Excess sulfate supply and onion‐induced human antiplatelet activity

Awareness is growing of health‐promoting functional foods and the use of various plants as nutraceuticals. Due to a suite of organosulfur compounds, onion, and other vegetable Alliums possess a unique antiplatelet effect that may promote cardiovascular health because aggregating platelets can lead to heart attack and stroke. Investigation of the consequences of S nutrition in onion has primarily focused on levels of S ranging from deficiency to just above sufficiency; however, little work has been conducted to examine the effects of supraoptimal S nutrition on organosulfur‐based traits. Four onion selections were grown in hydroponic solutions with 2, 7, and 12 mM SO₄^2—‐S in greenhouse experiments during 1995—1996 and 1996—1997. Onion plants were separated into root, leaf, and bulb portions and analyzed for mineral content. Onion bulb extracts were assayed for in vitro human antiplatelet activity. Bulb and leaf S were not affected by increasing solution culture S, but root S was increased by 98 % when solution culture S was increased from 2 mM to 12 mM. Similar increases in root Ca and Al were detected, suggesting CaSO₄ and AlSO₄⁺ were accumulated in and on the root. No directional change in antiplatelet activity was detected as S was increased from 2 to 12 mM. This lack of significant change in antiplatelet activity with increasing S levels suggests that modification of this trait by simply increasing S levels may not be feasible in a solution culture environment.     

Sulfur uptake and remobilization are differentially affected by N deficiency in winter oilseed rape cultivars

Genotypic variation in nitrogen (N) efficiency of rapeseed is caused by differences in reproductive growth. This might be related to genotypic variation in sulfur (S) utilization. In this study it was tested if S deficiency in growing plant parts is induced under N-limiting conditions due to high sulfate accumulation in mature leaves which is poorly remobilized. Leaf S remobilization was compared under high and low N supply in four rapeseed cultivars that were grown in hydroponics with leaf-senescence induction by shading. Low N conditions did not increase sulfate accumulation in mature leaves. Total S remobilization from the leaves was higher under N-limiting than N-sufficient conditions. The proposed S deficiency in young plant parts therefore may not be more probable under low than under high N conditions. However, genotypic variation in S uptake and remobilization was found under N-limiting conditions only and might therefore contribute to genotypic variation in reproductive growth.     

Effects of chloride and sulfate application on root growth of rice

In several studies, the beneficial effects of the application of chloride on root growth have been reported. However, the effect of chloride application on the morphology of roots has not been studied extensively. The effects of the use of chloride salts and sulfate salts on the growth of rice (Oryza sativa L.) until the 7-leaf stage were investigated in soil and water culture experiments. In the soil culture experiments, the root biomass in the chloride treatment showed a 58% increase compared with the sulfate treatment. Total root length, top root ratio (T / R ratio) and root length per primary root revealed the existence of root growth promotion by chloride. In the water culture experiments, root growth was also stimulated by chloride, as in the soil culture experiments. In order to analyze the effect of chloride application, the ion composition and pH of the soil solution or water culture solution were used to determine the amounts of ion species in the solution using the MINTEQA2 computer program, and the results were applied to estimate the osmotic pressure of these solutions. The osmotic pressure of chloride salts was obviously higher than that of sulfate salts based on van't Hoff's law of osmotic pressure and a positive correlation between the osmotic pressure and root length was obtained. The results suggest that the higher osmotic pressure induced by chloride would be involved in the root growth promotion of rice.     

Growth and uptake of Cd and Zn by Leucaena leucocephala in reclaimed soils as affected by NaCl salinity

Heavy metal accumulation in reclaimed soils is increasing rapidly in developing countries where the use of saline waters for irrigation is a common practice, even though salinity-heavy metal interactions are not fully understood. An example for this development is the Bangar area of Egypt where the application of contaminated amendments during the last 30 years has increased the Cd and Zn concentrations in topsoils from 0.08 to 0.76 mg · kg^—1 and from 17 to 73 mg · kg^—1 respectively. This work aimed at evaluating the uptake of Cd and Zn by Leucaena leucocephala, a leguminous tree cropped for fodder and green manure, as affected by the addition of 10 mM NaCl to irrigation water. During a 6 month field experiment, salinized and control plots were compared with respect to soil solution composition and root development as well as the uptake of Cd and Zn and their translocation to the leaves. NaCl treatment raised the concentration of organic carbon, Cd and Zn in soil solution and enhanced the uptake of Cd and Zn significantly. Salinized plants showed shorter roots, reduced retention of Cd and Zn in roots and stems and considerable translocation of both elements to the leaves. This work demonstrates that NaCl salinity affects not only the bioavailability of soil Cd and Zn but also modifies plant functions related to their acquisition and translocation to the leaves. The results provide evidence that the risk of transfer of heavy metals to the food chain and their leachability to the ground water may be greater under saline conditions than generally assumed.     

Pungency of Spring Onion as Affected by Inoculation with Arbuscular Mycorrhizal Fungi and Sulfur Supply

ABSTRACT

The influence of sulfur (S) supply and mycorrhizal colonization on the growth and pungency of spring onion (Allium fistulosum L.) seedlings grown for four months in Perlite and nutrient solution containing three levels of sulfate [0.1, 1.75, and 4 mM sulfate (SO₄ ^2?)] were investigated. Plants were inoculated with Glomus etunicatum, Glomus intraradices, or Glomus mosseae, and uninoculated controls were included. Shoot and root dry weights of mycorrhizal and control plants supplied with 4 mM SO₄ ²⁺ were higher than with 0.1 or 1.75 mM SO₄ ^2?. Enzyme produced pyruvic acid (EPY) and plant sulfur concentrations increased with increasing SO₄ ^2? supply. The EPY and plant S concentrations were usually higher in mycorrhizal plants than controls irrespective of S supply, and shoot total S concentrations and EPY were strongly correlated. Arbuscular mycorrhizal colonization appeared to make a substantial contribution to the sulfur status of spring onion, and may thus have had a strong influence on its flavor characteristics.     

氯化钾对玉米茎腐病抗性反应中酚类物质代谢的影响

采用田间试验,比较人工接种禾谷镰刀菌（Fusarium graminearum）后,不同氯化钾处理对玉米酚类物质代谢的影响,揭示氯化钾提高作物抗病过程中的酚类物质代谢机理。结果表明,诱导接菌加速了玉米对K+的吸收,且施用氯化钾可以提高接菌后玉米茎髓中苯丙氨酸解氨酶（PAL）的诱导活性,加速多酚氧化酶（PPO）活性的升高,提高过氧化物酶（POD）活性的峰值。此外,施钾还有利于增加茎髓中固有木质素的含量,增加诱导产生的木质素和总酚的积累量。说明钾素可以通过调节酚类物质的代谢,增强次生代谢能力,提高玉米对茎腐病的抗性。     

玛纳斯河流域不同地貌单元弃耕地土壤盐分差异研究

本文在玛纳斯河流域中,选择冲洪积扇、冲积平原和干三角洲等不同地貌部位撂荒多年的弃耕地,分析土壤盐分动态变化及盐渍化类型的差异,探究土壤盐分的积聚特征,以期对弃耕地的生态重建提供参考依据。结果表明,自冲洪积扇缘带经冲积平原到干三角洲地区土壤盐分逐渐降低,土壤盐分表聚发生在冲洪积扇缘带和冲积平原中部,流域下游存在盐分向底层聚集的漏斗效应。7~10月份除冲洪积扇缘带外其他地貌类型区土壤盐分没有显著变化。流域表层盐渍土在冲洪积扇区以硫酸盐型或氯化物硫酸盐型为主,在冲积平原中部则为氯化物型,经冲积平原下部到干三角洲地区又逐渐演变为以氯化物硫酸盐型为主。     

Dynamics of sulfate and basic cations in soil solution as affected by gypsum fertilization in an Ultisol of Southern Brazil

ABSTRACT

The objective of this study was to evaluate the short-term dynamics of chemical species of sulfate and the main basic cations in the soil solution affected by the application of different sulfur (S) rates using agricultural gypsum. The experiment was carried out in an Ultisol with 14% clay, managed under no-tillage for 14 yrs in Southern Brazil. Four rates of S (0, 5, 10 and 20 kg of S ha^?1) were evaluated using agricultural gypsum (CaSO₄) as S-source. The soil solution was collected using porous capsule lysimeters before and at 9, 17, 37, 60, 76 and 109 d after the gypsum application, at depths of 20 and 60 cm. Surface application of gypsum rapidly increases the sulfate concentration in the soil solution at 20 cm depth. However, in less than 30 d, the effect of the S rates on the soil solution at 20 cm was minimal, with an increase in sulfate concentration in the soil solution at 60 cm depth after 17 d. Sulfated fertilization via agricultural gypsum at rates greater than 10 kg ha^?1 in sandy soil with low cation exchange capacity increased the mobility of Ca and Mg in the soil profile.     

An automated turbidimetric method for total sulfur in plant tissue and sulfate sulfur in soils

Abstract

An automated turbidimetric method has been developed for the rapid and accurate determination of sulfate. The method is practical and useful for accurately measuring total sulfur in plant tissues, and extractable sulfate in soils. The principle of intermittent reagent addition is used which eliminates drift and sensitivity changes caused by coating of BaSO₄ on tubing and cell walls. Also, the appropriate chemistry is used to minimize interactions of the wash with the sample at a sampling rate of 30/H. The sensitivity of the method is excellent with a working range of 0 to 15 ppm sulfur for soils. For plant digests the sample solutions are diluted to 0–35 ppm S. The precision as determined by repeated analysis of a soil sample extract was 0.58% RSD with a mean of 9.26 pg/g extractable SO⁼ ₄‐S. On another soil sample using a different extractant and extraction procedure the RSD was 0.64%, mean of 9.26 μg/g. Multiple automated sulfur analyses on a plant tissue digest resulted in an RSD of 0.41% for a sample containing 0.21% S. The automated turbidimetric method for sulfate has excellent precision and sensitivity in plant tissue and soil analyses where gravimetric BaSO₄ assays are not practical.     

Barley growth,yield, antioxidant enzymes,and ion accumulation affected by PGRs under salinity stress conditions

Application of plant growth regulator (PGR) may alleviate some negative effects of environmental stresses such as salinity. A controlled environment experiment was conducted to study barley (Hordeum vulgare L. cv. Reyhane) growth, yield, antioxidant enzymes and ions accumulation affected by PGRs under salinity stress conditions at Shiraz University during 2012. The treatments were PGRs at four levels—water (as control), cycocel (CCC, 19 mM), salicylic acid (SA, 1 mM), and jasmonic acid (JA, 0.5 mM)—and four salinity levels—no stress (0.67 dS m^?1, as control), 5, 10, and 15 dS m^?1, which were arranged in a factorial experiment based on completely randomized design with four replicates. The results showed that salinity stress significantly decreased plant height, peduncle length, leaf area, ear length, grain number, dry weight, grain yield, harvest index, potassium (K⁺) accumulation, and potassium/sodium (K⁺/Na⁺) concentration ratio, which were closely associated with stress severity. However, PGRs compensated some of these negative effects, so that SA foliar application had the most ameliorative effect. Salt stress also increased Na⁺ accumulation as well as the activity of peroxidase, catalase, and superoxide dismutase (SOD). Since ion discrimination and enhanced antioxidant enzymes are associated with salt tolerance, in this experiment PGRs application might have enhanced K⁺ accumulation and antioxidant enzyme activity. The activity of SOD and K⁺/Na⁺ ratio were found to be useful in salt tolerance manipulation in barley plants.     

共施磷酸二氢钙和硫酸铵对土壤中钾形态转化的影响

Soil potassium (K) deficiency has been increasing over recent decades as a result of higher inputs of N and P fertilizers concomitant with lower inputs of K fertilizers in China; however, the effects of interactions between N, P, and K of fertilizers on K status in soils have not been thoroughly investigated for optimizing N, P, and K fertilizer use effciency. The influence of ammonium sulfate (AS), monocalcium phosphate (MCP), and potassium chloride application on K fractions in three typical soils of China was evaluated during 90-d laboratory soil incubation. The presence of AS significantly altered the distribution of native and added K in soils, while addition of MCP did not significantly affected K equilibrium in most cases. Addition of AS significantly increased water-soluble K (WSK), decreased exchangeable K (EK) in almost all the soils except the paddy soil that contained considerable amounts of 2:1 type clay minerals with K added, retarded the formation of fixed K in the soils with K added, and suppressed the release of fixed K in the three soils without K added. These interactions might be expected to influence the K availability to plants when the soil was fertilized with AS. To improve K fertilizer use effciency, whether combined application of AS and K was to be recommended or avoided should depend on K status of the soil, soil properties, and cropping systems.     

Selection at the Ms locus in open pollinated onion (Allium cepa L.) populations possessing S-cytoplasm or mixtures of N- and S-cytoplasms

The bulb onion (Allium cepa L.) was historically seed propagated by open pollination (OP). Cytoplasmic-genic male sterility (CMS) and protandry encourage outcrossing among individual onion plants. The most common source of CMS in onion is conditioned by the interaction of sterile (S) cytoplasm with a single nuclear male-fertility restoration (Ms) locus. We previously reported that the majority of OP onion populations possess normal (N) male-fertile cytoplasm and varying frequencies of the dominant Ms allele. It was unclear why N-cytoplasmic onion populations often possess relatively high frequencies of the Ms allele, which has no obvious function. We used computer simulations to estimate changes in allelic frequencies at Ms for onion populations possessing S-cytoplasm or a mixture of N- and S-cytoplasms, and to determine if frequencies of the Ms allele stay constant or change due to failure of male gamete production from male-sterile (S msms) plants. The models revealed selection against the recessive ms allele over generations in onion populations possessing S-cytoplasm and varying amounts of self pollination and inbreeding depression. These models were consistent with field and molecular analyses documenting that N-cytoplasm and the dominant Ms allele predominate in OP onion populations.     

Forage and Grain Yield Response to Applied Sulfur in Winter Wheat as Influenced by Source and Rate

ABSTRACT

Recently, environmental quality issues related to sulfur (S) have made it necessary to reduce its release into the atmosphere in wet or dry forms, which in turn might influence the S requirement of crops. It is anticipated that by 2020, S deposition will decrease by up to 30% in eastern portions of Oklahoma and by 15% throughout the remainder of the state. This change calls for frequent monitoring and evaluation of S nutrition in wheat and other crops. Experiments were conducted at Hennessey and Perkins research stations for a period of seven years starting in the fall of 1996, with the objective of assessing the effect of different levels of elemental and sulfate-S fertilizers on the grain and forage yields of winter wheat in Oklahoma. The experimental design was a randomized complete block with three replications. Four S rates, 0, 56, 112, and 224 kg S ha^{? 1}, were applied to the plots from 1996 to 2002 as CaSO₄. Another two rates, 56 and 112 kg S ha^{? 1}, were included in the trials beginning in 1998 using 92% elemental S. Gypsum, as a source of S for winter wheat, resulted in a greater yield than did elemental S in cases where S fertilizer sources were deemed significant. In six of 14 trials from 1996 to 2002, applied S as CaSO4 significantly increased wheat-grain yields. Observing significant grain and forage yield increases due to applied S was important, but the response was sporadic and unpredictable from one year to the next.     

Interactions Between Sulfur and Selenium Uptake by Corn in Solution Culture

Interactions between sulfur (S) and selenium (Se) uptake and accumulation in corn (Zea mays) plants were investigated in solution culture. Two concentrations (5 and 10 μ M) of Se (as selenate) and three concentrations of S (as sulfate) (0.5, 1.5, and 2.5 mM) were used. Results showed that shoot and root biomass were affected significantly by different S concentrations in solution, but not affected by Se application when S concentrations in solution were lower than 1.5 mM. Selenium concentrations as well as Se accumulation in shoots and roots on a dry weight basis increased dramatically with increasing Se concentrations in solution. At a constant Se level, increasing S in solution reduced Se concentrations. Selenium accumulation in plants was not affected by S application, except in nutrient solution with Se at a concentration of 10 μ M. Sulfur concentrations and S accumulation in shoots increased significantly with increasing Se concentrations in solution, while those in roots were unaffected by Se addition. Solution-to-shoot transfer factors and shoot-root distribution coefficients of Se and S were also discussed. These data suggest that it is necessary to manage carefully both S and Se levels in solution or in soils for supplementation of Se in plants. Results from this study indicate that human Se nutrition can be improved by supplementation of Se in crops.     

Comparative evaluation of Ca chloride and Ca phosphate for extractable sulfur in soils with a wide range in pH

Deficiency of sulfur (S) is becoming widespread in the rainfed systems of India, and there is increasing need for diagnosing the deficiency. Calcium chloride and Ca phosphate are commonly used for extracting available S in soils. Because of cost and the ease of availability locally, we prefer using Ca chloride as an extractant over Ca phosphate, for extracting available S. However, there is paucity of data on the comparative evaluation of the two extractants to extract available S, especially in soils having a wide range in natural pH (from acidic to alkaline range). It is recognized that soil pH plays a dominant role in the adsorption–desorption and extractability of sulfate‐S in soils. We compared the extraction of S by Ca chloride and Ca phosphate in 86 Indian soils having a wide range in pH (4.5 to 10.6). Sulfur in the extracts was determined by ICP‐AES. Considering all the 86 soil samples tested, there was an excellent agreement between the values of extractable S determined by using the two extractants (r = 0.96, p < 0.001). However, the correlation coefficient (r) between the values of extractable S by the two reagents, although highly significant, varied among the groups of soil samples according to the range in soil pH. The highest correlation coefficient (r = 0.99, p < 0.0001, n = 17) was found for soils with pH in the alkaline range (8.5–10.6), and the lowest correlation coefficient (r = 0.71, p < 0.0001, n = 58) was obtained with a set of soil samples with pH in the acidic range (4.5–6.5). For soil samples having pH in the near‐neutral range (6.7–7.3), an excellent agreement was observed (r = 0.93, p < 0.0001, n =11) between the extractable‐S values obtained by the two extractants. While Ca phosphate extracted higher amount of S compared to Ca chloride in soil samples with pH in the acidic range, the two extractants were equally effective for soil samples with pH in the neutral or alkaline range. Our results suggest that for most of the soils in the semiarid tropical regions, which have pH in the neutral to alkaline range, Ca chloride can replace Ca phosphate as an extractant for removing available S in such soils.     

Alleviation of salinity stress in red cabbage plants by urea and sulfur applications

Environmental stresses, such as salinity, are becoming critical constraints to plant production especially in arid and semi-arid regions, one of the main targets of agricultural studies is to combat the environmental stresses on plants. An open field experiment was carried out to study the influence of sulfur (S) and urea on red cabbage plants under salt stress. The experiment was arranged as a split-plot design with three replications, the main plots included sulfur levels (0, 350, and 700 kg ha^?1), while subplots included urea levels (0, 1, 2, and 4 g L^?1). Results showed that urea spraying and sulfur soil additions resulted in improvement of growth and yield, and raised the level of potassium and nitrogen while lowering sodium content in plant leaves under salt stress conditions. Generally, larger and heavier heads were found with the application of 700 kg ha^?1 sulfur and 2 g L^?1 urea.     

Sulfur Alleviates Growth Inhibition and Oxidative Stress Caused by Cadmium Toxicity in Rice

A hydroponic experiment was conducted to investigate the effect of sulfur (S) on growth inhibition and oxidative stress caused by Cd²⁺ toxicity, using two rice cultivars with different grain Cd²⁺ content. Treatments consisted of factorial arrangement of three S levels (0.2, 0.4, and 0.8 mmol), two cadmium (Cd) levels (0 and 1 μ mol), and two rice cultivars (‘Bing 97252,’ a cultivar with low grain Cd²⁺ content, and ‘Xiushui 63,’ a cultivar with high grain Cd²⁺ content). The results showed that Cd²⁺ addition in the medium generally increased Cd²⁺ and malondialdehyde (MDA) content in both roots and shoots; the increases were more pronounced in ‘Xuishui 63’ than in ‘Bing 97252.’ Dramatic reductions in growth parameters, including plant height, root and shoot weight, tillers per plant, chlorophyll content, and net photosynthetic rate were found in the plants exposed to Cd stress relative to the plants without Cd²⁺ treatment. ‘Xiushui 63’ showed more sensitivity than ‘Bing 97252’ under Cd²⁺ exposure. In comparison with the lower S level (0.2 mmol), the higher S levels (0.4 and 0.6 mmol) helped alleviate Cd toxicity, characterized by a significant increase in growth parameters, and a decrease in Cd²⁺ and MDA content in both roots and shoots. In addition, superoxide dismutase (SOD) activity in the plants varied among tissues, cultivars, and Cd treatments. High Cd²⁺ and MDA content was consistently accompanied by higher SOD activity, and higher S levels caused a marked increase in glutathione content and a reduction in SOD activity, indicating a positive effect of S in alleviating oxidative stress.     

自动电位滴定法测定肥料和土壤中氯离子含量

介绍了自动电位滴定法测定肥料和土壤中氯离子含量的方法，采用了简单的前处理步骤，与佛尔哈德法及莫尔法相比，具有快速、准确、精密度高的优点，且不受溶液颜色和浊度的干扰。     

Significant Nitrogen by Sulfur Interactions Occurred for Canola Grain Production and Oil Concentration in Grain on Sandy Soils in the Mediterranean-Type Climate of Southwestern Australia

The nitrogen (N) by sulfur (S) interaction for canola (Brassica napus L.) grain production and oil concentration in grain has been quantified in temperate climates, but it is not known if these results also apply to sandy soils common in the Mediterranean-type climate of southwestern Australia where canola is now a major crop. Seventeen field experiments were undertaken with canola in the region during 1994 to 2005 in which 4 rates of both N (0–138 kg N/ha) and S (0–34 kg S/ha) were applied. Significant grain yield responses to applied N occurred in all experiments and the responses increased as more S was applied. Grain yield responses to applied S only occurred when N was applied and tended to increase as more N was applied. When no S was applied the two largest rates of N applied, 69 and 138 kg N/ha, induced S deficiency reducing grain yields. The oil concentration in grain tended to decrease as more N was applied and increased as more S was applied, particularly when the two largest rates of N were applied. Consequently significant N × S interactions were obtained in all experiments for grain production and in 15 experiments for oil concentration in grain.