The Effect of Cyclopropane on Ion Uptake and Protoplasmic Streaming in Barley Roots

Increasing concentrations of cyclopropane up to about 95 % C₃H₆—5 % O₂ caused an increasing inhibition of uptake by excised barley roots from KC1 solution, much more so for Cl than K. No inhibition of K uptake from K₂SO₄ occurred under similar conditions. It is suggested that the small decrease in K uptake from KC1 is related to the large decrease in Cl uptake and that C₃H₆ primarily inhibits Cl uptake with little or no effect on K uptake. Time curves of uptake in 80 % C₃H₆ 20 % O₂ revealed no indication of cumulative injury in either KC1 or K₂SO₄ for periods up to 3 hours. The amount of organic acid production associated with K uptake from K₂SO₄ was about the same in 80 % C₃H_g— 20 % O₂ as in air. Oxygen consumption in K₂SO₄ was unaffected by the gas mixture and only slightly affected in KC1. Protoplasmic streaming in epidermal cells was rapidly stopped at C₃H₆ concentrations of 20 % or higher. In 80 % C₃H₆–20 % O₂ the effect on streaming was confined mostly to the outer two or three layers of root cells. A connection between the cessation of streaming and the inhibition of Cl uptake appeared to exist but very little if any relationship between streaming and K uptake was observed.     

Dynamics of Charged Dust Grains in Limited-Size Cluster Systems

Plasma Physics Reports - The results are presented from numerical studies of the dynamics of limited-size ensembles of charged dust grains in the potential field of electrostatic trap. The...     

Effect of Dust Charge Fluctuation on Ion Acoustic Waves in a Plasma with Nonextensive Electrons

Plasma Physics Reports - The linear dispersion for ion acoustic waves (IAWs) including the effects of dust charge fluctuation and electron nonextensivity is derived. It is shown that the presence...     

Mineral Ion Nutrition of Developing Barley Grains 1. Effect of Magnesium Deficiency on Ion Content of Immature Embryos and Endosperms

The effect on the mineral ion nutrition of developing barleyembryos and endosperms was studied when both Mg and Mn werewithdrawn simultancously from the rooting medium. Both embryosand endosperms had lower Mg levels, on average 40 and 50 percent, respectively, over the developmental period, than thosefrom control plants grown in complete nutrient solution. Comparedto the controls, higher levels of Mn (average 20 per cent) andCa (average 20 per cent) were found in Mg-deficient embryosfrom test plants, but Mn levels were lower (average 30 per cent)and Ca levels unaffected in Mg-deficient endosperms. K levelsin both embryos and endosperms were not changed. The endospermsfrom test plants had lower total N levels than the controls. Hordeum vulgare L., barley, embryo, endosperm, sand culture, magnesium, manganese, calcium, potassium, nitrogen, mineral nutrition     

Charging of Dust Grains in a Nuclear-Induced Plasma at High Pressures

The process of dust-grain charging in plasmas produced by radioactive decay products or spontaneous fission fragments in air and xenon at high pressures is studied numerically in the hydrodynamic approximation. It is shown that, at sufficiently high rates of gas ionization, the dust grains in air are charged by electrons rather than ions, so that the grain charge in air is comparable to that in electropositive gases. The results of numerical calculations based on a complete model agree well with the experimental data. The time evolution of the grain charge is investigated, and the characteristic time scales on which the grains acquire an electric charge are established. The validity of approximate theories of dust-grain charging in electropositive and electronegative gases at high pressures is examined.     

Ion Diffusion Selectivity in Lecithin-Water Lamellar Phases

The diffusion coefficients of Na⁺, Rb⁺, and cl^- were determined in lecithin-water lamellar phases at 18°C as a function of phase hydration. Diffusion was measured within the phase with no transfer between phase and bulk aqueous medium. The relative diffusion coefficients of anion and cation depended strongly on phase hydration. At low water content, the diffusion coefficient of Cl^- was greater than that of Na⁺ or Rb⁺ whereas at high water content both cations diffused faster than the anion. The change in relative diffusion coefficient occurred at 0.24 g water/g phase (24% water). The possibility that a change in conformation of the lecithin polar head occurs at a phase water content of 24% is considered. The diffusion coefficients of all three ions decreased at the water content where the relative diffusion rates inverted. Freeze fracture and polarizing microscopy studies were carried out to obtain information on phase structure. The latter study indicated that a change in long-range organization of the phase occured at 24% water. This change accounts for the decrease in the ion diffusion coefficients at this water content. The change in conformation of the choline phosphate group proposed as an explanation for the change in ion selectivity could lead to changes in long-range organization of the phase as a second order-effect.     

Observation of Pseudocapacitive Effect and Fast Ion Diffusion in Bimetallic Sulfides as an Advanced Sodium‐Ion Battery Anode

Sodium‐ion batteries (SIBs) are promising next‐generation alternatives due to the low cost and abundance of sodium sources. Yet developmental electrodes in SIBs such as transition metal sulfides have huge volume expansion, sluggish Na⁺ diffusion kinetics, and poor electrical conductivity. Here bimetallic sulfide (Co₉S₈/ZnS) nanocrystals embedded in hollow nitrogen‐doped carbon nanosheets are demonstrated with a high sodium diffusion coefficient, pseudocapacitive effect, and excellent reversibility. Such a unique composite structure is designed and synthesized via a facile sulfidation of the CoZn‐MOFs followed by calcination and is highly dependant on the reaction time and temperature. The optimized Co₁Zn₁‐S(600) electrode exhibits excellent sodium storage performance, including a high capacity of 542 mA h g^?1 at 0.1 A g^?1, good rate capability at 10 A g^?1, and excellent cyclic stability up to 500 cycles for half‐cell. It also shows potential in full‐cell configuration. Such capabilities will accelerate the adoption of sodium‐ion batteries for electrical energy applications.     

Isoenzyme Polymorphism in Flowering Plants I. Diffusion of Enzymes Out of Intact Pollen Grains

Esterases, leucine aminopeptidases, catalases, amylases and acid phosphatases diffuse out of intact and ungerminated pollen grains of Oenothera organensis, whether suspended in 1 % sodium chloride or in pollen medium. A total of 15 esterase isozymes are recorded; 5 of them appear within 5 minutes, 8 within 30 minutes, 9 within 2 hours, and 13 within 19 hours. Pollen grains suspended for 19 hours gave much stronger isozyme bands than macerated pollen grains. However, one esterase hand was consistently missing from the 19 hour suspensions, although present in all others. It is suggested as a working hypothesis that the early growth of pollen tubes and possibly even germination of pollen grains may be influenced by the metabolic products of pistillate tissues caused by the diffused pollen enzymes, and that inactivation of these enzymes by stigmatic or stylar components could lead to incompatibility reactions.     

Effect of Thermolability of Milk Proteins on Ion Distribution in Skimmed Milk-Water-Salt,Two-Phase System

Significant increases in concentrations of bivalent metals (Ca²⁺, Mg²⁺, and Cd²⁺) in the protein phase were observed after acidification (pH 4.7) of skimmed milk preheated at 95°C for 90 min. The increase was caused by denaturation of milk whey proteins and formation of protein–protein and protein–carbohydrate aggregates. Preheating did not influence the distribution of nitrate ions in the two-phase system.     

Effect of Seawater on Photosynthesis and Dry Matter Accumulation in Developing Rice Grains

To understand the physiology of rice under seawater salinity, potted rice plants were irrigated with different concentrations of Japan seawater (electrical conductivity 0.9, 5.7, 11.5, or 21.5 mS cm^-1) from 10 d after transplanting (DAT) to 35 DAT, and from 75 to 100 DAT. Seawater salinity decreased the net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, transpiration rate, leaf water and osmotic potentials, and relative water content, and increased leaf temperature. The contents of chlorophylls, carotenoids, and total sugars significantly decreased in the leaves but content of non-reducing sugars decreased only slightly. With increasing salinity the Na⁺ concentration increased, while Ca²⁺, Mn²⁺, and K⁺ concentrations decreased. Salinity decreased the contents of sugars and proteins, dry mass, and rate of dry mater accumulation in developing grains.     

Control of Nutrient Solution pH with an Ion Exchange System: Effect on Soybean Nodulation

Growth and nodulation response of soybean (Glycine max (L.) Merr.) to various single nitrogen sources in solution culture is confounded by unequal shifts in solution pH. A recirculating ion exchange system was designed in which a cation exchange resin (Amberlite IRC 50) was used to control the pH of solutions in which soybeans were grown. Nutrient solution pH levels were established at range extremes of 9.0 to 3.7 with 100% Ca²⁺ or H⁺ forms of resin, respectively. Intermediate pH levels were established by varying the ratio of Ca²⁺ to H⁺ forms of resin. The system is capable of maintaining pH within 0.5 to 0.9 units of the initial pH over a two-week growth period of soybeans with either nitrate- or urea-N sources. In the absence of the resin column, pH of the urea nutrient solution rapidly declined to less than pH 4 which resulted in depressed plant nodule development. The optimum pH range for nodule mass and N₂ fixation (measured by acetylene reduction) was between 5.2 and 7.0 with urea nutrition. Both nitrate- and ammonium-N sources were inhibitory to acetylene reduction in comparison with urea which allowed extensive nodule development and activity.     

Inhibitory Effect of Magnesium Ion on the Human Placental Alkaline Phosphatase-Catalyzed Reaction in a Reverse Micellar System

Human placental alkaline phosphatase is a membrane-anchored protein. Entrapping the enzyme into a reverse micellar vesicle mimics the in vivo conditions and allows examination of the properties of the enzyme. Placental alkaline phosphatase is enzymatically active in Aerosol-OT/isooctane reverse micelles. Substantially different kinetic behavior of the enzyme has been observed in aqueous or reverse micellar systems. In aqueous solution, Mg²⁺ is a nonessential activator of the enzyme. In the experiments described in the present report Mg²⁺ was found to be an inhibitor for the enzyme in reverse micelles. This inhibition is presumably due to a time-dependent conformational change of the enzyme molecule, which resulted in a curvature in the recorder tracings of the enzyme assays. The Mg²⁺-induced conformational change of the enzyme was completely prevented by phosphate and partially reserved by EDTA. High concentrations of Zn²⁺ also strongly inhibited enzyme activity in both aqueous and reverse micellar solvent systems, presumably by occupying the Mg²⁺ (M3) site of the enzyme. However, binding of Zn²⁺ at the M3 site did not cause conformational change of the enzyme and the enzyme assay tracing was linear. The M3 site of the enzyme is proposed to have a modulatory role in vivo using magnesium ion as the modulator.     

Quasiperiodic Route to Chaos for the Dust Ion Acoustic Waves in Magnetized Dusty Plasmas

Plasma Physics Reports - Quasiperiodic and chaotic features of the dust ion acoustic (DIA) waves in a magnetized dusty plasma is studied. Reductive perturbation technique (RPT) is used to derive...     

Optimized Temperature Effect of Li‐Ion Diffusion with Layer Distance in Li(NixMnyCoz)O2 Cathode Materials for High Performance Li‐Ion Battery

Understanding and optimizing the temperature effects of Li‐ion diffusion by analyzing crystal structures of layered Li(Ni_xMn_yCo_z)O₂ (NMC) (x + y + z = 1) materials is important to develop advanced rechargeable Li‐ion batteries (LIBs) for multi‐temperature applications with high power density. Combined with experiments and ab initio calculations, the layer distances and kinetics of Li‐ion diffusion of LiNi_xMn_yCo_zO₂ (NMC) materials in different states of Li‐ion de‐intercalation and temperatures are investigated systematically. An improved model is also developed to reduce the system error of the “Galvanostatic Intermittent Titration Technique” with a correction of NMC particle size distribution. The Li‐ion diffusion coefficients of all the NMC materials are measured from ?25 to 50 °C. It is found that the Li‐ion diffusion coefficient of LiNi_0.6Mn_0.2Co_0.2O₂ is the largest with the minimum temperature effect. Ab initio calculations and XRD measurements indicate that the larger Li slab space benefits to Li‐ion diffusion with minimum temperature effect in layered NMC materials.     

Effect of Nonreciprocal Forces on the Stability of Dust Clusters

Plasma Physics Reports - Results are presented from studies of the stability of the plane dust clusters in the form of a regular polygon with the number of particles from two to five. It is assumed...     

Effect of Post-anthesis Drought on Cell Division and Starch Accumulation in Developing Wheat Grains

Wheat plants (Triticum aestivum L., cv. Warigal) were subjectedto 20 d of water deficit during the period of endosperm celldivision. Drought accentuated the differences in final grainweight between spikelets and between grains within spikelets.The distal grains of top spikelets were most affected by drought.The maximum number of endosperm cells was, respectively, 30and 40 per cent lower in basal grains and distal grains of draughtedplants. In basal grains of middle spikelets, the number of largestarch granules per cell was unaffected but the number of smallstarch granules per cell was 45 per cent lower in grains ofdraughted plants. The initiation of small starch granules wasmore affected than cell division because severe water deficitoccurred earlier during the former process than the latter.Final dry weight appeared to correlate well with the maximumnumber of endosperm cells, but depended also on the number ofstarch granules per cell. Consequently, the amount of dry matterper cell was not constant in both treatments. The concentration of sucrose per endosperm cell was lower onlyin the droughted distal grains of top spikelets. The supplyof sucrose to endosperm cells did not regulate the initiationof small starch granules. Triticum aestivum L., wheat, drought, grain growth, cell division, starch     

离子注入氧化葡萄糖酸杆菌的诱变效应

本文运用离子注入对维生素C前体2—酮基—L—古龙酸的产生菌氧化葡萄糖酸杆菌的诱变效应进行了研究,确立了以8％甘油作保护剂,并就低能离子注入条件进行了参数设定。     

Toxic Effect of Terbium Ion on Horseradish Cell

The toxic effect of terbium (III) ion on the horseradish cell was investigated by scanning electron microscopy, gas chromatography, and standard biochemical methods. It was found that the activity of horseradish peroxidase in the horseradish treated with 0.2 mM terbium (III) ion decreased and led to the excessive accumulation of free radicals compared with that in the control horseradish. The excessive free radicals could oxidize unsaturated fatty acids in the horseradish cell and then increase the cell membrane lipid peroxidation of horseradish. The increase in the lipid peroxidation could lead to the destruction of the structure and function of the cell membrane and then damage of the horseradish cell. We propose that this is a possible mechanism for the toxic action of terbium in the biological systems.