     

扁蓿豆体细胞胚的诱导和植株再生

扁蓿豆实生苗的根、下胚轴、子叶、叶片和叶柄外植体,在含２,４—Ｄ２—０．２５ｍｇＬ－１与ＫＴ０．２５－２ｍｇＬ－１及２,４—Ｄ０．５ｍｇＬ－１与ＺＴ０．５ｍｇＬ－１或ＢＡＰ０．５ｍｇＬ－１与ＮＡＡ０．０５ｍｇＬ－１的ＭＳ琼脂培养基上均可产生愈伤组织．愈伤组织在含２,４—Ｄ０．５—０．１ｍｇＬ－１与ＫＴ０．５—０．１ｍｇＬ－１或ＢＡＰ０．２５＋ＮＡＡ０．０５ｍｇＬ－１的ＭＳ培养基上可诱导分化出体细胞胚．体细胞胚在无激素的培养基上发育成完整植株．用海藻酸钠包襄体细胞胚制成人工种子,其发芽率和植株转换率分别为９５％和５３％．     

安祖花胚性愈伤组织诱导及植株再生研究

为构建安祖花(Anthurium andreanum)胚性愈伤组织再生体系,以3个盆栽品种幼嫩叶片和叶柄为外植体,分析了基本培养基、植物生长调节剂组合和培养条件等因素的影响。结果表明,安祖花胚性愈伤组织诱导的最佳培养基为改良MS3+1.5 mg L–1 2,4-D+0.5 mg L–1 KT+4%蔗糖+2%葡萄糖+0.25%Phytagel,且胚性愈伤组织诱导能力差异显著,表现为?粉冠军??罗宾奴??冠军?和叶片叶柄,其中?粉冠军?叶片的胚性愈伤组织诱导率可达57.9%。胚状体分化的最佳培养基为1/2改良MSa+2%蔗糖+0.25%Phytagel,其中?粉冠军?叶片诱导的胚状体分化率可达31.6%,且在光、暗下分化率的差异不显著。分化苗移栽后的成活率可达100%。     

枣树体细胞胚发生和组织学研究

以临泽小枣子叶切块为外植体,在附加０．２mg/L IBA 1．0mg/L 6-BA的ＭＳ培养基上１周后切块边缘可诱导出白色胚愈伤组织,继续培养１个月后愈伤组织中产生体细胞胚。体细胞胚发生不同步,经历球形胚、心形胚、子叶胚等阶段,与合子胚发育途径相似。组织切片表面胚性愈伤组织细胞体积小,细胞核大、细胞质浓,细胞排列紧密;而非胚性愈伤组织细胞体积大、细胞核小、细胞质稀薄,子叶胚时期体细胞胚内部出现维管束,并观察到螺纹导管。     

防风组织培养中畸形胚状体的发生和控制

采用组织培养和石蜡切片法,分析多种因素对防风畸形胚状体发生和发育过程的影响及控制。结果表明,诱导正常体细胞胚高频发生的培养基组合是：启动胚性愈伤组织的培养基是MS 0．5mg／L 2．4-D,蔗糖浓度3％;分化培养基是MS 1mg／L 6-BA 0．2mg／L NAA 0．5mg／L ABA,蔗糖浓度4％～5％;成熟培养基是MS培养基,蔗糖浓度3％。结论：一定浓度的生长素是诱导防风胚性愈伤组织的关键因素,细胞分裂素在体细胞胚的分化和发育过程中起协同作用;蔗糖浓度、ABA、接种方法以及适宜的培养条件和培养容器等均可有效降低畸形胚状体的发生率。     

诱导植物体细胞胚发生的几个生理因素

介绍了影响植物体细胞胚发生的几个主要生理因素,并对其可能作用机制作了分析.     

胁迫诱导植物体细胞胚发生的研究进展

诱导植物体细胞胚发生是一个多因素事件,其发生机理的研究也是多层次多方面的.本文从诱导体细胞胚的胁迫因子和体细胞的响应角度,分析了高浓度2,4-D、重金属、高渗透等胁迫因子对体细胞胚发生的诱导,以及体细胞产生的ABA、胼胝质沉积、几丁质酶活性增强、热激蛋白特异表达等生理响应,概述了植物体细胞胚发生的一些研究成果和理论认识.     

影响大豆体细胞胚诱导因素的研究

体细胞胚的诱导是大豆体外再生的关键。基因型,诱导光周期,外植体的英位,蔗糖浓度等因素,可导致诱导频率及正常胚比例不同,影响植株再生。本研究选用黑龙江省主栽大豆基因型的未成熟子叶,在含高浓度生长素的MSB培养基上诱导体细胞胚产生。合丰25和东农7819为优选基因型,生育前期下部英位大小为2－4mm未成熟子叶体细胞胚发生效果最好;四种光周期下体细胞胚诱导频率相近,但连续弱光了正常胚比例高;NAA诱导优于2－4,D;10mg/1NAA与1．5％蔗糖配比组合最佳。     

红花酢浆草地上部分的化学成分研究

为了解红花酢浆草(Oxalis corymbosa DC.)地上部分的化学成分,从其70%乙醇提取物中分离鉴定了6个化合物,经理化性质和波谱数据分析,分别鉴定为:芫花素(1)、corniculatin A(2)、槲皮素(3)、咖啡酸(4)、肉桂酸(5)、木犀草素-7-O-β-D-葡萄糖苷(6)。所有化合物均为首次从红花酢浆草地上部分分离得到。     

石刁柏非胚性细胞与体细胞胚胚体细胞的超微结构研究

对石刁柏（Ａｓｐａｒａｇｕｓｏｆｆｉｃｉｎａｌｉｓ）体细胞胚发生过程中细胞的超微结构进行了观察,非胚性细胞内液泡大,大量的自体吞噬泡出现,胚性细胞内细胞核大,核移中,核仁结构明显,线粒体、质体、核糖体、高尔基体、内质网等细胞器增多,淀粉、脂滴积累,有较活跃的自体吞噬现象,梨形细胞内质体向叶绿体转变。     

Influence of growth regulators on somatic embryogenesis in sesame

Somatic embryos were induced from hypocotyl-derived callus of sesame (Sesamum indicum Var. TMV 6). The influence of different auxins and cytokinins on somatic embryogenesis was investigated. Among the different auxins tested, 2,4-dichlorophenoxy acetic acid was the most effective and resulted in the highest frequency of responding cultures and highest average number of somatic embryo per responding cultures napthaleneacetic acid, indoleacetic acid, indolebutyric acid and 2,4,5-trichlorophenoxypropionic acid were also effective for embryogenesis, but 2,4,5-trichorophenoxyacetic acid and napthoxyacetic acid were not beneficial. The combined effect of cytokinins with 2,4-d was also studied. Among the four cytokinins tested, 2.2 chμM benzyladenine with 13.6 chμM 2,4-d slightly enhanced embryogenic efficiency; while kinetin, zeatin, 6-γ-γ-dimethylallylaminopurine enhanced the frequency of responding cultures. There was a decrease in the number of somatic embryos per culture in the presence of all cytokinins. This revised version was published online in June 2006 with corrections to the Cover Date.     

柑橘愈伤组织生长速度与体细胞胚胎发生的关系

为了探讨柑橘愈伤组织不能再生的原因,试图寻找柑橘愈伤组织生长速度与其体细胞胚胎发生之间的关系,对7种柑橘类型的29种基因型的愈伤组织的生长速度进行了测定,并对愈伤组织生长速度与体细胞胚胎发生之间的相关性进行了统计分析。结果表明,柑橘愈伤组织生长速度与体细胞胚胎发生之间的相关系数为r=-0.3683。由此推断在这两者之间还存在其它影响因素。     

Genotype and plant growth regulator-dependent response of somatic embryogenesis from Gentiana spp. leaf explants

Gentiana kurroo (Royle), Gentiana cruciata (L.), Gentiana tibetica (King. ex Hook. f.), Gentiana lutea (L.), and Gentiana pannonica (Scop.) leaves derived from axenic shoot culture were used as explants. For culture initiation, leaves from the first and second whorls from the apical dome were dissected and cultured on Murashige and Skoog (MS) basal medium supplemented with three different auxins: 2,4-dichlorophenoxyacetic acid, 1-naphthaleneacetic acid (NAA), or 3,6-dichloro-o-anisic acid (dicamba) in concentrations of 0.5, 1.0, or 2.0 mg/l; and five different cytokinins: zeatin, 6-furfurylamonopurine (kinetin), N-phenyl-N′-1,2,3-thiadiazol-5-ylurea (TDZ), N-(2-chloro-4-pyridyl)N′-phenylurea, or 6-benzylaminopurine (BAP). The cytokinin concentrations used were dependent on the type of cytokinin and varied between 0.25 and 3.0 mg/l. After 2 mo. of culture, the morphogenic response of explants was assessed. Frequency of embryogenesis was the highest for G. kurroo (54.7%) and dependent on plant growth hormones (PGRs). This gentian was the only species showing morphogenic capabilities on media supplemented with all applied combinations of PGRs, while none of the 189 induction media permutations stimulated somatic embryogenesis from G. lutea explants. G. tibetica and G. cruciata both produced an average of 6.6 somatic embryos per explant, while G. pannonica and G. kurroo regenerated at 15.7 and 14.2 somatic embryos per explant, respectively. Optimum regeneration was achieved in the presence of NAA combined with BAP or TDZ. This auxin also stimulated abundant rhizogenesis. Somatic embryos were also regenerated from adventitious roots of G. kurroo, G. cruciata, and G. pannonica. Somatic embryos converted into plantlets on half strength MS medium.     

Characteristics of Citrus cell cultures during undifferentiated growth on sucrose and somatic embryogenesis on galactose

Growth of willow-leaf mandarin ( Citrus deliciosa Ten.) nucellar callus cultures without embryo formation was supported on sucrose as the sole carbon source. Somatic embryogenesis was obtained by substituting galactose for sucrose at the same concentration (0.15 M ). A histocytological study revealed proliferation of young globular embryos during the first half of the 18-day culture cycle, irrespective of the carbon source. However, during the second half of the cycle, further embryo development failed in cell cultures on sucrose-containing medium. The rate of cell growth and the carbohydrate depletion of the medium were 3-fold higher on sucrose than on galactose-containing medium. Cell suspensions on sucrose differed by an increase in calcium, phosphorus, magnesium and potassium utilization soon after subculturing, followed by a sharp decrease. Finally, the phosphorus utilization rate per g dry weight formed was 2-fold higher in cell cultures on galactose during the second half of the culture cycle, coinciding with further embryo ontogenesis.     

Noninvasive evaluation of somatic embryogenesis

Callus Suspension Cultures of Ipomea batates Poir. cv. White Star were grown in an airlift bioreactor. A machine vision system was used to monitor nondestructively callus growth during a 10 day culture period. Growth data obtained with this system included the overall reactor population and population estimates for the 200-1200-mum fractions at 200-mum intervals. A model of callus growth was developed to explain the mechanics of callus enlargement. The model was based on the assumptions that (1) the calli could not subdivide or shrink, (2) there was a fixed percentage of the initial population for each fraction that was nonviable, and (3) growth rates did not vary with time during the culture period. It was determined that the growth rates and nonviable ratios decreased as fraction size increased.     

Developmental pathways of somatic embryogenesis

Somatic embryogenesis is defined as a process in which a bipolar structure, resembling a zygotic embryo, develops from a non-zygotic cell without vascular connection with the original tissue. Somatic embryos are used for studying regulation of embryo development, but also as a tool for large scale vegetative propagation. Somatic embryogenesis is a multi-step regeneration process starting with formation of proembryogenic masses, followed by somatic embryo formation, maturation, desiccation and plant regeneration. Although great progress has been made in improving the protocols used, it has been revealed that some treatments, coinciding with increased yield of somatic embryos, can cause adverse effects on the embryo quality, thereby impairing germination and ex vitro growth of somatic embryo plants. Accordingly, ex vitro growth of somatic embryo plants is under a cumulative influence of the treatments provided during the in vitro phase. In order to efficiently regulate the formation of plants via somatic embryogenesis it is important to understand how somatic embryos develop and how the development is influenced by different physical and chemical treatments. Such knowledge can be gained through the construction of fate maps representing an adequate number of morphological and molecular markers, specifying critical developmental stages. Based on this fate map, it is possible to make a model of the process. The mechanisms that control cell differentiation during somatic embryogenesis are far from clear. However, secreted, soluble signal molecules play an important role. It has long been observed that conditioned medium from embryogenic cultures can promote embryogenesis. Active components in the conditioned medium include endochitinases, arabinogalactan proteins and lipochitooligosaccharides.     

Optimized somatic embryogenesis in Pinus strobus L.

Summary Somatic embryogenesis (SE) initiation in Pinus strobus was optimized by the manipulation of plant growth regulator (PGR) concentrations in the culture medium. Modified Litvay medium (MLV) of Litvay et al. (1985) supplemented with lower than routinely used PGR concentration increased initiation of established embryogenic cultures from approximately 20 to 53%. The original developmental stage of zygotic embryos had a pronounced effect on the SE response. The optimum stage was the pre- to shortly post-cleavage stage. A substantial genetic influence on initiation of SE was indicated by a significant variance component due to families. Genotype X collection date and genotype X media interactions had large effects on initiation of SE. The PGR levels in the culture medium prior to maturation had a significant effect on subsequent production of mature somatic embryos. Embryogenic tissue initiated and proliferated on medium with a low level of PGR consistently produced a high number of somatic embryos, indicating that optimized initiation protocol also enhanced somatic embryo production. Somatic embryos of 93 embryogenic lines (representing five families) that were initiated on media with different PGR concentrations were converted to plants at an overall frequency of 76%, and grown in the greenhouse. With these improved protocols, application of P. strobus SE in commercial clonal forestry is feasible as an alternative to traditional breeding and reforestation.