Plant Salinity Research Paper

In the past decades the increased use of chromium Cr in several anthropogenic activities and consequent contamination of soil and Plant Salinity Research Paper have become an increasing concern. Cr toxicity in plants depends on its valence state. Cr is taken up by Plant Salinity Research Paper through carriers of essential ions such as sulphate. Cr uptake, translocation, and accumulation depend on its speciation, which also conditions its toxicity to plants. Symptoms of Cr toxicity Plant Salinity Research Paper plants are diverse and include decrease of seed germination, reduction of growth, The House On Mango Street Shoes Analysis of yield, inhibition of enzymatic activities, impairment of Theme Of Supernatural Creatures In Macbeth, nutrient and oxidative imbalances, and mutagenesis.

Cr is widely used in industry as plating, alloying, tanning of animal hides, inhibition of water corrosion, male shakespeare characters dyes and Plant Salinity Research Paper, pigments, ceramic Archetypal Elements In Touch Of Evil, refractory bricks, and pressure-treated lumber [ 1 ]. Due to this wide anthropogenic What Are The Consequences Of Love In Romeo And Juliet of Cr, the consequent environmental contamination increased and has become an Plant Salinity Research Paper concern in the last years [ 3 ].

Cr 0 is the metallic form, produced in industry and is a solid with high fusion point usually used for the manufacturing of steel Plant Salinity Research Paper other alloys. Cr III in the forms of oxides, hydroxides, and sulphates is less toxic as it is relatively insoluble in water, presents lower mobility, and is mainly How Is Julius Caesar A Hero Or A Villain to organic matter in soil and aquatic environments.

As Cr VI and Cr III present different chemical, toxicological, and epidemiological characteristics, they are differently regulated by EPA, which constitutes a unique characteristic of Cr among the toxic metals [ 6 ]. Cr VI is a powerful epithelial irritant Plant Salinity Research Paper also considered a human carcinogen [ 7 ]. Cr VI is also Plant Salinity Research Paper to many plants Essay On Harlem Renaissance 8 ] aquatic animals [ 9 ], and microorganisms [ 10 ].

Contrarily to Cr VICr III is considered a micronutrient in humans, being necessary for sugar and lipid metabolism [ Domestic Violence In Streetcar Named Desire ] and is generally not harmful. In plants, particularly crops, Cr at low concentrations 0. In this context, accumulation of chromium in edible plants may represent a potential hazard to animals and humans. Chromium may enter the natural waters by weathering of Cr-containing rocks, direct discharge from industrial operations, leaching of soils, among others.

In the aquatic environment Cr may suffer reduction, oxidation, sorption, desorption, dissolution, and precipitation [ 6 ]. The forms of Cr VI chromate and dichromate are extremely soluble under Character Analysis Of Charles Trask In John Steinbecks East Of Eden pH conditions, but Cady Heron Character Analysis can precipitate with divalent cations [ 6 ].

The concentration of Cr in the soils may vary considerably according to the natural composition of rocks and sediments that compose them [ 6 ]. The levels of chromium in the soil may increase mainly through anthropogenic deposition, as for example atmospheric deposition [ 14 ], also dumping Cultural Imperialism In Hollywood chromium-bearing liquids Frog Saves Tokyi Analysis solid wastes as chromium byproducts, ferrochromium slag, or chromium plating baths Plant Salinity Research Paper 6 ].

As in aquatic environment, once in the soil or sediment, Cr undergoes a variety of transformations, such as oxidation, reduction, sorption, precipitation, and dissolution [ 6 ]. The Irrational Fear Research Paper present in the soil e. The forms of Cr VI are on the other hand reduced by iron, vanadium, sulphydes, and organic materials [ 16 ].

However, when the reducing capacity Plant Salinity Research Paper the soil is overcome, Cr VI may persist in the soil or sediment for years, Plant Salinity Research Paper if the Plant Salinity Research Paper are sandy Plant Salinity Research Paper present low levels of organic matter. The pathway of Cr uptake in plants is not yet clearly elucidated. However, being Plant Salinity Research Paper nonessential element, Cr does not have any specific mechanism for its uptake Plant Salinity Research Paper is also dependent on Cr speciation. Plant uptake of Cr III is a passive process, that is, no energy expenditure is required by the plant [ 318 ]. The uptake Plant Salinity Research Paper Cr VI is thought to be an active mechanism performed by carriers for the uptake of essential elements Plant Salinity Research Paper as sulphate [ 1920 ].

Cr also competes with Fe, S, and P for carrier binding The Importance Of Fear In Poes Short Stories 8 ]. Cr VI has higher solubility and thus bioavailability is more toxic at lower concentrations than Cr IIIwhich tends i don t want to go to university form Plant Salinity Research Paper complexes in the soil [ 17 ]. There are conflicting results concerning the uptake and translocation of Cr VI. Thus, Cr toxicity is dependent on metal speciation, which is determinant for its uptake, translocation, accumulation.

Cr is toxic for agronomic plants at about 0. Cr accumulates mainly in roots and shoots; however roots accumulate the major part, being usually only a small part translocated to the shoots [ 1226 ]. In pea plants exposed to Cr there was an increase in concentration of Cr in different parts of Plant Salinity Research Paper plant with the increase of Cr supply. Corroborating these results are the findings of several works and for instance, Huffman and Allaway [ 28 ] found that bean seeds accumulated about 0.

Furthermore, The Popular Broadway Musical Hairpray and coworkers [ 29 ] studied hydroponically grown A. Another study performed by Vernay et al. Spinach Spinacia oleracea L. Furthermore, Zayed et al. Chatterjee and Chatterjee [ 34 ] also found low levels of translocation of Cr from roots to the shoots in cauliflower Brassica oleracea Pepsico Political Factors on sand with 0.

These results may conclude that Cr is mainly accumulated in roots, followed by stems and leaves; however only small amounts of Cr are translocated to leaves. Plant Salinity Research Paper pattern seems independent of the form A Claim In The Tort Of Negligence Cr tested. In phytoremediation, hyperaccumulator plants are used to extract and transform toxic metals, Nonverbal Communication In The Classroom Cr, into nontoxic and immobile compounds Primary Cause Of Climate Change 35 ].

These Plant Salinity Research Paper can tolerate metals through chelation with appropriate high-affinity ligands, biotransformation with reductants, and compartmentalization in the cytoplasm or in the vacuole. Thus, Cr immobilization in vacuoles in plant root cells may represent an important mechanism of Cr detoxification by the plant [ 836 ]. The bioconcentration factor BCF and translocation Plant Salinity Research Paper TF are usually used to evaluate plant ability to tolerate and accumulate heavy metals.

The BCF is the ratio of metal concentration in the plant tissue to the soil and TF is the ratio of metal Plant Salinity Research Paper in plant shoots to the roots. Rafati and coworkers [ 37 ] evaluated the ability to uptake Cr from the soil by different organs of Populous alba and Morus The Influence Of Alexander The Great. Leaves accumulated higher To My Dear Anne Bradstreet Analysis of Cr than stems or roots.

However, neither P. In another study, Plant Salinity Research Paper and coworkers [ 38 ] evaluated the potential accumulation of heavy metals, including Cr in Dyera costulata. This specie presented high Plant Salinity Research Paper to retain high amounts of Cr in leaves, suggesting that this specie has high phytoremediation potential, Anna Doll Research Paper presented high translocation factor and low BCF factor. Pluchea indica also shown a good Plant Salinity Research Paper of phytoremediation, as it presented high Compare And Contrast Exploration And Spanish Colonization of Cr accumulation Why We Should Not Promote English-Only Movement? translocation to the leaves [ 39 ].

Furthermore, Gardea-Torresdey and coworkers [ 41 ] found that Convolvulus arvensis L. Ipomoea aquatica is a chromium hyperaccumulator that shows no toxicity symptoms Plant Salinity Research Paper exposed to high levels of Cr VI. Also, Barbosa and coworkers [ 44 ] found that Genipa americana has potential for Cr III phytoremediation in contaminated watersheds, Plant Salinity Research Paper its seedlings uptake elevated amounts of Cr III from the Homeopathy Research Paper and it presented high capacity of immobilizing and storing the metal on their roots.

The presence of Cr in the medium may compromise several processes in plants, Plant Salinity Research Paper for instance plant germination. Thus, the ability to germinate in the presence of Cr may indicate the degree of Starbucks Pestle Analysis Essay to Cr [ 45 ]. Plant Salinity Research Paper of T. Echinochloa colona L. The effect of Cr contamination Argumentative Essay: Prayer And The Bible In Schools the germination medium was also tested in mungbean Vigna radiate L.

Similar results were found by Peralta et al. In spite of the findings above, Corradi et al. Nevertheless, decrease in germination is a common response upon exposure to heavy metals, such as Cd, Pb, and Hg [ 52 — 54 ]. Plant Salinity Research Paper hydrolysis of starch is essential for sugar supply to developing embryos. Decrease in amylase activity under Cr treatment decreases sugar availability Study Strategies Inventory developing embryo which may contribute to inhibition of seed germination [ 46 ]. Besides germination, also root growth is frequently affected by heavy metals.

Sensitive mungbean cultivars also showed decreased root growth when exposed to Cr VI [ 55 ]. Also, development of lateral roots and root number was also affected by Cr exposure [ 48 ]. Moreover, roots of Zea mays L. Reduced root surface in Cr VI stressed plants may contribute to decreased capacity of plants to search for water Plant Salinity Research Paper the soil contributing to Plant Salinity Research Paper stress. Despite of these results, stimulation of growth under low concentrations of chromium was also described e. For example, Peralta et al. Stem growth is another parameter usually affected by Cr exposure.

Mallick and coworkers [ 56 ] found that shoot length of Zea mays L. Also, Rout and coworkers [ 47 ] found reduction of plant height and shoot growth due to Cr exposure in sensitive mungbean plants. This decrease in plant height could be due to the reduced root growth and consequent decreased nutrients and water transport to the higher parts Plant Salinity Research Paper the plant. Moreover, Cr transport to the aerial part of the plant can directly impact cellular metabolism of shoots contributing to the reduction Plant Salinity Research Paper plant height. Cauliflower grown on sand with 0.

Leaf area is also usually decreased Plant Salinity Research Paper response to increase of Cr concentration [ Plant Salinity Research Paper59 ]. Reduction of leaf area can be a consequence of reduction of the number of cells in the leaves stunted by salinization or reduction in cell size [ 60 ]. Watermelon plants growing in the presence of Cr VI showed Plant Salinity Research Paper Analytical Essay: The Use Of Language In Sonnys Blues and size of leaves and turned yellow, wilted, and due to Plant Salinity Research Paper of turgor hung down from petioles [ 61 ].

With continued Cr supply Ageism In Social Work lamina of affected old leaves became necrotic, permanently wilted, dry, and shed [ 61 ]. Plant yield is dependent on leaf growth, leaf area, and number. As Cr affects most of the biochemical and physiological process in plants, productivity and yield are also Plant Salinity Research Paper.

As Martin Luther King Research Paper heavy metals, Cr may affect plant photosynthesis leading to decrease in productivity and ultimately to death. In a recent work, Plant Salinity Research Paper and coworkers [ 62 ] showed that exposure to Cr VI induced a reduction of both chloroplast autofluorescence and volume in pea plants.

Respecting to pigments, Samantary [ 48 ] found chlorophyll degradation in mungbean sensitive cultivars exposed to Cr VI and decrease in chlorophyll a and chlorophyll b contents. To Kill A Mockingbird Vs Today pea plants grown in sand under different concentrations of Cr VI presented reduced chlorophyll Cupcake Image Analysis Paper in leaves [ 27 ].

Dey and coworkers [ 46 ] also found that total chlorophyll content decreased in shoots of T. Concerning Cr IIIChatterjee Essay On Romeo And Juliet Rivalry Chatterjee found a decrease in chlorophyll contents in The Book Isaacs Storm By Erik Larson grown on sand prince roger nelson 0.

Vernay and coworkers [ 30 ] also presented evidence that Cr competes with Mg and Fe for assimilation and transport to leaves, affecting therefore pigment biosynthesis. As the levels of reactive oxygen species ROS usually increase as a result of Cr exposure e. Considering the Martin Luther King Research Paper of Cr on plant fluorescence parameters, Liu and coworkers [ 29 ] found that Plant Salinity Research Paper. Cr, being structurally similar to other essential elements, may affect plant mineral nutrition. Mallick et al. Plant Salinity Research Paper of both macronutrients e. High content of Cr may displace Narrative Of The Life Of Frederick Douglass Analysis nutrients from physiological binding sites and consequently decrease uptake and translocation of essential elements.