Ammonium (NH4 + ) represents a primary nitrogen source for many plants, its effective transport into and between tissues and further assimilation in cells determine greatly plant nitrogen use efficiency. However, biological components involved in NH4 + movement in woody plants are unclear. Here, we report kinetic evidence for cotton NH4 + uptake and molecular identification of certain NH4 + transporters (AMTs) from cotton (Gossypium hirustum). A substrate-influx assay using 15 N-isotope revealed that cotton possessed a high-affinity transport system with a Km of 58 μM for NH4 + . Sequence analysis showed that GhAMT1.1-1.3 encoded respectively a membrane protein containing 485, 509 or 499 amino acids. Heterologous functionality test demonstrated that GhAMT1.1-1.3 expression mediated NH4 + permeation across the plasma membrane (PM) of yeast and/or Arabidopsis qko-mutant cells, allowing a growth restoration of both mutants on NH4 + . Quantitative PCR measurement showed that GhAMT1.3 was expressed in roots and leaves and markedly up-regulated by N-starvation, repressed by NH4 + resupply and regulated diurnally and age-dependently, suggesting that GhAMT1.3 should be a N-responsive gene. Importantly, GhAMT1.3 expression in Arabidopsis improved plant growth on NH4 + and enhanced total nitrogen accumulation (∼50% more), conforming with the observation of 2-fold more NH4 + absorption by GhAMT1.3-transformed qko plant roots during a 1-h root influx period. Together with its targeting to the PM and saturated transport kinetics with a Km of 72 μM for NH4 + , GhAMT1.3 is suggested to be a high-affinity NH4 + permease that may play a significant role in cotton NH4 + acquisition and utilization, adding a new member in the plant AMT family.

Although many members encoding different ammonium- and nitrate-transporters (AMTs, NRTs) were identified and functionally characterized from several plant species, little is known about molecular components for NH4+- and NO3- acquisition/transport in tobacco, which is often used as a plant model for biological studies besides its agricultural and industrial interest. We reported here the first molecular identification in tobacco (Nicotiana tabacum) of nine AMTs and four NRTs, which are respectively divided into four (AMT1/2/3/4) and two (NRT1/2) clusters and whose functionalities were preliminarily evidenced by heterologous functional-complementation in yeast or Arabidopsis. Tissue-specific transcriptional profiling by qPCR revealed that NtAMT1.1/NRT1.1 mRNA occurred widely in leaves, flower organs and roots; only NtAMT1.1/1.3/2.1NRT1.2/2.2 were strongly transcribed in the aged leaves, implying their dominant roles in N-remobilization from source/senescent tissues. N-dependent expression analysis showed a marked upregulation of NtAMT1.1 in the roots by N-starvation and resupply with N including NH4+, suggesting a predominant action of NtAMT1.1 in NH4+ uptake/transport whenever required. The obvious leaf-expression of other NtAMTs e.g. AMT1.2 responsive to N indicates a major place, where they may play transport roles associated with plant N-status and (NH4+-)N movement within aerial-parts. The preferentially root-specific transcription of NtNRT1.1/1.2/2.1 responsive to N argues their importance for root NO3- uptake and even sensing in root systems. Moreover, of all NtAMTs/NRTs, only NtAMT1.1/NRT1.1/1.2 showed their root-expression alteration in a typical diurnal-oscillation pattern, reflecting likely their significant roles in root N-acquisition regulated by internal N-demand influenced by diurnal-dependent assimilation and translocation of carbohydrates from shoots. This suggestion could be supported at least in part by sucrose- and MSX-affected transcriptional-regulation of NtNRT1.1/1.2. Thus, present data provide valuable molecular bases for the existence of AMTs/NRTs in tobacco, promoting a deeper understanding of their biological functions.

In this article, by using a nutrient-hydroponic culture method, 15N-substrate labeling and mass spec-trum-based element measurement techniques, we identified firstly a minimum time when N was not transported to upper parts of two tobacco (Nicotiana tabacum) varieties after their root uptake of NH4+and NO3-, and subse-quently characterized processes and components of N absorption by roots. Our data show that the time for the movement of N from its uptake by the roots to the upper parts of the two varieties happened within only several minutes, and that at least two different systems for the N uptake should exist in the tobacco roots. When exter-nal N concentrations were ≤1 mmol·L-1, the process of the root N-uptake displayed an enzymatic action prop-erty; KM values [i.e. 'K326': 84.5 μmol·L-1; 'Honghuadajinyuan' ('HD'): 47.8 μmol·L-1] for NO3- absorbed by the roots were significantly lower than that for NH4+ ('K326': 93.5 μmol·L-1; 'HD': 90.4 μmol·L-1), suggesting that the lower KM for NH4+ or NO3- uptake by 'HD' would be one of critical physiological factors for a better tolerance of 'HD' to low N than that of 'K326'. As external N>1 mmol·L-1, N acquisition by the roots was posi-tively proportional to external N concentrations; the rate of NO3- uptake by 'K326' was more than 2-fold higher than that of by 'HD', and the rate of NH4+uptake by 'K326' was 2.4-fold lower than that of by 'HD'; the uptake rate of 'K326' for NO3- was 3.6-fold higher than for NH4+, and 'HD' for NO3- was half as many as for NH4+. Our results may provide physiological evidence for further exploration of molecular mechanisms of N uptake by the roots of tobacco plants.

Although biological functions of ammonium (NH4+) transporters (AMTs) have been intensively studied in many plant species, little is known about molecular bases responsible for NH4+ movement in tobacco. Here, we reported the identification and functional characterization of a putative NH4+ transporter NtAMT1.3 from tobacco (Nicotiana tabacum). Analysis in silico showed that NtAMT1.3 encoded an integral membrane protein containing 464 amino acid residues and exhibiting 10 predicted transmembrane α-helices. Heterologous functionality study demonstrated that NtAMT1.3 expression facilitated NH4+ entry across plasma membrane of NH4+-uptake defective yeast and Arabidopsis qko mutant, allowing a restored growth of both yeast and Arabidopsis mutant on low NH4+. qPCR assay revealed that NtAMT1.3 was expressed in both roots and leaves and significantly up-regulated by nitrogen starvation and resupply of its putative substrate NH4+ and even nitrate, suggesting that NtAMT1.3 should represent a nitrogen-responsive gene. Critically, constitutive overexpression of NtAMT1.3 in tobacco per se improved obviously the growth of transgenic plants on NH4+ and enhanced leaf nitrogen (15% more) accumulation, consistent with observation of 35% more NH4+ uptake by the roots of transgenic lines in 20min root-influx test. Together with data showing its plasma membrane localization and saturated transport nature with Km of about 50μM for NH4+, we suggest that NtAMT1.3 acts an active NH4+ transporter that plays a significant role in NH4+ acquisition and utilization in tobacco.

Quaternary ammonium based ionic liquids can be used as eco-friendly solvents/solubilizers for pesticide formulation processing without organic solvents.

Different mixed proportions of 1-butyl-3-methylimidazolium bromide ([C4mim][Br], A) and 1-decyl-3-methylimidazolium bromide ([C10mim][Br], B) can be used as solubilizers for water-insoluble pesticides.

Strawberry fruits are increasingly produced under continuous cultivation and K deficiency, but the response of strawberry to this combination of stresses has not been extensively studied. Pot and tissue culture grown strawberry (Fragaria ananassa Duch.) plants were used to determine the effect of strawberry root exudates on the growth of strawberry plants and Fusarium oxysporum under continuous cultivation and potassium (K) deficiency. The pot experimental results showed that the Fusarium wilt disease rating and index were very high (62% and 86, respectively), and the lateral roots of strawberry plants were significantly restricted under the continuous cultivation and K deficiency treatment. The growth of tissue culture plantlets was inhibited by a high concentration (4%) and promoted by a low concentration (1%) of root exudates from the replanted pot strawberries. The number of lateral roots of tissue culture plantlets was significantly lower in the 4% root exudate treatment. Growth of F. oxysporum was promoted by the relatively high concentration of root exudates of the replanted pot strawberry under continuous cultivation and K deficiency. Total phenolics and three individual phenolics (ferulic acid, p-coumaric acid and cinnamic acid) were detected in the rhizosphere soil of replanted pot strawberries and were higher in the K-deficiency treatments. Fusarium oxysporum growth was promoted by the addition of exogenously added phenolic acids. A positive relationship was observed between the growth of F. oxysporum and the higher concentration ranges of ferulic acid and p-coumaric acid.

离子型谷氨酸受体(iGLuR)是哺乳动物中一类由L-氨基酸(如谷氨酸、甘氨酸)等配体门控的阳离子通道,具有调节兴奋性神经信号传递和引导神经元发育等分子功能.1998年研究者在拟南芥(Arabidopsis thaliana)中发现了20个与iGLuRs同源的序列(即AtGLRs),它们的功能涉及植物光信号传递、根尖分生细胞活性、花粉管生长、胞质Ca2+流以及应答多种生物和非生物环境胁迫等.该文从谷氨酸受体(GLR)的结构特征、离子通道激活与配体的关系、表达模式及可能的生物学功能等方面,综述了近十几年来关于植物GLR和氨基酸信号的研究成果,旨在为相关领域的同行提供有益的参考.

Emulsifiers for pesticide microemulsions contain a part of volatile organic compounds (VOCs), and ionic liquids (ILs) are becoming potential substitutes. In order to apply ILs in pesticide microemulsions, the study of interaction between ILs and surfactants is necessary. Therefore, the surface properties and aggregation of anionic surfactant sodium dodecyl sulfate (SDS) in ILs, including N-hexyl-N-methylmorpholinyl bromide ([C6mm][Br]), N-hexyl-N-methylpiperidyl bromide ([C6mp][Br]), N-hexyl-N-methylpyrrolidyl bromide ([C6mpyr][Br]), N-octyl-N-methylpyrrolidyl bromide ([C8mpyr][Br]), N-dodecyl-N-methylpyrrolidyl bromide ([C12mpyr][Br]) and N-hexadecyl-N-methylpyrrolidyl bromide ([C16mpyr][Br]), were investigated in terms of surface tension, conductivity, dynamic light scattering (DLS), viscosity, fluorescence, pseudo-ternary phase diagram and 1H NMR measurements. Generally in agreement, the methods afforded the evaluation of various micellar parameters such as critical micelle concentration (CMC), degree of counterion ionization (α), the maximum surface excess concentration (Γmax), the minimum area per surfactant headgroup (Amin) as well as some thermodynamic parameters, including standard free energy of micellization (ΔG), standard enthalpy of micellization (ΔH) and standard entropy of micellization (ΔS). The results indicated a hydrophobic effect as the primary force of a spontaneous, exothermic, entropy driven micellization process. 1H NMR technique was applied to reveal the solubilization site and interaction of ILs in aqueous SDS micellar solutions. Fluorescence, DLS and viscosity measurements revealed considerable micellar morphologies and various phase behaviors. Furthermore, the 10% difenoconazole microemulsion was successfully prepared and showed good stability and spreadability in mixtures which indicated ILs' potential application in pesticide formulation.

Through the saturated water solution method,the guest body pendimethalin was tried to be included by the host body γ-cyclodextrin( γ-CD). Ultraviolet spectrum was used to determine the inclusion ratio in accordance with the Job's method,clarified that the inclusion molar ratio was 1∶ 1. Infrared spectrum proved that the benzene ring structure of the pendimethalin could be entered into the γ-CD's hydrophobicity cavity.The melting point of the pendimethalin was proved to be increased after the inclusion by thermal analysis. The emergence of the new diffraction peaks in powder X-ray diffraction atlas was attributed to the formation of new phase. The appearance of the inclusion was intuitively showed by the scanning electron microscopy( SEM).All of the results above indicated that the γ-CD-pendimethalin inclusion complex were obtained,and the equilibrium constant K was 1123. 99 L / mol. Both the melting point and the solubility of the pendimethalin were significantly improved by including,therefore,pendimethalin could be processed into water-based pesticide formulations in the form of the inclusion.

Tri-block poly (lactide)-poly (ethylene glycol)-poly (lactide), diacrylated derivative and the cypermethrin-loaded microcapsule were prepared, respectively. The structure of the copolymer was characterized by 1HNMR, FTIR, TGA and DSC. The microcapsules were characterized by OM(optical microscope), SEM, FTIR, TGA and DSC. The encapsulation efficiency of the microcapsules is 91.3%. The microcapsules showed good dispersity and sustained release behavior in 50% ethylene glycol aqueous solution.

Silica and a copolymer of silica–N-isopropyl acrylamide–bis-acrylamide were used as a controlled release material for preparing single- and double-shelled cyhalothrin microcapsules.

Three surface active ionic liquids (ILs) containing organic anions but no halides were used as solubilizers for water insoluble pesticides and as well as alternates for similar ILs with halide anions, which have been increasingly popular in the agricultural practice. The solubilities of five pesticides (fluazifop-P, clethodim, pyrethrin, fosthiazate, and prochloraz) in three aqueous micellar systems, each containing 1-octyl-3-methylimidazolium-tartrate ([OMIM][Tart]), 1-octyl-3-methylimidazolium-L-proline ([OMIM][Prol]), 1-octyl-3-methylimidazolium-L-lactate ([OMIM][lact]), respectively, were measured. The solubilities of all five pesticides were found to increase with the increasing concentrations of ILs solubilzers The enhancements in solubilities were related to surface activities of these SAILS, as indicated in the results of the measurements of their corresponding critical aggregation concentration (CAC), lowest surface tension (gamma(cac)), maximum surface excess concentration (Gamma(max)) and minimum area per molecule (A(min)) of aqueous solutions of ILs. When comparing with similar ILs with halides as counter anions, we found that these ILs with organic counterions are at least comparable, often more effective solubilizers for all of the five very different pesticides we tested. We conclude that these novel SAILs with organic counterions would serve as at least similarly effective and more environmentally-friendly solubilizers over the more traditional ones with halides. (C) 2015 Elsevier B.V. All rights reserved.

The adsorption of methacrylic acid-styrene-acrylic polyethers (MAA-St-APEG) copolymer on the insecticide imidacloprid particles was studied to calculate the kinetic, isotherm and thermodynamic parameters. The kinetic data followed the pseudo-second order kinetic model, and the equilibrium data were well fitted by the Langmuir isotherm model with the maximum adsorption amount of 7.610 mg·g-1 at 298 K. The calculated thermodynamic parameters including ΔG, ΔH and ΔS, demonstrated that this adsorption was a spontaneous and exothermic process in nature. Therefore, MAA-St-APEG copolymer are eligible for the dispersion of imidacloprid particles in aqueous solution as a effective dispersant.

Ionic liquids may be considered as "environment-friendly solvents" for sparingly soluble pesticides. In this study, a series of aqueous ionic liquids (ILs) with different cations and different anions was used as environment-friendly alternative to harmful organic solvents sparingly dissolved in soluble pesticides (metolachlor, acetochlor, clethodim, thiamethoxam, and prochloraz). The aggregation behavior of aqueous ILs was investigated through surface tension measurement. Minimum area per IL molecule (Amin) values from the surface tension measurement showed that alkyl chain length and the halide anions strongly affect the aggregation behavior of ILs and the solubilization of pesticides. The solubility of metolachlor, acetochlor, clethodim, thiamethoxam, nitenpyram, and prochloraz in aqueous ILs increased. More importantly, the solubility of prochloraz in [C10mim][I] became 5771-fold higher than that in pure water. The substantially enhanced solubility of the above pesticides proved that aqueous ILs are promising environment-friendly solvents for pesticides that are commercially processed in emulsifiable concentrate (EC) formulation.

Porous microspheres with different sizes were prepared through solvent evaporation method with ethylcellulose as a matrix material and abamectin as a core material. The abamectin-loaded microspheres were characterized through scanning electron microscopy (SEM), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The chemical structure of the microspheres was determined through FTIR. DLS analysis showed that the diameter of the microspheres range from 10 to 100 μm. SEM analysis revealed that the inner structure of the microspheres is characterized by a porous network. TGA revealed that the microspheres are thermally stable below 125 °C. The controlled release of abamectin from the microspheres into water and soil was also investigated. Abamectin was released from microspheres into water through diffusion. The release of abamectin into soil was mainly caused by erosion, a result that was verified through SEM.

Powdery mildew of strawberry is a major limitation for strawberry production in most strawberry growing areas of the world. Bio-control management is a good way to cope with this disease. Bacillus TS02 is a bio-control strain which was isolated from soil. The TS02 bio-controlling experiments were done according to the standard field experimental rule of pesticide controlling effect of China. The results indicate that TS02 can control strawberry powdery mildew. For the fermented liquid of TS02, above 3x10(7)CFU/ml live bacteria concentration can achieve ideal effects, the best effect is 52.23% with 3x10(9)CFU/ml live bacteria. There were 48.98, 34.89 and 24.63% bio-control effects respectively with the bacteria fermented liquid, pure live bacteria and filtrated bacteria fermented liquid, respectively, on strawberry powdery mildew, which showed the corporate results of live bacteria and secretion of bacteria. On the basis of the field experiments, the bio-control mechanism was studied in laboratory with the leaves in vitro. There was 100% growth inhibition by TS02 on Sphaerotheca macularis, TS02 can inhibit infection by the pathogen and control the strawberry disease.TS02 was identified as a new strain of Bacillus cereus based on the homology of its 16SrRNA sequences to the reference strains registered in Genbank. TS02 formed a monophyletic group with strains of the B. cereus complex group in the 16SrDNA sequence analysis, and shared similarity values of 99.9% with the Bacillus cereus strains in the sequence analysis.

The adsorption thermodynamics and kinetics of three dispersants(Morwet D-425,GYD-1252and LG-3)onto pesticide imidacloprid particle surface were studied in order to compare adsorption properties.Adsorption data of three dispersants onto imidacloprid were fitted with Langmuir and Freundlich isotherm equations,and the former fitted better.The thermodynamic parameters:ΔH <0,ΔG<0,ΔS>0,indicated that the adsorption was a spontaneous exothermic process.Theoretically,higher temperature was not beneficial to adsorption process,|ΔH|<40kJ·mol-1indicated that the adsorption process was physical adsorption.The conclusion obtained by comparing adsorption properties showed that Morwet D-425 had higher adsorption stability and was not susceptible to temperature effects,LG-3 had lower adsorption stability and was susceptible to temperature effects,adsorption stability of GYD-1252 was in between.The adsorption process followed the pseudo-second-order with a good correlation coefficient.The step of adsorption process included the external diffusion and adsorption onto particle surface,without intraparticle diffusion.Descending order of adsorption rate was Morwet D-425,GYD-1252 and LG-3.The result of adsorption layer thickness by XPS showed that Morwet D-425had smaller adsorbed layer thickness which changed little with increasing temperature due to higher adsorption stability.GYD-1252 and LG-3had larger adsorbed layer thickness which decreased significantly with increasing temperature due to weak adsorption stability.