Morphological Alterations in Sterile Mutant of Pisum Sativum Obtained Via Somatic Embryogenesis

A sterile mutant of pea (Pisum sativum L. line HM-6) with a number of morphological alterations was found after plant regeneration via somatic embryogenesis. Embryogenic callus was derived from the whole immature zygotic embryo on medium with 2.26 M 2,4-dichlorophenoxyacetic acid. Morphological changes included altered leaflet shape, one pair of leaflets only, altered stipule morphology, shortened internodia, irregular or opposite leaf position on the stem, shortened flower stalk, and aborted flowers resulting in complete sterility. If the isolation of the shoot apex and axillary buds from evidently sterile plant and their culture in vitro resulted in morphologically normal and fertile regenerated plants, the chimaeric nature of R₀ mutant is considered.     

Evolution of Ethylene and Methane in Relation to Somatic Embryogenesis in Chickpea

In four genotypes of chickpea (Cicer arietinum L.) BG 362, BG 372, BG 329 and C235 the relationship between somatic embryogenesis of leaf explants and ethylene and methane evolution was studied. In BG 362, which was more embryogenic than other genotypes, a higher ethylene:methane ratio of 5.8:1 at day one after inoculation in the induction medium and a lower ethylene:methane ratio of 2.89:1 in the maturation medium was found. On the contrary, in BG 372 with the least embryogenic potential, a lower ethylene:methane ratio of 1.7:1 in the induction medium and a higher ethylene:methane ratio of 4:1 in the maturation medium was found. Thus, these ratios in induction and maturation stages seems to be markers for embryogenesis in leaf explants of chickpea. This revised version was published online in July 2006 with corrections to the Cover Date.     

Somatic Embryogenesis and Regeneration of in Plantlets in Pomegranate

Plantlets were regenerated from somatic embryos originatingfrom cotyledonary tissues of pomegranate (Punica granatum) throughmultiple somatic embryogenesis. Embryogenic cell clusters proliferatedvigorously with regular sub-culturing after 20 d on RBM-II mediumcontaining 1 µM kinetin (KN), 2 µM benzylamino purine(BAP) and 5 µM 2,4-dichlorophenoxyacetic acid (2, 4-D).Developmental stages of somatic embryos were expressed on sub-culturingwith a low level of 2, 4-D (2.5 µM). Embryogenic initialscells were small, round to oval, thick-walled, contained densecytoplasm which stained with acetocarmine and were usually attachedto non-embryogenic cells. Embryo maturation was obtained onRBM-III and IV media to produce young seedlings on the initiationof the first long tap root. Punica granatum L., pomegranate, multiple somatic embryogenesis, callus culture, plant regeneration     

Interruption of Somatic Embryogenesis in Daucus carota L. by 5-Bromodeoxyuridine

Embryogenic Daucus carota L. cells grown in 9 micromolar 2.4-dichlorophenoxyacetic acid are resistant to greater than 5 micromolar 5-bromodeoxyuridine (BrdU). In contrast, 5 micromolar BrdU strongly inhibits somatic embryogenesis within 24 hours after transfer of cells to an auxin-free medium. DNA synthesis rates in control and BrdU-treated cultures are rapid and similar; however, the DNA content does not reach levels as great in the presence of BrdU as in control cultures. BrdU substitutes for thymidine in the DNA in 28% of the available sites 48 hours after auxin removal. Following DNA repair, somatic embryogenesis resumes. BrdU DNA incorporation leads to somatic embryogenesis inhibition and provides an alternative to auxin treatment for the interruption of carrot cell culture differentiation.     

Expression in Escherichia coli of Three Different Soybean Late Embryogenesis Abundant (LEA) Genes to Investigate Enhanced Stress Tolerance

In order to identify the function of late embryogenesis abundant (LEA) genes, in vitro functional analyses were perfo rmed using an Escherichia coli heterologous expression system. Three soybean late embryogenesis abundant (LEA) genes, PM11 (GenBank accession No. AF004805; group 1), PM30 (AF1 17884; group 3), and ZLDE-2 (AY351918; group 2), were cloned and expressed in a pET-28a system.The gene products were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and identified by mass spectrometry. E. coli cells containing the recombinant plasmids or empty vector as controls were treated by salt and low temperature stress. Compared with control cells, the E. coli cells expressing either PM11 or PM30 showed a shorter lag period and improved growth when transferred to LB (Luria-Bertani) liquid media containing 800 mmol/L NaCl or 700 mmol/L KCl or after 4 ℃ treatment. E. coli cells expressing ZLDE-2 did not show obvious growth improvement both in either high KCl medium or after 4 ℃ treatment. The results indicate that the E. coli expression system is a simple, useful method to identify the functions of some stress-tolerant genes from plants.     

Erratum to: Proteomic Analysis of Somatic Embryogenesis in Cyclamen persicum Mill

Plant Molecular Biology Reporter -     

The Role of Calcium and Calmodulin in Carrot Somatic Embryogenesis

The role of Ca²⁺ and calmodulin in carrot somatic embryo formationwas examined. Embryogenic cell clumps were induced to form embryosin medium containing 0–3 mM Ca²⁺. Embryo formation wasnot affected until the concentration of Ca²⁺ was lower than200 µM and after this threshold was reached the percentof embryo formation decreased with lower Ca²⁺ concentrations.Treatment of developing embryos with either verapamil or nifedipine,Ca²⁺ -channel blockers, or the Ca²⁺ ionophore A23187[GenBank], inhibitedembryo formation. These results suggest that exogenous Ca²⁺or the maintenance of Ca²⁺ gradients are required for properembryo development. Analysis of membrane-associated Ca²⁺ andtotal membrane distribution using the fluorescent dyes chlorotetracyclineand N-phenyl-1-napthylamine, respectively, indicated changesin the distribution of membranes during embryogenesis withoutany significant alterations in the concentration of Ca²⁺ associatedwith the membranes. In heart- and torpedo-stage embryos, calmodulin-Ca²⁺complexes were localized in regions containing the developingmeristems of both the cotyledon tips and rhizoid regions whiletotal calmodulin protein appeared to be more uniformly distributed.Calmodulin mRNA levels increased slightly when cell clumps wereinduced to form embryos. (Received July 7, 1993; Accepted September 27, 1993)     

植物体细胞胚胎发生及其相关应答基因的研究进展

体细胞胚胎发生途径不仅是植物大规模克隆繁殖的重要途径,也是研究从单细胞到整体植株发育全过程的理想试验体系。植物体细胞胚胎发生的研究已经取得了很大的进展,但是也依然存在许多问题。根据近年来的相关研究报道,简述植物体细胞胚胎发生及此过程中相关应答基因的研究概况,探讨植物体细胞胚胎发生的生理生化基础,并对今后应该加强研究的关键问题提出了自己的看法。     

植物组织培养中畸形胚的发生和控制

文章介绍植物组织培养中畸形胚的常见类型、发生原因、发生机制,调控手段及畸形胚成苗等研究进展.     

Somatic Embryogenesis in Cassava: The Anatomy and Morphology of the Regeneration Process

Anatomical and morphological studies demonstrated that somaticembryos developed similarly on mature seed and clonal leaf explantsof cassava (Manihot esculenta Crantz) cultured for 20–24d on Murashige and Skoog (MS2) basal medium supplemented with4.0 mg l^–1 2,4-D (Stage 1) before transfer to MS2 basalmedium supplemented with 0–01 mg l^–1 2,4-D and 0–1mg l^–1 6-benzylaminopurine (Stage II medium). Within 7d of inoculation onto Stage I medium, cell divisions occurredin the adaxial tissues of cotyledon-piece and leaf-lobe explants,and associated with this was the development of embryogeneticprotusions and ridges on the adaxial surface. Foliose structuresand somatic embryo initials developed from these tissues oncotyledon, embryonic axis and leaf-lobe explants and, when cultureswere transferred to Stage II medium, further somatic embryodevelopment occurred. Somatic embryos apparently originatedfrom groups of cells and were identified by the presence ofa closed root axis, a shoot axis and cotyledons of similar shapeand venation to those of zygotic embryos. Somatic embryos hadno vascular connection with parental cultures. Manihot esculenta, cassava, somatic embryogenesis, tissue culture, anatomy, morphology, morphogenesis     

Temporal Regulation of Somatic Embryogenesis by Adjusting Cellular Polyamine Content in Eggplant

Four critical stages of embryogenesis, including callus induction, cellular acquisition of morphogenetic competence, expression of embryogenic program, and development and maturation of somatic embryos during somatic embryogenesis from leaf discs of eggplant (Solanum melongena L.), were identified by scanning electron microscopy. Temporal changes in arginine decarboxylase (ADC) activity and polyamines (PAs) during critical stages of embryogenesis revealed that high levels of PAs (especially putrescine [PUT]), due to higher ADC activity in discs from the apical region (with high embryogenic capacity) than from the basal region of the leaf (with poor embryogenic capacity), were correlated with differential embryogenesis response. Kinetic studies of the up- and down-regulation of embryogenesis revealed that PUT and difluoromethylarginine pretreatments were most effective before the onset of embryogenesis. Basal discs pretreated with PUT for 4 to 7 d showed improved embryogenesis that was comparable to apical discs. PA content at various critical steps in embryogenesis from basal discs were found to be comparable to that of apical discs following adjustments of cellular PA content by PUT. In contrast, pretreatment of apical discs with difluoromethylarginine for 3 d significantly reduced ADC activity, cellular PA content, and embryogenesis to levels that were comparable to basal discs. Discs from the basal region of leaves treated with PUT for 3 d during the identified stages of embryogenesis improved their embryogenic potential.     

Response to Propranolol and Diazepam in Somatic and Psychic Anxiety

A total of 12 chronically anxious psychiatric outpatients were treated with racemic propranolol (Inderal), diazepam (Valium), and placebo for one week each, using a balanced cross-over experimental design. Six patients had predominantly somatic anxiety, complaining mostly of bodily symptoms, and six had mainly psychic anxiety, complaining primarily of psychological symptoms. Clinical ratings of anxiety were made by patient and psychiatrist after each treatment. Though diazepam was in general more effective than propranolol or placebo in relieving anxiety, propranolol was more effective than placebo in patients with somatic anxiety but not in those with psychic anxiety. We suggest that propranolol should be reserved for patients whose anxiety symptoms are mainly somatic.     

Alterations in the Heat Response of Chlorella ellipsoidea by Deuteration

For the elucidation of the isotope effect on cell functionsof deuterium (D) incorporated into cell constituents, alterationsin the heat response of D-exchanged Chlorella ellipsoidea (D-Chlorella)were investigated. D-Chlorella cells obtained by culture inmedium that contained 60 mol% D₂O were assayed for their responseto heat in H₂O medium to rule out the solvent isotope effectof D₂O. Upon heating at 41–45?C, the heat sensitivityof D-Chlorella was greater than that of ordinary (H-Chlorella)cells; at 43?C, the heat sensitivity of D-Chlorella was 1.5–1.6times higher than that of H-Chlorella. For the induction ofresistance to heating, preheating of the cells at a lower temperaturethan that used for heat treatment was effective in the caseof both D- and H-Chlorella. However, the optimum temperaturefor preheating of D-Chlorella (34?C) was lower than for H-Chlorella(36–37?C). With preheating at 34?C, heat-shock proteins(HSPs), in particular proteins of 62 and 79 kDa, were inducedsimilarly in both types of cell. However, the gel-electrophoreticpatterns of HSPs induced at 37?C were differed somewhat betweenD- and H-Chlorella. These results suggest that the responseof cells to heat, in particular the induction of resistanceto heating and the synthesis of HSPs, was altered by deuterationof cell constituents. (Received June 11, 1990; Accepted November 24, 1990)     

逆境处理和DNA甲基化影响柑橘体细胞胚发生

对 1 5种柑橘胚性愈伤组织进行体细胞胚诱导 ,发现逆境处理有利于体细胞胚发生 ,并可以恢复部分品种的体细胞胚发生能力。对具有和失去体细胞胚发生能力的两种纽荷尔脐橙 (CitrussinensisOsb .)愈伤组织进行随机扩增多态性DNA (RAPD)分析没有检测到带型的差异 ,而对它们的甲基化敏感扩增多态性 (MSAP)进行分析则发现两种愈伤组织间具有明显的DNA甲基化差异 ,具体细胞胚发生能力的愈伤组织的甲基化水平较失去体细胞胚发生能力的低     

Effects of Salicylic and Acetylsalicylic Acid on Direct Somatic Embryogenesis in Oncidium

The effects of salicylic and acetylsalicylic acid on direct somatic embryogenesis were investigated using leaf explants of two cultivars of Oncidium on 1/2 MS medium with or without thidiazuron. In cv Gower Ramsey, salicylic acid (1, 5, 10, 15, 20, 50 μM) either alone or in combination with thidiazuron (4.54 μM) retarded and delayed embryogenesis. In contrast, in the presence of 4.54 μM of thidiazuron, acetylsalicylic acid at 0.1 μM concentration promoted embryogenesis. In cv Sweet Sugar, all concentrations of salicylic acid with or without thidiazuron proved inhibitory on embryo induction. However, in the presence of 0.45 μM thidiazuron, 0.1 and 1 μM acetylsalicylic acid promoted embryogenesis. In addition, in the presence of 4.54 μM thidiazuron, 0.01, 0.1 and 1 μM acetylsalicylic acid promoted embryogenesis.