Flying seeds, floating seeds, or fruits are carried far by wind or water. Some plants have exploding seed pods that fling seeds into the air. Others are eaten by animals and pass through the other end, unharmed. Plants have three basic parts. They are the roots, stems, and leaves. The roots anchor the plants to its substrate what it is on and absorb water and minerals.
The stems hold the plant up. The leaves have to do a lot with the plant making food. Plants come in many varieties. Some plants are as large as Giant Sequoias, while others are as small as Rootless Duckweed.
Plants can live from months to centuries. Some plants are climbers. They are called epiphytes. They reach out for objects to climb on. They like to climb on poles, fences, statues, and other plants mainly trees. Some plants eat insects. These plants have moving parts, sticky substances, or pools of fluid to help them catch food. When these plants live on trees, they do not harm the trees. Some plants that live on other plants do harm the plants they are living on.
These plants are called parasitic plants. These plants do not need sunlight, one of the basic elements, because they steal their food from other plants. These plants are usually hidden from sight. Plants have adapted to living in many climates, including underwater, in very cold places, and in very dry places.
We have cultivated some plants to fit our food needs by making them bigger and more plentiful. How would you rate this essay? Help other users to find the good and worthy free term papers and trash the bad ones. Like this term paper? The platypus, apparently, is a surprisingly deep sleeper. The material may be surface sterilized with saturated chlorine water and then thoroughly washed with sterilized distilled water and to remove all traces of chlorine. If the material is fairly hard, as are some fruits and seeds, it may be surface sterilized by rinsing in alcohol.
Proper aeration of the cultured tissue is also an important aspect of culture technique. Here, two legs remain medium. This is the capacity of nature cells showing that when freed from the plant body, they had the ability to reorganize themselves into the new individuals. Steward and his co-workers showed this phenomenon in the carrot cultures. Here the small pieces of mature carrot root were grown in a liquid medium supplemented with coconut milk, in special containers.
These cultures were shaken generally which freed all the cell clusters into the medium Some developed into rooting clumps When these were transferred to the tubes containing a semi-solid medium, they gave rise to whole plant that flowered and set seeds. On the basis of these experiments, it can be inferred that, at least theoretically, every living plant cell, irrespective of its age and location is totipotent.
However, this phenomenon cannot be compared with the mode of the development of the zygote, wherein the divisions give predictable manner. But in case of cultured cells, the isolated single cells of tobacco divide, quite irregularly to form a mass from which roots and shoot buds differentiate eventually.
However, Guha and Maheswari, while culturing mature anthers of Datura innoxia with an aim of understanding the physiology of meiosis, accidentally noticed that on basal nutrient medium containing kinetin, coconut milk, or grape juice numerous embryo-like structure appeared from the inside of anthers, which eventually developed into plants.
Later on these workers confirmed the origin of the embryoids from pollen gram. As expected, the plantlets of pollen-origin were haploid. During the Past 30 years, the technique has been successfully extended to about 20 species including some economic plants, e. It is also utilized for producing viable plants from crosses which normally fail due to the death of immature embryos, e. Here, some coconuts develop soft, solid, fatty tissue in Place of the liquid endosperm.
These are rare and very expensive, served only at special banquets in the Philippines. Under normal conditions the coconut seeds fail to germinate. Using the technique of in vitro culture of excised embryos, the scientists have succeeded in plantlets from makapuno nuts. It is possible to raise complete hybrid plants through embryo culture.
This method has been profitably used for many interspecific crosses. There are a variety of forms of seed plants, such as trees, herbs grass, which exhibit the basic morphological units, i. They are capable of division and growth. For this reason, the explants from healthy and young part of the plant are used. Presence of parenchyma is first consideration in a particular species, parenchyma from stems, rhizomes, tubers; root is easily accessible and will generally respond quickly to culture conditions in vitro.
In nature, callus develops by infection of microorganisms from wounds due to stimulation by endogenous growth hormones, the auxins and cytokinins.
However, it has been artificially developed by adopting tissue culture techniques. A callus is an amorphous mass of loosely arranged thin walled parenchyma cells developing from proliferating cells of the parent tissue. The unique feature of callus is that the abnormal growth has logical potential to develop normal root, shoots and embryoids ultimately forming a plant.
In callus culture, cell division in the explant forms a callus, an un-organised mass of cells. It is maintained on a medium gelled usually with agar. The medium ordinarily contains the auxin 2, 4 — D 2, 4 — dichlorophenoxyacetic acid , and often a cytokinin BAP benzylaminopurine.
When an explants is placed on such a medium, many of the cells become meristematic and begin to divide. In about 2 to 3 weeks, a callus mass is obtained. A suspension culture consists of single cells and small groups of cells suspended in liquid medium.
Cell suspension is prepared by transferring a fragment of callus about mg. The medium ordinarily contains the auxin 2, 4 — D. Suspension cultures must be constantly agitated at — rpm revolutions per minute. Suspension cultures grow much faster than callus cultures. It is difficult to have suspension of single cell. However, the suspension includes single cell, cell aggregates varied number of cells , residual inoculum and dead cells. King has described that a good suspension consists of a high proportion of single cells than small cluster of cells.
After some time, the under-mentioned three things happen in all types of plant tissue cultures: Hence, if tissue cultures were kept in the same culture vessel, they will die in due course of time. This process is called sub-culturing. Precaution is taken that during sub-culture, only a part of the culture from a vessel is transferred into the new culture vessel. The callus and suspension cultures can be used to achieve cell biomass production which may be used for biochemical isolation.
Plants cells cultured in vitro can ultimately give rise to complete plants. Potentiality of a plant cell to regenerate the entire organism or plant is called totipotency. This potentiality has been exploited through the culture of protoplasts, cells, tissues and organs in vitro. Gottlieb Haberlandt in , for the first time started the technique of plant tissue culture, when he attempted to culture isolated single cells from leaf mesophyll to determine their totipotency. Regeneration describes the development of an organised structure, such as root, shoot or somatic embryo from cultured cells.
In cultured materials it has been possible to study such process as differentiation of a parenchyma cell into tracheid i. Besides the study of fundamental process of differentiation, the capacity of cell to form organs and embryos can be exploited to regenerate plantlets for clonal propagation. The process by which cells and tissues are forced to undergo changes which lead to the production of a structure, known as shoot or root primordium. This system is commonly produced in callus cultures.
The earliest reports on controlled organogenesis in vitro were by White who obtained shoots on callus of a tobacco hybrid and by Nobecourt , who observed root formation in carrot callus.
The earliest report on controlled somatic embryogenesis in vitro was with carrot reported simultaneously in by Reinert and Steward see Fig 9. The process occurs naturally in a wide range of species from both reproductive and somatic tissues. Somatic embryos can be formed on callus, in cell suspensions and protoplasts cultures, or directly from cells of organised structures, such as stem segments or zygotic embryo.
There are several advantages of plantlet regeneration through plant biotechnological methods using organogenesis or embryogenesis, in comparison to conventional methods of propagation.
The advantages include the efficiency of process, i. Till now about species from angiosperms and gymnosperms have been reported to produce somatic embryos in culture. Shoot regeneration is promoted by a cytokinin, such as BAP benzylaminopurine.
While root regeneration is promoted by an auxin, such as NAA naphthalene acetic acid. Thus, shoot and root regenerations are generally controlled by auxin- cytokinin balance. Usually, an excess of auxin promotes root generation, and that of cytokinin promotes shoot generation.
Callus cultures are first kept on a BAP cytokinin containing medium. After sometime shoots regenerate from callus cells. When the shoots become cm long, they are excised and transferred to an auxin-containing medium.
After sometime, roots regenerate from the lower ends of these shoots to give rise to complete plantlets. Plant cells are totipotent and can produce complete new plants under favourable conditions of nutrients and plant growth regulators.
Steward and Reneirt, almost simultaneously reported for the first time, somatic embryo formation in carrot cell suspension cultures in These somatic embryos were similar to zygotic embryos in development and structure. A somatic embryo develops from a somatic cell. The pattern of development of a somatic embryo is similar to that of a zygotic embryo. Somatic embryo regeneration is induced usually by a relatively high concentration of an auxin like 2, 4-D 2, 4-dichorophenoxyacetic acid.
The young embryos develop into mature embryos either in the same medium or on another medium. Mature somatic embryos germinate to yield complete plantlets. During somatic embryo generation in cell suspension cultures, embryos of different sizes are produced. For any experimental or micro-propagation method, embryos of uniform size are required. This can be achieved by sieving or fractionation of suspension with appropriate sieve size.
Somatic embryo regeneration is a versatile technique for micro-propagation of plant species. A large number of herbaceous dicots and monocots have been regenerated through somatic embryogenesis. Plantlets are produced through rooting of isolated shoots or germination of somatic embryos.
Now, the plantlets can be removed from culture vessels and established in the field. This stage is concerned with transfer of plantlets in pots, their hardening and establishment in soil. Hardening of plants imparts some tolerance to moisture stress and plants become autotrophic from heterotrophic condition. During hardening, plantlets are kept under a reduced light and high humidity for a suitable period of time. Hardening procedures make the plantlets capable of tolerating the relatively harsher environments outside the culture vessels.
Hardened plants are then transferred to glass or poly-houses with normal environmental conditions. Generally the poly-houses are erected by mounting polythene or polycarbonate sheets on metal frame support. Now, plants are irrigated frequently and their growth and variation monitored regularly.
Plants are generally transferred to fields, e. In India, there are now many commercial companies which produce millions of plantlets through micro-propagation.
Large glass houses and green houses are essential components of micro-propagation industry. Hardening and acclimatization of delicate in vitro raised plantlets is carried out in these glass houses. Now-a-days chambers made of polycarbonate and polypropylene sheets are used for creating large working place.
These houses are fitted with mist and fog generating units with cyclic auto-regulation. Light is provided through proper light sources. Tissue culture has been successfully employed for the multiplication of orchids and many other ornamental plants. In the developed countries tissue culture is a routine method of multiplication while in developing countries, such as India, the techniques are largely used for producing plants for export markets.
With tree species, the technique of tissue culture remained restricted for many years to the laboratory stage and has generally invited only academic interest.
However, practical applications of plant tissue culture are mainly based on the ability of plant cells to give rise to complete plantlets. The use of plant cells to generate useful products is called plant biotechnology. In most of its activities, the useful product is plantlet that, in many cases may have been genetically altered.
Clonal propagation by vegetative methods is a practice followed since man started cultivation of plants. The main objective of clonal propagation has been to reproduce plants of selected desirable qualities uniformly and in bulk. The traditional propagation methods, require long duration, whereas tissue culture helps in rapid plant multiplication.
A clone is a group of individuals or cells derived from a single parent individual or cell through an asexual reproduction. All the cells in callus or suspension culture are derived from a single explants by mitotic division.
Hence, all plantlets regenerated from a callus or suspension culture generally have the same genotype and constitute a clone. Selected examples of clonal multiplication of trees and horticulture plants are as follows: Oil palm, citrus peach, prunus, poplar, etc.
Improved cultivars developed by biotechnological methods are then clonally multiplied to replace inferior cultivated varieties, e. In vitro cell and tissue cultures of plant give rise to genetic variation spontaneously. While spontaneous variation is not desired during propagule multiplication, it has been useful in providing some genetic variants among crop species.
The observed frequencies of such somaclonal variants vary widely and are probably related to both time and culture. Several point mutations have been observed; the majority of analysed spontaneous genetic variants from somatic cultures appear to have resulted from induction of aneuploidy, loss of interchanges or intra-chromosomal segment duplication, deletions or structural arrangements. Spontaneous or mutagen induced genetic variation in somatic cell culture coupled with in vitro selection techniques have been effective in isolating desired novel genetic variants with cellular level expression while in heterozygous condition.
The somaclonal variation has been used to develop several useful varieties of crop plants. A gene that is transferred into an organism by genetic engineering is called transgene. An organism that contains and expresses a transgene is called transgenic organism.
The plants, in which a functional foreign gene has been incorporated by any biotechnological methods that generally not present in plant, are called transgenic plants. However, a number of transgenic plants carrying genes for traits of economic importance have either been released for commercial cultivation or are under field trials. However, transgenes can be introduced into individual plant cells.
The cells containing and expressing transgenes can be easily selected in vitro. Ultimately, plantlets can be regenerated from these cells. These plantlets yield highly valuable transgenic plants. Some of the commercially grown transgenic crop plants in developed countries are: So far more than 60 transgenic dicot plants including herbs, shrubs and trees, and several monocots, such as maize, oat, rice, wheat, etc. In future the number of these crops certainly will go up.
These transgenic plants contain certain selected traits such as herbicide resistance, insect resistance, virus resistance, seed storage protein, modified ripening, modified seed oil, agglutinin, etc. The meristem is a dome of actively dividing cells about 0. Shoots of all flowering plants grow by virtue of their apical meristems. The totipotency of the plant cells forms the basis of meristem culture.
Here, one can use an explant containing pre-existing shoot meristems, and produce shoots from them. Such, cultures are known as meristem culture. The explants generally used in meristem culture are shoot tips or nodal segments.
These explants may be cultured on a medium containing a cytokinin, usually BAP benzylaminopurine. Cytokinins promote axillary branching by overcoming apical dominance. Hence, they support multiple shoot development from each explant.
When axillary branching takes place, individual shoots are cultured, whereas when axillary branching does not take place, the single shoot is cut into nodal segments, which are then cultured. Shoots of cm are excised and rooted on a suitable medium.
The in vitro culture of meristem and shoot tip involves several phases such as initiation of culture and establishment of explant, growth and differentiation, proliferation of shoots and finally plantlet fomation by rooting of shoots. Meristem cultures are used for rapid clonal multiplication.
Development of virus free plants is one of the most significant application of meristem culture. Generally this technique has applications in diverse areas such as clonal multiplication of vegetatively propagated crop plants, virus elimination and germplasm preservation.
Interspecific crosses may fail due to several reasons, but when the development of embryo is arrested owing to the degeneration of the endosperm, or when the embryo aborts at an early stage of development, embryo culture is the only technique to recover hybrid plants.
It is being used extensively in the extraction of haploid barley Hordeum vulgare from the crosses H. Embryo culture is also a routine technique employed in orchid propagation and inbreeding of those species that show dormancy. Das and Burman developed the method of regeneration of tea shoots from embryo callus.
Excision of young embryos from developing seeds and their cultivation on a nutrient medium is called embryo culture.
The plant that grew the most out of the three plants was the plant in the sun which grew 10 cm. The plants under the fluorescent light bulbs grew 1cm from the 1st week and grew cm the next week. Overall the fluorescent plant grew cm in the three weeks.
The Journal of Plant Research is an international publication that gathers and disseminates fundamental knowledge in all areas of plant sciences. Coverage extends to every corner of the field, including such topics as evolutionary biology, phylogeography, phylogeny, taxonomy, genetics, ecology.
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Research Paper # 1. Meaning of Plant Tissue Culture: Plant tissue culture is the maintenance and growth of plant cells, tissues and organs on a suitable culture medium in vitro, e.g., in a test tube or any other suitable vessel. the holocaust research paper expression homework effects on students youtube political science research paper introduction conclusion decalogue film analysis essay essay med383.tk essay on unemployment with headings essay about biomagnification video I'M LIKE FIFTY FUCKING WORDS OFF THE ~10% WORD LIMIT OF THIS FUCKING ESSAY FUCK infatuation or.