The solid lithium-ion electrolyte ''Li 7 La 3 Zr 2 O 12 '' (LLZO) with a garnet-type structure has been prepared in the cubic and tetragonal modification following conventional ceramic syntheses routes. Without aluminium doping tetragonal LLZO was obtained, which shows a two orders of magnitude lower room temperature conductivity than the cubic modification. Small concentrations of Al in the order of 1 wt% were sufficient to stabilize the cubic phase, which is known as a fast lithium-ion conductor. The structure and ion dynamics of Al-doped cubic LLZO were studied by impedance spectroscopy, dc conductivity measurements, 6 Li and 7 Li NMR, XRD, neutron powder diffraction, and TEM precession electron diffraction. From the results we conclude that aluminium is incorporated in the garnet lattice on the tetrahedral 24d Li site, thus stabilizing the cubic LLZO modification. Simulations based on diffraction data show that even at the low temperature of 4 K the Li ions are blurred over various crystallographic sites. This strong Li ion disorder in cubic Al-stabilized LLZO contributes to the high conductivity observed. The Li jump rates and the activation energy probed by NMR are in very good agreement with the transport parameters obtained from electrical conductivity measurements. The activation energy E a characterizing longrange ion transport in the Al-stabilized cubic LLZO amounts to 0.34 eV. Total electric conductivities determined by ac impedance and a four point dc technique also agree very well and range from 1 Â 10 À4 Scm À1 to 4 Â 10 À4 Scm À1 depending on the Al content of the samples. The room temperature conductivity of Al-free tetragonal LLZO is about two orders of magnitude lower (2 Â 10 À6 Scm À1 , E a = 0.49 eV activation energy). The electronic partial conductivity of cubic LLZO was measured using the Hebb-Wagner polarization technique. The electronic transference number t eÀ is of the order of 10 À7. Thus, cubic LLZO is an almost exclusive lithium ion conductor at ambient temperature.

Land plants evolved from charophytic algae, among which Charophyceae possess the most complex body plans. We present the genome of Chara braunii; comparison of the genome to those of land plants identified evolutionary novelties for plant terrestrialization and land plant heritage genes. C. braunii employs unique xylan synthases for cell wall biosynthesis, a phragmoplast (cell separation) mechanism similar to that of land plants, and many phytohormones. C. braunii plastids are controlled via landplant-like retrograde signaling, and transcriptional regulation is more elaborate than in other algae. The morphological complexity of this organism may result from expanded gene families, with three cases of particular note: genes effecting tolerance to reactive oxygen species (ROS), LysM receptor-like kinases, and transcription factors (TFs). Transcriptomic analysis of sexual reproductive structures reveals intricate control by TFs, activity of the ROS gene network, and the ancestral use of plant-like storage and stress protection proteins in the zygote.

A new subfamily of sucrose transporters from Arabidopsis ( AtSUT4 ), tomato ( LeSUT4 ), and potato ( StSUT4 ) was isolated, demonstrating only 47% similarity to the previously characterized SUT1. SUT4 from two plant species conferred sucrose uptake activity when expressed in yeast. The K m for sucrose uptake by AtSUT4 of 11.6 ؎ 0.6 mM was ‫ف‬ 10-fold greater than for all other plant sucrose transporters characterized to date. An ortholog from potato had similar kinetic properties. Thus, SUT4 corresponds to the low-affinity/high-capacity saturable component of sucrose uptake found in leaves. In contrast to SUT1, SUT4 is expressed predominantly in minor veins in source leaves, where high-capacity sucrose transport is needed for phloem loading. In potato and tomato, SUT4 was immunolocalized specifically to enucleate sieve elements, indicating that like SUT1, macromolecular trafficking is required to transport the mRNA or the protein from companion cells through plasmodesmata into the sieve elements. INTRODUCTIONThe reduced carbon produced through photosynthesis in mature leaves is distributed by the vascular system, mainly in the form of sucrose, to support the growth of heterotrophic (sink) tissues such as developing leaves, the shoot apex, roots, and reproductive organs. Within the vascular tissue, the sieve elements in the phloem form the conduits for long-distance transport. Sieve elements are highly specialized, lacking many organelles (including a nucleus and vacuole) at maturity, and hence depend on tightly associated companion cells for metabolic support (Sjölund, 1997). The loading of sucrose into the sieve element/companion cell (SE/CC) complex in many plants requires the active uptake of sucrose from the extracellular space. Because of variability in the rate of photosynthesis according to changes in environmental conditions, and because sink demands change depending on development and external factors, we can reasonably assume that the rate of phloem loading of sucrose is regulated. In fact, the phenotype of transgenic plants overexpressing pyruvate decarboxylase indicates that sugar export from potato leaves can be upregulated by as much as 10-fold (Tadege et al., 1998). The increase in sucrose transport activity caused by modification of a conserved histidine in the first external loop (Lu and Bush, 1998) indicates that sucrose transporters may be directly regulated at the protein level. In addition, the amounts of mRNA for sucrose transporter SUT1 from potato are developmentally controlled and hormonally regulated (Riesmeier et al., 1993;Harms et al., 1994).Clearly, multiple kinetic components of sucrose uptake are present in leaves (Delrot and Bonnemain, 1981;Maynard and Lucas, 1982). As demonstrated by autoradiography, 14 C-sucrose, externally applied to source leaves of Vicia faba or Beta vulgaris , is taken up by mesophyll cells and phloem (Fondy and Geiger, 1977;Giaquinta, 1977;Delrot, 1981). The overall K m for sucrose uptake into leaves is pH dependent, with greater affinity being measured at ...

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