eChapters

Gladiolus is a flower of breathtaking beauty with a wide range of colours, size and form. Its magnificent inflorescence has won for it, a place of pride in gardens and value as a cut flower. Except true blue and green practically all colours are available in gladiolus. Flowers are long lasting and stand transport well. They are widely used in flower arrangements, bouquets and indoor decorations. It is estimated that gladiolus is grown throughout India over on area of 1270 ha (Arora et al. 2002).

Gerbera, commonly known as Transvaal Daisy, Barberton Daisy or African Daisy, is cultivated throughout the world under a wide range of climatic conditions for its attractive flowers. It is highly suitable for beds, borders, pots and rock gardens. The wide range of colour and the attractive shape of flowers suit very well in flower arrangements. The cut blooms have long vase life. Today Gerbera is known as an important commercial flower crop and belongs to the most important plant species in the world, together with the rose, chrysanthemum, carnation and tulip. Gerbera is amongst the ten most important commercially grown flower crops in the world.

Chrysanthemum (chrysos =golden; anthos = flower) is a popular flower crop of commercial importance known as the “Queen of the East”. It ranks next only to rose among flower crops in the world.

China aster (Callistephus chinensis) belonging to family Asteracea is a native of China. It is a half hardy annual, erect plant, hispid hairy branches bearing alternate, broadly ovate or triangular ovate, deeply and irregularly toothed leaves. Flowers are solitary, usually blue, lavender rose or white coloured. China aster is one of the most important among garden annuals grown throughout the world. Among annual flowers China aster ranks third next to chrysanthemum and marigold. It is grown by small and marginal farmers in Karnataka, Tamil Nadu, West Bengal and Maharashtra. Due to its long vase life, China aster is a popular cut flower used in vases and for floral decoration and also for making garlands and venis in Karnataka. Asters are popular as bedding plants and used to fill gap in mixed herbaceous borders. Dwarf cultivars are also suitable for edging and window boxes.

Carnation is one of the important cut flower crops grown throughout the world and occupies prime position because of the attractive colour, shape and good vase life. Due to the excellent keeping quality, wide range of forms, ability to withstand long distant transportation and remarkable ability to rehydrate after continuous shipping, carnation is preferred by growers to roses and chrysanthemums in several flower exporting countries.

Although cut carnations are sold in western countries all the year round, they are in particular demand for the Valentines Day, Easter, Mothers Day and Christmas. While standard carnations are in great demand, the miniature types are fast gaining popularity for their potential role in floral arrangement and also as cut flower at comparatively low price. White and pink standard carnations are in the greatest demand followed by red, yellow and bicolour. The liking for a colour depends upon the time or season. The re standard types are preferred to other colours, especially during the Christmas. In contrast in miniatures, the terminal flower bud is pinched to encourage clusters of short-stemmed small flowers. These types are mainly used for flower arrangement. (Bhatt, 1989)

Anthuriums are tropical flowering plants with attractive foliage. These flowers are bewitchingly beautiful with attractive form and long lasting characters making it a favourite choice for flower arrangement and for bouquet making.  Anthurium is a large neotropical genus of 600-800 species belonging to family Araceae. Two flowering species in this genus Anthurium andreanum and Anthurium scherzerianum are extremely fascinating and commercially important.  The flowers of anthurium are popular with flower arrangers because of their bold effect and lasting qualities (Bhatt and Desai, 1989 and Singh, 1995). Together with some of its many hybrids, A. andreanum today forms the basis of a substantial cut flower industry chiefly in Hawaii, where much research is done in its hybridization and cut flower.

Bonsai culture is an important branch of Ornamental horticulture. History of Bonsai is very old dating back to many centuries in China where it originated, as most Chinese arts and from there it spread to Japan and became highly specialized.  In fact, bonsai culture is in the present day more known as Japanese than as a Chinese art.  In Japanese homes, there are plants which are hundreds of years old. This treasured art is passed from generation to generation in Japanese society.

The word Bonsai is a combination of two Japanese words, Bon (meaning shallow pan) and Sai (meaning plant) which can be interpreted as ‘Tray planting’.  The idea conveyed is that of a small beautiful tree growing in a container as in nature with all its parts performing their natural functions throughout the times.  The artistic look of plant in a miniature form maintained for many years is the prime criteria.  Bonsais are grown outdoors and are displayed in living room, as and when, needed.  They cannot be treated as house plants.

Dry flowers are naturals, dried and preserved with an everlasting value the can be cherished for longer period. According to APEDA investigations, dried flowers accounted for 15% in the total floriculture export during 1988-89 and increased to 64% in 1994-95. Export value of dried plants and planting materials increased from Rs. 109.21 million in 1993-94 to Rs. 364.55 million in 1995-96.
 
India exports dry flowers to U.K., Germany, Italy, The Netherlands, U.S.A., Japan and Singapore. Dry flower production is labour intensive, provides self-employment and job opportunities for a large number of workers and aids in development of subsidiary industries. The industry has many advantages.

A ‘flower’ is an intricate organ composed of different morphological units including sepals, petals, androecium, gynoecium, stem and leaves. These units differ functionally with each other which ultimately decide the longevity of flowers. A cut flower may be defined as flower or an inflorescence containing more than one floral unit in the opened or unopened state which is harvested and marketed for ornamental purposes. Cut flowers in general are highly perishable commodities and highly vulnerable to huge post harvest losses. Once severed from the plant, they are deprived of their natural sources of water and nutrients and they wilt rapidly. It is claimed that 70% of the potential lasting quality of cut flowers is pre-determined at harvest. While post harvest factors influence 30% of the effects nearly 20-80% of the cut flowers are lost due to improper post harvest handling (Salunkhe et al., 1990).

Orchids belong to family Orchidaceae, which is the most highly evolved among monocotyledons with over 800 genera and 35,000 species and over 74,400 natural and manmade registered hybrids. Orchid is the first horticultural plant cloned by tissue culture methods on a commercial scale (Goh, 1990). Rapid multiplication using tissue culture techniques is an important strategy for preserving the valuable orchid wealth in India. Vegetative propagation through division of rhizomes and separation of offshoots and keikis is very slow. Both these problems can now be successfully alleviated through micropropagation. The technique has revolutionized the orchid industry and now it is possible to multiply unlimited number of desirable clones. Rotor (1949) was the first to have employed tissue culture techniques to multiply Phalaenopsis, and since then micropropagation potential of a variety of monopodial taxa has been successfully tested.

Seed is a vital input for successful flower production and it is considered as the starting material for most bedding plants and many of the cut flowers produced. The production of bedding plants and cut flowers is both capital and labour intensive. In order to optimize production efficiency and maximize profit, it is important for growers to use high quality seeds. Production of seeds of annual flowers has immense scope as an area of diversification in floribusiness. The flower seed industry is international, operating in many countries of the world. Large quantities of flower seeds are required both by developed and developing countries for adding to the beauty of private and large gardens and also for cut flower production. Worldwide, nurseries engaged in production of seeds of seasonal flowers have a booming business. The great diversity of flower seed crops is a fascinating facet of the world seed industry and they are of high value and low volume in contrast to the high volume and low value seeds of cereal seed crops.

Indian floriculture industry is shifting from traditional flowers to cut flowers for export purpose. The liberalized economy has given an impetus to Indian entrepreneurs for establishing export oriented units (EOUs) under controlled climatic conditions.

The wide variation in the agro climatic conditions in India permit us to grow various types of tropical and subtropical plants and flowers. Though such plants grow successfully without cover, they fail to meet the export requirements of being seldom blemish free. High quality ornamental plants meant for export should be scientifically grown only in plastic, glass or fiberglass greenhouses, or at least under partial cover. Though initial investment is high in protected cultivation, the products in them will obtain far more attractive prices.

Quality is an increasingly important factor in the production and marketing of biological products. Consumers are becoming more discerning as their affluence increases, and would be suppliers of products must meet these demands if they are to maintain or increase market share. The term ‘quality’ is one of the most defined terms in use in food industry today. Quality may be defined as ‘The totality of features and characteristics of a product that bear on its ability to satisfy a given need’. The first part, ‘The totality of features and characteristics of a product…..’ concerns objective factors related to the product.  The second part, ‘…… to satisfy a given need’, concerns subjective factors related to user or consumer of goods.

Transportation and distribution of fruits and vegetables are important stages   of post-harvest loss. In India,  transportation of perishable commodities is in the most precarious stage. For local market, the produce is brought either by bullock cart or tractor trollies. The long distance transportation is mainly by rails and trucks, which is very costly. The basic reason for preference to road transportation is that it takes short transit period.

Packaging is an integral part of fruit and vegetable processing. It has  major influence on storage life and on marketability of fresh as well as processed products. Packaging fulfills several functions including containment, facilitating transportation, protection of fruit/vegetable from further damage, protection of environment from contents of package (for example, if the contents are dirty), marketing, product advertising, and stock control.

Minimally processed fruits and vegetables are products that have the attributes of convenience and fresh like quality. Their forms vary widely, depending on nature of unprocessed commodity and how it is normally consumed. In many cases, minimally processed product is raw and cells of tissues are alive, but these characteristics are  not regarded as essential. It is important that products have fresh-like character, regardless of   state of cells.  Minimally processed products for both retail and food service applications have increasingly appeared in market place recently.  In coming years, it is commonly perceived that this industry will have unprecedented growth.

Fermentation was known to mankind from time immemorial. But, development of biochemical principles of  fermentation  was originated by  Lavoisier in France in 1789 by way of analysing chemical composition of  sugar and its fermentation products such as ethanol, carbon dioxide and  acetic acid. Many products are produced by fermentation process. In fermentation, controlled action of selected microorganisms is used to alter  texture of foods, preserve foods by production of acids or alcohol or to produce fine flavours and aromas which increase value of raw materials.

Fruit beverages

Fruit beverages are highly refreshing, thirst quenching, appetizing, easily digestible and nutritionally far superior to synthetic drinks. The fruit beverages includes natural and sweetened juices, squash, syrup, cordial, nectar, Ready to Serve (RTS) beverages, fruit juice concentrate and citrus juice barley water. Fruits most commonly used to prepare beverages are oranges, lime, pineapple, grapes, cashew fruit, mango, jack fruit, apple etc. To prepare fruit beverages select fresh, fully ripe, tart, juicy and seasonal fruits.

The technique of preserving fruit by the use of low temperature dates from the eighteenth century with the first use of ice house in 1750. Later in 1800s commercial cold storages have come up for the storage of perishables like meat, dairy and fruit products.  The main change took place in the cold store in recent years has been the introduction of multi temperature chambers with humidity control for specific products. Cold preservation can be either refrigeration or freezing. Household refrigerators usually run at 4-7^ºC. Chilling or cold storage usually uses a slightly lower temperature on the basis of the food to be refrigerated. In freezing a temperature of -18^ºC or below is used. Chilling will preserve perishable foods for days or weeks and freezing will preserve foods for months or even years.

Drying is the oldest known method of preserving food. Drying or dehydration is removal of majority of water contained in fruit or vegetable. Although preservation is the primary reason for dehydration, it also lowers cost of packaging, storing and transportation by reducing both weight and volume of final product. In addition, dried foods add variety to our diets. In the process of drying, sufficient moisture is removed to protect product  from  spoilage. Processing should be done in such a way that food value, natural flavour and characteristic cooking quality of fresh material are retained after drying.

Processing of fruits  and vegetables into various products which could be preserved for a long time and add to value of product using proper cost effective technology will be a viable tool for improving   economic status of  farmer as well as our country. Modern methods of fruit and vegetable preservation are  broadly classified as follows:

Storage is one of the most important aspects of post harvest handling of fruits and vegetables. The main objective of storage is to extend storage life of fruits and vegetables and increase their period of availability. A substantial quantity of fruits go waste in India due to lack of proper storage facilities. Storage of fruits and vegetables is practiced for various reasons. Proper post harvest handling of fresh horticultural produce helps in extending  period of availability of wide range of  fruits and vegetables round the year, prevention of seasonal market gluts, orderly marketing, better return to grower and  preservation of  nutritional qualities. The   long  term  storage  of  fruits  and  vegetables is expensive and requires high level of technical  knowledge of crop. However, an orderly marketing reduces storage period considerably. 

Various systems were developed to take produce from field to consumer and selection of a particular method depends on several factors, including perishability and value of crop.  One method is to harvest the crop and take it to a packhouse for various unit operations like grading, cleaning, post-grading treatments, and packing for transport and marketing. When deciding upon where to locate a packinghouse, access to field and market point, adequate space for vehicles to enter and leave  packinghouse and ease of access to labor will all be considered.
 
In the simplest packinghouse, produce is delivered in picking containers, immediately after harvest, directly to packers.  Packers then sort, grade, size and pack the produce directly into appropriate transport containers. In this case, each worker must be aware of produce defects, grade and size requirements, and packing methods.

Maturity at harvest is the most important determinant of storage life and final fruit quality. Maturity indices are determined for many fruit, vegetable and floral crops. Harvesting crops at proper maturity allows handlers to begin their work with the best possible quality produce. Produce harvested too early may lack flavour and may not ripen properly, while produce harvested too late may be fibrous or over ripe.
 
Almost all fruits reach their best eating quality when allowed to ripen on the tree or plant (exceptions e.g., pears, avocados, and bananas). In general, fruits become sweeter, more colourful, and softer as they mature. A few fruits are usually picked mature but unripe so that they withstand post harvest handling system when shipped long distances.  Most of  currently used maturity evaluation is based on a compromise between those methods that would ensure the best eating quality and those that provide flexibility in transportation and marketing.  Optimum harvesting stage depends upon type of fruit or vegetable and their final use. Such a division is usually based on their classification according to physiology, environmental conditions, ripening bahaviour and nutritional aspect. Some of the classifications, important for their harvesting and storage are briefed in  subsequent sections.

Structure

Structural unit of edible portion of most fruits and vegetables is the parenchyma cells and makes up bulk of cells. A parenchyma cell is rather thin walled and may be polygonal or cubical in shape.  Walls of parenchyma cells in young plants are composed almost entirely of fibrils of cellulose. In parenchyma cells of plants actively metabolising protoplast portion represents only about 5% of total cell volume. This protoplast is rather film like and is pressed against cell wall by large water filled central vacuole.  Protoplast has inner and outer semi permeable membrane layers between which is confined cytoplasm and its nucleus. 

Fruits and vegetables are very important food commodities. India has become the largest producer of fruits and the second largest producer of vegetables. Though the production of fruits and vegetables make us believe in our strength for self-sufficiency, a significant qualitative and quantitative loss occur in the produce from harvest till consumption.  For self sufficiency and also for processing, export and to meet additional requirements, a lot of emphasis need to be given to reduce post harvest losses, besides increasing  production and productivity of horticultural produces. Processing plays an important role in  conservation and effective utilisation of these perishable commodities. However, only less than 2% of total production of fruits and vegetables are processed.  The new industrial policy has placed this sector in the list of high priority areas.

Tissue culture consists of growing plants cells as relatively on organized masses of cells on an agar medium (callus culture) or as a suspension of free cells and small cell masses in a liquid medium (suspension culture). In other words, In plant cell culture, plant tissues and organs are developed in vitro on artificial media, under aseptic and controlled environment. The procedure depends mainly on the concept of totipotentiality of plant cells (Haberlandt, 1902) which refers to the ability of a single cell to express the full genome by cell division.

1. Microscope

The microscope is a precious instrument. There are many small objects or details of objects which cannot be seen by the unaided human eye.
 
A microscope (from Greek: mikrós, means “small” and skopeîn, means “to look”) is an instrument used to see objects that are too small for the naked eye.  In another word microscope is an optical instrument that uses a lens or a combination of lenses to produce magnified images of small objects, especially of objects too small to be seen by the unaided eye.

Electrophoresis is a method used to separate charged particles from one another based on differences in their migration speed. In the course of electrophoresis, two electrodes (typically made of an inert metal, e.g. platinum) are immersed in two separate buffer chambers. Gel electrophoresis is a technique used to separate molecules based on physical characteristics such as size, shape, or isoelectric point. A gel is composed of agarose or polyacrylamide. Agarose is used for separating DNA fragments in size range of 100bp to 20kb. Polyacrylamide is preferred for smaller DNA fragments. Separation is achieved by moving the negatively charged nucleic acid molecules through agarose matrix with an electric field. Rate of migration of DNA molecules is inversely proportional to their molecular weight. Smaller molecules move faster than larger ones. But conformation of the DNA molecule is also an important factor. Conformations of a DNA plasmid that has not been cut with a restriction enzyme will move with different speeds such as: supercoiled plasmid DNA will move fastest followed by linearised DNA, while open circular DNA will move at the slowest pace. To visualise DNA, gels are stained with ethidium bromide which intercalates in DNA and fluorescse under UV.

Blotting is the procedure through which nucleic acids or proteins are immobilized onto a solid support generally nylon or nitrocellulose membranes. Blotting of nucleic acid is the central technique for labeling and hybridization on membranes have formed the basis for a range of experimental techniques involving understanding of gene expression, organization, etc. More recently the identification of abnormal genes in genomic DNA has become increasingly important in clinical research and genetic counseling. We can identify inherited disease, infectious agent present in the sample by using blotting technique. It is also used to mapping restriction sites in single copy gene.

Experiment - 1
 
Aim: Molecular analysis of putative transformed plants by Polymerase Chain Reaction

The expression of transgenes are not identified at that time but it can be achieved through DNA analysis of that plant. The presence of transgene are generally identified of PCR-based detection followed by gel electrophoresis and comparison with standard samples. The main achievement of PCR-based detection is that it is very sensitive. The Polymerase Chain Reaction (PCR) provides a rapid and sensitive method to amplify a specific gene sequence. 

Experiment - 1 
Aim: Mobilization of recombinant Ti plasmid (with gene of interest) from  
(E. coli) to an Agrobacterium tumefaciens strain. 

Principle: Due to ease of cloning and harvesting plasmids, E. coli is most popular for maintenance of plant transformation vectors. Consequently, the plant transformation vector with cloned gene of interest is mobilized to recipient Agrobacterium strain harbouring vir plasmid. Plasmid are closed, circular DNA molecules that are able for autonomous replication with a host cell. 

Experiment- 1

Aim: Direct DNA delivery to Plant by Particle Bombardment
 
In direct gene transfer method, the foreign gene of interest is delivered into the host plant cell without the help of vector. Klein and Coworkers (1987) evolved a procedure through which the delivery of DNA into cells of intact plant organs or cultured cells is done by a process called Projectile Bombardment. The microprojection (Small and high density particles) are accelerated to high velocity by particle gun apperatus. These particles with very high kinetic energy penetrate the cells and membranes and transmit foreign desired DNA inside of the bombardment cells.

Experiment - 1

Aim: Isolation of plant genomic DNA through modified CTAB method

Principle: Genomic DNA is extracted from plant material requires cell lysis, inactivation of cellular nucleases and separation of the desired genomic DNA from cellular debris. Ideal lysis method is rigorous enough to disrupt the complex starting material (plant tissue), yet gentle enough to preserve the target nucleic acid. The cetyltrimethylammonium bromide (CTAB) procedure is sufficient for the extraction and purification of DNA from plants and plant derived food stuff.  This is particularly suitable for the elimination of polysaccharides and polyphenolic compounds otherwise affecting the DNA purity and hence quality.

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:

A. Somatic Embryogenesis
 
In plant tissue culture, the developmental pathway of various well organised, small embryoids resembling the zygotic embryos form the embryogenic potential somatic cell of callus tissue or cells of suspension cultures is known as somatic embryogenesis. The capability of somatic cell of a culture to produce embryoids is known as embryogenic potential.

Embryoid: Embryoid is a small, well organised structure comparable to the sexual embryo, which is produced in tissue culture of dividing embryogenic potential somatic cells.

The ultimate success of commercial propagation depends on the capacity to transfer plants out of culture on a huge range, at low cost and with high survival rates. The plants multiplied in vitro are exposed to a unique set of growth conditions (high levels of inorganic and organic nutrients, growth regulators, sucrose as carbon source, high humidity, low light, poor gaseous exchange) which may support rapid growth and multiplication but also induce structural and physiological abnormalities in the plants, rendering them unfit for survival under in vivo conditions. Poor control of water loss and heterotrophic mode of nutrition are main cause of deficient growth of in vitro plants.  Hence, gradual acclimatization is necessary for these plants to survive transition from culture to the greenhouse or field. During acclimatization the in vitro formed leaves do not recover but the plant develops normal leaves and functional roots. Once roots are well formed the plants are ready to be transferred into soil.The procedure of acclimatization of regenerated plantlets are: 

A. Anther and Pollen Culture (Production of Haploid Plants)

Haploid plants possess a single set of chromosomes (gametophytic no of chromosomes i.e. n) in the sporophyte in contrast to diploids which contain two sets of chromosomes (2n). The existence of haploid plants was reported by Bergner (1921) in Datura stramonium. Guha and Maheswari (1964) reported the direct development of haploid embryos and plantlets from microspores of Datura inoxia by the cultures of excised anthers. After this, haploid plants have been produced via anther culture in more than 170 species. The anther culture technique is useful in haploid production.

Experiment - 1
 
Aim: Micropropagation of Tobacco plant by leaf disc culture

Principle: The totipotency of the plant cells and tissues form the basis for in vitro cloning i.e., generation or multiplication of genetically identical plants in in vitro culture. The ability to propagate new plants from a cells or tissues of parent plant has many interesting possibilities.

Micropropagation /Clonal propagation

Micropropagation or clonal propagation is the growing of plants from meristematic tissue or somatic cells of superior plants on nutrient suitable media under controlled aseptic physical conditions. Sexually propagated plants (through generation of seeds) demonstrate a high amount of heterogeneity since their seed progenies are not true to type whereas asexual reproduction (by multiplication of vegetative parts) gives rise to genetically identical copies of parent plant. Thus, it permits perpetuation of the parental characters of the cultivars among the plants resulting from micropropagation. Micropropagation proves useful for propagation of: 

Modes of Culture 

Callus is a mass of undifferentiated plant tissues formed from plant cells or tissue cuttings when grown in culture. Tissues and cells of plant cultured in a liquid medium aerated by agitation grow as suspension of single cells and cell clumps. For growth, the cells require to divide, whereas, the cells breaking up from explant are mature, nondividing. Hence, the differentiated tissue undergoes modifications to become meristematic. This phenomenon of a mature cell reverting back to meristematic state to form undifferentiated callus tissue is called dedifferentiation.

Explant

The tissue obtained from plant to be cultured is known as Explant. It may include the parts of shoots, leaves, stems, roots, flowers and callus.

Maintenance of Aseptic Environment

All culture vessels, media and instruments used in handling tissues as well as the explants must be sterilized. The importance is to keep the air surface and floor free of dust. All operations are carried out in laminar air-flow, a sterile cabinet.In general, the methods of elimination of these sources of infection can be grouped under different categories of sterilization procedures: 

Sterilization Techniques

Sterilization: All the materials, e.g., vessels, instruments, medium, explants, etc., used in culture work must be freed from microbes. This can be achieved by one of the following approaches:

One of the most essential factors governing the growth and morphogenesis of plant tissues in culture is the composition of the culture medium. The basic nutrient requirements of cultured plant cells are very similar to those of whole plants. The basic nutritional requirements of cultured plant cells as well as plants are very similar. However, the nutritional composition varies according to the cells, tissues, organs and protoplasts and also with respect to particular plant species.  The appropriate composition of the medium largely determines the success of the culture. A wide variety of salt mixtures  have been reported in various media. A nutrient medium is defined by its mineral salt composition, carbon source, vitamins, plant growth regulators (PGR) and other organic supplements. When referring to a particular medium, the intention is to identify only the salt composition unless otherwise specified. Any number and concentration of amino acids, vitamins, growth regulators and organic supplements can be added in an infinite variety of compositions to a given salt composition in order to achieve the desired product.

Common rules for fine laboratory techniques call for:

    ·    A laboratory should have a record and a complete up to-date record of all the equipments and their operating manual.
    ·    A laboratory should have a record and detailed up to-date record of all the chemicals including the name of manufacturer with their     grade and arranged alphabetically in specific area
    ·    Strong acid and bases in safe area.
    ·    Chloroform, alcohol which are volatile or toxic must be stored in fume hood.

A tissue culture laboratory can be placed in any geographical area. The internal controlled environmental conditions permit isolation with a minimum of external influence. To decide where to build the tissue culture laboratory, the following factors must be taken into consideration:

Year    Contributor    Description
1756    Duharmel du Monceau H.L.    Discovered callus formation in decorticated elm tree. 
1839    Schwann, T.H.    Proposed the view that each living cell of a multicellular organism would be capable of developing independently if provided with proper external conditions.
1853    Trecul, A.    Performed experiment on callus formation by decorticated trees such as Robinia, Pawlonia and Ulmus.

Practical have a significant role in the study of any theoretical subject. Whatever a student learns in theory, he verifies it by actual doing with his own hands.  Thus, these reduce any doubts and misbelieve from his mind. These verifications by actually doing the things are performed in the laboratories.  A laboratory is a place with the basic and essential equipments and adequate facilities for students and teachers to perform and observe experiments.  Plants will continue to provide novel products as well as chemical models for new drugs in the coming centuries.  The arrival of chemical analysis and the characterization of molecular structures have helped in precisely identifying these plants and correlating them with their activity under controlled experimentation.

Collection of faecal samples: To diagnose gastro-intestinal parasites of ruminants or other animals, the parasites or their eggs/larvae must be recovered from the digestive tract of animal or human or from the faecal/stool material.
 
The faecal samples for parasitological examination should be collected from the rectum of animals. If rectum samples cannot be obtained, fresh faecal samples may be collected from the pastures. Several samples should be collected and immediately dispatched to the diagnostic laboratory in suitable containers such as:

Small ruminants is a composite term used for sheep and goats. Throughout the developing countries, small ruminants make a very valuable contribution, especially to the poor in the rural areas. These contributions range from precious animal proteins (meat and milk) to fibre and skins, draught power in the highlands, food security and stable households. By and large, the importance and extent of the contributions are inadequately understood as a consequence of which these valuable genetic resources continue to be generally neglected. Research and development investments to improve the relatively low level of contribution do not match their potential importance, the contribution to nutritional security and livelihoods of the poor in rural areas. Species like goat and sheep are of short-generation interval, have a high prolificacy rate and require less land, investment and operational expenses and are better suited to the resource endowment of the poor.