eChapters

5.1. Irrigation requirement of field crops

Water is an extremely essential component in plant growth and development. It is of utmost importance for photosynthesis, cell division, cell growth / elongation, respiration, nutrient uptake, mineral utilization and much other metabolic process, which directly affect the quantity and quality of the produce. Hence quantity and quality of water play a vital role in performance of a crop. A well distributed water supply, throughout the growth of plant is essential. Rainfall is the major source of water for the crops. Rainfall recharges the surface water resources such as rivers, streams and ponds and also the ground water resources like wells.

Pumps play a critical role in irrigation systems by providing the necessary force to move water from its source (such as a well, river, or reservoir) to the f ields where crops are grown. The selection and proper operation of irrigation pumps are crucial for the efficiency and success of agricultural practices. Here’s a detailed overview of pumps used in irrigation:

Types of Irrigation Pumps

Centrifugal Pumps

Principle of Operation: Centrifugal pumps are the most common type used in irrigation. They work by converting mechanical energy into kinetic energy in the form of fluid flow. Water enters the pump through the center (eye) of a rotating impeller and is accelerated outward.

7.1 Introduction

For maximization of yield of crops, it is essential to provide irrigation to crops. When either the natural sources like rainfall, dew, snowfall and other forms of precipitation or when the capillary rise of groundwater is not sufficient to meet the crop water demand, then there is need to supply irrigation. This irrigation water is a precious resource and need to be used cautiously. There are three important things need to be understood for optimum utilization of irrigation water with basic purpose to maximize the yield and returns. These three things are:

(i) When to irrigate?

(ii) How much to irrigate? and

(iii) How to irrigate?

In fact these three things form the core concept of irrigation scheduling.

8.1 Introduction

For maximization of yield of crops, it is essential to provide irrigation to crops. When either the natural sources like rainfall, dew, snowfall and other forms of precipitation or when the capillary rise of groundwater is not sufficient to meet the crop water demand, then there is need to supply irrigation. This irrigation water is a precious resource and need to be used cautiously. There are three important things need to be understood for optimum utilization of irrigation water with basic purpose to maximize the yield and returns. 

The purpose of irrigation scheduling is to decide upon the amount of water to be applied for irrigation and timing of irrigation in order to avoid wastage of precious water. The irrigation scheduling is also used to determine the number of irrigations required for a crop during its growth cycle and judicious use of water depending upon the weather forecasts issued from time to time. The irrigation scheduling has to be planned for either full irrigation or supplementary irrigation depending upon the availability of water resources and the season during which crops are grown. Crops grown during the dry season requires full irrigation and crops grown during the rainy season require supplementary irrigation. The third category of irrigation is protective irrigation which is practiced in dryland areas. The protective irrigation is given when the crops are experiencing severe moisture stress due to prolonged dry spells wherever the farmers has access to small ponds and tanks developed within his own field as water harvesting structures.
10.1. Full Irrigation
Under full irrigation, the crops are provided with irrigation right from land preparation till the crop is getting ready for harvest maturity. The full irrigation will be usually planned for maximum yields of the crop (Fig.10.1).

The following various types of irrigation methods and their systems are used in crop production in greenhouses and plant nurseries.

1.Hand Watering

2.Perimeter Watering System

3.Tube Watering System

4.Drip Irrigation System

5.Overhead Spray System

6.Ebb and Flow System.

Efficient irrigation water management is essential for achieving high crop productivity while conserving limited water resources and minimizing environmental hazards. This chapter presents the principles and practices required to manage irrigation according to crop demand and soil-water conditions. It begins with how plants obtain water from soil and explains irrigation requirements, crop water requirement terminology, water-use efficiency, field water balance and the effective root zone. Crop response to water at different growth stages is considered for important crops including rice, wheat, maize, sugarcane and mustard. Different irrigation methods are described, including surface, corrugation, sub-irrigation, sprinkler and drip irrigation. The chapter provides several approaches to irrigation scheduling based on water-holding capacity, degree of water depletion, soil-water potential, evaporation pans, leaf-water potential, canopy temperature, crop water stress index and leaf reflectance. Methods for measuring irrigation water and flowing water, including water-measuring devices and current meters, are also discussed. Scheduling based on IW/CPE ratio and depletion of available soil moisture provides practical approaches for improving water-use efficiency.

For better yield irrigation water must be free from soluble salts and from concentration of specific chemical substances that may hazard to soil with respect to salinity, sodicity, alkalinity and toxicity. Water analytical data which helpful to predict the magnitude of the effect of irrigation water on soil and plant growth under specific environmental circumstances so irrigation water must be analyzed for EC, pH, Na+, Ca⁺⁺, Mg⁺⁺, Cl^-, CO₃–, HCO₃-  and SO₄.^– 

Water Quality Parameters
Irrigation water contains impurities in varying concentration. The suitability of irrigation water mainly depends up on the amount and type of salts present in the water. The main soluble constituents are calcium, magnesium, sodium as cations and chloride, sulphate, bicarbonates as anions. The other ions present in minute quantities are boron, selenium, molybdenum and fluorine which are harmful to animals fed on plants grown with excess of these ions.
Quality of irrigation water is judged with three parameters
1. Total salt concentration
2. Sodium absorption
3. Bicarbonate and boron content.
Total Salt Concentration
Salt content of irrigation water is measured as electrical conductivity (EC). Conventionally, water containing total dissolved salts to the extent of more than 1.5m mhos /cm has been classified as saline. Saline waters are those which have sodium chloride as predominant salt. Brackish water is one that is contaminated with acid, bases, salts or organic matter, whereas saline water contains mainly dissolved salts, Based on EC irrigation water is classified as below.

6.1. Quality of irrigation water

Asia per capita water availability has fallen by around 80 per cent during last five decades.

Suitability of waters for a specific purpose depends on the types and amounts of dissolved salts.

Some of the dissolved ions such as NO₃ are useful for crops.

Water required for irrigation of cropped land is being degraded in terms of quantity and quality due to fast increasing demand for its use. Furthermore, the soil quality and crop productivity is linked to the quality of the water available for irrigation. In general, evaluation of irrigation water quality should focus on salt content, sodium concentration, the occurrence of nutrients and trace elements, alkalinity, acidity, and hardness of the water.

Introduction

Irrigated agriculture is dependent on an adequate water supply of usable quality. The water quality used for irrigation is essential for the yield of crops, maintenance of soil productivity, and protection of the environment as well. The quality of irrigation water is defined with respect to its effect on plant growth, soil properties, soil biological equilibrium, and irrigation technology. Conceptually, water quality refers to the characteristics of a water supply that will influence its suitability for a specific use, i.e. how well the quality meets the needs of the user. Specific uses have different quality needs and one water supply is considered more acceptable (of better quality) if it produces better results or causes fewer problems than an alternative water supply. For example, good quality river water which can be used successfully for irrigation may be unacceptable for municipal use without treatment to remove its sediment load. Similarly, snowmelt water of excellent quality for municipal use may be too corrosive for industrial use without treatment to reduce its corrosion potential.

1.1 Introduction

Water scarcity is seen as a major constraint to intensify agriculture in a sustainable manner as an attempt to meet the food requirements of a rapidly growing human population. The ever-increasing human population, climate change due to increased emissions of greenhouse gases (GHGs), and intensification of agriculture, are putting severe pressure on the world’s two major non-renewable resources of soil and water, and thus pose a big challenge to produce sufficient food to meet the current food demand. The present world population of 7.3 billion people is predicted to grow to over 9 billion by 2050, with the majority of this population increase occurring in developing countries, most of which already face food shortages. A 70% increase in current agricultural productivity will be required to produce sufficient food if these human population growth predictions prove to be correct. In this context, concerted efforts are being made globally to improve the effectiveness of water which will be used for enhancing the production of irrigated crops. Additionally, efforts are also being made to improve water harvesting and water conservation in rain-fed agriculture.

The injudicious use of saline/brackish water is all too often associated with the development of soil salinity, sodicity, ion toxicity, and groundwater pollution. Because of these negative effects, it is important to have a better understanding of exactly how the quality of water influences the management of irrigated agriculture, especially in arid and semi-arid regions.

Irrigation

Irrigation is defined as the artificial application of water to the soil for the purpose of crop production in supplement to rainfall and ground water contribution.

Time of Irrigation

The time schedule which indicates when irrigation water is to be applied and the quantity of water to be applied at that time is called irrigation schedule. There are several approaches for scheduling irrigation:

1. Soil moisture depletion approach based on the available soil moisture in the root zone.
2. Climatological approach based on the amount of water lost by evapotranspiration.
3. Combination approach based on soil moisture depletion and climatological approaches.
4. Critical stage approach which indicates the growth stages at which moisture stress leads to yield loss. These stages are known as critical period or moisture sensitive period. In cereals and millets panicle initiation and flowering stages are moisture sensitive stages. In pulses and oilseeds, flowering and pod development stages are critical stages. In sugarcane active tillering or formative stage is critical and in cotton boll development is the critical stage.

Technical Term            Definition

Infiltration                    Infiltration is movement of water from the surface into the soil or ground.

Introduction

Irrigation is the artificial application of water to soil or land to assist in the growth of crops, vegetation, or landscaping. It is a crucial agricultural practice used to supplement natural rainfall and provide controlled and consistent moisture to plants when needed. Irrigation systems can vary in complexity, from simple methods like watering cans and hoses to more advanced systems like drip irrigation, sprinklers, and flood irrigation.

The primary purpose of irrigation is to ensure that plants receive an adequate and consistent supply of water, especially in regions with insufficient or irregular rainfall. This helps promote healthy plant growth, increase crop yields, and prevent drought-related crop damage. Irrigation is not only used in agriculture but also for landscape maintenance, recreational fields, and other applications where controlled watering is essential.

OBSERVATION

The examination of the IRS - 1A imagery under raw and the digitally enhanced modes vividly display heavy concentration of suspended sediments in certain sectors along the east coast of Tamil Nadu. Such pockets of suspended sediments are seen as long and linear bodies trending parallel to the coast to the strike length of 20 - 30 km and width of 5 - 10 km. Such Phenomenon of suspended sediments concentration are strikingly observed in two sectors. One in between Tuticorin harbour and Vaippar river mouth and the other just at the mouth of Ponnaiyar river along Cuddalore-Pondicherry coast. Both of them are observed along conspicuous (Fig.1& 2) concave coasts.

Introduction

Agriculture as a primary sector in India is mostly production oriented. Global agriculture is experiencing significant changes in terms of technological and digital revolution, rapid urbanization, faster growth in middle income groups, changing food habits, market oscillations, and above all, climate change. During the last 50 years, India has recorded 4 to 10-fold increase in agriculture and food production(food grains-290 MT, horticultural produce -315 MT, milk production nearly 180 MT, and fish production approaching 12 MT), rendering the country as the second largest agrarian economy in the world (Singh, 2019). Despite the excellent progress, the country is home to over one third of the world’s small and marginal farm holders, with scattered land holding. Eighty f ive percent of the farmers are small and marginal. On the other hand, world’s population is growing and to meet the growing food demand there is a need to increase agricultural output by at least 60 percent globally, and 100 percent in developing countries (FAO, 2014a)

Introduction

Agriculture has historically been the primary source of income in India. It has the potential to alleviate poverty, increase income, and enhances food security for 80% of both the world’s poor and people who reside in rural areas primarily work in agriculture. One of the most effective strategies to eradicate extreme poverty, increase shared prosperity, and feed an estimated 9.7 billion people by 2050 is agricultural development. Compared to other modes, the agro - based sector’s progress is two to four times more successful in enhancing the earnings of the poorest people (www.worldbank.org).

Nearly 5 billion hectares, or 38% of the world’s land surface, is used for agriculture. Around one of this is devoted for farming, and the remaining two thirds are pastures and meadows for grazing animals. Over 10% of cropland is assigned to permanent crops like cocoa plantations, oil palm plantations, and fruit tree orchards. Yet another 21% of land is primed for irrigation, a crucial agricultural land management technique.

Introduction

Urbanization, a vital global phenomenon, refers to the process of city establishment and growth; the term commonly connotes population increase in the city from internal growth and immigration as well as their spatial expansion (Revi, 2007). Recent developments, uncontrolled population growth have been linked with the process of urbanization. Urban areas cover 3% of the global land but it gives shelter to nearly 26% of the global population (U.S. De, 2009). Increase in population growth and industrialization is posing threat to natural resources such as land air and water. Anthropogenic factors have led to change in land use pattern, high energy consumption, high level of generation of waste etc. As per UN survey, by 2050, approximately 70 percent of the global population will be living in cities (UN, World Urbanization Prospects, 2014). Unplanned growth is damaging the existing ecosystems along with that causing climate change and loss of biodiversity.

12.1. Origin and distribution

• Native of Persia and neighbouring tracts of Western and Southern Asia

• In India, North Guj arat, Raj asthan, Haryana and Bihar are the maj or states.

• Husk and peel - exported to USA, Germany, UK and France

12.2. Economic importance

• Psyllium from Greek meaning flea, in reference to colour, size and shape.

• Economic part - Seed coat, husk used in indigenous medicine. Seeds contain glucoside and tannin.

• Works as an anti-diarrhoea drug.

• Seed - Pentose, a sugar is isolated.

The cotton aphid: Aphis gossypii: Aphididae

Symptoms of Damage

Both nymphs and adults cause the damage by sucking the plant sap from shoot tips, pods and leaves. Severe infestation may result in complete drying of affected parts. Attacked leaves curl up, wither and fall. These are yellowish green or brown coloured aphids. The total life cycle from first instar nymph to adult occupies an average of 8-10days. It reproduces parthenogenetically and viviparously. The female may produce 10-30 young ones in a life span of 10-12 days. The nymphs transform into adult in 5-8 days after passing through four moults. 

Scientific name: Plantago ovata Forsk.
Family: Plantaginaceae
Isabgol, or Psyllium husk or Blond psyllium, belongs to the family Plantaginaceae. This medicinal herb has been used for centuries in India, particularly for its seed's therapeutic properties. The name "Isabgol" originates from Persian, with "Isab" meaning horse and "Gol" meaning ear, describing the seed's distinctive shape. Isabgol is cultivated globally and is valued for its medicinal and industrial applications. The seed's medicinal properties make it an effective remedy for constipation and digestive issues. Additionally, Isabgol is used in the food industry to produce various products, such as candies, biscuits, and ice cream.
Origin and distribution
Isabgol (Plantago ovata) is native to the Mediterranean region, West Asia, and parts of Pakistan, including Sindh and Sutleg. Its distribution also extends to the Canary Islands, Southern Spain, the Middle East, North Africa, and North- Western Asia.
Botany
It is 10-15 cm tall short-stemmed annual herb. Flowers in terminal spikes; fruit is a capsule. Theflowers are white in colour and minute. It is highly selfpollinated. The capsule is ovate, 8 mmlong, releasing the smooth, dull, ovate seeds. The seeds are covered with a translucent membrane, known as the husk. The husked seeds are dark red and hard.

The geographical area of the union territory of Andaman and Nicobar Islands is 8, 24,900 ha with 86.9 % of it under reserve and protected forests. The humid tropical climate that prevails in the Andaman and Nicobar islands provides a unique opportunity to grow various crops. Owing to a number of factors, hardly 4.8% of the area is under cultivation. Maximizing the productivity and farm income mainly depends on effective management of natural resources like rain, soil, land as well as labour present in the Island ecosystem.  On an average, the Islands receive 3074 mm of rainfall distributed over 8 months. The rainfall is intense from June to September and may have even up to 30 rainy days per month sometimes, however, from January to April, the rainfall is scanty or absent, particularly in March. The undulating terrain results in severe water crisis during the period which is aggravated by higher evapotranspiration. The Islands receive south-west monsoon from May to September and north-east monsoon during October to January. The topography of A&N Island is undulating with a stiff terrain exposed to soil erosion due to heavy rainfall.  The crop growing season can be divided in to two major seasons viz., wet 
and dry seasons.

It 9001:2000 Means customer satisfaction and continuous improvement

ISO (International Organization for Standardization) is a worldwide federation of national Standards bodies from each country. The object of ISO is to promote the development of Standardization and related activities in the world with a view to facilitating international exchange of goods and services, and to developing cooperation in the spheres of intellectual, scientific, technological and economic activity. The results of ISO technical work are published as International Standards.

Quality management Systems (QMS) certification as per ISO 9001 : 2000 is an important opportunity that can enable the companies acquire the label of an enterprise caring for the customer needs and improve their economic performance at the same time. QMS provides an organization a systematic structured documented and effective approach to consistently maintain the product quality meeting customer requirements.

Hunter and Mohler discovered the isozymes. In 1959 Markert and Moler introduced the concept of isozymes, which they defined as the different molecular forms in which proteins may exist with the same enzymatic specificity (Buth 1984). This means that different variants on the same enzymes have identical or similar functions and are present in the same individual. As such, their importance for understanding gene action in development and differentiation was exploited during the1960s in both animals and plants. Nevertheless, isozymes played a minor role in research on plant biochemistry until 1966 when genetic polymorphism for isozymes within the same population was discovered (Stebbins 1989, Wendel 1989). That revealed the possibility for population genetics to make precise quantitative estimates of genetic variability based upon one parameter of the molecular structure of the primary products of the genes themselves.

Plant population genetics were not long in following their zoological colleagues and the investigation of both animals and plants increased explosively. This application, however, necessitated a partitioning of the isozyme concept, since the relevant isozyme subset, defined by Prakash (Buth 1984) as the variant proteins produced by allelic forms of the same locus, to avoid the now common confusion with isozymes which are the various polymer produced from monomers specified by different loci. The development of genetic distance or similarity coefficients (Lukasová 1985) allowed the summarization of isozyme data for intersample comparisons and so quantified isozyme data were soon applied to comparative studies of taxa.

Polysomes consist of two or more ribosome traversing a strand of mRNA, translating the nucleotide sequence into the corresponding amino acid sequence. Usually at any time, many ribosomes are translating an mRNA simultaneously forming a structure called a polyribosome or polysomes. One reason for isolating polyribosomes is to resolve them on sucrose gradients to determine the extent of ribosome loading. The second main reason is to provide a source of mRNA for in vitro translation.

Polyhydroxyalkanoates (PHAs) are diverse biopolyesters synthesized by many bacteria as carbon and energy reserved materials under unbalanced growth conditions. Sand-dunes have low nutrient contents especially nitrogen (N) and phosphorus (P) thus could harbor potential PHA accumulating bacteria. There is no report of isolation of PHA producing bacteria from the sand-dunes environment.  Sand samples of rhizosphere and non-rhizosphere regions of the coastal sand-dunes were processed on Nutrient Agar and TYG-Agar media for isolation of heterotrophic bacteria.

Introduction

Solanum trilobatum L., an important medicinal plant, belonging to Solanaceae is widely distributed in South Asia and has been used in Indian traditional medicinal systems of Siddha and Ayurveda. The members of Solanaceae accumulate steroidal alkaloids based on a C₂₇ cholestane skeleton, e.g. solasodine and tomatidine. Recently, mixtures of solasodine glycosides have been successfully used for the treatment of certain human skin carcinomas (Cham, 1994). Solasodine glycosides have antineoplastic activity in cell culture, animals and in humans (Cham and Daunter1990). It has been demonstrated that specific endogenous lectins which are present on the plasma membranes of susceptible cells recognize and bind the sugar moiety of the solasodine glycosides and the glycosides are subsequently internalized and cause cell death (Cham and Daunter1990). Hence the present study was undertaken to isolate the solasodine from S. trilobatum.

Introduction

Peripheral blood mononuclear cells (PBMCs) consist of chiefly of lymphocytes and monocytes. Purified PBMCs are used in vitro to evaluate a variety of functions of lymphocytes viz; a) proliferation to mitogenic (PHA, Con-A) stimulation, b) monitoring of prior sensitization in antigen recall assays by scoring lymphocyte proliferation, c) immunophenotyping for surface markers as well as intracellular molecules in monocytes and lymphocytes etc. Activation of monocytes/macrophages by small molecules, cytokines and pathogen components can also be monitored. PBMCs can also be used for a variety of structural and functional studies for addressing issues in human immunology such as scoring for apoptosis and production of cytokines as well as other mediators in vitro.

Background information

Blood is a liquid mixture comprised of plasma, cells and proteins. The liquid portion, plasma, makes up half of the blood volume, and cells the other half. Isolation of lymphocytes is a common procedure in immunology and cell biology that involves separating and collecting lymphocytes.

Introduction

Photosynthetic bacteria are autotrophs and anaerobes. These bacteria produce Hydrogen sulphide. These are predominant in the bottom of stagnant water enriched with mud.

Requirements

1. Mud sample
2. Enrichment medium of Photosynthetic bacteria or salt solution (1.0g/lt. of (NH⁴)₂SO⁴ 1 g; K²HPO⁴, 1 g; MgSO⁴,0.2g; NaCl, 5g; pH 7.2)
3. Sterilized bottle with plug
4. Fluorescent tube

Isolation of Protoplasts

Protoplast is the living material of the cell however an isolated protoplast is the cell from which the  cell wall is removed. In plant breeding programme many desirable combination of characters could not be transmitted through the conventional method of genetic manipulation. Higher plants that could lead to the genetic process involving fusion between the subsequent developments of a product to a hybrid plant is known as somatic hybridization. Plant protoplasts can be isolated from cells by two methods:

Introduction

The actinomycetes are gram positive, non-motile, non-sporulating and nonacid fast bacteria. Sometimes these are called ray fungi and are connecting link between the bacteria and the true fungi. They possess a very fine vegetative mycelium that does not fragment into bacillary or coccoid forms and therefore their colonies on agar are commonly cohesive or tough in consistency. In many soils, the actinomycetes accounts from 10 to 25% of the total count on agar plates. Their number is higher in soils of low moisture content than in wet soils. They are responsible for degrading more resistant carbon material in soil like humus. They are also important flora of manure heaps. Most of these, particularly Streptomyces, produce antibiotics and so are of a great value

Introduction

Soil is the natural habitat of a number of microbes viz. bacteria, fungi, actinomycetes, algae and many viruses. Out of these, bacteria are morphologically very simple as made up of just one cell of small size, therefore can multiply rapidly. Each viable bacterium at appropriate dilution can develop into a colony. Hence by counting the number of these colonies which develop on a selective growth medium, the number of viable cells of bacteria present in soil can be ascertained. Since the number of the bacteria present in soil is very high, the soil suspension is to be sufficiently diluted to reduce the number of colonies and to prevent their overlapping. The number of colonies formed from a diluted sample multiplied by the extent of dilution (dilution factor) gives the number of viable cells present

Introduction

Fungi constitute an important part of microflora of normal soil. In soils, fungal propagules vary from 2 x 10⁴ to 1 x 10⁶ per gram soil. The propagule being considered as fungal hyphae, spore, and hyphal fragments which is capable of giving colony on the plate. Most soil forms have a filamentous organisation capable of reproduction by means of spores. Their development is especially favoured by soils having acidic reactions. Soil fungi has significant role in organic matter decomposition, as a plant pathogens and in the interaction with other soil microorganisms. Agar plate count method is commonly used as a measure of fungal population in soil.

1. Deoxyribo Nucleic Acid (DNA)

DNA is a genetic material, originally confined to nucleus of a cell. In plants, some DNAs are also present in mitochondria and chloroplasts. DNAs are vital macro molecules having high molecular weight.

Isolation of plant DNA is cumbersome or difficult primarily because of the presence of a number of secondary plant products. Secondly, a protocol, which is found suitable for isolation of DNA in one plant, may not work in other. The efficiency of DNA extraction depends on many factors, such as sample material, ionic conditions of the extraction medium and type of lysing agent used etc.

There are two methods, one developed by Dellaporta et al. (1983) and the other by Murray and Thompson (1980) which are most commonly used for extraction of DNA in a number of plant genera.

Murray and Thompson’s (1980) method is described here below with minor modifications.

Special Staining
A. Spore stain
Spores may be spherical or oval and may be central subterminal or terminal in position within the cell. Shape, size and position of the spore in the cell are useful for the identification of sporulated organisms. Spores are difficult to stain and when once stained, they are difficult to decolourize. With Gram’s stain, mature spores remain unstained bodies. Modified Ziehl-Neelsen’s method of staining will be used for the staining of spores.
Composition
a. Concentrated carbol fuchsin
b. Sulphuric acid 0.5 % solution.
c. Loeffler’s alkaline methylene blue
Materials
Old cultures of B. subtilis and Cl. Chauvoei and staining solutions.
Procedure
1. Make smears and fix over flame.
2. Stain with carbol fuchsin and steam for 3 to 4 minutes.
3. Wash with tap water.
4. Decolourize with 0.5% sulphuric acid.
5. Wash with water.
6. Counter stain with Loeffler’s methylene blue for 2 minutes.

The chief functions of Clinical Microbiological laboratory are to examine and culture specimens for microorganisms, to make accurate species identification of important isolates and to perform antibiotic susceptibility tests when indicated. These tasks will assist physicians in the diagnosis and treatment of infectious diseases.

Once the specimen is received in the laboratory, the specimens are examined visually depending on the physicians order and the nature of the specimen. Wet mounts and smears may be prepared and stained for microscopic examination. Observations may or may not be immediately reported to the physicians depending on the definitiveness of the results. Timely information may often be used to establish a presumptive diagnosis and institute a specific course of therapy. Specimens that require definitive identification of potentially pathogenic microbes are processed further. All agar plates are streaked for colony isolation; then plates and broths. All cultures are placed in an incubator with appropriate temperature and environmental conditions to maximize the growth and replication of microbes. Often a presumptive microbial identificationcan be made. A final report should be delayed while subcultures and additional test procedures are performed to identify the organisms definitively.

Preliminary Identification of Unknown Bacteria
A number of techniques may be used in the direct microscopic examination of clinical specimens to demonstrate the presence of microbes The examination of wet mounts of unstained materials by phase contrast or
dark field microscopy is useful for demonstrating motility, spirochaetes and endospores. Giemsa, Wright or acridine orange stains may be helpful in observing bacterial forms that stain poorly or that have little contrast from
back ground material.

Cell culture is the most convenient and widely used system for the isolation and propagation of many viruses. Either primary cell culture or established cell lines can be used to isolate the suspected viruses. One can normally get 10-100 virus particles per cell inoculated. Many details of the infection process are controllable to a high degree (including cell density, age, multiplicity of infection (M.O.I.), medium composition, cell type and length and temperature of incubation). Many cell types from different species can be susceptible to a particular virus and vice versa. For replication to occur, the cell type used must be permissive for a particular virus under study.

Protoplasts are cells which have had their cell wall removed, usually by digestion with enzymes. Cellulase enzymes digest the cellulose in plant cell walls while pectinase enzymes break down the pectin holding cells together. Once the cell wall has been removed the resulting protoplast is spherical in shape. Digestion is usually carried out after incubation in an osmoticum (a solution of higher concentration than the cell contents which causes the cells to plasmolyse). This makes the cell walls easier to digest. Debris is filtered and/or centrifuged out of the suspension and the protoplasts are then centrifuged to form a pellet. On resuspension the protoplasts can be cultured on media which induce cell division and differentiation.

Viruses are smaller than bacteria and require living cell for their growth. They can be detected through the bacteria to which they parasitise. Viruses are associated with both eukaryotes as well as prokaryotes and contain either DNA or RNA; only few have both DNA and RNA.

Viruses that infect bacteria are called bacteriophage. They consist of head or capsid and a tail. The head may be round, oval, polyhedral and is made up of proteins while tail is hollow and provides an exit for nucleic acid to enter in bacterial cell. The tail also helps in attachment to the cell wall surface of bacteria. After injection of the nucleic acid into bacteria they multiply and form large number of bacteriophage particles which cause lysis of the bacterial cell wall releasing many bacteriophages. Phages that cause lysis are known as lytic phages and that do not cause lysis are called temperate phage. The most common lytic phage is E.coli – a coliphage.

1. VARIETAL SEED PRODUCTION

3 m : Rice, soybean

5 m : Blackgram, greengram, cowpea, field lab lab lab lab

5-10 m : Groundnut

25 m : Tomato

Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. Alkaloids showed quite diverse medicinal properties (Rates, 2001). Many of them possess local anesthetic properties, but their practical use is limited for clinical purposes (Hesse, 2002). Morphine is one of the most known alkaloids isolated from Papaver somniferum (opium poppy), which had been used and still is for medical purposes. This alkaloid is a powerful narcotic which is used for the relief of pain, but its usefulness is limited because of its addictive properties.

The isolation of microbes is commonly done using serial dilution technique.

1. Trichoderma

Trichoderma is one of the important biocontrol agents. The colonies first produce mycelial growth and then turn yellow and finally produce a dark green color mat.

Anthocyanins are members of the flavonoid group of phytochemicals, a group predominant in teas, honey, wines, fruits, vegetables, nuts, olive oil, cocoa and cereals. The primary players in this group include the anthocyanins (eg, cyanidin, pelargonidin, petunidin), flavonols (quercetin, kaempferol), flavones (luteolin, apigenin), flavanones (myricetin, naringin, hesperetin, naringenin), flavan-3-ols (catechin, epicatechin, gallocatechin), and although sometimes classified separately, the isoflavones (genistein, daidzein) (Skibola and Smith, 2000).

Introduction

The isolation of mutants is often critical to the study of cellular process, especially when such studies are performed at the molecular level. The phenotype of a particular mutant is attributable to the loss of a particular cellular function; the loss of that function is actually attributable to a mutation in a gene necessary for that function. In this experiment we will isolate auxotrophic mutant which can grow only if provided with specific amino acid. For example arg^- mutant have lost the catalytic function of an enzyme involved in arginine biosynthesis due to mutation in the structural gene that encodes the enzyme.

Mutagenic Agent

Mutation is an alteration in the coding sequence of a gene. Mutation occur spontaneously at a frequency of about 10^-8 per bacterial cell per generation. The rate of mutation can be increased with mutagenic agents. Mutants are strains with any structural alteration of their DNA that gives rise to a mutant phenotype. Mutagens are chemical agents (e.g. nitorsoguanidine, 5 bromouracil), physical (e.g.UV) and biological agents (e.g. trnasposons) that cause mutation to occur.

1. Bacterial (Prokaryote) Genome

The chromosome of most bacteria is a single super coiled double stranded circular DNA molecule. A complex packaging mechanism is necessary in order to ensure that the entire DNA is folded within the bacterial cell in a manner, which will not inhibit transcription nor allow entanglement of the two daughter strands to occur during replication (Highly condensed >10 mg/ml in region less than l ìm in diameter). This is achieved by two main mechanisms.

• First the DNA is folded into between 40-100 loops
• Second each of the quasicircles is it self super coiled independently of the others each loop are abolished by Ribonuclease.

Deoxyribonucleic remove the super helical nature of the loops, though limited treatment with this enzyme will attack only a small number of the loops and therefore leads to removal of only some of the super coiling. The intact folded chromosome or nucleoid can be isolated in the presence of non ionic detergents and high molarities of salt in two possible forms free and membrane associated. The free form which sediments at 1600-1700s consists of about 60%DNA, 30%RNA and 10%protein the bulk of which is the enzyme RNA polymerase. The membrane bound form contains an additional 20% of membrane-attached protein. Bacterial genome size ranges from 580 to 9900kbp, & the average gene size is constant from 900 to 1100bp of which 87-94% are protein coding (Rickettisa’s 76% and Borelia Plasmid’s 41% are exceptions).

ABSTRACT

A plant grows in a highly competitive environment. It is continually being threatened by other plants encroaching upon the space from which it draws its sustenance, by microorganisms, by insects, avian, reptilian or mammalian herbivores. In order to survive, each plant must draw upon a complex of defenses, which may be physical, such as Spines or Leathery Leaves or Chemical. These defenses are passive, coming into action only when the plant is attacked which repel insects or the herbivores that attempt to feed on them. Plants protect themselves from insect attack by providing a multitude of repellent chemicals including toxic and bitter alkaloids and tannins. Non-specialist insects and other animals that attempt to feed on the plant may be repelled, injured through severe gastrointestinal malfunction or even killed. The cabbage, spinach, mustard etc. are well known for their mustard pungent flavor that deters most animals from consuming it. Even most medicinal plants like Cynanchum collialatum of the family Asclepediaceae have tannins or alkaloids like “cardenolides” that repel most animals and insects. All these plants have a basic enzyme “Myrosinase” which react with these specific tannins to produce the toxic metabolite, which repels insects and animals. But caterpillars of few insects are known to tolerate these toxic alkaloids (ex: caterpillar of Striped Tiger Butterfly-Danaus genutia) and in turn sequester the toxic alkaloids into their tissues making themselves non-palatable to their enemies. We hypothesize the analysis of possible roles of toxic alkaloids isolated from these butterflies as bio-insecticides