Plant Responses to Brief Touching: A Mechanism for Early Neighbour Detection?

In natural habitats plants can be exposed to brief and light contact with neighbouring plants. This mechanical stimulus may represent a cue that induces responses to nearby plants. However, little is known about the effect of touching on plant growth and interaction with insect herbivores. To simulate contact between plants, a soft brush was used to apply light and brief mechanical stimuli to terminal leaves of potato Solanum tuberosum L. The number of non-glandular trichomes on the leaf surface was counted on images made by light microscope while glandular trichomes and pavement cells were counted on images made under scanning electronic microscope. Volatile compounds were identified and quantified using coupled gas chromatography–mass spectrometry (GC-MS). Treated plants changed their pattern of biomass distribution; they had lower stem mass fraction and higher branch and leaf mass fraction than untouched plants. Size, weight and number of tubers were not significantly affected. Touching did not cause trichome damage nor change their total number on touched terminal leaves. However, on primary leaves the number of glandular trichomes and pavement cells was significantly increased. Touching altered the volatile emission of treated plants; they released higher quantities of the sesquiterpenes (E)-β-caryophyllene, germacrene D-4-ol and (E)-nerolidol, and lower quantities of the terpenes (E)-ocimene and linalool, indicating a systemic effect of the treatment. The odour of touched plants was significantly less preferred by the aphids Macrosiphum euphorbiae and Myzus persicae compared to odour of untouched plants. The results suggest that light contact may have a potential role in the detection of neighbouring plants and may affect plant-insect interactions.     

Drought-Tolerance of Wheat Improved by Rhizosphere Bacteria from Harsh Environments: Enhanced Biomass Production and Reduced Emissions of Stress Volatiles

Water is the key resource limiting world agricultural production. Although an impressive number of research reports have been published on plant drought tolerance enhancement via genetic modifications during the last few years, progress has been slower than expected. We suggest a feasible alternative strategy by application of rhizospheric bacteria coevolved with plant roots in harsh environments over millions of years, and harboring adaptive traits improving plant fitness under biotic and abiotic stresses. We show the effect of bacterial priming on wheat drought stress tolerance enhancement, resulting in up to 78% greater plant biomass and five-fold higher survivorship under severe drought. We monitored emissions of seven stress-related volatiles from bacterially-primed drought-stressed wheat seedlings, and demonstrated that three of these volatiles are likely promising candidates for a rapid non-invasive technique to assess crop drought stress and its mitigation in early phases of stress development. We conclude that gauging stress by elicited volatiles provides an effectual platform for rapid screening of potent bacterial strains and that priming with isolates of rhizospheric bacteria from harsh environments is a promising, novel way to improve plant water use efficiency. These new advancements importantly contribute towards solving food security issues in changing climates.     

Ordered Network of Interconnected SnO2 Nanoparticles for Excellent Lithium‐Ion Storage

An ordered network of interconnected tin oxide (SnO₂) nanoparticles with a unique 3D architecture and an excellent lithium‐ion (Li‐ion) storage performance is derived for the first time through hydrolysis and thermal self‐assembly of the solid alkoxide precursor. Mesoporous anodes composed of these ≈9 nm‐sized SnO₂ particles exhibit substantially higher specific capacities, rate performance, coulombic efficiency, and cycling stabilities compared with disordered nanoparticles and commercial SnO₂. A discharge capacity of 778 mAh g^–1, which is very close to the theoretical limit of 781 mAh g^–1, is achieved at a current density of 0.1 C. Even at high rates of 2 C (1.5 A g^–1) and 6 C (4.7 A g^–1), these ordered SnO₂ nanoparticles retain stable specific capacities of 430 and 300 mAh g^–1, respectively, after 100 cycles. Interconnection between individual nanoparticles and structural integrity of the SnO₂ electrodes are preserved through numerous charge–discharge process cycles. The significantly better electrochemical performance of ordered SnO₂ nanoparticles with a tap density of 1.60 g cm^–3 is attributed to the superior electrode/electrolyte contact, Li‐ion diffusion, absence of particle agglomeration, and improved strain relaxation (due to tiny space available for the local expansion). This comprehensive study demonstrates the necessity of mesoporosity and interconnection between individual nanoparticles for improving the Li‐ion storage electrochemical performance of SnO₂ anodes.     

Isolation, X-ray single crystal and theoretical study of quinquevalent metal oxoisopropoxides, Nb6O8(PrO)14(PrOH)2 and Re4O6(OPr)10

Oxoisopropoxide complexes of niobium, Nb₆O₈(ⁱPrO)₁₄(ⁱPrOH)₂ (I), and rhenium, Re₄O₆(OⁱPr)₁₀ (II), were isolated as byproducts of anodic oxidation of these metals in ⁱPrOH in the presence of LiCl as conductive additive. The common feature of both structures consists in the occurrence in their molecules of an M₄O₁₆ planar core formed in the formal absence of M-M bonding for I and in the presence of electron-deficient but surprisingly short (Re-Re 2.52-2.54 Å) metal-metal bonds in II. The stability of this core for the oxoalkoxide derivatives of rhenium(V,VI) and niobium(V) and poor stability for those of tantalum(V) are discussed based on the results of quantum-chemical calculations.     

The synthesis of iron (III) ethoxide revisited: Characterization of the metathesis products of iron (III) halides and sodium ethoxide

Interaction of FeX₃, X = Cl, Br with 3 equiv. of NaOEt in toluene/ethanol media provides mixtures of iron (III) oxoethoxide, Fe₅O(OEt)₁₃, and its halide alkoxide analogs. The latter have been identified by mass-spectrometric study as Fe₅O(OEt)₁₂X and Fe₅O(OEt)₁₁X₂. Application of FeBr₃ as a starting material leads to much more pure samples of Fe₅O(OEt)₁₃ isolated with higher yields.