Cadmium accumulation and distribution in cucumber plant

An experiment developed in soilless culture was used to study the cadmium (Cd) accumulation, and distribution of Cd in cucumber (Cucumis sativus var. peonero‐mixfl) plant. Four treatments were established (0, 5, 10, and 20 mg Cd⁺² L^‐1). Uptake, and transport of Cd were increased with time, and Cd concentration in the nutrient solution. Fruit accumulation of Cd varied from 16 to 92 mg kg^‐1 depending on the treatments. The fresh weight, and dry matter accumulation of cucumber plant organs (roots, stem, leaves, and fruits) was affected by cadmium treatment. A decrease of the total, a, and b chlorophyll increasing Cd concentration in nutrient solution, and time of experiment were observed. The incidence of this metal on the content of chlorophyll b seem to be faster than chlorophyll a. Cucumber plant could be a feasible plant for pollution experiments due to their high sensibility, and transport efficiency.     

Modeling Salinity Build-Up in Recirculating Nutrient Solution Culture

Abstract

This paper presents a simple model for the changes in ion concentration and electrical conductivity (EC) of the recirculating nutrient solution in a closed-loop soilless culture of tomato (Lycopersicon esculentum Mill.). The model was designed on the basis of a balanced equation for plant nutrient uptake: for macrocations (K⁺, Mg²⁺ and Ca²⁺), a linear dependence of concentration on crop water uptake was assumed, while for non-essential ions, such as sodium (Na⁺), a non-linear function was used. The model was developed for closed-loop hydroponic systems in which crop water uptake (namely, transpiration) is compensated by refilling the mixing tank with complete nutrient solution. In these systems, EC gradually increases as a result of the accumulation of macro-elements and, principally, of non-essential ions, like Na⁺, for which the apparent uptake concentration (i.e., the ratio between nutrient and water uptake) is lower than their concentration in the irrigation water. For model calibration, data from both the literature and a previous work were used, while validation was performed with data from original experiments conducted with tomato plants in different seasons and using water with different sodium chloride (NaCl) concentrations (10 and 20 meq/L). The results of validation indicate that the model may be a useful tool for the management of closed-loop hydroponics, because it simulates rather well the salt accumulation that occurs in the recirculating nutrient solution when it is prepared with irrigation water of poor quality. Furthermore, the model is able to estimate the amount of crop evapotranspiration that leads to a value of EC at which flushing is necessary, thus enabling one to predict the water and nitrogen runoff of the semi-closed soilless culture.     

Cobalt‐induced stress in tomato plants: Effect on yield,chlorophyll content,and nutrient evolution

An experiment developed in soilless culture was used to study the effect of several levels of cobalt (Co) (0, 5, 15, and 30 mg.L^‐1) on yield and nutrient evolution of the tomato fruits (Lycopersicon esculentum M. cv. Ramy). The incidence of this pollutant in leaf chlorophyll contents was also studied. Increasing concentration of Co in nutrient solution reduced drastically yield in tomato plants. Total, a and b chlorophyll contents were affected by Co level in nutrient solution. A significant increase of nitrogen (N), phosphorus (P), calcium (Ca), and copper (Cu) in the fruit in function of Co treatments were observed. Similar evolution in iron (Fe) and manganese (Mn) fruit content affected by Co presence in higher treatment were obtained. No significant effect of Co presence on potassium (K), magnesium (Mg), sodium (Na), and zinc (Zn) fruit contents were observed. Cobalt absorption was very high, with values of Co in fruit around 250 μg Co g^‐1.     

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.     

Calcium deficiency and CaCO3 on micronutrient status of plants grown in solution culture

Abstract

Plants were grown in solution culture with different levels of Ca to further evaluate Ca relationships to trace metal uptake and to toxicity of trace metals. When tomato plants (Lycopersicon esculentum L., Tropic) were grown at a low level of Ca, the Zn, Cu, Fe, Mn, Al, and Ti concentrations of leaves, stems, and roots were considerably increased. The use of an excess of CaCO₃ which increased pH did not influence the trace metal concentrations of plants any more than did Ca⁺⁺. In a factorial experiment with bush beans (Phaseolus vulgaris L. C.V. Improved Tendergreen) with Ca (10^‐4,10^‐2, 10^‐2 N) and Ni (0, 2 × 10^‐6 M, 2 X10^‐5 M), Ni phytotoxicity and Ni uptake were decreased somewhat at the highest Ca level. High Ni tended to decrease the Ca concentration in leaves. High Ca and Ni both tended to decrease Fe, Cu, Zn, and Mn concentrations in leaves. The Ni had some interactions on the P concentrations of shoots.     

Effects of humic acids and herbicides,and their combinations on the growth of tomato seedlings in hydroponics

The morphology and length of roots and shoots of tomato (Lycopersicon esculentum Mill.) seedlings grown on a nutrient medium for fourteen days in a controlled environment chamber were apparently not affected, whereas the dry matter content of roots was significantly enhanced when 200 mg L^?1 of humic acid (HA) isolated from either a non-amended soil or a sewage-sludge-amended soil was present in the nutrient medium. In contrast, the HA-like fraction isolated directly from the sewage sludge caused, under the same conditions, extensive alterations of tomato morphology and a significant reduction of the length and dry weight of both shoots and roots. The presence in the nutrient medium of the herbicides alachlor or imazethapyr at concentrations of 1 and 0.01 mg L^?1, respectively, caused a marked decrease of tomato root and shoot length and dry weight. Differently, the herbicide rimsulfuron at a concentration of 0.01 mg L^?1 produced a slight decrease in shoot and root length and a slight increase in their dry weight. A combination of 200 mg L^?1 soil HA and each of the herbicides alachlor, rimsulfuron and imazethapyr at concentrations of 1, 0.01 and 0.01 mg L^?1, respectively, in the nutrient medium attenuated the growth depression of tomato shoots and roots observed in the presence of the herbicide alone. However, the simultaneous presence of sewage sludge HA and any herbicide in the nutrient solution caused negative synergistic effects on tomato growth. The volume of nutrient solution and the amount of electrolytes taken up by tomato plants during the growth experiments correlated highly significantly with the total plant dry weight. Tomato seedlings induced a pH decrease in the nutrient medium in all treatments except in those where sludge-HA was present, either alone or in combination with any herbicide.     

Effects of chromium on the nutrient element content and morphology of tomato

An hydroponic experiment was conducted to study the effects of chromium (Cr³⁺) on the distribution of nitrogen (N), phosphorus (P), potassium (K), sodium (Na), calcium (Ca), magnesium (Mg), and Cr in the plant, and the growth and yield of a tomato plant. Three Cr treatments were established (0, 50, and 100 mg Cr/L in a nutrient solution). In general, the nutrient element concentration in stems and branches was significantly affected by the Cr treatments. Chromium accumulated preferentially in the roots and low transport was detected to the aerial parts. Growth was diminished due to Cr presence in the nutrient solution. Total yield was not affected, however the number of fruits was diminished and the mean fresh weight of fuit increased with each increment of Cr in the nutrient solution. Chromium was not detected in the edible part (fruit) of the plant.     

Effects of calcium deficiency on nutrient concentration of xylem sap of excised tomato plants

The effects of calcium (Ca) deficiency on cation uptake and concentration of xylem sap from tomato roots after excision of the aerial parts, were studied. The measurements were made on tomato plants grown on nutrient solutions with +Ca or without‐Ca, over a period of 48 hours. Calcium deficiency entailed a significant increase of the flux of xylem sap between the 6th and 14th hour on the first day after excision. In spite of the lack of Ca in the nutrient solution, the Ca concentration in xylem sap was unaffected in regard to that of excised roots with +Ca. The maintenance of the Ca concentration in xylem sap of plants grown on a Ca deficient solution was related to a reuse of the Ca from the apoplastic root stores. So, this regulation indicates a possible translocation of the Ca available in the root supply and a mobility of this element out of the roots only during the early stages of exposure to a Ca deficiency. The presence of NH₄ ⁺ in xylem sap with both +Ca and‐Ca treatments confirms the nitrogenous reduction activity of tomato roots. The accumulation of free ammonium 24 h after excision in both xylem saps (+Ca and‐Ca) is likely to be evidence of an alteration process of protein synthesis which is related to the depletion of the root water soluble carbohydrate supply.     

MITIGATION EFFECTS OF SILICON ON TOMATO PLANTS BEARING FRUIT GROWN AT HIGH BORON LEVELS

Interactive effects of silicon (Si) and high boron (B) on growth and yield of tomato (Lycopercison esculentum cv. ‘191 F1’) plants were studied. Treatments were: 1) control (B1), normal nutrient solution including 0.5 mg L^?1 B (boron), 2) B1 +Si treatment: 0.5 mg L^?1 boron plus 2 mM Si, 3) B2 treatment: 3.5 mg L^?1 B, 4) B2 +Si treatment: 3.5 mg L^?1 B plus 2 mM Si, 5) B3 treatment: 6.5 mg L^?1 B, and 6) B3 +Si: 6.5 mg L^?1 B plus 2 mM Si. High B reduced dry matter, fruit yield and chlorophyll (Chl) in tomato plants compared to the control treatment, but increased the proline accumulation. Supplementary Si overcame the deleterious effects of high B on plant dry matter, fruit yield and chlorophyll concentrations. High B treatments increased the activities of superoxide dismutase (SOD; EC 1.15.1.1), peroxidase (POD; EC. 1.11.1.7) and polyphenol oxidase (PPO; EC 1.10.3.1). However, supplementary Si in the nutrient solution containing high B reduced SOD and PPO activities in leaves, but POD activity remained unchanged. These data suggest that excess B-induced oxidative stress and alterations in the antioxidant enzymes. Boron (B) concentrations increased in leaves and roots in the elevated B treatment as compared to the control treatment. Concentrations of calcium (Ca) and potassium (K) were significantly lower in the leaves of plants grown at high B than those in the control plants. Supplementing the nutrient solution containing high B with 2 mM Si increased both nutrients in the leaves. These results indicate that supplementary Si can mitigate the adverse effects of high B on fruit yield and whole plant biomass in tomato plants.     

Arsenic uptake,distribution, and accumulation in tomato plants: Effect of arsenite on plant growth and yield

The response of tomato (Lycopersicum esculentum Mill, cultivar Marmande) plants to different levels of arsenic (As) in nutrient solution was investigated—the processes of uptake, distribution and accumulation of As, and the effect of arsenite on yield and plant growth (plant height, diameter of stem, stem and root length, fresh and dry weight of root, stems, leaves, and fruit). The experiment was performed at three levels of As: 2, 5 and 10 mg/L [added as sodium arsenite (NaAsO₂)] in a nutrient solution, together with the corresponding control plants. Arsenic uptake depended on the As concentration in solution and As content in the roots increased as the time of treatment increased. The most important finding was the high toxicity of arsenite to roots. The concentration in stems, leaves, and fruit was correlated with the As level in the nutrient solution. Although the As level of 10 mg/L damaged the root membranes, resulting in a significant decrease in the upward transport of As. Arsenic exposure resulted in a drastic decrease in plant growth parameters (e.g., maximum decrease of 76.8% in leaf fresh weight) and in tomato fruit yield (maximum reduction of 79.6%). However, it is important to note that the As concentration in the fruits was not toxic or harmful for human consumption.     

Synergistic trace metal effects in plants

Abstract

An experiment was conducted in Yolo loam soil with bush beans (Phaseolus vulgaris L. C.V. Improved Tendergreen) with single and combination treatments of moderately high levels of Cd, Li, Cu, and Ni to test whether or not effects could be additive or synergistic. Copper and Ni together were more toxic than either alone. Copper, Ni, and Cd were more toxic together than any one alone. These effects were probably additive and may be related to a 0.2 pH change caused by Cu which increased uptake of Ni and Mn. Synergistic effects were observed in the Cd and Ni concentrations, especially in the stems of the plants. Because of these interactions, the effects were then tested in solution culture. In solution culture with bush beans Cu and Ni when applied together had synergistic effects on plant concentrations of P, Zn, and Fe (all were decreased) and on the Ni concentration in roots. Also, in solution culture with (2.5 × 10^‐5 M) Zn, Cu, and Cd added singly, in pairs, and together, Zn and Cu additively decreased Cd concentrations in roots. Synergistic effects on yield depressions were observed in solution culture for 5 × 10^‐5 M Zn + 3 × 10^‐5 M Cu+ 2 x10^‐5 M Ni. An additive effect on yield depression was observed for 2 × 10^‐4 MCd + 2 × 10^‐5 M Ni. There were many complex interactions among the trace metal concentrations in these plants.     

Effect of Free Manganese Activity on Yield and Uptake of Micronutrient Cations by Barley and Oat grown in Chelator-buffered Nutrient Solution

The uptake of micronutrient cations in relation to varying activities of Mn²⁺ was studied for barley (Hordeum vulgare L. var. Thule) and oat (Avena sativa L. var. Biri) grown in chelator buffered nutrient solution. Free activities of Mn²⁺ were calculated by using the chemical speciation programme GEOCHEM-PC. Manganese deficient conditions induced elevated concentrations of Zn and Fe in shoots of both species. The corresponding antagonistic relationship between Mn and Cu could only be seen in barley. The observed antagonistic relationships were only valid as long as the plant growth was limited by Mn deficiency. The Mn concentration in both plant species increased significantly with increasing Mn²⁺ activity in the nutrient solution. The concentration of Mn in the shoots of oat was higher than for barley except under severe Mn deficiency where it was found equal for both species. Manganese was accumulated in the roots of barley at high Mn²⁺ activity. The different shoot concentrations of Mn between barley and oat are therefore attributed to the extent of Mn translocation from roots to shoots. Manganese deficiency induced a significant increase in the shoot to root ratio in both species.     

铜、镉毒害对番茄生长和膜功能蛋白酶活性的影响及外源NO的缓解效应

为探讨外源NO（SNP为供体）对50 mol/L铜、镉毒害的缓解效应,采用营养液培养方法,研究了不同程度的铜、镉毒害（5 mol/L和50 mol/L）对番茄幼苗生物量、根系活力、硝酸还原酶、光合特性及生物膜ATPase、H+-PPase等功能蛋白酶活性的影响。结果表明,铜、镉胁迫显著抑制番茄生长。随处理浓度增加,番茄根系活力、硝酸还原酶活性显著降低,番茄长势越差; 铜、镉胁迫对根系离子吸收的影响远远大于叶片,尤其是铜胁迫,50 mol/L铜胁迫使番茄根系铜含量增加了12倍。铜浓度的增加对镉含量无影响,镉浓度的增加降低了铜的吸收。铜、镉胁迫使番茄净光合速率（Pn）、气孔导度（Gs）和蒸腾速率（Tr）显著降低,胞间CO2浓度（Ci）显著增加,表现为非气孔限制。50 mol/L 铜、镉处理显著降低叶片、根系质膜H+-ATPase、Ca2+-ATPase和根系液泡膜H+-ATPase、Ca2+-ATPase和H+-PPase活性; 提高了5和50 mol/L部分处理叶片液泡膜H+-ATPase、Ca2+-ATPase和H+-PPase的活性。表明生物膜功能蛋白对不同程度铜、镉胁迫的响应时间和部位存在差异。铜毒害对细胞质膜ATPase的影响较大,而镉毒害对液泡膜伤害的程度较大。100 mol/L SNP可以显著缓解铜、镉胁迫导致的番茄生长受抑,铜、镉总吸收量显著高于胁迫处理。     

秋葵连作土壤浸提液对番茄生长的障碍研究

单一耕作制度和作物品种,使设施连作障碍日益加剧。番茄和秋葵都是重要的设施蔬菜类型,但种植发现秋葵对番茄存在生长障碍,研究秋葵对番茄的生长障碍发生的生理生态机制具有重要意义。本研究选取种植秋葵的1 a和10 a土壤浸提液（简称1 a浸提液和10 a浸提液）,以全素营养液为对照（简称CK）,探讨秋葵连作土壤浸提液对番茄萌发期种子和幼苗生长的影响。结果表明：同一浓度土壤浸提液处理下,10 a浸提液的番茄萌芽期种子表现出主根畸形,侧根增多但细弱;番茄幼苗分根增多,根系活性低于1 a浸提液且都显著低于CK,顶部嫩叶失绿异常,活性氧代谢系统紊乱。同一年限不同秋葵土壤浸提液浓度处理下,番茄萌发期种子随浸提液浓度的升高表现出主根畸形,侧根增多且细弱,番茄幼苗分根增多,1 a和10 a浸提液的番茄根尖数、分根数分别最高达1 146、3 321和2 291、1 947,显著高于对照（1 071、385）;秋葵土壤浸提液浓度高于250 mg·mL^-1处理下番茄幼苗根系活性都显著低于CK,顶部嫩叶失绿异常,活性氧代谢系统紊乱。研究表明秋葵根系物及分泌物在土壤中残留,对后茬番茄的生长造成不良影响,这些物质随种植年限增加而富集,从而对番茄产生更严重的毒害。     

Heavy Metal and Nutrient Ion Accumulation by Two Black Gram Cultivars Treated with Copper and Lead

ABSTRACT

A pot experiment was conducted to examine the uptake of nutrients (K⁺ (potassium) and Ca²⁺ (calsium)) and heavy metal (Cu²⁺ (copper) and Pb²⁺ (lead)) ions by leaves, seeds, and roots of two black gram [Vigna mungo (L.) Hepper] cultivars, ‘Mash-95018’(V₁) and ‘Mash-97’(V₂) treated with copper (Cu) and lead (Pb) at 25mg L^?1 and 50mg L^?1. This study was conducted in a greenhouse in the Botanical Garden, University of Agriculture, Faisalabad, Pakistan, during the spring of 2003. Heavy-metal treatments were applied 30 d after germination, and nutrient and heavy-metal ion uptake data were collected 10 d after treatment application. Both heavy metals in both cultivars substantially reduced nutrient ion accumulation and its translocation to seeds. Leaves had proportionately more K⁺ and Ca²⁺ than that recorded for roots and seeds after heavy-metal treatments. Nevertheless, both heavy metal (Cu²⁺ and Pb²⁺) ions ware predominantly sequestered in the roots, rather than in leaves and seeds, under their respective treatments. As the external concentrations of heavy metals increased, their uptake by the respective treated plants also increased, but nutrient ion (K⁺ and Ca²⁺) uptake was gradually reduced. This result suggests a concentration-dependent phenomenon. Overall, lead (Pb²⁺) showed more toxic effects on the uptake of essential nutrients compared with Ca²⁺, while ‘Mash-97’proved more sensitive to heavy metals than ‘Mash-95018.'     

Silicon nutrition of tomato and bitter gourd with special emphasis on silicon distribution in root fractions

Two plant species, tomato (Lycopersicon esculentum Mill.) and bitter gourd (Momordica charantia), were used for in‐depth studies on the dynamics of silicon (Si) uptake and translocation to the shoots and compartmentation of Si in the roots. The experiments were conducted under controlled environmental conditions in nutrient solutions, which were partly amended with 1 mM Si in the form of silicic acid. At harvest, xylem exudates were collected, and Si concentrations and biomass of roots and shoots were determined. Mass flow of Si was calculated based on the Si concentration of the nutrient solution and transpiration determined in a parallel experiment. Plant roots were subjected to a fractionated Si analysis, allowing attributing Si to different root compartments. Silicon concentrations in the roots compared to the shoots were higher in tomato but lower in bitter gourd. A more ready translocation from the roots to the shoots in bitter gourd was in agreement with Si concentrations in the xylem exudates which were higher than in the external solution. In tomato, the xylem‐sap Si concentration was lower than in the nutrient solution. Calculated Si mass flow to the root exceeded Si uptake in tomato, which was consistent with the measured accumulation of Si in the root water‐free space (WFS). In contrast, Si concentration in the root WFS was lower than in the nutrient solution in bitter gourd, reflecting the calculated Si depletion at the root surface based on the comparison of Si mass flow and Si uptake. Within the roots, more than 80% of the total Si was located in the cell wall and less than 10% in the cytoplasmic fractions in tomato. In bitter gourd, between 60% and 70% of the total root Si was attributed to the cell‐wall fraction whereas the proportion of the cytoplasmic fraction reached more than 30%. Our results clearly confirm that tomato belongs to the Si excluders and bitter gourd to the Si‐accumulator plant species for which high Si concentrations in the cytoplasmic root fraction appear to be characteristic.     

Regulation of xylem transport of calcium from roots to shoot of maize by growth-related demand

The aim of the present experiments was to study the effect of growth-related nutrient demand on Ca²⁺ translocation from roots to shoot of maize (Zea mays L.). The plants were grown under controlled environmental conditions in nutrient solution with constant Ca²⁺ supply. The growth-related demand for Ca²⁺ and other nutrients was modified by growing the plants with their apical shoot meristem either at air temperature (24°C/20°C day/night) or at 14°C. Reduction of the shoot meristem temperature (SMT) to 14°C decreased shoot growth without affecting root growth in the first five days, which diminished the growth-related demand of the shoot for nutrients per unit of roots. This decrease in shoot demand led to a reduction not only of Ca²⁺ translocation rates in intact transpiring plants but also of Ca²⁺ fluxes in the xylem exudate of decapitated plants. This indicates that the decrease in xylem flux of Ca²⁺ at low SMT was not only the result of low transpiration-related water flux, and thus possibly low apoplasmic bypass transport of Ca²⁺ into the stele. In decapitated plants precultured at low SMT, the water flux through the roots was diminished even more than Ca²⁺ flux, leading to a significant increase in the Ca²⁺ concentration of the exudate, and thus presumably an increase in the Ca²⁺ gradient between cytosol and apoplast of stelar parenchyma cells. When the osmotically driven water flux was reduced by addition of mannitol to the nutrient solution, Ca²⁺ concentration in the exudate markedly increased, whereas Ca²⁺ translocation was only slightly affected. From these results it is suggested that the decrease in Ca²⁺ translocation rates at low shoot demand was not related to low water flux but to direct effects on the capacity of Ca²⁺ transport mechanisms in the roots.     

Formation of manganese oxide plaque on rice roots in solution culture under varying pH and manganese (Mn2+) concentration conditions

Roots of rice (Oryza sativa L.) exposed to 25, 50, and 100 ppm concentrations of manganese (Mn²⁺) in solution culture at pH 4.0, 5.0, 6.0, 7.0, and 8.0 for 48 hours developed visible brown coatings (plaque) of oxidized Mn. Most plaque was deposited on a region of the root 1–6 cm long above the root tip. Manganese in root plaque was removed by dithionite‐bicarbonate‐citrate extraction and internal root Mn released by pressure digestion. Concentrations of Mn were determined by atomic absorption spectrometry. Mean concentrations of Mn in plaque exceeded concentrations of Mn remaining in roots after the DCB wash in all treatment conditions. Concentrations of plaque and internal Mn increased with increasing pH and Mn²⁺ concentration in the treatment solution. Significant positive correlations existed between plaque and internal Mn concentrations at high pH. A larger percentage of total root metal remains in Mn plaqued roots after DCB treatment than has been previously observed in similarly treated iron (Fe) plaqued roots.     

二氧化碳施肥对番茄幼苗生长与养分吸收利用的影响

Exposing tomato seedlings to elevated CO2 concentrations may have potentially profound impacts on the tomato yield and quality. A growth chamber experiment was designed to estimate how different nutrient concentrations influenced the effect of elevated CO2 on the growth and nutrient uptake of tomato seedlings. Tomato (Hezuo 906) was grown in pots placed in controlled growth chambers and was subjected to ambient or elevated CO2 (360 or 720 μL L-1), and four nutrient solutions of different strengths (1/2-, 1/4-, 1/8-, and 1/16-strength Japan Yamazaki nutrient solutions) in a completely randomized design. The results indicated that some agricultural characteristics of the tomato seedlings such as the plant height, stem thickness, total dry and fresh weights of the leaves, stems and roots, the G value (G value = total plant dry weight/seedling age),and the seedling vigor index (seedling vigor index = stem thickness/(plant height × total plant dry weight) increased with the elevated CO2, and the increases were strongly dependent on the nutrient solution concentrations, being greater with higher nutrient solution concentrations. The elevated CO2 did not alter the ratio of root to shoot. The total N, P, K, and C absorbed from all the solutions except P in the 1/8- and 1/16-strength nutrient solutions increased in the elevated CO2 treatment. These results demonstrate that the nutrient demands of the tomato seedlings increased at elevated CO2 concentrations.