Tissue culture of wild-type, interspecific genome/plastome hybrids and plastome mutants of evening primrose (Oenothera): controlled morphogenesis and transformation

A favourable combination of genetic features in the genus Oenothera offers access to fundamental biological aspects that are not readily approached with other materials. We have developed protocols for cell and tissue culture as well as for transformation, in order to establish the basis for a comprehensive cell and molecular biology of Euoenothera species, their genome/plastome hybrids and plastome mutants. Regeneration of plants from excised seedling parts (roots, hypocotyl, cotyledons, shoot tips) and leaf explants was optimal on NT medium containing 1 mg ⋅ l^–1 6-benzylaminopurine and 3 mg ⋅ l^–1 α-naphtalene acetic acid. This medium also proved to be efficient in the propagation of various wild-type genotypes, interspecific hybrids and plastome mutants. Using Ti-based approaches we also succeeded in generating transgenic Oenothera plants with relatively high efficiency. Received: 17 February 1997 / Revision received: 16 April 1997 / Accepted: 20 April 1997     

Lack of correlation between effects of tentoxin on chloroplast coupling factor and chloroplast ultrastructure

The mediation of tentoxin-induced chlorosis through inhibition of chloroplast coupling factor 1 (CF₁) ATPase activity was investigated through an examination of the effects of tentoxin on electrophoretically-separated CF₁ ATPases from sensitive and insensitive Nicotiana species. Sensitive species exhibited three major ATPases, only one of which was inhibited at some concentrations of tentoxin. Insensitive Nicotiana species showed the same three "isozymes"upon electrophoresis but none of the isozymes were tentoxin sensitive. CF₁ isolated from Zea mays L. cv. Pioneer 3541, which is insensitive to tentoxin in vivo based on lack of chlorosis, exhibited two ATPases, one of which was sensitive to tentoxin. The concentration/activity relationships between tentoxin and ATPase inhibition of the sensitive isozyme did not correlate well with the chlorosis induced at similar levels of tentoxin in vivo. Both Oenothera hookeri Torr. & Gray and the CF₁-deficient I iota mutant derived from it are sensitive to tentoxin as determined by loss of chlorophyll and ultrastructural changes typical of the tentoxin syndrome. These results support a mechanism of action different from inhibition of CF¹ for tentoxin-induced chlorosis.     

Artemisia tilesii Ledeb hairy roots establishment using Agrobacterium rhizogenes-mediated transformation

An efficient and rapid protocol for the establishment of Artemisia tilesii “hairy” root culture is reported. Leaf explants of aseptically growing plants were cocultured with Agrobacterium rhizogenes A4 wild strain or A. rhizogenes carrying the plasmids with nptII and ifn-α2b genes. Root formation on the explants started in 5–6 days after their cocultivation with bacterial suspension. Prolongation of explant cultivation time on the medium without cefotaxime led to stimulation of root growth. The effects of sucrose concentration as well as of the levels of synthetic indole-3-butyric acid (IBA) and native growth regulator Emistim on the stimulation of A. tilesii “hairy” root growth were studied. Maximum stimulating effect both for the control and for transgenic roots was observed in case of root cultivation on the media supplemented with IBA—up to 7.95- and 9.1-fold biomass increase, respectively. Cultivation on the medium with 10 μl/L Emistime has also led to the control roots growth stimulation (up to 2.75-fold). Emistime at 5 μl/L concentration led to 5.46-fold mass increase in only one “hairy” root line. Higher sucrose content (40 g/L) stimulated growth of two hairy root lines but had no effect on growth of the control roots.     

双褶贝母兰的重新发现及其植物地理学意义

自从1903年Rolfe报道双褶贝母兰产中国云南后,在中国一直未再采到标本,直到最近在云南省麻栗坡县发现了它的野外居群。作为中国国内首次采到的活体标本,对其进行野外生境、开花生物学调查和形态补充描述、绘图以及植物地理学意义讨论。     

大孔吸附树脂对海边月见草总黄酮的吸附及解吸特性

通过比较3种大孔吸附树脂对海边月见草(O enothera littaralisSchlect.)总黄酮的吸附能力,选择了吸附量较大且易洗脱的树脂AB-8,研究了提取液浓度、pH值对该树脂静态吸附能力的影响,以及洗脱剂种类、乙醇浓度对动态解吸能力的影响。结果表明,AB-8树脂对海边月见草总黄酮有良好的吸附纯化性能,当原液浓度为1.076mg.mL-1时,树脂达饱和吸附量36.11 mg.g-1;提取液pH值对该树脂的吸附能力影响显著,pH值达4.0~4.5时树脂吸附量最大;用60%乙醇为洗脱剂,流速为1 mL.m in-1,总黄酮的动态洗脱率达83.41%,获得的总黄酮纯度为24.13%,得率3.54%;而30%乙醇(6倍柱床体积)和50%乙醇(6倍柱床体积)组合是最佳动态洗脱剂。     

Potential Antidiabetic and Anti-Genotoxic Activities of Silver Nanoparticles of Alkaloid Extract of <i>Rhazya stricta</i> in Rat Animal Model

In most of Arabian courtiers Rhazya stricta is extensively utilized in public medicine for several diseases treatment. In this study, crude alkaloid extract of R. stricta (CAERS) coated with silver nanoparticles (CAERS-AgNPs) as potential treatment against diabetes in DM animal model was evaluated. Swiss albino male rats (n = 80) were injected with STZ to induce Diabetes Mellitus type-2 (DM). DM-rats were injected different doses of CAERS or CAERS-nanoparticles (CAERS-NPs) for 2 months. The results exhibited that mRNA expression of insulin and insulin receptor was down-regulated, activity levels of antioxidant enzymes were decreased, generation of ROS mediated DNA adducts and apoptosis in DM-rats was increased significantly than those in negative control rats. In contrast, the expression of insulin and insulin receptor genes was up-regulated, activity levels of antioxidant enzymes, ROS generation, DNA adducts and apoptosis incidence in DM-rats supplemented with high dose of CAERS and all doses of CAERS-NPs were improved. In conclusion: R. stricta nanoparticles improved the anti-diabetic effect of the plant much more than the powder form of the extract. This action could be attributed to modification of the chemical and physical properties of the plant materials. The properties modification might be improved the ability of plant compounds to penetrate the cell membrane which facilitating release of plant materials into the target cells.     

Effects of long-term elevated [CO2] from natural CO2 springs on Nardus stricta: photosynthesis, biochemistry, growth and phenology

Plants of Nardus stricta growing near a cold, naturally emitting CO₂ spring in Iceland were used to investigate the long-term (> 100 years) effects of elevated [CO₂] on photosynthesis, biochemistry, growth and phenology in a northern grassland ecosystem. Comparisons were made between plants growing in an atmosphere naturally enriched with CO₂ (≈ 790 μ mol mol^–1) near the CO₂ spring and plants of the same species growing in adjacent areas exposed to ambient CO₂ concentrations (≈360 μ mol mol^–1). Nardus stricta growing near the spring exhibited earlier senescence and reductions in photosynthetic capacity (≈25%), Rubisco content (≈26%), Rubisco activity (≈40%), Rubisco activation state (≈23%), chlorophyll content (≈33%) and leaf area index (≈22%) compared with plants growing away from the spring. The potential positive effects of elevated [CO₂] on grassland ecosystems in Iceland are likely to be reduced by strong down-regulation in the photosynthetic apparatus of the abundant N. stricta species.