Nutrient Stress

Arbuscular mycorrhiza (AM) having a great influence on overall plant physiology contributes to improved plant health and growth, particularly under suboptimal conditions (Peuss 1958 Hirrel and Gerdemann 1980 Sharma et al. 1992). AM can improve the uptake of water (Auge 2001) and nutrients (George 2000). Carbon assimilation and export from leaves may also be increased in mycorrhizal plants (Douds et al. 2000 Gernns et al. 2001). Soil Salinization is an ever-present threat to crop yield. It is a...

O

O-acetyl serine (OAS), 213, 216 O-acetylserine sulphydrylase, 416 O-antigen, 321 OBF5, 232 Ochthochloa compressa, 153-154, 158-159 9, 387 Olea Europea, 290 Onobrychis gracilis, 290 Ononis spinosa, 290 Onopordum tauricum, 290 Onosma bracteosum, 290 Onr gene, 390-391 Organic pollutant, 2-3, 15, 175, 179, 181-182, 184-185, 240, 246-248, 252, 258, 314-315, 317-320, 384-385, 408-409, 434 Organics, 11, 18, 20, 180, 184-185, 315, 328, 408, 412 Organochlorine, 428-430, 438, 440 Organocyanate, 401...

Cyanides

Cyanides are organic compounds that comprise the cyano group (C N) in their structure. Cyanide toxicity is also known as prussic acid poisoning (Vogel et al. 1987). Different forms of cyanides include hydrogen cyanide (HCN), potassium cyanide (KCN) and sodium cyanide (NaCN). Among these, HCN is a colorless gas with odor just like a bitter-almond while NaCN and KCN are white powders with a similar odor as that of HCN. Both NaCN and KCN are converted into HCN when they get mixed in water and...

Info

Fig. 12.1 Distribution characteristics of trace elements in various desert taxa Halopeplis pygmea, Amaranthus retroflexus, Limonium sogdianum, Sonchus maritima Puccinella scleroides, Sorghum bicolor, Peganum harmala, Haloxylon aphyllum, as well as annual and perennial species of the genus Salsola. These pioneer plant species were growing well on mined areas despite unfavourable conditions such as extreme pH, high salinity and phytotoxic levels of several elements. 4 Salt Accumulation,...

Toxins and Their Phytoremediation

Muhammad Ashraf, Munir Ozturk, and Muhammad Sajid Aqeel Ahmad Abstract The agricultural and industrial revolutions in the last few decades have resulted in increased concentration of toxins in our environment that are now-a-days a major cause of toxicity in plants and animals. Among different toxins, increasing levels of salts, heavy metal, pesticides and other chemicals are posing a threat to agricultural as well as natural ecosystems of the world. These contaminants result in soil, air and...

Physical and Chemical Forms of Cyanide

The specific form of cyanide determines the environmental fate and transport of cyanide, as well as its toxicity. Cyanide occurs as various physical metal-cyanide complexes and metal-cyanide solids in water and soil. Figure 18.1 has described distribution of various forms of cyanide in aqueous, solid and gaseous phases. Chemically, cyanide can be classified into inorganic and organic forms, as indicated in Fig. 18.1. Inorganic forms, which occur in all three physical states, include free...

I

Fig. 10.3 a Pathway for the production of volatile forms of Se, DMSeP and DMSe from selenomethionine (SeMet). b Additional pathway of production of the volatile DMDSe from selenocysteine (SeCys) (c) Selenium accumulator plants - the pathway for assimilation of inorganic Se is thought to be mostly the same as described above for Se non-accumulator plants. However Se accumulators differ in that they metabolise the SeCys primarily into various seleno amino acids which are not incorporated into...

Effects of Herbicides and Pesticides on Aquatic Life

Pollution to aquatic life is mostly land based and caused by agricultural overspill and waste materials carried by wind. The surface flow can contaminate water sources as 1-6 of the applied pesticides may be lost to the aquatic environment by runoff and drainage depending on the slope of the field, agronomic practices, presence or absence of subsurface drains, and the quantity and timing of rainfall after applications. Sometimes these deposited chemicals react in such a way that they may cause...

Cyanide Dihydratase CynD

Cyanide-degrading enzyme has been isoalted from Bacillus pumilus C1. The enzyme consisted of three polypeptides of 45.6, 44.6, and 41.2 kDa and the molecular mass is 417 kDa. CynD is a multimeric, rod-shaped protein approximately 9 by 50 nm. Cyanide can be rapidly degrades into formate and ammonia by this enzyme. Enzyme activity is optimal at 37 C and pH 7.8 to 8.0. Enzyme activity can be enhanced by Sc3+, Cr3+, Fe3+, and Tb3+ and enhancement is independent of metal ion concentration at...

Salts as Potential Environmental Pollutants Their Types Effects on Plants and Approaches for Their Phytoremediation

Abstract Demand for food dramatically increases as the world gets populated, and this problem is of central attention all over the world. Under these circumstances, the balance between food production and consumption depends on the agricultural productivity. However, an increase in the world population and decrease in the agricultural areas due to many reasons such as industrializations, global warming, use of marginal water etc. have been forcing us to use arable lands efficiently as well as...

H2c C Ch2

Glycerol trinitrate(GTN) Pentaerythritol tetranitrate(PETN) Fig. 17.1 Some common explosives and their properties Contamination of soil with explosives is largely due to manufacturing, storage, testing and inappropriate waste disposal of explosive chemicals. The primary explosives at hazardous waste sites are 2,4,6-trinitrotoluene (TNT), hexahydro-1,3, 5-trinitro-1,3,5-triazine (Royal Demolition explosive-RDX) and octahydro-1,3,5, 7-tetranitro-1,3,5,7-tetrazine (High Melting explosive-HMX). TNT...

Perspective on Phytoremediation for Improving Heavy Metal Contaminated Soils

Hong-Bo Shao, Li-Ye Chu, Fu-Tai Ni, Dong-Gang Guo, Hua Li, and Wei-Xiang Li Abstract Heavy metal pollution of soil is a significant environmental problem and has its negative potential impact on human health and agriculture. Phytoremediation strategies with appropriate heavy metal-adapted rhizobacteria (for example, myc-orrhizae) have received more and more attention. Some plants possess a range of potential mechanisms that may be involved in the detoxification of heavy metals, and they manage...

A

Abscisic acid, 41-43, 99, 110-111, 124, 128, 231-234, 293-300,363 Acacia ampliceps, 342, 351 Acacia holosericea, 80, 351 Acacia nilotica, 342, 344, 348-349, 351 A. canina, 54 Acanthaceae, 157 Acantholimon acerosum, 290 Acanthus hirsutus, 290 A. caucasica, 185 ACC deaminase, 324-325 ACC oxidase, 109,414 ACC synthase, 109-110 Acer macrophyllum, 282 Acetylcholinesterase, 433, 440 Acharya, S. N., 152 Achillea wilhelmsii, 290 Achromobacter, 430 ACR2, 318 ACR3, 318 ACS2, 109-110 ACS6, 109-110...

Phytoremediation Detoxification of Explosives by Plants

High explosives such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and 2,4, 6-trinitrotoluene (TNT) are important contaminants in the environment and phytore-mediation has been viewed as a cost-effective abatement. There remains, however, an insufficient knowledge-base about how plants respond to explosives, especially in the steady state (Rao et al. 2009). The two greatest advantages of phytoremediation compared with traditional abatement methods are (1) cost effectiveness, and (2) soils...

Ascorbic Acid Vitamin C

Among the non-enzymatic antioxidants AsA is the most extensively studied molecule and is found in various plant cell types (Horemans et al. 2000 Smirnoff 2000). Although the precursor of L-ascorbic acid is D-glucose, its biosynthetic pathway is still unclear (Foyer and Noctor 2005). Normally, ascorbate occurs in the reduced form (AsA). (90 of the ascorbate pool) and its intracellular concentration ranges from 20 mM in the cytosol to 300 mM in the chloroplast (Noctor and Foyer 1998). The...

Conclusion About Plant Adaptation

Herbicides and pesticides are used to increase the agricultural products and it is based on the effective use of technology and inputs. Their direct or indirect toxic potential to biological systems has been proven extensively. This technology could be economical and effective if a number of factors are considered before selection and application of herbicides and pesticides. Further improvement is required to progress for the appliance of this technology to analyze the herbicides and...

Adverse Effects of Herbicides and Pesticides on Ecosystem 31 Effects on Structure and Functions of Ecosystem

Application of herbicides and pesticides is meant to reduce the effect of pests to below economically acceptable threshold, estimated on the basis of the amount of damage that can be tolerated to crops. However, sometimes their application can adversely affect the invertebrate species especially within arthropoda (Schluz 2004). The structure as well as the function of microbes may be imbalanced by toxicity of herbicides and pesticides. Studies show that spray drift and surface water runoff...

References

Aboul-Kassim TAT, Simoneit BRT (2001) Organic pollutants in aqueous-solid phase environments types, analyses and characterizations. In Aboul-Kassim TAT, Simoneit BRT (eds) The handbook of environmental chemistry. Pollutant-solid phase interactions mechanisms, chemistry and modeling, vol. 5E, Springer, Berlin Ahmad MSA, Hussain M, Saddiq R, Alvi AK (2007) Mungbean a nickel indicator, accumulator or excluder Bull Environ Contam Toxicol 78 319-324 Aken BV (2009) Transgenic plants for enhanced...

Conclusion

Although phytoremediation is very helpful in removing contaminants from polluted soil and water, it is absolutely not the complete answer to all contamination problems. It is a fact that once pollutants are added to the environment, they cannot be completely removed due to their ability to circulate among different environmental components and food chains. Therefore, as a first strategy, we must try to avoid or reduce the addition of pollutants to the environment. Secondly, if soil or water...

Mechanism of Salt Tolerance

Salt Stress Plant

Although plant responses to salinity are one of the most widely researched subjects in plant physiology, the mechanisms that impart salt tolerance are still unresolved (Cheeseman 1988 Munns 1993 Ashraf and Foolad 2007). Plants which were able to obtain more water than others from a soil under low water potential would grow better in saline conditions (Cruz and Cuartero 1990). So, plants have developed various mechanisms for survival under high salinity stress. Some tolerate high concentrations...

Glutathione Reductase GR EC 1642

GR is a flavo-protein oxidoreductase, found in both prokaryotes and eukaryotes that catalyses the NADPH-dependent reduction of oxidized glutathione (GSSG) to its reduced form (GSH). In the cell, GR is located in the chloroplast stroma, mitochondria, cytosol and peroxisomes. Plants have multiple forms of this enzyme, eight in pea (Edwards et al. 1990) and two in wheat (Dalal and Khanna-Chopra 2001). There are reports which showed that different environmental stresses induce GR activity. For...

Phytoremediation

Phytoremediation is the use of vascular plants, algae, or fungi to metabolize, sequester, or to induce contaminants breakdown in soil or other plant growing medium (McCutcheon and Schnoor 2003). Plant sequestration of contaminants is important as an alternative to physically based treatment approaches. The use of plants for remediation seems less expensive, but it depends on certain factors. Phytoremediation has gained importance in the last one decade and approximately US 6-8 billion per year...

Phytoremediation Case Studies

A large number of studies have proved that free cyanide can be rapidly biodegraded by micro-organisms (Knowles and Bunch 1986 Kunz et al. 1994 Fernandez and Kunz 2005), however, many cyanide complexes including iron cyanide complexes tend to be resistant to microbial degradation (Aronstein et al. 1994). There are only few reports of microbial (Cherryholmes et al. 1985 Dursun et al. 1999) and fungal (Barclay et al. 1998) biodegradation of metal cyanide complexes, but this has only been observed...

Mechanism of Free Radical Scavenging and Role of Phytohormones in Plants Under Abiotic Stresses

Parvaiz Ahmad, Shahid Umar, and Satyawati Sharma Abstract Environmental stresses result in the generation of reactive oxygen species (ROS) in plants. ROS accumulate in cells and lead to the oxidation of proteins, chlorophyll, lipids, nucleic acids, carbohydrates etc. Cells have evolved intricate defense systems including enzymatic (superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductases (GR), monodehydroascorbate reductases (MSHAR), dehydroascorbate...

Cyanide Phytoremediation Technologies

Phytoremediation is a family of emerging biotechnologies that utilize plants for the remediation of environmental contamination. Bushey et al. (2006) described five important steps for phytoremediation Phytoextraction is the use of plants to remove metals, or other contaminants from soil and concentrate those contaminants in above-ground plant tissues and finally these contaminants are removed by harvesting the aerial tissues. Rhizofiltration is the use of plant roots to remove contaminants...

Phytoremediation Strategies for Overcoming Salinity Problems and Use of Halophytes as Companion Plants

In recent years, salinity has become the most important issue in fields, gardens and greenhouses as well. This, of course, has forced us to control saline areas, and therefore, many control mechanisms that have been put forward. Many of them (genetics, biochemical and physical) have not brought the desired success. Since salt is due to irrigation and natural causes, so, alternative control mechanisms should be provided. Recent advancement in this area is to obtain quick results from...

Phytoremediation of Herbicides and Pesticides

Overall, herbicides and pesticides have harmful effects on soil and pesticide-soil interactions need future research. Herbicide and pesticide contamination is usually too expensive to clean up with current mentioned technologies. Studies have shown that certain tolerant plants and microbes can be used in biological remediation which can be cost-effective and simpler, due to the in-situ advantage, pollution can be exacerbated by the pesticides herbicides involved, but these, too can be...

Biochemical and Molecular Aspects in Phytoremediation of Selenium

Abstract The element selenium (Se) is considered a finite and non-renewable resource on earth, and has been found to be an essential element in humans, animals, micro-organisms and some other eukaryotes but as yet its essentiality to plants is in dispute. There is no doubt that adequate levels of selenium are important to animal and human health, and some selenium compounds have been found to be active against cancers. A limited number of plants growing on selenium rich soils can accumulate...

U

Fig. 5.1 Ethylene Biosynthesis pathway and signaling in stressed plants. In MPK 6 in Arabidopsis and SIPK in tobacco regulates ACC synthase (ACS) whose activity is controlled with cytoso-lic free Ca2+. Ethylene gets attached to ethylene receptots (ETR) and signaling is transmitted through EIN2 ST-ACS5 (Tuomainen et al. 1997 Schlagnhaufer et al. 1997). Liu and Zhang (2004) observed that ACS accumulation is due to MPK6 induced phosphorylation in ACS2 and ACS6 (Fig. 5.1) and thus leads to elevated...

Transgenic Plants for Phytoremediation of Explosive Compounds

Although plants are capable of reducing the concentrations of some organic environmental pollutants, the activity is often too slow to be of practical value. Because phytoremediation proceeds primarily only during the growing season, substantial remediation must be achieved during a limited time period. The effectiveness of phytoremediation can be greatly enhanced by introducing genes known to be involved in metabolism of pollutants in other organisms (Table 17.2). For example, the...

M

Macronutrients, 36 Maireana, 349 Malathion, 7, 429 Malic acid, 47 Malonate, 389 Malondialdelyde, 370 Malpigila, 261-262 Malpigilian hairs, 262 Malus sylvestris, 290 Manganese (Mn), 6, 36-37, 40, 50, 52, 72-73, 76, 83-84, 102, 127, 175-176, 183, 249-250, 258,291,316 Mangrove, 162, 165 MAPK, 110,231,234 MAPK1, 109 MAPK3, 109 Marrubium parviflorum, 290 MATE transporters, 389 Matthiola longipetala, 289 MDAR, 106 MeCys, see S-methylcysteine (MeCys) Medicago media, 365 Medicago sativa, 78, 198, 282,...

Formamide Hydrolyase FHL3 EC 42166

Formamide hydrolyase is a constitutive or inducible protein, which is induced by HCN. Mostly it is found in fungal pathogens of cyanogenic plants and also in non-pathogenic fungus (Fry and Evans 1977). Maximum FHL activity can be observed by the addition of 1-5 mM HCN and within 12-18 h after addition of HCN. Pathogens of cyanogenic plants produced moderate to high amounts of FHL after induction by HCN. The specific activities of FHL3 range between 4 and 66 moles min-1 mg-1 protein. The range...

Mechanism of Salt Tolerance in Glycophytes and Halophytes

On the basis of their tolerance or sensitivity, plants are commonly distinguished as halophytes or glycophytes. Glycophytes (sweet plants) tolerate only low concentrations of salt, while halophytes (halas salt, salt plants) tolerate relatively high concentrations of salt (Flowers and Yeo 1986 Flowers and Yeo 1988). It was estimated by Flowers et al. (1986) that there were at least 800 species of halophytic angiosperms in more than 250 genera. This illustrates the point that there are many...

Heavy Metals

Although some of the metals function as essential elements such as copper and zinc in low concentrations, they may become toxic if they accumulate at higher concentrations in the environment (Verkleij and Prast 1990). Other metals (non-essential) may become toxic to organisms even at very low concentrations (Verkleij and Prast 1990 Loska et al. 2000 Islam et al. 2007). The concentration of essential elements in organisms is generally controlled homeostatically i.e., they are taken up from the...

S

Sabater, C., 432, 437 Sabeh, F., 212 Saccharomyces cerevisiae, 53, 304 Sacher, R. F., 366 Sachs, J., 37 S-adenosyl L-methionine, 109 Sadowsky, M. J., 15 Safferman, S. I., 18 Safir, G. R., 121 Safranin, 247 Sage, R. F., 282 Sahrawat, K. L., 349 Saiki, M. K., 196 Saito, K., 212, 414, 416-418 Sakcali, S., 275-305 S. alba, 79, 81 Salicornia bigelovii, 2l5, 350 Salicornia europaea, 369 Salicornia fruiticosa, l57 Salicyl hydroxamic acid, 415 Salicylic acid, 105, 231,328 Salix alba, 19 Salix...

N

Fig. 13.1 Permeability of biological membranes that allow or prevent the passage of molecules solutes according to their size, charge, chemical properties, concentration and pressure (Modified from Alberts et al. 2004) xylem loading. Among the ten BOR1 hypothetical transmembrane domains, Takano et al. (2002) found a difference of two amino acids in the second transmembrane domain of the putative protein expressed by Arabidopsis mutants which requires higher levels of boron. Frommer and von...

Boron and Plants

Munir Ozturk, Serdal Sakcali, Salih Gucel, and Huseyin Tombuloglu Abstract Boron is found naturally in the earth's crust in the oxidized form as borax and colemanite, particularly in the oceans, sedimentary rocks, coal, shale, and some soils. It is never found in the elemental form in nature possessing a complex chemistry similar to that of silicon, with properties switching between metals and non-metals. Boron has become an important and strategic element in terms of developing technologies....

Phytoremediation of Toxic Explosives

Abstract Widespread contamination of the environment by explosives resulting from the manufacture, disposal and testing of munitions is becoming a matter of increasing concern. Most explosives are considered to be a major hazard to biological systems due to their toxic and mutagenic effects. Interest on the bioremediation of lands contaminated with explosives has recently been focused on phytoreme-diation. Unfortunately, whilst plants have many advantages for the remediation of contaminated...

Phytoremediation of Saline Soils for Sustainable Agricultural Productivity

Yasin Ashraf, Muhammad Ashraf, Khalid Mahmood, Javed Akhter, F. Hussain, and M. Arshad Abstract Salinization of soils is one of the major factors which severely affect the agricultural productivity worldwide. Due to salinity, more than half a billion hectares of land are not being properly used for crop production. Thus, there is a need to search means to improve saline soils so that such soils could support highly productive and meaningful land-use systems to meet the current challenges of...

Conclusion Of The Plant Adaptation

Plants and their associated microbes can remediate cyanide via cyanide uptake, transport, degradation and assimilation in plants. Experiments using free cyanide have shown that many terrestrial and aquatic plants including willow, sorghum, cassava and water hyacinth can remove cyanide from the growing medium. Cyanide uptake in plants can be associated with a very complex physiological mechanism which includes transport and assimilation of cyanide within the plants for catering plant's nitrogen...

The Structural and Functional Characteristics of Asiatic Desert Halophytes for Phytostabilization of Polluted Sites

Khujanazarov, Shoaib Ismail, and Yoshiko Kawabata Abstract Phytoremediation, the use of plants to extract, sequester, and or detoxify pollutants through biological processes is an effective, in situ, non-intrusive, low-cost, ecologically friendly, socially accepted technology to remediate polluted soils. Crystalline to fibrillar wax formations, appressed to surfaces of guard cells appear to originate from guard cells in the vicinity of the stomatal aperture....

Roots Plant Enginee Rganapathy

Abrol IP, Yadav JSP, Massoud FI (1988) Salt Affected Soils and their Management. FAO Soils Bulletin-39. Food and Agricultural Organization of the United Nations, Rome Adams P, Ho LC (1993) Effects of environment on the uptake and distribution of calcium in tomato and on incidence of blossom end rot. Plant Soil 154 127-132 Agarie S, Shimoda T, Shimizu Y, Baumann K, Sunagawa H, Kondo A, Ueno O, Nakahara T, Nose A, Cushman JC (2007) Salt tolerance, salt accumulation, and ionic homeostasis in an...

Toxins and Their Types

Toxins are generally classified into biodegradable (organic) and non-biodegradable (inorganic) pollutants (Verhaar et al. 2000 Gramatica et al. 2002). Biodegradable toxins are easily broken down into simpler molecules (CO2 and water) by the activity of living organisms when they enter in the biogeochemical cycles. Such toxins are generally not harmful as they occur in low quantities in our environment. However, at high concentrations they prove to be highly toxic to all living organisms. In...

Root

In plants, roots are the first organs to come into contact with toxic elements and they usually accumulate more metals than shoots (Salt et al. 1995 Wojcik and Tukiendorf 1999 Rout et al. 2001). The inhibition of root elongation appears to be the first visible effect of metal toxicity. Root elongation can be reduced by either the inhibition of root cell division and or the decrease of cell expansion in the elongation zone (Fiskesjo 1997). Since inhibition of root elongation appears to be the...

Uptake and Transport of Cyanide By Plants

Uptake of pollutants by plant roots is different for organics and inorganics. Organic pollutants are usually manmade, and xenobiotic to the plant. As a consequence, there are no transporters available for these compounds in plant membranes. Organic pollutants therefore tend to move into and within plant tissues driven by simple diffusion, depending on their chemical properties. An important property of the organic pollutant for plant uptake is its hydrophobicity (Briggs et al. 1982 Trapp and...

Slc4a11

These results may suggest that short-term (1 week) boron treatment induces mainly DNA damage, which causes the specific RAPD band intensity to either increase or decrease. Although our results strongly suggest that boron-induced genomic DNA instability is reflected by the RAPD-PCR method, it is important to note the change of RAPD band patterns do not show a dose-dependent tendency to boron exposure. This might be explained with the short exposure time which may not be enough for the toxic...

Phytoremediation of Toxins

Phytoremediation, a subcategory of bioremediation, is generally defined as removal of toxins from the environment by the use of hyperaccumulator plants. This word has been derived from the Greek Phyto meaning plant, and Latin Remedium meaning refurbishing balance, removal, or remediation. Thus, in the process of phytoremediation, pollutant toxins from contaminated soils, water or air are mitigated removed by using plants which are able to hold, breakdown or remove metals, salts, insecticides,...

Molecular Mechanisms and Genetic Basis of Heavy Metal Toxicity and Tolerance in Plants

Abstract Heavy metal pollutants are mainly derived from growing number of anthropogenic sources. As the environmental pollution with heavy metals increases, some new technologies are being developed, one of these being phytoremediation. Hyperaccumulator plant varieties can be achieved by using methods of genetic engineering. An uptake of excessive amounts of heavy metals by plants from soil solution leads to range of interactions at cellular level which produce toxic effects on cell metabolism...

Rhyzoremediation

Fig. 14.1 Mechanisms involved in inorganic and organic pollutant decontamination degradation in phytoremediation processes Xenobiotic pollutants that can be remediated metabolised include thrichloroethy-lene (TCE), polychlorinated biphenyls (PCBs), pesticides, explosives, trinitrotoluene (TNT), petroleum hydrocarbons (PHC), polycyclic aromatic hydrocarbons (PAHs) and detergents (Macek et al. 2000 Newman and Reynolds 2004). Soils that have been contaminated by weathered hydrocarbons and heavy...

Drought Stress

Stress is defined an external factor that exerts a disadvantageous influence on the plant. In most, cases stress is measured in relation to growth or to the primary assimilation processes (CO2 and mineral uptake) which are related to overall growth. Under both natural and agricultural conditions, plants are constantly exposed to stress. Some environmental factors (such as air temperature) can become stressful in just a few minutes, whereas others may take days to weeks (soil water) or even...

Contributors

Firoz ud Din Ahmad Institute of Geology, University of the Punjab, Lahore 54590, Pakistan, hamzafiroz yahoo.com Muhammad Sajid Aqeel Ahmad Department of Botany, University of Agriculture, Faisalabad 38040, Pakistan, sajidakeel yahoo.com Nasir Ahmad Institute of Geology, University of the Punjab, Lahore 54590, Pakistan, nasir geo.pu.edu.pk Parvaiz Ahmad Department of Botany, Baramulla College, University of Kashmir, Srinagar 193101, India, parvaizbot rediffmail.com pervaiz_iitd2002...

Factors Affecting Uptake and Transport

There are several factors which could affect cyanide uptake 1. For phytoextraction and phytostabilization, selection of plant species with the desired properties is useful. Screening studies under uniform conditions will be a supportive strategy to compare cyanide uptake characteristics of different species. 2. Agronomic practices may also be employed to maximize cyanide uptake. Plant species may be selected for suitable rooting depth and root morphology (Negri et al. 2003) and plant roots can...

Heavy Metal Stress

An immense load of heavy metals such as Pb, Cr, As, Cu, Cd and Hg is being added to our soils through industrial, agricultural and domestic effluents. These elements can either be absorbed in soil particles or leached into ground water. Problems associated with the contamination of soil and water such as animal welfare, health, fatalities and disruption of natural ecosystems is well documented He et al. 2005 . Human exposure to these metals through ingestion of contaminated food or uptake of...

Transgenics for Cyanide Remedy

Phytodegradation of cyanide can be optimized by selecting or engineering plant species with higher activities of the enzymes thought to be involved and rate-limiting in cyanide detoxification. There are some examples of promising transgenic approaches which have been used in other cases. For example, the expression of bacterial enzymes in plants involved in reductive transformation of TNT tetranitrate reductase or nitroreductase resulted in enhanced plant tolerance and degradation of TNT...

Plant Resistance to Anthropogenic Toxicants Approaches to Phytoremediation

Valida Ali-Zade, Esmira Alirzayeva, and Tamilla Shirvani Abstract The problem of soil preservation and restoration has became more intense due to continued deterioration of the ecological systems of the world. This problem is especially important for Azerbaijan, where environmental pollution by heavy metals and oil products is increasing. Though the nature of toxicity of these two factors is different, they both affect plant productivity, including agricultural crops and human health. This...

Water Relation

Water can be considered as a major factor in the plant growth regulation since it affects directly or indirectly all growth process Kramer and Boyer 1995 . Plants raised in metal contaminated soils often suffer drought stress mainly due to poor physicochemical properties of soil and shallow root system, therefore, researchers are interested in investigations on plant water relation under heavy metal stress. Selection of drought resistance species can be considered to be an important trait in...

Cyanide Assimilation and Metabolism

In phytoremediation, cyanide uptake is not always associated with cyanide assimilation but sometimes after cyanide uptake, this toxic substance can be accumulated in certain plant species. In all cases where potentially cyanide pollutants are accumulated in plant tissues, phytoremediation in the field should include a risk assessment study because the plant material may pose a threat to wildlife. The degree of tox-icity depends on leaf concentration and also on the form of the cyanide pollutant...

Heavy Metal Toxicity in Plants

Fazal Ur Reliman Shah, Nasir Ahmad, Khan Rass Masood, Jose R. Peralta-Videa, and Firoz ud Din Ahmad Abstract Although many metal elements are essential for the growth of plants in low concentrations, their excessive amounts in soil above threshold values can result in toxicity. This detrimental effect varies with the nature of an element as well as plant species. Heavy metal toxicity in plants depends on the bioavailabil-ity of these elements in soil solution, which is a function of pH, organic...