Arsenic uptake,distribution, and accumulation in bean plants: Effect of Arsenite and salinity on plant growth and yield

The response of bean plants (Phaseolus vulgaris L.) to different levels of arsenic (As) and salinity was investigated, including the processes of uptake, distribution, and accumulation of As and the effect of arsenite and salinity on plant growth and fruit production. The experiment was performed in soilless culture at two levels of As: 2 and 5 mg As L^‐1 [added as sodium arsenite (NaAsO₂)], and three saline levels [only sodium chloride (NaCl) was added]: 1,000,2,000, and 4,000 μS#lbcM^‐1. Arsenic uptake and concentration in root increased upon increased NaAsO₂ concentration in the nutrient solution. However, the increase in the As root content was not proportional to the As level in the nutrient solution. High levels of salinity in solution decreased As uptake and the concentration of As in root, stem, and leaf. Upon uptake, As was readily translocated to the aerial organs and approximately half of the absorbed As was transported to the upper parts of the bean plants. The As concentration in fruit always remained below the recommended limit for As content in fruit and edible vegetal products. While salinity did not significantly affect plant growth, arsenite was found to be phytotoxic to the bean plants.     

Arsenic species: effects on and accumulation by tomato plants.

The uptake of arsenic (As) species by Lycopersicum esculentum, growing under soilless culture conditions, was studied. A 4 x 3 x 2 factorial experiment was conducted with four As species (arsenite, arsenate, methylarsonate, and dimethylarsinate), three As concentrations (1, 2, and 5 mg L(-)(1)) and two tomato cultivars (Marmande and Muchamiel). The phytoavailability and phytotoxicity were primarily determined by the As species. The concentrations of As in plant increased significantly with increasing As concentration in solution. Both MA and DMA showed a higher upward translocation than arsenite and arsenate, and treatments with MA and DMA clearly reduced plant growth and fruit yield. The As concentration in tomatoes treated with arsenite or arsenate were within the range considered normal in food crops; however, the As concentration in tomatoes treated with MA and DMA were close to or even above the maximum limit. When tomato plants are exposed to high concentrations of As in nutrient solutions, they may uptake As to concentrations unacceptable for human food.     

Effect of sulfur deficiency and excess on yield and sulfur accumulation in tomato plants

Abstract

Tomato (Lycopersicon esculentum Mill. var. hybrid 6C‐204) plants were grown for 95 days after germination until each one bore 6 ripe clusters in a greenhouse using nutrient solutions with nine added sulfate levels ranging from 0 to 105 me/1.

Sulfur‐deficiency symptoms and characteristics of plants growing under hign SO₄‐S levels were observed and described. Fruit yields were negatively affected by both S‐deficiency and high SO₄‐S concentrations. Top growth was affected more than root growth by changes in the amount of SO₄‐S supplied. The critical SO₄‐S concentration in the growth media ranged from 2 a 22.5 me/1.

Leaf sulfate‐S increased gradually in leaves and roots as SO₄‐S supply in the nutrient solution increased while organic‐S remained relatively constant. Leaf sulfate‐S critical value was growth stage dependent. Maximum yields at flowering were associated with leaf concentrations of 0.48–1.2% SO₄‐S and 0.25–0.35% organic‐S.     

Manganese toxicity in tomato plants: Effects on cation uptake and distribution

Two experiments are described in which tomato plants (Lycopersicon esculentum L. var Ailsa Craig) were grown in water culture supplied with 10–300 μM Mn. Toxicity symptoms associated with a yield reduction were observed only in treatments in excess of 50 μM Mn indicating that this species is relatively tolerant of high Mn supply. Dark brown/black spots appeared first in the cotyledons. Similar symptoms were observed in the leaves, progressively from the oldest leaf. Manganese concentration in the shoot tissues ranged from 286 to 4240 μg. g^‐1 dry weight. The high Mn concentration values found in the shoot tissues of the toxic plants indicate that Mn was highly mobile in the xylem as confirmed by xylem sap analysis.

The concentrations of both Ca and Mg were lower in the smaller Mn toxic plants. Not only was uptake of Ca and Mg retarded but so also was the distribution of Ca and Mg to the younger tissues as illustrated by measurements of Ca and Mg concentrations along a leaf age sequence. This is in accord with the cation‐anion balance of the xylem exudates collected from decapitated plants.

Higher cation exchange capacity (CEC) was found in the leaf tissues of toxic plants particularly in the older leaves but similar values of C.E.C were recorded for the younger leaf tissues of both control and toxic plants.     

施肥方式对滴灌加工番茄干物质积累、养分吸收和产量的影响

通过加工番茄大田试验,研究了不同施肥方式下,膜下滴灌加工番茄的干物质积累与养分吸收规律及产量构成。结果表明,在滴灌追施100%氮肥和初果期之后滴灌追施70%钾肥的基础上,基施65%磷肥和初果期之前滴灌追施35%磷肥(优化处理)比100%磷肥基施的加工番茄干物质增加11.51%,产量提高3.59%,氮、磷、钾肥的利用率分别增加了6.06、4.15和5.26个百分点。氮肥和磷肥在初果期之前滴灌追施,氮肥和钾肥在初果期之后滴灌追施的滴灌配方肥处理的产量显著低于优化处理,且优化处理的肥料效益也好于滴灌配方肥处理。加工番茄在初果期之前滴灌追施氮与磷,在初果期之后滴灌追施氮与钾可以提高加工番茄产量,增加肥料利用效率。     

Effect of magnesium fertilization on yield and leaf composition of tomato plants

Tomato plants were grown for 2 years at 4 different rates of Mg fertilization on a Princeton loamy sand at pH 4.8 with 29 kg exchangeable Mg/ha. Calcareous limestone was used to provide a pH treatment in the second year. Magnesium deficiency symptoms were observed on plants grown on plots having ≤ 38 kg/ha NH₄OAC‐extractable Mg. Application of 56 kg Mg/ha corrected Mg deficiency and produced a significant increase in yield. Application of calcitic limestone also produced significant yield increases, but did not affect the development of Mg deficiency symptoms. Tomato yield was increased 27.9% by Mg application and 17.7% by lime application. Highest tomato yield was obtained with application of 112 kg Mg/ha. Symptoms of Mg deficiency were observed when the Mg concentration in recently mature leaf tissue was in the 0.30 to 0.32% range. Magnesium concentration in leaf tissue increased linearly with increasing Mg rate. Leaf Mg concentration at various growth stages of the tomato plant was variable depending on Mg treatment. Magnesium fertilization rate bad little effect on Ca or K leaf concentrations. Application of Calcltic limestone increased leaf tissue Ca and reduced leaf tissue Mg and Mn concentrations.     

Effects of plant age on nitrogen uptake and distribution by greenhouse plants

Water‐soluble nitrogen (N) fertilizer is intensively used in greenhouse crop production. Any N not used by a crop is subject to leaching as nitrate (NO₃‐N), which may pollute groundwater. A close correlation between N supply and N uptake by plants would increase the efficiency of N fertilization and minimize the possibility of NO₃‐N pollution. The objectives of this study were to measure N uptake by American marigold (Tagetes erecta L. ‘First Lady') and New Guinea Impatiens (NGI) (Impatiens hawkeri Bull. ‘Selenia') during growth, to determine the effect of plant age on N uptake, to determine if the two species have a preference for NO₃‐N or ammonium (NH₄‐N), and to determine the total N required for 70 days of growth.The plants were grown in solution culture using solutions supplying 120 mg each of NO₃‐N and NH₄‐N. At ten day intervals, six cultures were chosen at random for nutrient solution analysis and plant sampling for dry weight and tissue analysis. Nitrate‐N uptake was greater than NH₄‐N uptake throughout the experiment for both marigold and NGI. Total N uptake by marigold was greater during the first 50 days after transplanting with maximum N uptake during the period 30 to 50 days. In contrast, N uptake by NGI was greater during the period 40 to 70 days after transplanting. Maximum N uptake for NGI occurred during the period 60 to 70 days. Results of this study suggest that early N fertilization of marigold could be more important for their growth and quality than N applied later. For NGI, N fertilization later in the crop's development appears to be more important than early on. The total N absorbed by marigold during the experiment was 1.1 gm N plant^‐1; for NGI the quantity was 0.5 gm N plant‐¹.     

Effect of sodium arsenite on arsenic accumulation and distribution in leaves and fruit of Vitis vinifera

Sodium arsenite (NaAsO₂) was applied to two Vitis vinifera varieties, Aledo and Italia, for three years at a concentration of 1.25 kg NaAsO₂100 L^‐1 applied by spraying or by direct application with a paint brush. Accumulation of arsenic (As) in leaves and fruits during these three years was not detected. Spraying resulted in the highest levels of As in the leaf with the concentration decreasing as the vegetative cycle advanced. The amount of As that accumulated in the plant was related to the proximity of the As application to bud break. The As levels detected in the eatable part (table grape) never reached concentrations that would be considered harmful to human beings.     

氮素运筹对玉米干物质积累、氮素吸收分配及产量的影响

田间小区试验,研究了氮素运筹对玉米干物质累积、氮素吸收分配及产量的影响。结果表明,施氮和有机肥可以延长干物质积累的旺盛时期,使玉米干物质总量积累速率最大的时刻推后1～3d,增加了玉米的干物质积累量。氮肥配施有机肥能延长氮素积累的旺盛时期,其中,N2+M处理氮素积累的旺盛时期△t分别比N0、N1、N2、N3和FP处理延长了6、4、6、1和7d,该时段吸N量比FP处理增加 0.25 g/plant,比等氮量的N2处理增加0.24 g/plant。播前施有机肥 30 t/hm2,在减 N 26.83%的情况下,玉米吸氮量比常规施肥（FP）提高 6.52%,氮素利用率达54.31%,高于常规施肥的 33.27%;玉米增产24.12%,比常规施肥增收2696元/hm2。     

Effect of lead increments on the yield and lead content of tomato plants

Water, Air, & Soil Pollution - One seedling of tomato was planted in each pot containing 3 1.c. of either clay, CaCO3-rich, sandy soils or washed sand. Increments of Pb(NO3)2 were added to the...     

土壤紧实度对温室番茄生长发育、产量及品质的影响

试验研究土壤紧实度对日光温室番茄生长发育、产量及品质的影响结果表明 ,随土壤紧实度增大而植株生长发育迟缓 ,产量和品质下降 ,果实风味品质变差。而土壤疏松处理植株生长发育良好 ,座果节位下降 ,水分利用效率提高 ,果实游离氨基酸、可溶性糖和可溶性蛋白质含量增加 ,硝酸盐含量下降 ,果实风味好且产量高 ,经济系数较高。     

Effect of zeolite and phosphogypsum on yield,plant uptake,and content of strontium in soil

Abstract

Natural zeolite (clinoptilolite containing tuff) can be used as an adsorbent of strontium (Sr) from phosphogypsum when applied as a solonetzic soil amendment. This study investigated the influence of the zeolite on biological yield, content of water‐soluble Sr in soil, its availability, and plant uptake. A field experiment was conducted from 1993 to 1995 in the Volgogradskaya region of Russia. Two methods of phosphogypsum and zeolite application were used: “separate” and “as a mixture” (10 tons ha^‐1 of phosphogypsum and 0.5 ton ha^‐1 of zeolite in both cases). After the application of the amendments, barley (Hordeum vulgare) and grass sorghum (Sorghum sudanensis) were grown on the ameliorated sites in 1994 and 1995, respectively. Our results suggest that zeolite, being applied with phosphogypsum as a mixture, decreased by 15 to 75% the content of water‐soluble Sr in the soil, minimizing the risk of soil pollution. The uptake of Sr by plants depended on the biological character of the crop grown. Barley was found to be a “strong‐anticoncentrative” type of plant. However, grass sorghum was found to be more sensitive to the rise of Sr content in the soil. The highest biomass production of barley and grass sorghum was obtained with the application of zeolite and zeolite plus phosphogypsum. Plants grown on a single phosphogypsum‐treated sites had a declining tendency in biological yield. Our results suggest a positive influence of zeolite applied with phosphogypsum for the amelioration of solonetzic soils on the growth and uptake of Sr by plants.     

Diurnal uptake of nitrate and potassium during the vegetative growth of tomato plants

Tomato plants (Lycopersicon esculentum Mill.) of the F₁ hybrid variety Turbo were grown in a NFT system for 22 days. On days 16 and 20–22 inclusive of the experiment, the diurnal variation in nitrate (NO₃), potassium (K), and water uptake rates were measured. Nitrate and K uptake rates were subject to large diurnal variation with maximum uptake rates occurring during the day period. Two peaks of diurnal uptake rates were identified, one large peak during the day period and a second much smaller one during the first 2–4 hours of the night. Under the conditions of the experiment, night nutrition made up 35 to 40% of the total daily uptake of K and NO₃. Water uptake rates followed a diurnal oscillation with a single peak pattern. Highest rates occurred at the middle of the photoperiod and lowest rates were measured at night. Over the entire day and night cycle there was no correlation between the rates of water and nutrient uptake. This may be of importance in the fertilization of hydroponically grown plants since in horticultural practice nutrients and water are supplied together in quantities large enough to meet plant water demand but not nutrient requirements.     

施肥对马铃薯钼吸收分配的影响

通过设对照(CK)、有机肥(M)、氮磷肥(NP)、有机肥与氮磷肥配合(M+NP)4个处理的田间试验,研究了施肥对马铃薯(品种为紫花白)钼吸收分配规律的影响。结果表明,马铃薯生育期中,全株钼含量变化在0.73～1.83mg/kg,叶、茎、块茎平均含量依次为3.20、0.98、0.57 mg/kg。随生育进程推进,全株及各器官钼吸收量呈"S"型曲线变化,均可用一元三次方程表达。块茎增长期是全株钼素吸收量最多、吸收速率最快的时期,最大吸收速率出现在出苗后55 d左右;最大吸收量出现在出苗后85 d左右。随着生长中心由茎叶向块茎的转移,钼在体内的分布相应由茎叶向块茎移动,收获期茎叶分布69%,钼的运转率为31%。每生产1000 kg鲜块茎,平均吸收钼0.506 g,消耗系数0.00017。有机肥或氮磷肥配施,均可大幅度提高马铃薯钼含量、吸收速率、吸收量;对促进钼素吸收呈正交互作用。     

Simulating NaCl accumulation in a closed hydroponic crop of zucchini: Impact on macronutrient uptake,growth, yield,and photosynthesis

Zucchini squash (Cucurbita pepo L.) plants were grown in a closed‐loop hydroponic system and supplied with nutrient solution (NS) containing NaCl at different concentrations (0.7, 3, 5, and 7 mM). The primary aim of the study was to define the relationship between the concentration of Na⁺ and Cl⁻ in the root zone solution and the respective Na⁺/water or Cl⁻/water uptake ratios (uptake concentrations, UC). A second objective was to determine the UC of macronutrients (i.e ., N, P, K, Ca, and Mg) and to test whether they are influenced by the gradual increase of the root zone salinity due to progressive NaCl accumulation. Two experiments were conducted, of which one (spring crop) was used to parameterize an existing empirical model, while the second one (autumn‐winter crop) was commissioned to test the validity of the determined model parameters. Both Cl⁻ and Na⁺ ions accumulated progressively in the root zone solution over time, showing a tendency to stabilize at final concentrations according to the corresponding NaCl treatment. The relationship between the Na⁺ and Cl⁻ concentrations in the root zone and the Na⁺/water or Cl⁻/water uptake ratios was exponential and the model parameters successfully fitted to data from crops cultivated in different growth seasons. This model may be used to monitor Na⁺ and Cl⁻ concentrations in the root environment of zucchini crops as relationships of the plant water consumption. The exposure of plants to NaCl affected the UC of N, K, Ca, and Mg, but the results for some nutrients were not consistent in both growth seasons. The measurements of plant growth characteristics (i.e ., biomass, yield, fruit quality, and photosynthesis) revealed that water resources containing up to 3 mM NaCl do not cause unacceptable yield losses in zucchini crops grown in completely closed hydroponic systems.     

Effect of salinity on growth,mineral composition,and water relations of grafted tomato plants

A greenhouse experiment was designed in order to evaluate growth, water relations, and nutrient concentrations of grafted and ungrafted tomato plants grown under varying levels of salinity (0, 30, or 60 mM NaCl). Two cultivars, ‘Fanny’ and ‘Goldmar’, were grafted onto AR‐9704, using the cleft‐grafting method. Growth of grafted ‘Fanny’ plants was higher than that of ungrafted plants. Growth of ‘Goldmar’ plants was not affected by salinity treatments or grafting, but it was slower than for ‘Fanny’. Leaf turgor showed no significant differences between grafted and ungrafted plants or between salinity levels. The stomatal conductance (G_s) was higher for grafted than for ungrafted plants, and salinity decreased it significantly and progressively in both grafted and ungrafted plants and in both varieties. The concentrations of Na⁺ and Cl^– were significantly higher in ungrafted than in grafted ‘Fanny’ plants. ‘Fanny’ was more tolerant when grafted, probably due to reduced accumulation of Na⁺ and/or Cl^– in the shoot.     

Effect of ammonium or nitrate nutrition on photosynthesis,growth, and nitrogen assimilation in tomato plants

Nitrogen (N) is taken up by most plant species in the form of nitrate (NO ) or ammonium (NH ). Plant response to continuous NH nutrition is species‐dependent. In this study, we compare the responses of tomato (Solanum lycopersicum L. cv. Rio Grande) plants to N source (NO or NH ). To this end, early plant growth, photosynthesis, chlorophyll, carbohydrate, and N‐compound concentrations as well as the activities of main enzymes involved in N metabolism (nitrate reductase, nitrite reductase, glutamine synthetase, and glutamate dehydrogenase) were analyzed. Early plant growth was remarkably ameliorated under NH ‐ in comparison to NO ‐based nutrition. Concomitantly, photosynthetic activity, total chlorophyll, and carbohydrate concentrations were significantly increased. With increasing external NH concentration, NH accumulated mainly in roots. In addition, root protein concentration was significantly increased, reflecting high NH incorporation into organic nitrogen. Root glutamine synthetase (GS) activity was enhanced by NH for concentrations below 5 mM, whereas root glutamate dehydrogenase (GDH) activity increased in parallel to NH availability. Together with the positive effect of NH on tomato plant cv. Rio Grande growth, these results reveal that GDH could have, in addition to GS, a possible role in NH detoxification and tolerance of NH ‐based nutrition.     

Effect of increased cobalt treatments on cobalt concentration and growth of tomato plants

An experiment developed in soilless culture was used to study the effect of several levels of Co²⁺ (0, 5, 15, and 30 mg L^‐1 ) on the growth of tomato plants (Lycopersicon esculentum M. cv. Ramy). Absorption, transport, and accumulation of this metal in roots, stems, leaves, and fruits were also studied. Uptake was increased by application of this metal concentration in the nutrient solution, efficiency of root uptake of cobalt decreased with increased Co²⁺ treatment in the soilless culture system. The translocation of Co²⁺ from roots to aerial vegetative parts was increased with the time of experiment and Co²⁺ concentration in the nutrient solution. The presence of this metal in nutrient solution reduced tomato leaf production and elongation, specially at higher treatments.     

氮肥运筹对棉花干物质积累、氮素吸收利用和产量的影响

通过膜下滴灌田间试验,研究不同氮肥运筹模式对棉花干物质积累、氮素吸收利用及产量的影响。结果表明,各处理棉花干物质及氮素积累均符合Logistic方程;棉花干物质积累最快时期出现在出苗后83～139 d。不同的氮肥运筹可明显影响到棉花氮素吸收最大速率及其出现日期,以有机无机氮肥配施（N2+M）处理的氮素吸收最大速率较高,且其出现日期相对较早。棉株对干物质分配中心与氮素吸收分配中心一致。各施氮处理氮肥利用率在32.11%～49.24%之间,N2+M处理氮肥利用率最高,其它处理氮肥利用率随施氮量的增加而降低。本试验中,N2+M处理产量达1890 kg/hm2,显著高于其它处理。     

氮磷钾肥对紫云英产量及养分积累的影响

通过田间试验,研究了NPK肥对紫云英生长、产量及养分积累的影响.结果表明,NPK配施能促进紫云英生长,显著提高产量和养分积累量.NPK处理(施N 75 kg/hm2 、P2O5 60 kg/hm2和K2O 60 kg/hm2)的紫云英茎数、株高和每茎复叶数分别是不施肥处理的3.77、1.81和1.60倍,是施PK处理的2.19、1.23和1.16倍,是施NK处理的2.11、1.16和1.11倍,是施NP处理的1.44、1.19和1.16倍.NPK配施的鲜草产量分别比不施肥、PK配施、NK配施及NP配施处理增加26.47、14.22、7.18和10.74 t/hm2.不同施肥处理都能使紫云英的养分积累量显著提高,其中NPK配施处理的紫云英地上部N、P2O5、K2O和C的积累量最大,分别是不施肥处理的3.66、3.27、2.85和2.80倍.试验结果说明,合理施用N、P、K肥能明显促进紫云英的生长,提高产量和养分积累量,有利于提高紫云英种植效益.