eChapters

Abstract

Agroforestry is an intensive land use management system that integrates trees, shrubs, crops, etc. on a landscape level to achieve optimum benefits. Agroforestry is not only concerned with beneficial effects of one component on another, but it also involves the manipulations of negative effects to minimize their influence on the productivity of the overall system. In an agroforestry, trees and crops compete inevitably for light, nutrients, moisture and other resources. The interactions between tree and crop roots can also have an effect on soil organisms, which play an essential role in the functioning and productivity of agroforesty systems. Arbuscular mycorrhizal fungi (AMF) are one of the most important components of the soil biota in monoculture and agroforestry systems. AM fungi can rehabilitate degraded lands subjected to agroforestry systems and common mycorrhizal network may further enhance the benefits of agroforestry through vertical niche expansion of AMF. However, management practices of agroforestry affect mycorrhization, AMF community composition and diversity of AM fungi. This review focuses on AMF diversity, which plays a significant role in agroforestry systems.

Abstract

C. albicans is a diploid, dimorphic yeast producing three morphologic forms: yeast cells, pseudohyphae and true hyphae. It is an opportunistic pathogen causing various types of candidiasis which are on the increase around the globe. It is a polymorphic yeast with its genome organized in eight diploid chromosome with its genome size ranging between 14.3 and 16 Mb having 5,733 to 6, 318 genes. It has two mating-type like (MTL) alleles that control the mating behavior. In its genetic makeup it resembles with Saccharomyces cerevisiae hence classified in the Saccharomycetales. The chromosome number from tetraploid to diploid is brought about by the parasexual mechanism. Keeping in view the increase of incidence of candidiasis due to C. albicans around the globe, it is important to identify the causative organisms to the species level correctly. Morphological, biochemical, germ tube test and growth on different media are often used for identifying isolated yeasts which sometimes takes days to week to develop in culture hence, rapid identification of Candida species in clinical laboratory is becoming increasingly important. Molecular techniques utilizing amplification of target DNA or PCR amplification of conserved regions of the genome and sequencing of the resulting PCR product and restriction fragment length polymorphism (RFLP) analysis of the ribosomal DNA, provides quick and precise methods for diagnostics or, identification of Candida species.

Abstract

Eight species including 1 variety, 2 macro and 6 micro-lichens from Garhwal Himalaya, c 1500-2700 m, have been found to glow and emit fluorescent light, when exposed to long wave-length (254 nm) ultra-violet radiataions. Taxonomy and chemistry of all these species have been critically evaluated. The recorded taxa belong to families Physciaceae (4 species); Pertusariaceae, Rhizocarpaceae (1 species each) and Lichen imperfecti (2 species). The reported taxa are: Buellia hemispherica Singh and Awasthi, B. sub-glaziouana Singh and Awasthi; Pertusaria pertusa (Weig.) Tuck., Pyxine berteriana (Fee) Imsh. var. himalayensis Awasthi; P. cocoes (Swartz) Nyl., Rhizocarpon geographicum (L.) DC.; Lepraria taxonomic species I and II.

Abstract

Higher plants can be exploited for the discovery of new bioactive products that could serve as lead compounds in pesticide development because of their novel modes-of-action. Different secondary metabolites of higher plants have been reported to exhibit efficacy as fungitoxicants as well as mycotoxin inhibitors. Pest controls using the botanicals are safer to the user and the environment because they break down into harmless compounds within hours or days in the presence of sunlight. The article presents different plant products found efficacious as antimicrobial and inhibitory to mycotoxin secretions by fungi. Their prospect as safe alternatives to synthetic antimicrobials in plant protection has been discussed.

Abstract
 
Much attention has been paid to mycorrhza as a tool for improving the growth and health of plants.  The use of mycorrhiza in agricultureal, horticultural and forestry has been described. The significance of AM fungi in sustainable agriculture has been a subject of growing interest for the past several decades. In sustainable agriculture it is imperative to maximize benefits with low input costs. The fact remains that stable and lower human population is an integral component of sustainable agriculture and more so in an Indian context. Therefore, it is imperative to collect further information on the different aspects of AM fungal symbiosis as discussed in this article so as to utilize this plant microbe symbiotic system for the increased production and productivity in a sustainable manner. This may become possible when the integrated approach is made to study AM fungi right from the isolation of AM fungal spores to the high quality inoculum production and its application in the field. It is also imperative to stimulate new mutualism between mycorrhizal scientists and ecologists. It this regard, recent advancement made in the molecular techniques should be encouraged in order to obtain more authentic results. Adequate field testing of mycorrhizal inoculation and commercial exploitation of the potential benefits of mycorrhiza still rests on the development of suitable technology for mycorrhizal inoculum preparation.

Abstract

Production technology has been worked out for crops and several inputs have been recommended which are to be applied in proper quantity at most suitable time to get the maximum return. Nutrition in the form of fertilizers is a must. However, injudicious use of agro-chemicals has resulted in diseases called ‘iatrogenic plant diseases’. Under the circumstances it is important to know the relationship between soil nutrients and plant pathogens which are causing the diseases of economic importance. Author has given adequate emphasis to micronutrients as at a very minor quantity they reduce the disease to an acceptable level. He has also discussed in detail about all the major and minor nutrients required by the plants and how their deficiency or over doses affect the plant pathogens and in turn the diseases.

Keywords:  Soil nutrients, plant pathogens, diseases, relationship

Abstract

Various cropping systems and ecologies illustrate the positive use of chemicals both as fertilizers and pesticides and organic/biological sources within the frame work of Integrated Plant Nutrition and Plant Protection System (IPPS). While considering the organic/biological sources, green manures seem to be the best alternative that may largely suffice to the organic matter requirements of the soil under crop cultivation. Green manuring can be defined as a practice of ploughing or turning into the soil undecomposed green plant tissues for the purpose of improving physical structure as well as fertility of the soil. “Green manure” refers to fresh plant matter, which is added to the soil largely for supplying the nutrients contained in its biomass. The agricultural practices consisting of growing and ploughing under a green crop or addition of a green organic matter in the form of leaves and other succulent parts from outside to improve soil productivity is known as green manuring. In this review, advantages of green manuring, decomposition of green manure,   process of decomposition, factors affecting decomposition and effects of green manuring have been discussed in detail.

Abstract

In nature the roots of most of the plants are infected by fungi to form mycorrhizal associations, which play a central role in nutrient capture from the soil. These fungi are found in almost every terrestrial ecosystem; even in pioneer zones or very saline environments, and are reported to represent the second largest biomass component of many terrestrial ecosystems. Mycorrhizal associations are found in a broad range of habitats ranging from aquatic to deserts and alpine altitudes. In natural ecosystems mixed population of mycorrhizal fungi co-exist, with certain fungi becoming dominant in a particular patch and subsequently being replaced as environmental conditions change. Once this equilibrium is disturbed, the population dynamics is disrupted and a biomass may develop towards a few or even for one dominant fungus. Different species of mycorrhizae respond differently in response to the environmental conditions. In the present paper, all major types of mycorrhizal associations in different ecosystems are discussed.

Abstract

Different algal taxa involved in the formation of lichen/s are presented. To-date 43 algal genera, comprising members of Cyanophyta, Chlorophyta and one genus each of families Phaeophyceae (brown algae) and Xanthophyceae (yellow-green algae) are recorded, based on personal observations coupled with literature. The various algal taxa forming different lichens belonging to various families is presented. The taxa Trebouxia de Puymaly and Trentepohlia Born. amongst green algae; Scytonema Ag. and Nostoc Vauch. Among blue-green algae are dominant genera involved in the formation of lichens. The yellow and brown algae are only of rare occurrence.

Abstract

Soil is the natural growth media for living plants and microbes, and rhizosphere is niche for a group of soil microorganisms inhabiting around the plant root zone. The warmed and humid agro-climatic conditions of the area aggravate A. flavus contamination and aflatoxin production in maize grains from field to storage. In this article aflatoxin contamination in maize, antagonistic activity of rhizosphere microbes against toxigenic A. flavus, through fungi, antagonistic activity of rhizosphere bacteria against toxigenic A. flavus, bacterization of stored maize seeds for aflatoxin control and inhibition of aflatoxin production in stored maize seed with rhizobacteria has been discussed in detail.

Abstract

Many airborne fungal spores are important as allergens, human and plant pathogens, in the bio-deterioration of stored materials like paper, leather, textile, paintings, historical monuments and spoilage of food stuffs. Surveys have been conducted to elucidate the magnitude of the problem. Indoor environment also plays an important role in the precipitation of allergic symptoms caused by fungal spores. The present review briefly highlights some of the qualitative investigations carried out on indoor environments like bakery, building, cold storage, cow shed, dormitory, educational institutions, garbage disposal plant, ware house, hospital, library, food grain godown, leather godown, house dust, poultry house, chick hatcheries, plastic industries and textile industries.

Abstract

Microorganisms are potential tool for the production of large amount of potent and effective health care, food products and biofertilising agents. Recently, the marine microorganisms are considered as good sources of such products which may possess novel properties. There is a high scope for the exploration of marine microbes in order to search new product of economic importance from marine resources. Mangrove habitat is also part of marine habitat with the plant community having unique adaptation in their morpho- physiological and reproductive behavior. The high level of organic content in mangrove rhizosphre also leads to the colonization of degradative microorganisms and make them responsible for the creation of diverse and potential microbial community. Hence, mangroves are also considered as untapped resources of microbial metabolites and products. Several microorganisms including bacteria, fungi, algae, cyanobacteria, lichens are documented from mangrove habitats. These inhabitant microbes are the good source of secondary metabolites, therapeutic enzymes, food protective agents and mineral solubilisers. However, information on these aspects is very meager and thus the present review is an attempt to compile informations on the sources, properties and application of important microbes from mangrove ecosystems.

ABSTRACT

Microbes are integral part of the terrestrial ecosystem. Their function ranges from nutrients mineralization, stress alleviation to bioremediation in soils .There is a great possibility of using microbial inoculants as a biological tool for sustainable forestry and agriculture. This review gives an overview on the benefits of microbial technology and their contribution in development of green technology.

Keywords: Green technology, Microbes, AMF, PGPRs, Microbial consortium, Carbon sequestration.

ABSTRACT

Decomposition of litter is a dynamic process. It regulates cycling of nutrients in ecosystem. The productivity of an ecosystem depends on the turnover of carbon and other nutrients. Microbes play an important role in releasing of minerals locked up in organic complexes. The release of nutrients, however, is regulated by various climatic factors. The microbial succession at different stages of degradation of litter is controlled by the litter quality and species composition and biological activity. The present paper reviews the status of litter production, decomposition, species diversity and Biological activities as affected by the climatic and edaphic factors in tropical ecosystem.

Keywords : Litter decomposition, microbes, species diversity, biological activities, edaphic factors, tropical ecosystem.

Abstract

Trichoderma species play a vital role in the management of plant diseases in association with different commercial bioformutlations of the fungus. Its role as a successful pollution free environment and friendly mechanism of action has been highly exploited. The diversity of species based on location, type of agri-land and association with different fauna  and flora has been instrumental in large upsurge of biological methods of Plant disease management. Pollution of agri-land soils with chemicals, heavy metals and development of resistance to diseases has become an emerging problem coupled with the high costs of Infrastructure. Thus, the interest in alternative biologically based systems is the need for bioremediation, bioecology and biocontrol with Trichoderma.

Abstract

Nematodes are non-segmented worms typically 50 µm in diameter and 1 mm in length. Those few species responsible for plant diseases have received a lot of attention, but far less is known about the majority of the nematode community that plays beneficial roles in soil. Nematode diversity tends to be greatest in ecosystems with the least disturbance. Species of Aphelenchoides, Ditylenchus spp, Helicotylenchus, Meloidogyne spp., Pratylenchus, Scutellonema  and Rotylenchulus are obnoxious plant parasitic nematode beside Heterodera and Globodera. Soil temperature, soil structure, soil pH, soil moisture and soil texture play major role in movement of nematode, infestation and completion of life cycle under abiotic and biotic stresses.

Abstract

Elaboration of mycotoxins by several moulds in different agricultural commodities has been reported to be widespread. The mycotoxins are reported to cause variety of health hazards in different animals including Chicks, cow, horse, rat, Mouse, pig, rabbit, dog, including man. More than 150 species of moulds are reported to elaborate chemically and biologically diverse toxic metabolites. These mycotoxins  are known to induce variety of diseases commonly known as mycotoxicoses.The fungi which elaborate mycotoxins are diverse belonging to different groups of fungi.Mycotoxigenicity of these moulds not only differ among different genera but also among different species.  Some fungi such as Aspergillus flavus, A. terreus, Penicillium griseofulvum, P.expansum, P.nordicum, P.verrucosum, Fusarium acuminatum, F.culmorum, F. graminearum, F.moniliforme, F.oxysporum, F.solani, F. tricinctum and Cheatomium globosum are known to produce more  one  type of mycotoxin which differ in their chemical structure and biological activity.

ABSTRACT

The present paper describes application of synergistic action of microalgae viz., Spirulina platensis, Chlorella vulgaris, and Oscillatoria princeps coupled with state-of-the-art microbial biotechnology (that involved strains of Bacillus subtilis, Nitrobacter winogradskyi, Aspergillus flavus, and A. niger) developed by Biotechnology Resource Centre (BRC), Mumbai for treatment of secondary liquid effluents from a gelatine manufacturing industry. The growth of mixed cultures of selected microbial and algal species was measured respectively in terms of Colony Forming Units (CFUs) and Optical density (O.D.) of the culture. The results were indicative of efficient degradation potential of the proteinaceous liquid effluents. Moreover their BOD and COD loads reduced by 30.75 % and 84.10 % respectively after the treatment. Furthermore, the bio-safety of algal biomass cultured in selected effluents as feed supplement was tested on Swiss albino mice (Mus musculus). Mice in treated group didn’t exhibit any observable adverse effect on their growth or on their reproductive performance. In fine, the liquid effluents of gelatine manufacturing industries were polished along with production of probiotic food supplement.

ABSTRACT

Pesticide degradation is the breaking down of toxic pesticides into a non-toxic compounds and, in some cases, down to the original elements from which they were derived. The most common type of degradation is carried out in the soil by microorganisms, especially the fungi and bacteria. Microbial degradation depends not only on the presence of microbes with the appropriate degradative enzymes, but also on a wide range of environmental parameters. Pesticides which are rapidly degraded are called non-persistent while those which resist degradation are termed as recalcitrant (persistent). Microorganisms are able to degrade a large variety of compounds, including pesticides under laboratory conditions. However, methods have yet to be developed to decontaminate the environment from pesticide residues. Continuous efforts are required in this direction, and at present several PGPR capable of degrading pesticides have been isolated from the natural environment. Catabolic genes responsible for the degradation of several xenobiotics, including pesticides, have been identified, isolated, and cloned into various other organisms such as Streptomyces, algae, fungi, etc. In addition, recombinant DNA studies have made it possible to develop DNA probes that are being used to identify microbes from diverse environmental communities with a unique ability to degrade pesticides. Bioremediation treatment still requires more intense research through specific microbial degradation of broad range of organic pollutants. This review describes recent advances in biodegradation of pesticides by addressing the microbes involved in pesticide degradation.

Abstract

Mycorrhizal symbiosis is a highly evolved mutually beneficial relationship found between Arbuscular Mycorrhizal Fungi (AMF) and vascular plants. Knowledge of taxonomic and functional diversity of AM fungi is important in understanding the biology and ecology of such a widespread mycorrhizal symbiosis. Classification and identification of AM fungi remains in the formative stages of growth, with all the attendant turmoil. Since Glomus is known to be an important AM genera for providing multifacet benefit to several economically important plants. Hence, in this review article an attempt has been made to describe 120 Glomus species along with the line diagram of 63 Glomus species for their proper identification that can be used as an identification manual for mycorrhizal researchers.

ABSTRACT

Microorganisms play a key role for the proper running of the ecosystem. They help in nitrogen fixation, which is unique and most necessary property found only in this group. They help in decompositions, mineralization, nutrient cycling, phosphate solubilization, soil aggregate formation, symbioses, parasitism and many other important works. A great emphasis has been given by many scientists to conserve the microbial diversity. Developing human civilization has a great negative impact not only on the above ground biodiversity but also on the belowground biodiversity. This article is an overview, what important and crucial role nitrogen fixers play for maintaining soil and plant health. Nitrogen fixer not only fixes atmospheric nitrogen but also produces growth promoting hormones which are very important for plant growth. 

ABSTRACT

Biodiversity is often understood in terms of wide variety of plants, animals and micro-organisms existing on the earth. So far, about 1.75 million species have been identified, mostly small creatures such as insects. According to scientific estimates, there are actually about 13 million species, although range from 3 million to 100 millions. The present article deals with the importance and threats of biodiversity as well as tries to highlights the role of government and non-government sectors in conservation of biodiversity. The initial part of the article indicates the concept of evolution and biodiversity, wherein we have tried to identify the present scenario. We find that a wide range of microbial, plant and animal species are sources of various biological products for human use and welfare. These species are getting lost or extinct due to lack of conservation over a period of long time. Therefore, an effort has been made to highlight the conservation acts and important rules and regulations for protecting and conserving the bio-resources.

Abstract

Since the first oil well drilled successfully in 1859, crude oil has been a serious problem around world, including Indonesia. As a source of all petroleum products, crude oil is very complex component and divided into aliphatic, aromatic, resin and asphaltene. Petroleum products have been used for daily life and created large amounts of pollutants in environment and ecosystems around the globe. The pollutants should be treated by certain method; among them, bioremediation has several advantages to resolve the problem. In 2003, Ministry of Environmental (MoE) – Republic Indonesia was endorsed with a new regulation about biological treatment or bioremediation for crude oil contaminated soil (MoE regulation No. 128/2003). The most important to be noted in bioremediation process is the presence of microbes with certain metabolite capabilities. The degradation rate also can be improved and sustained by ensuring the adequate required factors. This article describes the removal of crude oil by utilization of microbial potentials, factors affecting biodegradation, and how they are applied in Indonesia.

Abstract

Sustainable landscape and forest management are of utmost concern in alleviating climate change. Fungal mutualism is one of the most significant positive biotic interactions responsible for forest structure and longevity. Coastal sand dunes imitate xeric habitats, while mangroves and river floodplains are often marshy. In spite of such extremities, mycorrhizal fungi are prominent component in coastal vegetation. Studies so far revealed that mycorrhizal association in herbaceous plant species is responsible for dune formation, stabilization and serve as potential inoculum in coastal habitats. Mycorrhizal association facilitates plant species to exploit larger volume of soil, supply nutrients (organic nitrogen, phosphorus and minerals), aggregates soil, provides tolerance to salinity stress, relieves from water stress and protects roots from pathogens. Human interference has severe impacts on plant-mycorrhizal mutualism in coastal habitats. Cultivation of exotic tree species and their uncontrolled exploitation further impoverish the habitats. Protection of native herbaceous flora, cultivation of native tree species and introduction of selected indigenous keystone species in disturbed habitats with mycorrhizal mutualism is an appropriate measure of rehabilitation.

Abstract

Alleviating plant salt stress and remediating saline soils are of great economic interest. Beneficial microbes such as arbuscular mycorrhizal (AM) fungi, plant growth promoting rhizobacteria (PGPR), etc. are associated with many plant species including trees. These beneficial microbes can cope up with salinity and help the plants to survive in such soils. Diversity status of beneficial microbes from the samples collected from different salt affected areas was investigated by many researchers. They screened and identified the efficient PGPR isolates isolated from saline areas for plant growth hormone (IAA) production and phosphate solubilization. The significance and highlights of the recent research as well as the past understanding of beneficial microbes and their role in reclamation of saline areas is discussed in this paper.

Abstract

Mine spoils pose adverse conditions for soil microbes and plant growth, due to its low organic content and other essential nutrients, unfavourable soil chemistry and poor soil texture. Poor microbial population inhibits nutrient transformation, consequently the establishment of the plants and ultimately affects the process of ecological succession. A synergy among different groups of beneficial microbes accompanied by plantation of suitable tree species on mined over area has proved to be effective for speedy and efficient revitalization of the mined affected lands. Inoculation of plantation with efficient strains of native microbes accelerates the soil redevelopment and helps to establish nutrients cycle readily which attracts native flora thereby the pace of natural regeneration is increased. It is therefore imperative to consider the application of effective microflora in restoration of mined lands along with the plantation.

Abstract
 
Opencast mining destroys the original land ecosystem and microbial community due to mining and stockpiling of mine rejects on adjoining land, which is a matter of great environmental concern. Mining creates formation of wastelands, formation of gullies, ravines, overburdens, reduced water infiltration and increased runoff. Reclamation of mined out areas is often difficult due to its chemical, physical and biological traits. Absence of topsoil is the most common feature of the mine spoils dumps. Arbuscular mycorrhizal fungi (AMF), the synonym of VAM fungi, are important microbes of soil that form symbiotic association with most of the terrestrial plants on the earth. Observations led to use of legume microsymbionts as biological substitutes for fertilizers. AMF diversity increases with species diversity of plants as the potential number of association increases. Dominant arbuscular mycorrhizal fungi can prevent the invasion of non-mycorrhizal plants on land where they have established symbiosis and promote their mycorrhizal host.

Abstract

Traditional practices of restoring and vegetating mine spoils, which include mechanical tillage, the addition of tons of organic and mineral inputs, seeding of herbaceous plants, and regular fertilization, are often expensive and not sustainable on the long term in the Canadian boreal forest biome. Phytobial restoration and remediation may be an excellent alternative to these traditional practices while accelerating ecosystem reconstruction and sustainable reforestation of mined sites. In this review, the role and importance of root symbionts – ectomycorrhizal fungi, PGPR, and Frankia – on boreal tree fitness are discussed. Furthermore, highlights of recent research studies done by our team in Canada on ecological restoration and bioremediation of boreal mined sites are presented.

Abstract

With recent advances in molecular biology and rapid developments in new analytical techniques, engineering of microbes for the bioremediation processes has been extensively studied as recombinant microbes can degrade various toxic pollutants effectively. The prospect of microbial engineering has greater potentialities for agriculture and environmental applications and this may provide us deeper insight in understanding the microbial interactions and biotransformation processes. Though much work has been carried out on bioremediation using genetically engineered microorganisms, its application is restricted to environment due to the concerns of health and environment over ecosystem. Nevertheless, evaluation of risk assessment has also been carried out in order to ascertain the potential benefits of transgenic microbes.

Abstract

Now a days, the public has become more sensitive towards the protection of the environment and general awareness has increased about the adverse effects of industrial effluents contaminate with various pollutants, including dyes on the environment. Dyes are an important class of synthetic organic compounds used in many industries, especially textiles. Consequently, they have become common industrial environmental pollutants during their synthesis and later during fiber dyeing. Textile industries are facing a challenge in the field of quality and productivity due to the globalization of the world market. The dyes, which are widely used in textile industries when left in water bodies without any treatment cause environmental pollution and in turn are toxic, carcinogenic and mutagenic. The efficient treatment of the sludge from the industries is not economical and a challenging task. Currently, a number of different technologies and methods such as biological, physical and chemical are widely used for the removal of dyes. The treatment technologies for the removal of textile dyes from the textile wastewater found that over the past two decades interestingly focused on biodegradation methods such as microbial decolourization, enzymatic decolourization, adsorption by microbial biomass (living or dead) and bioremediation systems as a better alternative as the available physico-chemical methods.

Abstract

Electronic waste or e-waste is one of the emerging problems in developed and developing countries worldwide. The constantly changing today’s world of technology has led to the serious problem of e-waste. The previous studies show that India has generated 0.6 million tons of e-waste in 2014 which may increase to 0.7 to 0.9 million tons by 2015–2016. E-waste constitutes multiple components some of which are toxic that can cause serious health and environmental issues if not handled properly. The challenge is to develop innovative and cost-effective solutions to decontaminate polluted environments, to make them safe for human habitation and consumption, and to protect the functioning of the ecosystems which support life. Biological approach is currently applied to recovery of metals from contaminated soil, groundwater, surface water, and sediments including air.

Abstract
 
Within the time scale for soil formation, humans appeared to the planet within the last 1 million years. They shifted their lifestyle from hunter-gatherer to nomadic animal husbandry and finally to cultivation of domesticated crops only within the last 10,000 yrs. Earlier, these crops were cultured in a semi-nomadic style as land was plentiful, so when soil lost its productivity, people abandoned it in favor of new-land. Gradually, as land became scarcer and population exploded, agriculture evolved to continuous cropping of the same parcel of land. This discovered the major concern for soil health. As organic matter is key to soil health, humus is the last stage of organic matter decomposition. Humus is a complex aggregate of dark brown colored amorphous substances, which have originated during the decomposition of plant and animal residues by microorganisms, under aerobic and anaerobic conditions. Humus and living microorganisms are connected by numerous ways which must be appreciated in order to understand the origin and nature of humus. Our attempt is to narrate the role of organic matter and vital role of microbes in humification process.

Abstract

Excessive use and treatment of soil with pesticides under the adage, “if little is good, a lot more will be better” has played havoc with human and other life forms and can also cause populations of beneficial soil microorganisms to decline, which indirectly affect soil fertility. Soil constitutes a major environmental sink for many pesticides. These pesticides are either taken up from soil by plants and then pass into the bodies of invertebrates, water or air, directly or indirectly and affect public health and beneficial biota of the ecosystem. Bioremediation provides very attractive, eco-friendly and economic solution to many of our hazardous pollution problems. For both economic and ecological reasons, biological degradation has become an increasingly popular alternative for treatment of hazardous wastes.

Abstract

Contamination groundwater and soil due to heavy metals (HMs) has aggravated into a threat not only for people inhabiting the polluted areas but also for the vegetation of the region. Relying on the use of obligate symbionts, arbuscular mycorrhizal fungi (AMF) in remediation of contaminated sites can be a productive approach. These fungi due to high cation exchange capacity have the ability to adsorb heavy metals (HMs) on fungal tissues; they also possess enzymes responsible for reduction of metals to less toxic forms. In areas with high toxicity of various HMs such as lead, AMF extends its extraradical mycelium (ERM) beyond the depletion zone of plant roots increasing the availability of nutrients such as potassium, phosphorus, magnesium, and sulphur resulting in increased plant growth and yield. Production of phenol and organic acids by the fungus have been reported to increase iron diffusion, that is a co-factor for antioxidant enzyme superoxide dismutase. AMF sequester HMs in fungal structures and bind them in their chitin cell walls preventing their translocation to aerial plant parts.

Abstract

Contamination of environment with heavy metals has become a serious global problem due to its threat to animal and human health. Removal of this non-biodegradable, hazardous heavy metals through bio-materials has received paramount interest and intense attention in the last few decades as bio-materials play crucial role in remediating heavy metal polluted environment through a process called “biosorption”. The term biosorption, therefore, has become a popular theme in recent years due to its relatively simple, inexpensive, eco-friendly with rapid mechanism of removing heavy metals from polluted environment. There have been burgeoning studies around the globe for alleviating the problem of heavy metal pollution by selecting and developing an effective bio-sorbent with minimum treatment process for field application. This review aims to provide vast information on types of biosorbent available, their exploitation for better efficiency and their economic attractiveness for the restoration of heavy metal polluted environment.

Abstract

Study was undertaken to investigate the toxicity of heavy metals on the structure and function of ectomycorrhizal fungi and their ability to colonize the pine seedlings. Ectomycorrhizal fungi were isolated, cultured and multiplied on MMN medium. Six heavy metals (Cd, Ni, Zn, Pb, Cu and Al) were selected and different concentrations viz; 0 ppm (control), 10 ppm, 50 ppm, 100 ppm, 200 ppm and 500 ppm were used for treating the seedlings. The study was continued for one year. Different growth parameters were measured. Factors such as soil moisture, pH and soil organic carbon on ectomycorrhizal colonization were also analyzed. The mycorrhizal colonization was more in those seedlings having lower concentration of heavy metal treatment. Statistical data analysis has shown that the heavy metals had negative correlation with mycorrhizal colonization. High concentration of metals were toxic to external mycelium, which ultimately resulted in reduction of ectomycorrhizal development. The accumulation of metals in the fungal mycelium and protecting root against metal toxicity was an important factor.

Abstract

The functioning and stability of terrestrial ecosystem are determined by plant biodiversity and species composition. So far, little attention has been paid to the effects of microbe-plant interactions, particularly the mycorrhizal symbiosis, on ecosystem variability, productivity and plant biodiversity. The most common type of mycorrhizal association is the arbuscular mycorrhizal (AM) type. The role of AM fungi in the uptake of diffusion limited nutrients like P and in conferring resistance to soil-borne-diseases is well documented.

Peer-reviewed academic journals publish a variety of article types, such as “research articles” that report original research, “reviews” of the literature, and “case reports” of a small number of interesting cases. Each article type has its own specific format, and it is important that you use the appropriate one.

Crop growth rate (g m^_-2 day^_-1)

Crop Growth Rate is referred to a whole crop, so you need to consider the area of the ground where crop is present. It is measured as mass increase in crop biomass per unit ground area per unit time.
Equation for that is, CGR= W₂-W₁ / t₁-t₂

Definition of terminologies and concept

Variables: Variables are the characteristic, number or quantity which increases or decreases over time and takes different values in different situations. Variables are those, whose value varies according to the situations. For example, maize yield, Stover, fertilizer, labor, land, pesticides, etc.
 
Dependent variable: Variables whose value is dependent on independent variables. These variables take different values only in response to independent variables. Yield of maize is dependent on amount fertilizer, fertilizer application methods, labor, pesticides etc. So in this case maize yield is dependent variables while amount fertilizer, fertilizer application methods, labor, pesticides are independent variables. However in other situation, maize yield can be used as independent variables also.

The first step in applying the correct rate of fertilizer is calculating crop nutrient requirements. A soil test is the only way to measure how much P₂ O₅ and K₂ O are available in soils, and soil tests are available through several private and public laboratories.

Fertilizer Calculation

To compute the equivalent amount of fertilizer necessary to supply the corresponding amounts of nutrients, the following formula is used:

Hypothesis: A statement about the value of a population parameter developed for the purpose of testing.

Type I and Type II Errors

•    Type I Error: Rejecting the null hypothesis when it should not be rejected.
    •    Therefore accepting the alternative hypothesis (your theory) when you should not.
    •    Probability of a Type I error is called a.
•    Type II Error: Failing to reject the null hypothesis when it should be rejected.
    •    Therefore not accepting the alternative hypothesis (your theory). Opportunity loss.
    •    Probability of a Type I error is called b.
•    Minimizing Type I errors is the main concern of hypothesis testing

Biometric observations

The phenological stages i.e. germination, tasseling, silking, and physiological maturity were recorded from fixed mid three rows of each plot. A particular stage was supposed to be completed while 90% of the observed plant showed the characteristics of that phase and number of days was counted from date of sowing.

Days to emergence (DOE)
 
When the plant shoot pokes through the soil surface. Count the 75% seedlings emerged from at least 50% of the total rows starting from the centre. If 75% of the total expected seedlings emerged, then can be considered as 75% emergence. How the growth stages of maize are distinguished can be observed from the chart below.

Plant diseases are of paramount importance to humans because they damage plants and plant products on which humans depends for food, clothing, furniture, the environment and in many cases the housing. The kinds and amounts of losses caused by plant diseases vary with the plant or plant products, the pathogen, the locality, the environment, the control measures practiced and combination of these factors (Agrios, 2005). Disease is one of the major biotic constraints to reduce crop yield and also deteriorate the quality of product that ultimately reduce the market price.

Introduction
Project title:
Objective (S):

Characteristics of a well-planned experiment
 
•    The treatments, design, management, and data collected should be consistent with the objectives.
•    The experiment should be planned and conducted so that there will be a high probability of measuring differences between treatments with an acceptable degree of precision. 
•    The experiment must be planned and executed to ensure that treatment effects are estimated in an unbiased way.

Formation of a Rectangle

Experiments are usually laid out in square or rectangular plots for data and yield estimation, even though the field may be irregular. The plot is usually placed on the contour, parallel with a road, or in a north-and-south alignment. To mark a plot, construct a right angle and then form a rectangle or square.

Progeny test

Progeny trials involve large numbers of progenies of a family type, such as full-sib, half-sib, or S1 lines. The progenies are evaluated to identify those that may be used to generate synthetic or experimental varieties, or recombined to form an improved population in a recurrent selection program. Progenies in the trials are normally a random sample from the particular population under study. Therefore, data obtained from progeny trials may be used to estimate genetic variances and covariances from which heritability estimates, predicted responses to selection, genetic correlation coefficients, and correlated responses to selection may be obtained. Progeny trials are normally researcher-managed. Progeny trials involve complex field designs, such as balanced incomplete block, lattice, and alpha-lattice. Some examples of lattice are 11 × 11 for 121 progenies, 14 ×14, 16 × 16, etc. Because of the large number of entries, single-row plots with only 2–3 replications in a few environments are used in progeny trials.

Terminology of experiments
    
Evaluation trials are important in plant breeding where the selected lines are compared with standard varieties. In most cases, it will be necessary to make comparable yield trials under field conditions. In such case, the field becomes the experimental unit. In these cases, the field becomes the experimental unit. It requires the use of small plots and adequately replicated.

Germplasm
 
Germplasm of crop may be defined as sum total of hereditary materials, i.e. all alleles of various genes present in a crop species and its wild relatives. The germplasm can be utilized in a breeding programme in following ways:
•    Direct release as a variety
•    It may be subjected to selection for developing a variety
•    It may be used as one of parents in hybridization programmes