Post-gastrulation synthetic embryos generated ex utero from mouse naive ESCs

1. Download : Download high-res image (243KB)
2. Download : Download full-size image

     

A Practicable Li/Na‐Ion Hybrid Full Battery Assembled by a High‐Voltage Cathode and Commercial Graphite Anode: Superior Energy Storage Performance and Working Mechanism

With the rapidly growing demand for low‐cost and safe energy storage, the advanced battery concepts have triggered strong interests beyond the state‐of‐the‐art Li‐ion batteries (LIBs). Herein, a novel hybrid Li/Na‐ion full battery (HLNIB) composed of the high‐energy and lithium‐free Na₃V₂(PO₄)₂O₂F (NVPOF) cathode and commercial graphite anode mesophase carbon micro beads is for the first time designed. The assembled HLNIBs exhibit two high working voltage at about 4.05 and 3.69 V with a specific capacity of 112.7 mA h g^?1. Its energy density can reach up to 328 W h kg^?1 calculated from the total mass of both cathode and anode materials. Moreover, the HLNIBs show outstanding high‐rate capability, long‐term cycle life, and excellent low‐temperature performance. In addition, the reaction kinetics and Li/Na‐insertion/extraction mechanism into/out NVPOF is preliminarily investigated by the galvanostatic intermittent titration technique and ex situ X‐ray diffraction. This work provides a new and profound direction to develop advanced hybrid batteries.     

Analysis of diaspore morphology and seed germination in Bubon macedonicum L., a rare species in Italy

Bubon macedonicum L. is a chasmophytic species of south-eastern Europe. In Italy, it has been detected only in Rocca Monforte (Campobasso, central Italy). This rare species is included in the IUCN Red Lists of Critically Endangered Italian Flora, and there are no studies relating to B. macedonicum biology. The seed germination dynamics of this species was studied with the aim of building up an appropriate germination protocol to be used in ex situ conservation. On the basis of an ISTA protocol, about 3,000 seeds were collected from Rocca Monforte in August 2013. Fifty seeds were measured. The considered parameters were seed length, width, thickness, seed surface, volume, density, surface/mass ratio and eccentricity index. The morphometric parameters examined showed morphological dormancy, where a short warm period is necessary for embryo growth and seed germination. The results showed high germination percentages under the different conditions of temperature, pH, GA₃ and photoperiod. Only at 5 °C was there no germination. Finally, the seeds maintain high germination percentages from the seed storage process after 130 and 390 days. This factor can be considered of great importance for the conservation of B. macedonicum over the medium and long term.     

A new natural allotriploid,Lycoris × hubeiensis hybr. nov. (Amaryllidaceae), identified by morphological,karyological and molecular data

A new natural hybrid, Lycoris × hubeiensis K. Liu, is confirmed and described based on morphological, karyological and molecular data. The new natural hybrid displays remarkable morphological differences relative to the putative parents L. radiata (2n = 22 = 22A) and L. aurea (2n = 14 = 8m + 6T), and has a karyotype of 3n = 29 = 4m + 22A + 3T. Two chloroplast intergenic regions of ndhF‐rpl32R and rpl32F‐trnL were sequenced with three haplotypes found in the three taxa. The putative hybrid and L. radiata shared the same haplotype (H1), while L. aurea had two other haplotypes (H2 and H3). Combined with the morphological, karyological and molecular data, we conclude that the hybrid is an allotriploid with L. radiata being the maternal parent offering an unreduced gamete and L. aurea being the male parent.     

秦艽体细胞愈伤组织诱导及继代研究

本文报道了秦艽取叶、幼苗为外植体诱导愈伤组织试验。结果表明,取幼苗６７－Ⅴ培养基,２４－Ｄ２５ｍｇ／Ｌ,ＮＡＡ０５ｍｇ／Ｌ,诱导频率最优,可高达１００％。继代培养,以６７％培养基,ＮＡＡ０５ｍｇ／Ｌ,２４－Ｄ（１－１５）ｍｇ／Ｌ最优     

Cluster root development in Grevillea robusta (Proteaceae). I. Xylem, pericycle, cortex, and epidermis development in a determinate root

The cluster roots of Grevillea robusta A. Cunn. ex R. Br. are composed of determinate rootlets that stop growing, but remain physiologically active for several months. Their apical organization, both before and after maturation, was studied by light and transmission electron microscopy. Each cell layer forms a dome, with an initial cell at its end. Xylem elements form a complicated triarch array at the base of the rootlet, passing along the rootlet as two files, and then joining at the tip to form a single file, surrounded by six pericycle cells. At the base of the rootlet, shorter xylem cells and thick-walled support cells are visible. A root cap, present in rootlets grown in vermiculite, was eventually displaced by root hair growth. Rootlets grown in Hoagland's solution lacked root caps and were significantly shorter than those grown in vermiculite. Cell fate was analysed in terms of cell position and is discussed in terms of pattern and development.     

Production of a highly asymmetric somatic hybrid between rice and Zizania latifolia (Griseb): evidence for inter-genomic exchange

 A highly asymmetric and fertile somatic hybrid plant was obtained via protoplast fusion in an intergenric combination. Gamma-ray-irradiated Zizania latifolia (Griseb). Turcz. ex Stapf mesophyll protoplasts were electrofused with idoacetamide-inactivated rice protoplasts derived from a 2-month-old suspension cell culture. Two of the six putative hybrid calli regenerated plants. Cytological observation showed that the somatic chromosome numbers of both plants were the same as the rice parent (2n=24). Nevertheless, the hybrid nature and inter-genomic exchange events of one of the plants, i.e. SH6 (SH for somatic hybrid), were confirmed by Southern analysis using both total genomic DNA and moderate-copy, Z. latifolia-abundant DNA sequences as probes; in both cases, parental specific and/or new intergenomic recombinant hybridization fragments were detected. In both plant and seed morphology, the hybrid (SH6) was distinct from its rice parental cultivar, as well as from the wild donor species, Z. latifolia. Received: 15 August 1998 / Accepted: 30 September 1998     

Fusion Experiments of Isolated Generative Cells in Several Angiosperm Species

The generative cells used for fusion experiments were isolated from pollen grains of Zephyranthes candida and Lycoris radiata by “2-step osmotic shock” and from those of Hippeastrum vittata, Hemerocallis minor and Iris tectorum by “weak enzyme treatment” as reported previously. Using PEG method, fusions have been successfully induced between generative cells of the same species mentioned above, between generative cells of Z. candida and L. radiata, between generative cells and petal protoplasts in L. radiata, and between generative cells of L. radiata and hypocotyl protoplasts of Brassica napus. In all cases either homokaryons or heterokaryons could be obtained. Fusion of nuclei was observed sometimes in homokaryons of generative cells in L. radiata. The generative nuclei in fusion products could be well identified by labelling the generative cells before fusion with DAPI. FDA test demonstrated that most of the fusion products were viable. Factors affecting fusion efficiency including cell density, PEG concentration, duration of PEG treatment and effect of calcium ions were studied in fusion of generative cells in Z. candida. Our experiments indicate that isolated generative cells are likely to be deprived of cell wails and may be regarded as a special kind of protoplasts for direct fusion experiments.