Uptake of Si by five plant species,as influenced by variations in Si-supply

Summary For 5 plant species it was investigated whether or not the uptake of Si proceeds metabolically. A gradual transition was found from metabolic absorption to metabolic exclusion, depending on the Si concentration in the culture solution. Absorption of Si increased in the order soybean, sunflower, wheat, sugarcane, rice.     

Seed germination and salinity tolerance in plant species growing on saline wastelands

Seven plant species including three chenopods:Suaeda fruticosa, Kochia indica, Atriplex crassifolia and four grasses:Sporobolus arabicus, Cynodon dactylon, Polypogon monspeliensis, Desmostachya bipinnata, varied greatly in their seed germination and growth responses to soil moisture or salinity. The germination percentage of each species was significantly lower at soil moisture level of 25 % of water holding capacity than at the levels ranging from 50 to 125 %. Increase in salinity resulted in gradual decrease in seed germination of each species. Growth responses of species to salinity varied widely from significant decrease with slight salinity to stimulation up to salinity levels of 20 dS m^-2. Higher K⁺Na⁺ratios in plant shoots of all species compared to that in the root medium indicated selective K⁺uptake. Higher tolerance in chenopod species seems to be attendant on their ability for internal ion regulation. We are thankful to Mr. Noor Ahmad for his assistance in experimental work.     

Metal-humic complexes and plant micronutrient uptake: a study based on different plant species cultivated in diverse soil types

There are several studies in the literature dealing with the effect of metal-humic complexes on plant metal uptake, but none of them correlate the physicochemical properties of the complexes with agronomic results. Our study covers both aspects under various experimental conditions. A humic extract (SHE) obtained from a sapric peat was selected for preparing the metal–humic complexes used in plant experiments. Fe–, Zn– and Cu–humic complexes with a reaction stoichiometry of 2:0.25 (humic:metal, w/w) were chosen after studying their stability and solubility with respect to pH (6–9) and the humic:metal reaction stoichiometry. Wheat and alfalfa plants were greenhouse cultured in pots containing one of three model soils: an acid, sandy soil and two alkaline, calcareous soils. Treatments were: control (no additions), SHE (53 mg kg^–1 of SHE), and metal (Cu, Zn and Fe)–SHE complexes (2.5 and 5 mg kg^–1 of metal rate and a SHE concentration to make 53 mg kg ^–1). Cu- and Zn–humic complexes significantly (p0.05) increased the plant uptake and the DTPA-extractable soil fraction of complexed micronutrients in most plant–soil systems. However, these effects were associated with significant increases (p0.05) of shoot and root dry weight only in alfalfa plants. In wheat, significant increases of root and shoot dry matter were only observed in the Cu–humic treated plants growing in the acid soil, where Cu deficiency was more intense. The Fe–humic complex did not increase Fe plant assimilation in any plant–soil system, but SHE increased Fe-uptake and/or DTPA-extractable soil Fe in the wheat–calcareous soil systems. These results, taken together with those obtained from the study of the pH- and SHE:metal ratio-dependent SHE complex solubility and stability, highlight the importance of the humic:Fe complex stoichiometry on iron bioavailability as a result of its influence on complex solubility.     

Availability of fluoride to plants grown in contaminated soils

Two pot experiments were carried out to study uptake of fluoride (F) in clover and grasses from soil. Fluoride concentrations in t Trifolium repens (white clover) and t Lolium multiflorium (ryegrass) were highly correlated with the amounts of H₂O– and 0.01 t M CaCl₂–extractable F in soil when increasing amounts of NaF were added to two uncontaminated soils (r=0.95–0.98, t p<0.001). The amounts of H₂O– or 0.01 t M CaCl₂–extractable F did not explain the F concentrations to a similar extent in t Agrostis capillaris (common bent) grown in 12 soils (Cambic Arenosols) collected from areas around the Al smelters at Å: rdal and Sunndal in Western Norway (r=0.68–0.78). This may be due to variation in soil pH and other soil properties in the 12 soils. Soil extraction with 1 t M HCl did not estimate plant–available F in the soil as well as extraction with H₂O or 0.01 t M CaCl₂. Fluoride and Al concentrations in the plant material were positively correlated in most cases. Fluoride and Ca concentrations in the plant material were negatively correlated in the first experiment. No consistent effects were found on the K or Mg concentrations in the plant material. The F accumulation in clover was higher than in the grasses. The uptake from soil by grasses was relatively low compared to the possible uptake from air around the Al smelters. The uptake of F in common bent did not exceed the recommended limit for F contents in pasture grass (30 mg kg^–1) from soil with 0.5–28 mg F(H₂O) kg^–1 soil. The concentration in ryegrass was about 50 mg F kg^–1 when grown in a highly polluted soil (28 mg F(H₂O) kg^–1 soil). Concentrations in clover exceeded 30 mg F kg^–1 even in moderately polluted soil (1.3–7 mg F(H₂O) kg^–1 soil). Liming resulted in slightly lower F concentrations in the plant material.     

Temporal variations in some plant and soil P pools in two pasture soils of widely different P fertility status

Temporal variations in plant production, plant P and some soil P (and N) pools were followed over 21 months in two New Zealand pasture soils of widely different P fertility status. Plant growth rates, and herbage composition at the high-fertility site, were closely linked to soil water use, with growth rates falling when soil water deficits exceeded 60 mm. Herbage P concentrations reflected P fertility, and varied with season, being generally higher in winter and lower in summer. A similar temporal pattern was also observed for labile organic P (NaHCO₃-extractable P₀) in both soils. In the low-fertility soil in spring, net mineralization was especially strong, but from early winter net immobilization occurred. Surprisingly, Olsen P also changed temporally in the high-fertility soil. The microbial biomass remained fairly constant throughout the year, whereas the P content of the biomass varied seasonally. Although microbial biomass was not a useful index of soil fertility, highest microbial P₀ contents coincided with periods of maximum labile P₀ mineralization, when herbage production was also at a peak. Net N-mineralization in the low-fertility soil, in contrast to the high-fertility soil, was low but varied seasonally, under standardised incubation conditions. Soil P and N dynamics were apparently synchronised in the low-fertility soil through soil microbial processes, with mineral N being negatively correlated with microbial P₀ in samples collected two months later. The results of this investigation suggest that the demands of rapid and sustained pasture growth in spring and early summer can best be met by maximising the build-up of organic matter during the preceding autumn and winter. This practice could help to alleviate the common problem of feed shortage in North Island hill country pastures in late winter-early spring.     

Different growth response of five co-existing stoloniferous plant species to inoculation with native arbuscular mycorrhizal fungi

Five species of stoloniferous plants originating from the same field site (Galeobdolon montanum, Glechoma hederacea, Potentilla anserina, Ranunculus repens and Trifolium repens) were studied with respect to their interaction with arbuscular mycorrhizal (AM) fungi. More specifically, the question was addressed whether mycorrhizal growth response of host plant species could be related to their vegetative mobility. The roots of all the species examined were colonised with AM fungi in the field, with the percentage of colonisation varying among species from approximately 40% to 90%. In a subsequent pot experiment, plants of all the species were either left non-inoculated or were inoculated with a mixture of three native AM fungi isolated from the site of plant origin (Glomus mosseae, G. intraradices and G. microaggregatum). AM fungi increased phosphorus uptake in all the plant species; however, plant growth response to inoculation varied widely from negative to positive. In addition to the biomass response, AM inoculation led to a change in clonal growth traits such as stolon number and length or ramet number in some species. Possible causes of the observed differences in mycorrhizal growth response of various stoloniferous plants are discussed.     

Effects of individual and combined exposure to sodium arsenite and sodium fluoride on tissue oxidative stress, arsenic and fluoride levels in male mice

Arsenic and fluoride are potent toxicants, widely distributed through drinking water and food and often result in adverse health effects. The present study examined the effects of sodium meta-arsenite (100 mg/l in drinking water) and sodium fluoride (5 mg/kg, oral, once daily), administered either alone or in combination for 8 weeks, on various biochemical variables indicative of tissue oxidative stress and cell injury in Swiss albino male mice. A separate group was first exposed to arsenic for 4 weeks followed by 4 weeks of fluoride exposure. Exposure to arsenic or fluoride led to a significant depletion of blood delta-aminolevulinic acid dehydratase (ALAD) activity and glutathione (GSH) level. These changes were accompanied by increased level of blood and tissues reactive oxygen species (ROS) level. An increase in the level of liver and kidney thiobarbituric acid reactive substance (TBARS) along with a concomitant decrease in the activities of superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx) and reduced GSH content were observed in both arsenic and fluoride administered mice. The changes were significantly more pronounced in arsenic exposed animals than in fluoride. It was interesting to observe that during combined exposure the toxic effects were less pronounced compared to the effects of arsenic or fluoride alone. In some cases antagonistic effects were noted following co-exposure to arsenic and fluoride. Arsenic and fluoride concentration increased significantly on exposure. Interestingly, their concentration decreased significantly on concomitant exposure for 8 weeks. However, the group which was administered arsenic for 4 weeks followed by 4 weeks of fluoride administration showed no such protection suggesting that the antagonistic effect of fluoride on arsenic or vice versa is possible only during interaction at the gastro intestinal sites. These results are new and interesting and require further exploration.     

Effects of plant diversity on invasion of weed species in experimental pasture communities

Studies have shown that weed invasion into grasslands may be suppressed if the resident plant community is sufficiently diverse. The objective of this study was to determine whether increased forage plant diversity in grazed pasture communities might be associated with reduced weed abundance both in the aboveground vegetation and soil seed bank. Data were collected from a pasture experiment established in 1994 in Missouri, USA. The experiment consisted of 15 m×15 m plots sown with Festuca arundinacea Schreb. or Bromus inermis Leysser as a base species in mixtures of 1, 2, 3, 6, or 8 forage species. The plots were grazed by cattle during each growing season from 1998 to 2002. Aboveground plant species composition in each plot was measured using a point step method. Soil cores were collected in 1999 and 2002, and the species composition of germinable weed seeds in plots were evaluated by identifying seedlings as they germinated over an 8-week period. Species diversity was measured using several indices: species richness (S), Shannon–Wiener diversity index (H^′), and forage species evenness (J). Aboveground weed abundance in plots was unrelated to forage species richness (S), but weed abundance declined as the evenness (J) of resident forage species increased in mixtures. The species composition of mixtures may have affected weed abundance. Weeds both in the soil seed bank and aboveground vegetation were less abundant in mixtures that contained F. arundinacea compared with mixtures that contained B. inermis. Although variables like forage plant productivity may also suppress weed abundance in pastures, our results suggest that maintaining an evenly distributed mixture of forage species may help suppress weeds as well.

Zusammenfassung

Untersuchungen haben gezeigt, dass die Unkrautinvasion in Grünländer unterdrückt sein kann, wenn die ansässige Pflanzengemeinschaft ausreichend divers ist. Die Zielsetzung dieser Untersuchung war es zu bestimmen, ob eine erhöhte Futterpflanzendiversität in beweideten Grünlandgemeinschaften mit einer verringerten Unkrautabundanz sowohl bei der oberirdischen Vegetation als auch in der Bodensamenbank verbunden sein kann. Die Daten wurden in einem Weidelandexperiment gesammelt, das 1994 in Missouri, USA, etabliert wurde. Das Experiment bestand aus 15 m×15 m Probeflächen, die mit Festuca arundinacea Schreb. oder Bromus inermis Leysser als Basisarten in Mischungen von 1, 2, 3, 6 oder 8 Futterarten eingesät waren. Die Probeflächen wurden während jeder Wachstumssaison von 1998 bis 2002 stark mit Vieh beweidet. Die oberirdische Pflanzenartenzusammensetzung wurde in jeder Fläche mit einer Punktstopmethode gemessen. Bodenproben wurden 1999 und 2002 gesammelt und die Artenzusammensetzung der keimfähigen Unkrautsamen wurde in den Probeflächen bewertet, indem die Keimlinge identifiziert wurden, die in einer 8-wöchigen Periode keimten. Die Artendiversität wurde unter Verwendung verschiedener Indizes gemessen: Artenreichtum (S), Shannon–Wiener-Diversitätsindex (H^′) und Futterarten-Äquitabilität (J). Die oberirdische Unkrautartenabundanz in den Probeflächen stand in keiner Beziehung zum Futterartenreichtum (S), aber die Unkrautabundanz nahm ab, wenn die Äquitabilität (J) der ansässigen Futterarten in den Mischungen zunahm. Die Artenzusammensetzung der Mischungen könnte die Unkrautabundanz beeinflusst haben. Sowohl die Unkräuter in der Bodensamenbank, als auch in der oberirdischen Vegetation waren weniger abundant in Mischungen, die F. arundinacea enthielten, im Vergleich zu denen, die B. inermis enthielten. Obgleich Variablen wie die Futterpflanzenproduktivität möglicherweise ebenfalls die Unkrautabundanz im Weideland unterdrücken, lassen unsere Ergebnisse vermuten, dass die Aufrechterhaltung einer gleichmäßigen Mischung von Futterarten ebenfalls helfen kann, die Unkräuter zu unterdrücken.     

Effect of time at pasture combined with restricted indoor feeding on production and behaviour in dairy cows

Extremely high nutrient loads have been reported in grazed grassland regimes compared with cutting regimes in some dairy systems that include the use of supplemental feeding. The aim of this study was, therefore, to investigate the effects on productivity and behaviour of high-yielding dairy cows with limited access to indoor feed and restriction in the time at pasture in a continuous stocking system. During a 6-week period from the start of the grazing season 2005, an experiment was conducted with the aim of investigating the effect of restrictive indoor feeding combined with limiting the time at pasture on the productivity and behaviour of high-yielding dairy cows (31.0 ± 5.4 kg energy-corrected milk) in a system based on continuous stocking. The herd was split into three groups allocated to three treatments consisting of 4, 6.5 and 9 h at pasture, respectively. Each group of cows grazed in separate paddocks with three replicates and was separately housed in a cubicle system with slatted floor during the rest of the day. All cows were fed the same amount of supplement, adjusted daily to meet the ad libitum indoor intake of the cows at pasture for nine hours. The herbage allowance was 1650 kg dry matter (DM) per ha, and the intake of supplemental feed was 9.1 kg DM per cow daily. The limitation of the time at pasture to 4 h in combination with restrictive indoor feeding reduced the daily milk, fat and protein yield and live weight compared with 9 h of access to pasture. The proportion of time during which the cows were grazing while at pasture increased from 0.64 to 0.86 and the estimated herbage intake per h at pasture decreased from 2547 g DM to1398 g DM, when time at pasture changed from 4 to 9 h. It can be concluded, that in systems with a high herbage allowance, the cow was able to compensate for 0.8 of the reduction in time at pasture by increasing the proportion of time spent grazing and presumably also both the bite rate and mass, although the latter two have not been directly confirmed in the present study.     

Effect of medium acidity on growth and rooting of different plant species growing in vitro

Micropropagated Choisya, Daphne, Delphinium, Hemerocallis, Hosta, Iris and Photinia were found to adjust the pH of Murashige and Skoog's plant tissue culture medium (initial pH 5.6 or 3.5) to different values depending on the species. When plant growth and rooting rates were determined after plants had been grown on media initially adjusted or buffered to values between 2.6 and 5.7 the different plant species were also found to have distinct pH requirements for optimal growth and/or rooting rates.Abbreviations MS Murashige & Skoog's (1962) medium - MS19 MS with additionally 10 g l^–1 sucrose - 80 mg l^–1 adenine sulphate and 130.9 mg l^–1 NaH₂PO₄ - BA 6-benzyladenine - NAA 1-naphthyl-acetic acid - IBA 3-indole-butyric acid - IAA 3-indole-acetic acid - 2iP N₆(2-isopentyl) adenine     

多年生黑麦草草地生态系统中放牧强度对草地结构及组织转化的影响

研究了放牧强度对多年生黑麦草人工草地蘖的形态、密度、草地生产率及组织转化的影响。结果表明,重牧条件下蘖密度大于轻牧,而轻牧的单株蘖重大于重牧。重牧划地净生产率大于轻牧,主要是由于轻和手条件下,草地的高的生长率被更高的枯死率所抵消。春夏之交,采用灵活的管理措施,转换放牧强度可以提高草地的生产率。     

Effect of dietary fluoride on selenite toxicity in the rat

Three factorial experiments were conducted to determine if high dietary fluoride (F) would inhibit selenite toxicity in rats. Initially, three levels of selenite (0.05, 3, and 5 mg/kg diet) were matched against three levels of F (2, 75, and 150 mg/kg diet). Fluoride failed to prevent the depressive effect of selenite on 8-wk food intake and body wt gain. Selenium (Se) concentration of plasma and kidney and enzymatic activity of whole blood glutathione peroxidase (GSH-Px) were also unaffected by F. Liver Se concentration, however, was slightly (12%) but significantly (p<0.025) reduced when the highest F and Se levels were combined. Fluoride (150 mg/kg) appeared to reduce liver selenite toxicity (5 mg/kg). Therefore, further study focused on liver histology with treatments that eliminated the middle levels of selenite and F. Fluoride prevented the hepatic necrosis seen in selenite-toxic rats. Similar histological lesions were not observed for kidney or heart. Fluoride partially (26%) but significantly (p<0.025) reduced thiobarbituric-reactive substances in selenite-toxic rats, but there was no F effect on intracellular distribution of liver Se, glutathione levels in liver and kidney, or on liver xanthine oxidase activity. Overall, the protective effect of F on selenite toxicity appears to be confined to liver pathology. The exact mechanism for this effect, however, remains unclear. Oregon Agricultural Experiment Station Technical Paper No. 9728.     

Parameter estimation of a plant uptake model for cyanide: application to hydroponic data

A plant uptake model is applied to describe free cyanide and ferrocyanide transport and fate in willow (Salix eriocephala var. Michaux) grown in hydroponics. The model is applied to experimental data to determine best-fit parameter values, their associated uncertainty, and their relative importance to field-scale phytoremediation applications. The fitted model results, using least-squares optimization of the observed log concentrations, indicate that free cyanide volatilization from leaf tissue and free cyanide cell wall adsorption were negligible. The free cyanide maximum uptake rate and assimilate (noncyanide 15N) first-order leaf loss rate were the only coefficients that significantly affected the model goodness of fit and were concurrently sensitive to data uncertainty in the parameter optimization. Saturation kinetics may be applicable for free cyanide uptake into plants, but not for ferrocyanide uptake, which may occur via preferential protein-mediated or inefficient transpiration stream uptake. Within the free cyanide system, the relative magnitudes of the saturation uptake parameters and the demonstration of an active role for plants in uptake relative to transpiration suggest the potential importance of preferential diffusion through the cell membranes as reported in the literature, rather than protein-mediated uptake. The fitted 13-parameter model matched the observed data well except for the predicted stem and leaf tissue assimilate concentrations, which were significantly underestimated, particularly in the free cyanide system. These low predicted values, combined with the slightly underestimated solution free cyanide removal, suggest that noncyanide 15N redistribution in phloem should be considered.     

Relative contributions of soil chemistry, plant physiology and rhizosphere induced changes in speciation on Ni accumulation in plant shoots

The aim of this study is to rank the relative importance of soil properties, root uptake and root-to-shoot redistribution on the transfer of the trace element nickel from soil to the shoots of non hyperaccumulatings plants. Two contrasting soils and seven plant species have been studied using the radioactive isotope, ⁶³Ni. Shoots and roots were analysed separately and the specific activity of each plant has been measured. The isotopic exchange properties of rhizosphere soil where compared with control non rhizosphere soil. Possible changes in Ni speciation in the rhizosphere have been assessed by comparing the isotopic exchange properties of the rhizosphere and control soil and by comparing the specific activities of Ni in each plant. The capacity of soil to immobilise added radiotracer largely determines root uptake, leading to between a 4- and 40-fold difference between soils for a given species. The redistribution of nickel from roots to shoots was fairly constant for plants grown on the rendzina, but varied strongly between species for the acid soil. This variation enhanced the contrast between species of the soil-to-shoot transfer factor. Root action significantly enhanced immobilisation of added nickel in an acid soil due to the modification of speciation of initially non exchangeable soil nickel, but had little effect on a neutral rendzina. Changes in rhizosphere pH were similar on the two soils. In the acid soil, these pH changes were accompanied by changes in Ni speciation but a causative link has not been established. In the neutral soil pH changes may have modified root uptake properties.     

Distribution of dominant arbuscular mycorrhizal fungi among five plant species in undisturbed vegetation of a coastal grassland

Most plant species in mixed grassland vegetation are colonized by arbuscular mycorrhizal (AM) fungi. Previous studies have reported differences in host preferences among AM fungi, although the fungi are known to lack host specificity. In the present study, the distribution of phylogenetic groups of AM fungi belonging to a clade of Glomus species was studied in five plant species from a coastal grassland in Denmark. The occurrence of the fungi was determined by PCR analyses of fungal large subunit ribosomal DNA sequences amplified from root fragments using a specific primer set. The results showed that the dominant Glomus species were able to colonize all the studied plant species, supporting the view that the AM fungi represent a large underground interconnecting mycelial network.     

植物物种丰富度对水培微宇宙中硝态氮去除的影响

在沙基质的人工湿地中植物多样性能够提高污水去除效果,但无基质水生系统中植物多样性对除氮效应的影响还未知.本研究在45个水培微宇宙(53 cm×37.5 cm×18.5cm)中配置了4个物种丰富度梯度(1、2、3和4),并定期供给硝氮为唯一氮形态的模拟污水,氮载荷率为548.5 gN· m-2 ·a-1.结果表明:物种丰富度对出水中氮去除有显著效应,4个种系统出水总无机氮浓度(54.3 mg·L-1)明显低于单种系统(129.0 mg·L-1);物种丰富度显著提高群落生物量,4个种微宇宙系统群落总生物量为1621.6 g·m-2,高于单种群落的1032.7 g·m-2.水培微宇宙的氮平均移除速率为466.8 g N·m-2·a-1,不低于已有报道的全尺度人工湿地的去除能力,同时,4个种的系统比单种系统约高13％,因而可以通过物种多样性配置提高人工湿地效能.     

Effect of cations on the tyrosine kinase activity of the insulin receptor: Inhibition by fluoride is magnesium dependent

We have recently reported that fluoride interacts directly with the insulin receptor, which causes inhibition of its phosphotransferase activity. The inhibitory effect of fluoride on phosphotransferase activity is not due to the formation of complexes with aluminium and occurs in the absence of alterations to the binding of ATP or insulin. In this report we substantiate that the tyrosine kinase activity of insulin receptors partially purified from rat skeletal muscle shows a strict requirement of Mg²⁺ ions (Ka near 11 mM). This effect of Mg²⁺ was inhibited in a competitive manner by Mn²⁺, which is compatible with competition of both divalent ions for binding sites. The inhibition of tyrosine kinase activity caused by fluoride was dependent on the concentration of Mg²⁺ in the medium and no inhibitory effect was detected at low concentrations of Mg²⁺. Moreover, the addition of increasing concentrations of Mn²⁺ in the presence of a constant high concentr rease in the inhibitory effect of fluoride. These results indicate that the Mg-insulin receptor complex is the major fluoride-susceptible form. Based on the characteristics of the inhibition of tyrosine kinase shown by fluoride it might be proposed that its action is exerted by the formation of multi-ionic MgF complexes analogous to Pi, which bind to the insulin receptor kinase.     

光照条件对土壤—植物系统氮素状况影响的研究

应用盆栽试验 ,通过调节不同光照强度并控制其它条件相互一致的条件下 ,研究了光照条件对土壤 植物系统N素状况以及作物 (莴笋 )产量的影响 .结果表明 ,光照强度的改变会引起作物生长状况的相应变化 ,同时也导致土壤N素 (NH 4 N、NO-3 N)状况、作物吸收N量以及作物对N素吸收速度等的改变 .在试验所处的光照强度范围内 ,光照较强时 ,则作物吸收N素的速度较快、吸收N量增加 ,且产量高 ,但土壤中相应的N素含量(NH 4 N、NO-3 N)则只能维持在相对较低的水平 ;光照较弱时 ,则出现与此相反的情况 .     

Temperature and pH effects on plant uptake of benzotriazoles by sunflowers in hydroponic culture

This article describes a systematic approach to understanding the effect of environmental variables on plant uptake (phyto-uptake) of organic contaminants. Uptake (and possibly phytotransformation) of xenobiotics is a complex process that may differ from nutrient uptake. A specific group of xenobiotics (benzotriazoles) were studied using sunflowers grown hydroponically with changes of environmental conditions including solution volume, temperature, pH, and mixing. The response of plants to these stimuli was evaluated and compared using physiological changes (biomass production and water uptake) and estimated uptake rates (influx into plants), which define the uptake characteristics for the xenobiotic. Stirring of the hydroponic solution had a significant impact on plant growth and water uptake. Plants were healthier, probably because of a combination of factors such as improved aeration and increase in temperature. Uptake and possibly phytotransformation of benzotriazoles was increased accordingly. Experiments at different temperatures allowed us to estimate an activation energy for the reaction leading to triazole disappearance from the solution. The estimated activation energy was 43 kJ/mol, which indicates that the uptake process is kinetically limited. Culturing plants in triazole-amended hydroponic solutions at different pH values did not strongly affect the biomass production, water uptake, and benzotriazole uptake characteristics. The sunflowers showed an unexpected capacity to buffer the solution pH.