Visible Toxicity Symptoms Research Articles

Growth of Spondias tuberosa Irrigated With Saline Water

Spondias tuberosa is a fruit tree species and its production is exploited by extractivism. The expansion of the planted area may be favored by using irrigation with saline water. Thus the objective of the present study was to assess the initial growth of S. tuberosa plants irrigated with saline water. The study was carried out in 12 L pots containing substrate composed of oxisol, sand and manure at 3:1:0.5. Respectively, in a greenhouse at the State University of Goiás, Campus Ipameri, Brazil. A completely randomized design was used with five treatments and six replications consisting of S. tuberosa plants irrigated with water with electric conductivity of 0 dS m-1; 2 dS m-1; 4 dS m-1; 6 dS m-1 and 8 dS m-1 for 40 days. The growth of the S. tuberosa plants was significantly affected by the salinity of the irrigation water. The plants did not show visible symptoms of toxicity but the saline conditions were enough to reduce the start of new leaves and growth as a whole. The expressive effect of salinity on dehydration of S. tuberosa plants, manifested by the low relative water content, transpiration and accentuated leaf fall, indicated that using saline water on S. tuberosa plants at the initial growth stage may result in significant delay in development and may influence the adult plant.

Effects of Vanadium and Nickel on Morphological Characteristics and on Vanadium and Nickel Uptake by Shoots of Mojito (Mentha × villosa) and Lavender (Lavandula anqustifolia)

Vanadium and Nickel may enter the human food chain through medicinal and culinary plants which in great doses are toxic to human, so it is important to determine their potential toxicity and health risk. Therefore, the objective of this work was to study the effects of Vanadium and Nickel on morphological characteristics and on Vanadium and Nickel uptake by shoots of mojito (Mentha × vilosa) and lavender (Lavandula anqustifolia). A completely randomized block design with five Vanadium treatments (0, 5, 10, 20, 40 mg V L-1) and five replications per treatment and another one with five Nickel treatments (0, 5, 10, 20 and 40 mg Ni L-1) and five replications per treatment for mojito and lavender were conducted in pots. No visible toxic or inhibitory symptoms were observed on the plants due to the increasing amounts of Vanadium or Nickel. Shoot dry matter and root dry matter of mojito and lavender decreased with increasing Vanadium rates. Vanadium uptake by shoots of mojito and lavender increased linearly with increasing Vanadium rates. Nickel uptake by shoots of lavender increased linearly with increasing rates of Nickel. Mojito is a Nickel accumulator.

Variation of tolerance and accumulation to excess iron in 24 willow clones: Implications for phytoextraction

Willows (Salix spp.) are characterized by having large biomass, high tolerance to flooding, and strong metal accumulation ability, exhibiting great promise in the phytoremediation of iron (Fe) from contaminated sites. In this study, the variation of Fe tolerance and accumulation in 24 willow clones was investigated with two levels of Fe(II)-EDTA, 0.025 mM (control) and 2.0 mM (treatment) by hydroponic system for 21 days in a greenhouse. Visual symptoms of Fe toxicity were observed in the leaves and roots of Fe sensitive clones. Clonal comparisons showed a great variation in Fe tolerance, and the high levels of Fe reduced biomass productions of most clones. Tolerance indexes (TIs) varied about five-fold based on shoot dry biomass and about six-fold based on root dry biomass among clones. Clones also exhibited a wide variation in Fe concentrations (mg g–1 DW), ranged from 0.80 to 3.41 in leaves, from 5.40 to 10.51 in stems, and from 3.25 to 17.10 in roots under Fe treatments among clones. Large differences varied in the transport of Fe from roots to aerial parts among clones. The results highlighted the selection of Salix clones with high resistance to Fe toxicity and high Fe accumulation to improve phytoremediation efficacy.

Spinach (Spinacea oleracea L.) Response to Salinity: Nutritional Value, Physiological Parameters, Antioxidant Capacity, and Gene Expression

Scarcity of good-quality irrigation water is a major impediment to meet food demand for a growing world population. Recycled waters may be available locally more affordably, but their higher salinity is a concern. Salinity effects on spinach mineral composition, antioxidant capacity, photosynthesis, and gene expression have not been established. Spinach cv. Raccoon was greenhouse-grown and irrigated with four levels of water salinity of electrical conductivities (ECiw) of 1.4 (control) or ranging from 3.6 to 9.4 dS m−1, combined with three levels of K (3, 5, and 7 meq L−1). Irrigation waters had 2, 20, 40, and 80 meq L−1 of NaCl. After 23 treatment days, plants significantly accumulated Na and Cl in shoots and roots with increasing salinity, regardless of the K concentration in the irrigation water. Plants exhibited no visual symptoms of salt toxicity and there were no differences in shoot growth. Plants maintained their overall concentrations of mineral nutrients, physiological parameters, and oxalic acid across salinity treatments. Leaves retained all their antioxidant capacity at 20 meq L−1 NaCl, and 74% to 66% at 40 and 80 meq L−1 NaCl, respectively. Expression analyses of ten genes, that play important role in salt tolerance, indicated that although some genes were upregulated in plants under salinity, compared to the control, there was no association between Na or K tissue concentrations and gene expression. Results clearly show that spinach maintains its growth, mineral composition, and antioxidant capacity up to ECiw = 9.4 dS m−1. As this salinity is equivalent to a soil salinity of 4.5 dS m−1, spinach can tolerate over two-fold its previously-considered salinity threshold. Thus, growers can cultivate spinach using recycled, saline, waters without detriment to shoot biomass accumulation, and nutritional value.

Effect of Silicon Fertilization on Physiological Parameters and Yield of Hybrid Maize under Irrigated and Rainfed Conditions

Mercury is a global pollutant, highly toxic, is a non-essential element with no biochemical or nutritional function in the organisms and is ubiquitous in the environment. In order to elucidate the participation of plants in uptake of mercury an experiment was carried out to study the plant behavior on mercury contamination in the Department of Environmental sciences, Tamil Nadu Agricultural University, Coimbatore with amaranthus and marigold as test crops. Four different concentration of mercury were spiked to a soil along with control (without mercury). Relatively higher amount of Hg was found accumulating in the roots of Marigold (3.35 μg.g-1) and Amaranthus (3.35 μg.g-1) and the plants did not express any visual symptoms of toxicity. Regarding the partition of mercury in different plant parts, it ranked in the order of roots > shoots > leaves. Among the treatments 20 mg.kg-1 Hg recorded higher enzymatic activity in both the test crops. Marigold being a non-food chain crop can be recommended for Hg contaminated soils.

The metal distribution and the change of physiological and biochemical process in soybean and mung bean plants under heavy metal stress

ABSTRACTSoybean [Glycine max (Linn.) Merrill] and mung bean [Vigna radiate (Linn.) Wilczek] plants were challenged with 5 kinds of heavy metals [cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb) and mercury (Hg)] in a hydroponic system. We applied 4 different metal treatments to study the effects of heavy metals on several physiological and biochemical parameters in these species, including root length, heavy metal concentrations and allocation in different organs, superoxide dismutase, catalase, and peroxidase activities, the content of malondialdehyde (MDA), protein and chlorophyll. The data showed that the growth of the roots of soybean and mung bean was equally sensitive to external Hg concentrations. Soybean was more sensitive to external Cd concentrations, and mung bean was more sensitive to external Cr, Cu and Pb concentrations. Normal concentrations of heavy metal would not cause visible toxic symptoms, and a low level of heavy metal even slightly stimulated the growth of plants. With the rise of heavy metal concentration, heavy metal stress induces an oxidative stress response in soybean and mung bean plants, characterized by an accumulation of MDA and the alternation pattern of antioxidative enzymes. Meanwhile, the growth of plants was suppressed, the content of chlorophyll decreased and leaves showed chlorosis symptoms at high metal concentrations.

Woody species Rhus chinensis Mill. seedlings tolerance to Pb: Physiological and biochemical response

Screening potential plant species is a crucial consideration in phytoremediation technology. Our previous study demonstrated that Rhus chinensis Mill. seedlings had potentials for phytoremediation of Pb contaminated soil. However, its bioaccumulation and tolerance characteristics remain unclear. Seedling growth, LMWOAs secreted by roots, Pb subcellular distribution and chemical forms, and mineral elements in R. chinensis tissues were evaluated under different Pb concentrations (0, 25, 50, 100, 200 and 400 mg/L) in culture solution at 14 days after planting. R. chinensis did not show visual symptoms of Pb toxicity under lower Pb treatments; however, Pb significantly declined the growth of seedlings under higher Pb treatments. Higher Pb stress also decreased the concentrations of nitrogen in leaves, but increased the concentrations of P and K in roots. Pb stress also decreased Mn concentrations in leaves. A great quantity of Pb was uptake and mostly retained in R. chinensis roots. Nonetheless, R. chinensis can still concentrate 459.3 and 1102.7 mg/kg Pb in leaves and stems, respectively. Most of Pb in R. chinensis tissues was stored in the cell wall with HAc-, HCl-, and NaCl-extractable form. LMWOAs secreted by R. chinensis roots showed a strong positive correlation with Pb concentrations in all plant tissues and with P in roots. Our results suggested that Pb deposited in the cell wall and integration with phosphate or oxalate might be responsible for the tolerance of R. chinensis under Pb stress in short period.

Phytoremediation of lead by a wild, non-edible Pb accumulator Coronopus didymus (L.) Brassicaceae

ABSTRACTCoronopus didymus was examined in terms of its ability to remediate Pb-contaminated soils. Pot experiments were conducted for 4 and 6 weeks to compare the growth, biomass, photosynthetic efficiency, lead (Pb) uptake, and accumulation by C. didymus plants. The plants grew well having no visible toxic symptoms and 100% survivability, exposed to different Pb-spiked soils 100, 350, 1500, and 2500 mg kg−1, supplied as lead nitrate. After 4 weeks, root and shoot concentrations reached 1652 and 502 mg Pb kg−1 DW, while after 6 weeks they increased up to 3091 and 527 mg Pb kg−1 DW, respectively, at highest Pb concentration. As compared to the 4 week experiments, the plant growth and biomass yield were higher after 6 weeks of Pb exposure. However, the chlorophyll content of leaves decreased but only a slight decline in photosynthetic efficiency was observed on exposure to Pb at both 4 and 6 weeks. The Pb accumulation was higher in roots than in the shoots. The bioconcentration factor of Pb was > 1 in all the plant samples, but the translocation factor was < 1. This suggested C. didymus as a good candidate for phytoremediation of Pb-contaminated soils and can be used for future remediation purposes.

Deciphering the molecular events during arsenic induced transcription signal cascade activation in cellular milieu.

Anthropogenic sources of arsenic poses and creates unintentional toxico-pathological concerns to humans in many parts of the world. The understanding of toxicity of this metalloid, which shares properties of both metal and non-metal is principally structured on speciation types and holy grail of toxicity prevention. Visible symptoms of arsenic toxicity include nausea, vomiting, diarrhea and abdominal pain. In this review, we focused on the dermal cell stress caused by trivalent arsenic trioxide and pentavalent arsanilic acid. Deciphering the molecular events involved during arsenic toxicity and signaling cascade interaction is key in arsenicosis prevention. FoxO1 and FoxO2 transcription factors, members of the Forkhead/Fox family, play important roles in this aspect. Like Foxo family proteins, ATM/CHK signaling junction also plays important role in DNA nuclear factor guided cellular development. This review will summarize and discuss current knowledge about the interplay of these pathways in arsenic induced dermal pathogenesis.

Leaf anatomy of cassava (Manihot esculenta Crantz. cv. IAC-12) after herbicides application to control weeds in Minas Gerais, Brazil

Micro-morphological changes precede the appearance of visible damage after herbicide application and are essential in providing data for the safe recommendation in chemical management of weeds. Therefore, the aim of this research was to verify the anatomical changes of leaf tissue caused by application of herbicides in cassava (Manihot esculenta Crantz. cv. IAC-12). A greenhouse experiment was conducted with post-emergence herbicides treatments as follows: nicossulfuron (60 g a.i ha-1), fluazifop (250 g a.i ha-1), fomesafem (250 g a.i ha-1), metribuzin (480 g a.i ha-1), oxyfluorfen (720 g a.i ha-1) and the mixture fluazifop + fomesafen (200 + 250 g a.i ha-1), and an untreated control, respectively. The results obtained have allowed to affirm the cassava plants (cultivar IAC-12), exhibited changes in leaf anatomy in response to herbicide application even on cassava leaves without no visual toxicity symptoms. The products caused alterations both in tissue thickness as in tissue proportion in the leaf blade. For the fluazifop, a eudicotyledonous selective herbicide, changes were observed in tissue thickness and proportion of leaf blade, even without any visual toxicity detected. Cassava plants (IAC-12), showed structural changes in leaf anatomy in response to application of herbicides. The leaf anatomy of cassava cv. IAC-12, can be used to indicate the herbicide effect on cassava (Manihot esculenta Crantz.cv. IAC-12) plants.

Modulation of cadmium-induced phytotoxicity in Cabomba caroliniana by urea involves photosynthetic metabolism and antioxidant status

Urea is a widespread organic pollutant, which can be a nitrogen source, playing different roles in the growth of submerged macrophytes depending on concentrations, while high cadmium (Cd) concentrations are often toxic to macrophytes. In order to evaluate the combined effect of urea and Cd on a submerged macrophyte, Cabomba caroliniana, the morphological and physiological responses of C. caroliniana in the presence of urea and Cd were studied. The results showed that high concentrations of urea (400mgL−1) and Cd (500µmolL−1) had negative effects on C. caroliniana. There were strong visible symptoms of toxicity after 4 days of exposure under Cd-alone, 400mgL−1 urea, and Cd+400mgL−1 urea treatments. In addition, 400mgL−1 urea and Cd had adverse effects on C. caroliniana's pigment system. Significant losses in chlorophyll fluorescence and photosynthetic rates, as well as Rubisco activity were also observed under Cd-alone, 400mgL−1 urea, and Cd+400mgL−1 urea treatments. 400mgL−1 urea markedly enhanced Cd toxicity in C. caroliniana, reflected by a sharp decrease in photosynthetic activity and more visible toxicity symptoms. The results of thiobarbituric acid reactive substances (TBARS) pointed to extreme oxidative stress in C. caroliniana induced under Cd or 400mgL−1 urea exposure. Exogenous ascorbate (AsA) protected C. caroliniana from adverse damage in 400mgL−1 urea, which further corroborated the oxidative stress claim under 400mgL−1 urea. However, results also demonstrated that lower urea concentration (10mgL−1) alleviated Cd-induced phytotoxicity by stimulating chlorophyll synthesis and photosynthetic activity, as well as activating the activity of catalase (CAT) and glutathione-S-transferase (GST), which may explain the alleviating effect of urea on C. caroliniana under Cd stress.

Potential use of germicides in vase solutions for gladiolus ‘White Friendship’

Gladiolus (Gladiolus x hortulanus) is one of the most important crops for cut flowers worldwide, however having a short longevity. Usually, stems are harvested at the bud stage and need water and carbohydrates to support inflorescence development and to ensure flower quality. Vase solutions can supply these elements. However, sugars may benefit bacterial proliferation, which eventually can block xylem vessels. Bactericides potentially inhibit microorganism proliferation and new compounds are being tested constantly. This experiment was conducted to evaluate ‘White Friendship’ cut gladiolus performance in vase solutions with sodium dichloroisocyanurate dihydrate (Na-DCC), 8-hydroxyquinoline (8-HQ) or polymeric biguanide (PB). Inflorescences harvested at commercial maturity were placed in distilled water with 4% w/v of sucrose plus the germicides and kept under ambient conditions. Vase life, inflorescence postharvest development, fresh mass, membrane stability index and water relations were evaluated. There were no visual symptoms of toxicity in the treatments. The highest values of vase life, fully-open flowers, fresh mass and water balance were obtained with the Na-DCC treatment. Inflorescences treated with 8-HQ exhibited the highest values of solution uptake and wilting flowers. PB had a limited effect in gladiolus postharvest since the obtained results were similar to the sucrose alone. There was no effect of germicides on membrane stability index and its reduction was due to flower senescence progress only. Vase solution with Na-DCC plus sucrose improved water balance, increased open flowers, reduced wilting of flowers and fresh mass loss. Therefore, vase solutions with sucrose 4% w/v and Na-DCC enhance postharvest quality of cut gladiolus inflorescences.

Impact of EDTA, Citric Acid and Humic Acid on Phytoremedation of Metal Contaminated Soil by Indian Mustard (Brassica juncea)

A pot experiment was conducted during winter season of (2013/2014) at Sakha Agricultural Research Station, Kafr El-Sheikh Governorate. The experiment aimed to investigate the effect of disodium ethylenediaminetetraacetic acid (EDTA) (0.0, 1.5, 3.0 and 4.5 mmol kg-1 soil), citric acid (CA) (0, 3, 6 and 9 mmol kg-1 soil) and humic acid (HA) (0.0, 0.2, 0.4 and 0.6 g kg-1 soil) on the phytoextraction of Cu, Zn and Pb from Al-Gabal Al-Asfar contaminated soil using indian mustard (Brassica juncea) and the leaching behavior of these metals from soil. The obtained results can be summarised in the following:- EDTA severely reduced indian mustard dry weight and visual symptoms of toxicity were observed, especially at 4.5 mmol EDTA kg-1 soil. Whilst, application of CA and HA ameliorated indian mustard growth.- EDTA was found to be the most efficient chelator in increasing concentrations of Cu and Zn in different indian mustard plant parts.- Increasing EDTA application rate up to 4.5 mmol kg-1 soil increased the concentrations of Cu by 1.91, 2.88, 3.04 and 1.56 folds and Zn by 1.43, 1.91, 1.83and 1.11 folds for roots, stem, leaves and seeds, respectively, compared to control treatment (0.0 mmol EDTA kg-1 soil).- Application of CA also increased Cu and Zn concentrations by different indian mustard plant parts, especially at 9 mmol kg-1 soil, but its efficacy was less than EDTA.- HA application increased Zn concentrations in different indian mustard plant parts with increasing its addition up to 0.6 g kg-1 soil, but its efficacy was less than that of EDTA and CA.- HA application did not affect Cu concentrations in indian mustard.- There were neither any perceptible concentrations of Pb in different plant parts of indian mustard except for roots clarifying that phytoextraction of Pb failed even after application of tested chelators. - Application of EDTA and CA to the soil increased the leaching of Cu, Zn and Pb under indian mustard cultivation with increasing application rate up to 4.5 and 9 mmol kg-1 soil, respectively. However, the effect of EDTA was many times higher than that of CA. Whilst, HA application did not affect the leaching of studied metals.- Using CA for the phytoremediation of Cu and CA and HA for the phytoremediation of Zn is favorable than EDTA despite the high efficiency of EDTA, due to the harmful effects of EDTA on plant growth and the increased risk of groundwater contamination via metal leaching.

Differential expression of Lead accumulation during two growing seasons by desert shrub Acacia victoriae L.

In desert reclamation strainer plants can be used for improvement and decrease pollution of soil and water. This technology can be used to remove both inorganic and organic contaminants in soil. In this study, one year old Acacia victoriae seedlings were exposed to Pb (NO3)2 in 5 different concentrations; 0, 50, 250, 500 and 1000 mg Pb L-1 for 45 days in two growing seasons. Subsequently, the heavy metal concentrations were measured in different plant tissues by Atomic Absorption Spectroscopy (AAS) for two growing periods. In addition, some physiological and morphological parameters (root and plant length, root diameter, leave area, dry weight, chlorophyll a, band total) were measured. Based on the results, the visible toxicity symptoms (chlorosis and necrosis) appeared only to the highest concentration (1000 mg Pb L−1) in both growing seasons. The results also showed that application highest concentration of Pbreduced the physiological and morphological parameters as compared to the control seedlings. The accumulation of Pbwas influenced by the Pbconcentration in the growth medium and the growing seasons as well. With respect to the more accumulation of Pbin the roots tissues than aboveground tissues, indicating A.victoriae as a good option for phytostabilization of Pbcontaminated soils. Furthermore if A.victoriae is planted for Pb phytoextraction, therefore the harvest of aboveground should be done at the fall season. Meanwhile concentrations of Pb in the aboveground parts were more than roots at the fall season. In conclusion A.victoriae a native to the arid zone appeared to be hyper tolerate, accumulate high concentrations of Pb and it could be regarded as a potential accumulator. In addition A.victoriae have high application value in repairing Pb contaminated soils and is suitable and effective choice to be used as a tool of phytoremediation in industrial sites of the arid zones. Our findings suggest that A.victoriae has the advantages of high capacity for adaptation to poor, easy cultivation, deep root system, high tolerance to the drought, saline soils and Pb and could use as candidate plant for environmetals monitoring.

How rootstocks influence salt tolerance in grapevine? The roles of conferred vigor and ionic exclusion

The aim of this work was to evaluate whether selected grapevine rootstocks can confer greater salt tolerance than own-rooted Vitis vinifera L. A trial was carried out with potted own-rooted 'Malbec' vines and also grafted onto three rootstocks (101-14 Mgt, 1103P and Cereza). Aditionally, the vines were irrigated with a solution containing 0, 50 and 100 mM NaCl. Vegetative growth was the most sensitive variable to salinity and was affected even at 50 mM. Above 0.1% dw Na+ and 0.6% dw Cl-, the leaf area was negatively correlated with Na+ and Cl- in leaf blades. Membrane integrity and chlorophyll content in leaves were affected only at 100 mM. At 50 mM, 1103P showed a decrease in leaf area but this parameter was not further affected at 100 mM. Own-rooted and 1103P vines showed fewer visual symptoms of toxicity and maintained higher leaf area (+450% higher relative to 101-14 Mgt) and higher membrane integrity (+81% higher relative to Cereza) at high salinity. Own-rooted and 1103P vines grown in 0 mM NaCl also showed higher leaf area and biomass production (i.e., vigor), suggesting that salt tolerance is linked to innate vigor. Regardless of the NaCl content, 101-14Mgt showed higher Na+ concentration in leaf blades than own-rooted and 1103P vines (+266%). At 50 mM, Cereza concentrated more Cl- than the others (+114%). At 100 mM, Cereza and 101-14 Mgt concentrated more Cl- than both 1103P and own-rooted vines (+133%). The 1103P limited the entry of Na+ and Cl- to the vines more than the others (-58 and -62% respectively), suggesting a higher exclusion capacity. The results suggest that the use of own-rooted 'Malbec' remains as a viable alternative under high soil salinity conditions. The use of the 1103P rootstock also appears as an alternative due to its excluding behavior.

Vegetation damage in the vicinity of an aluminum smelter in Brazil

A primary aluminum smelter, which is responsible for releasing fluoride and other pollutants to atmosphere, is located at the vicinities of rocky field ecosystem in Brazil. We aimed to evaluate the biological effects of the smelter emissions using Spondias dulcis as a bioindicator organism. Evaluations of rainwater quality, atmospheric oxidants and toxicity visual symptomatology were performed in 4 different sites. We also collected leaflets with and without visual toxicity symptoms for anatomical studies under light and scanning electron microscopes, histochemistry, X-ray microanalysis, and fluoride quantification. The fluoride detected on leaves was present in plants at all studied sites, principally at Site 1 (park entrance) and less detected at Site 3 (forest area). However, the fluoride quantity was not the main cause of damage, but the large amount of oxidants which was detected at the atmosphere. This amount of oxidants was increased with the distance from the emission source. It was noticed two types of visual symptoms on the leaflets: a darkening at the adaxial face and a wide brownish necrosis. The anatomical studies showed three damage patterns: superficial necrosis, reaching just the palisade and spongy parenchyma, deep necrosis, reaching the entire mesophyll and a punctual necrosis perceived only at the central veins. With scanning electron microscopy it was detected a turgor loss and a flattening of the cell's external periclinal wall. In the areas where the damage was more noticeable, there was an erosion of the epicuticular wax that lead to delayering, resulting on the epidermis rupture and internal tissue exposure. S. dulcis showed visual symptoms after few days of exposure, which culminated in structural alterations, thus indicating that these pollutants are impacting this important vegetation type from a rocky field ecosystem.

Response of Tomato Plants (Solanum lycopersicum) to Stress Induced by Sb(III)

Abstract Presented study evaluates effects of various Sb(III) concentrations on tomato plants (Solanum lycopersicum) cultivated hydroponically. Visual symptoms of antimony toxicity were observed only at two highest applied concentrations (50 and 100 mg/L). Dry weight of aboveground parts decreased significantly in variants treated with 25, 50 and 100 mg/L Sb(III), by ~12, 35 and 65 %, respectively, in comparison to the control. Statistically significant decrease of chlorophyll a and b was observed only after application of two highest studied concentrations 50 and 100 mg/L Sb(III). On the other hand concentration of total carotenoids in leaves rose with increasing external Sb(III) concentration. High concentrations (50 and 100 mg/L) of Sb(III) in nutrient solution caused that protein content in leaves dropped by ~20 and 39% relative to control. Accumulation of antimony in roots was about 5- (10 mg/L) to 27-times (25 mg/L) greater than that in shoots. The highest BAF factor value determined for shoots was ~55 at 10 mg/L Sb(III) and for roots it was ~821 at 50 mg/L Sb(III). Translocation factor values were in whole studied concentration range 5 – 100 mg/L Sb(III) &lt; 1. The most effective translocation of antimony from roots to shoots was observes for variants treated with 10 mg/L of Sb(III).

SELECTIVITY OF SAFLUFENACIL APPLIED SINGLY AND IN COMBINATION WITH GLYPHOSATE ON COFFEE AND CITRUS CROPS

ABSTRACT: Saflufenacil is absorbed by the plant leaves and roots, thus the residual permanence of this herbicide can cause losses to the crop plants. Therefore, the objective of this study was to evaluate the selectivity of the saflufenacil herbicide, applied singly and in combination with glyphosate, on coffee and citrus plants grown in a sandy soil. Two experiments were implemented and conducted in completely randomized design with four replications. The chemical treatments consisted of three sequential applications, with directed spraying of saflufenacil at rates of 0.035, 0.07 and 0.105 kg a.i. ha-1, glyphosate at rate of 2.160 kg a.e. ha-1, the two herbicides combined at the same rates, and a control without chemical treatment. The saflufenacil applied singly and in combination with glyphosate was selective for coffee and citrus plants, which presented no visual toxicity symptoms. The sequential application of saflufenacil, singly and in combination with glyphosate did not affect the growth of coffee and citrus plants. The saflufenacil has potential for use, in combination with glyphosate on controlling many weed species in coffee and citrus areas without any interference on the development of these species.

Heavy-metal-contaminated industrial soil: Uptake assessment in native plant species from Brazilian Cerrado

ABSTRACTPlants of the Cerrado have shown some potential for restoration and/or phytoremediation projects due to their ability to grow in and tolerate acidic soils rich in metals. The aim of this study is to evaluate the tolerance and accumulation of metals (Cd, Cu, Pb, and Zn) in five native tree species of the Brazilian Cerrado (Copaifera langsdorffii, Eugenia dysenterica, Inga laurina, Cedrela fissilis, Handroanthus impetiginosus) subjected to three experiments with contaminated soils obtained from a zinc processing industry (S1, S2, S3) and control soil (S0). The experimental design was completely randomized (factorial 5 × 4 × 3) and conducted in a greenhouse environment during a 90-day experimentation time. The plant species behavior was assessed by visual symptoms of toxicity, tolerance index (TI), translocation factor (TF), and bioaccumulation factor (BF). C. fissilis has performed as a Zn accumulator by the higher BFs obtained in the experiments, equal to 3.72, 0.88, and 0.41 for S1, S2, and S3 respectively. This species had some ability of uptake control as a defense mechanism in high stress conditions with the best behavior for phytoremediation and high tolerance to contamination. With economical and technical benefits, this study may support a preliminary analysis necessary for using native tree species in environmental projects.

Effect of cobalt ferrite (CoFe2O4) nanoparticles on the growth and development of Lycopersicon lycopersicum (tomato plants)

Nanoparticles (NPs) have been synthetized and studied to be incorporated in many industrial and medical applications in recent decades. Due to their different physical and chemical properties compared with bulk materials, researchers are focused to understand their interactions with the surroundings. Living organisms such as plants are exposed to these materials and they are able to tolerate different concentrations and types of NPs. Cobalt ferrite (CoFe2O4) NPs are being studied for their application in medical sciences because of their high coercivity, anisotropy, and large magnetostriction. These properties are desirable in magnetic resonance imaging, drug delivery, and cell labeling. This study is aimed to explore the tolerance of Solanum lycopersicum L. (tomato) plants to CoFe2O4 NPs. Tomato plants were grown in hydroponic media amended with CoFe2O4 nanoparticles in a range from 0 to 1000mgL−1. Exposure to CoFe2O4 NPs did not affect germination and growth of plants. Uptake of Fe and Co inside plant tissues increased as CoFe2O4 nanoparticle concentration was increased in the media. Mg uptake in plant leaves reached its maximum level of 4.9mgg−1 DW (dry weight) at 125mgL−1 of CoFe2O4 NPs exposure and decreased at high CoFe2O4 NPs concentrations. Similar pattern was observed for Ca uptake in leaves where the maximum concentration found was 10mgg−1 DW at 125mgL−1 of CoFe2O4 NPs exposure. Mn uptake in plant leaves was higher at 62.5mgL−1 of CoFe2O4 NPs compared with 125 and 250mgL−1 treatments. Catalase activity in tomato roots and leaves decreased in plants exposed to CoFe2O4 NPs. Tomato plants were able to tolerate CoFe2O4 NPs concentrations up to 1000mgL−1 without visible toxicity symptoms. Macronutrient uptake in plants was affected when plants were exposed to 250, 500 and 1000mgL−1 of CoFe2O4 NPs.