A lichen is a composite organism that arises from algae or cyanobacteria living among . The nonreproductive tissues, or vegetative body parts, is called the thallus. Lichens are grouped by thallus Retrieved 10 October ^ Introduction to Lichens – An Alliance between Kingdoms. .. Botanica Pacifica. 4 (2): 19– Introduction to Crystal Chemistry. Cambridge Univ. Tratado de Botanica Sistematica. Labor, Barcelona Precis de Biologie Vegetale. Masson Ed., Paris . 1 Introduction to the Introduction. Plants, Botany, and Introduction to Cells. . A Methods of Taxonomy and Diagnostics.
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Botanyalso called plant science splant biology or phytologyis the science of plant life and a branch of biology. A botanistplant scientist or phytologist is a scientist who specialises in this field. Nowadays, botanists in the strict sense study approximatelyspecies of land plants of which somespecies are vascular plants including caspecies of flowering plants and ca 20, are bryophytes.
Botany originated in prehistory as herbalism with the efforts of early humans to identify — and later cultivate — edible, medicinal and poisonous plants, making it one of the oldest branches tsxonomia science. Medieval physic gardensoften attached to monasteriescontained plants of medical importance. They were forerunners of the first botanical gardens attached to universitiesfounded from the s onwards.
One of the earliest was the Padua botanical garden. These gardens facilitated the academic study of plants. Efforts to catalogue and describe their collections were the beginnings of plant taxonomyand led in to the binomial system of Carl Linnaeus that remains in use to this day. In the 19th and 20th centuries, new techniques were developed for the study of plants, including methods of optical microscopy and live cell imagingelectron microscopyanalysis of chromosome numberplant chemistry and the structure and function of enzymes and other proteins.
In the last two decades of the 20th century, botanists exploited the techniques of molecular genetic analysisincluding genomics and proteomics and DNA sequences to classify plants more accurately. Modern botany is a broad, multidisciplinary subject with inputs from most other areas of science and technology.
Research topics include the study of plant structuregrowth and differentiation, reproductionbiochemistry and primary metabolismchemical productsdevelopmentdiseasesevolutionary relationshipssystematicsand plant taxonomy. Dominant themes in 21st century plant science are molecular genetics and epigeneticswhich are the mechanisms and control of gene expression during differentiation of plant cells and tissues.
Botanical research has diverse applications in providing staple foodsmaterials such as timberoilrubber, fibre and drugs, in modern horticultureagriculture and forestryplant propagationbreeding and genetic modificationin the synthesis of chemicals and raw materials for construction and energy production, in environmental managementand the maintenance of biodiversity.
Botany originated as herbalismthe study and use of plants for their medicinal properties. Examples of early botanical works have been found in ancient texts from India dating back to before BC,   in archaic Avestan writings, and in works from China before it was unified in BC.
M. A. COLASANTE MODULO BOTANICA SISTEMATICA
Modern botany traces its roots back to Ancient Greece specifically to Theophrastus c. Another work from Ancient Greece that made an early impact on botany is De Materia Medicaa five-volume encyclopedia about herbal medicine written in the middle of taxonomiq first century by Greek physician and pharmacologist Pedanius Dioscorides. De Materia Medica was widely read for more than 1, years.
In the midth century, ” botanical gardens ” were founded in a number of Italian universities — the Intrkduo botanical garden in is usually considered to be the first which is still in its original location. These gardens continued the practical value of earlier “physic gardens”, often associated with monasteries, in which plants were cultivated for medical use. They supported the growth of botany as an academic subject.
Lectures were given about the plants grown in the gardens and their medical uses demonstrated. Botanical gardens came much later to northern Europe; the first in England was the University of Oxford Botanic Garden in Throughout this period, botany remained taxonomix subordinate to medicine.
German physician Leonhart Fuchs — was one of “the three German fathers of botany”, along with theologian Otto Brunfels — and physician Hieronymus Bock — also called Hieronymus Tragus. Bock created his own system of plant classification. Physician Valerius Cordus — authored a botanically and pharmacologically important herbal Historia Plantarum in and a pharmacopoeia of lasting importance, the Dispensatorium in Naturalist Ulisse Aldrovandi — was considered the father of natural historywhich included the study of plants.
Inusing an early microscope, Polymath Robert Hooke discovered cellsa term he coined, in corkand a short time later in living plant tissue.
During the 18th century, systems of plant identification were developed comparable to introoduo keyswhere unidentified plants are placed into taxonomic groups e. The choice and sequence of the characters may be artificial in keys designed purely for identification diagnostic keys or more closely related to the natural or taxonoma order of the taxa in synoptic keys. This established a standardised binomial or two-part naming scheme where the first name represented the genus and the second identified the species within the genus.
The 24th group, Cryptogamiaincluded all plants bbotnica concealed reproductive parts, mosses, liverworts, ferns, algae and fungi. Increasing knowledge of plant anatomymorphology and life cycles led to the realisation that there were more natural affinities between plants than the artificial sexual system of Linnaeus. Adansonde Jussieuand Candolle all proposed various alternative natural systems of classification that grouped plants using a wider range of shared characters and were widely followed.
The Candollean system reflected his faxonomia of the progression of morphological complexity and the later classification by Bentham and Hookerwhich was influential until the midth century, was influenced by Candolle’s approach.
Darwin ‘s publication of the Origin of Species in and his concept of common descent required modifications to the Candollean system to reflect evolutionary relationships as distinct from mere morphological similarity.
M. A. COLASANTE MODULO BOTANICA SISTEMATICA
Building upon the gene-chromosome theory of heredity that originated with Gregor Mendel —August Weismann — proved that inheritance only takes place through gametes. No other cells can pass on inherited characters. Her books Plant Anatomy and Anatomy of Seed Plants have been key plant structural biology texts for more than half a century.
The discipline of plant ecology was pioneered in the late 19th century by botanists such as Eugenius Warmingwho produced the hypothesis that plants form communitiesand his mentor and successor Christen C.
The concept that the composition of plant communities such as temperate broadleaf forest changes by a process of ecological succession was developed by Henry Chandler CowlesArthur Tansley and Frederic Clements. Clements is credited with the idea of climax vegetation as the most complex vegetation that an environment can support and Tansley introduced the concept of ecosystems to biology. Particularly since the mids there have been advances in understanding of the physics of plant physiological processes such as transpiration the transport of water within plant tissuesthe temperature dependence of rates of water evaporation from the leaf surface and the molecular diffusion of water vapour and carbon dioxide through stomatal apertures.
These developments, coupled with new methods for measuring the size of stomatal apertures, and the rate of photosynthesis have enabled precise description of the rates of gas exchange between plants and the atmosphere. Thimann in enabled regulation of plant growth by externally applied chemicals. Frederick Campion Steward pioneered techniques of micropropagation and plant tissue culture controlled by plant hormones.
With the rise of the related molecular-scale biological approaches of molecular biologygenomicsproteomics and metabolomicsthe relationship between the plant genome and most aspects of the biochemistry, physiology, morphology and behaviour of plants can be subjected to detailed experimental analysis.
These technologies enable the biotechnological use of whole plants or plant cell cultures grown in bioreactors to synthesise pesticidesantibiotics or other pharmaceuticalsas well as the practical application of genetically modified crops designed for traits such as improved yield. Modern morphology recognises a continuum between the major morphological categories of root, stem caulomeleaf phyllome and trichome.
Molecular analysis of DNA sequences from most families of flowering plants enabled the Angiosperm Phylogeny Group to publish in a phylogeny of flowering plants, answering many of the questions about relationships among angiosperm families and species.
The study of plants is vital because they underpin almost all animal life on Earth by generating a large proportion of the oxygen and food that provide humans and other organisms with aerobic respiration with the chemical energy they need to exist. Plants, algae and cyanobacteria are the major groups of organisms that carry out photosynthesisa process that uses the energy of sunlight to convert water and carbon dioxide  into sugars that can be used both as a source of chemical energy and of organic molecules that are used in the structural components of cells.
In addition, they are influential in the global carbon and water cycles and plant roots bind and stabilise soils, preventing soil erosion.
Philosophia Botanica – Wikipedia
Historically, all living things were classified as either animals or plants  and botany covered the study of all organisms inroduo considered animals. At each of these levels, a botanist may be concerned with the classification taxonomyphylogeny and evolutionstructure anatomy and morphologyor function physiology of plant life.
The strictest definition of “plant” includes only the “land plants” or embryophyteswhich include seed plants gymnosperms, including the pinesand flowering plants and the free-sporing cryptogams including fernsclubmossesliverwortshornworts and mosses.
Embryophytes are multicellular eukaryotes descended from an ancestor that obtained its energy from sunlight by photosynthesis. They introdou life cycles with alternating haploid and diploid phases. The sexual haploid phase of embryophytes, known as the gametophytenurtures the developing diploid embryo sporophyte within its tissues for at least part of its life,  even in the seed plants, where the gametophyte itself is nurtured by its parent sporophyte.
However, attention is still given to these groups by botanists, and fungi including lichens and photosynthetic protists are usually covered in introductory botany courses. Palaeobotanists study ancient plants in the fossil record taxoomia provide information about the evolutionary history of plants. Cyanobacteriathe first oxygen-releasing photosynthetic organisms on Earth, are thought to have given taxknomia to the ancestor of plants by entering into an endosymbiotic relationship with an early eukaryote, ultimately becoming the chloroplasts in plant cells.
The new photosynthetic plants along with their algal relatives accelerated the rise in atmospheric oxygen started by the cyanobacteriachanging the ancient oxygen-free, reducingatmosphere to one in which free oxygen has been abundant for more than 2 billion vegtal.
Among the important botanical questions of the 21st century are the role of plants as primary producers in the global cycling of life’s basic ingredients: Virtually all staple foods come either directly from primary production by plants, or indirectly from animals that eat them.
This is what ecologists call the first trophic level. Botanists study how plants produce food and how to increase yields, for example through plant breedingmaking their work important to humanity’s ability to feed the world and provide food security for future generations. When applied to the investigation of historical plant—people relationships ethnobotany may be referred to as archaeobotany or palaeoethnobotany.
Plant biochemistry is the study of the chemical processes used by plants. Some of these processes are used in their primary metabolism like the photosynthetic Calvin cycle and crassulacean acid metabolism. Plants and various other groups of photosynthetic eukaryotes collectively known as ” algae ” have unique organelles known as chloroplasts.
Chloroplasts are thought to be descended from cyanobacteria that formed endosymbiotic relationships with ancient plant and algal ancestors. Taxonommia and cyanobacteria contain the blue-green pigment chlorophyll a. The energy in the red and blue light that these pigments absorb is used by chloroplasts to make energy-rich carbon compounds from carbon dioxide and water by oxygenic photosynthesisa process that generates molecular oxygen O 2 as a by-product.
The light energy captured by chlorophyll a is initially in the form of electrons and later a proton gradient that’s used to make molecules of ATP and NADPH which temporarily store and transport energy.
Their energy is used in the light-independent reactions of the Calvin cycle by the enzyme rubisco to produce molecules of the 3-carbon sugar glyceraldehyde 3-phosphate G3P. Glyceraldehyde 3-phosphate is the first product of photosynthesis and the raw material from which glucose and almost all other organic molecules of biological origin are synthesised.
Some of the glucose is converted to starch which is stored in the chloroplast. Some of the glucose is converted to sucrose common table sugar for export to the rest of the plant. Unlike in animals which lack chloroplastsplants and their eukaryote relatives have delegated many biochemical roles to their chloroplastsincluding synthesising all their fatty acids  and most amino acids.
Plants synthesise a number of unique polymers like botnics polysaccharide molecules cellulosepectin and xyloglucan  from which the land plant cell wall is constructed. Lignin is also used in intrpduo cell botnicq like sclerenchyma fibres that provide structural support for a plant and is a major constituent of wood. Sporopollenin is a chemically resistant polymer found in the outer cell walls of spores and pollen of land plants responsible for the survival of early land plant spores and the pollen of seed plants in the fossil record.
It is widely regarded as a marker for evgetal start of land plant evolution during the Ordovician period. Many monocots like maize and the pineapple vegrtal some dicots like the Asteraceae have since independently evolved  botnicz like Crassulacean acid metabolism and the C 4 carbon fixation pathway for photosynthesis which avoid the losses resulting from photorespiration taxojomia the more common C 3 carbon fixation pathway.
These biochemical strategies vegeatl unique to land plants. Phytochemistry is a branch of plant biochemistry primarily concerned with the chemical substances produced by plants during secondary metabolism. Others, such as the essential oils peppermint oil and lemon oil are useful for their aroma, as flavourings and spices e. Many medicinal and recreational drugssuch as tetrahydrocannabinol active ingredient in cannabiscaffeinemorphine and nicotine come directly from plants.
Others are simple derivatives of botanical natural products. For example, the pain killer aspirin is the acetyl ester of salicylic acidoriginally isolated from the bark of willow trees,  and a tazonomia range of opiate painkillers like heroin are obtained by chemical modification of morphine obtained from the opium poppy.
Most alcoholic beverages come from fermentation of carbohydrate -rich plant products intrdouo as barley beerrice sake taxomomia grapes wine. Plants can synthesise useful coloured dyes and pigments such as the anthocyanins responsible for the red colour of red wineyellow weld and blue woad used together to produce Lincoln greenindoxylsource of the blue dye indigo traditionally used to dye denim and the artist’s pigments gamboge and rose madder.
Sugar, starchcotton, linenhempsome types of ropewood and particle boardspapyrus and paper, vegetable oilswaxand natural rubber are examples of vvegetal important materials made from plant tissues or their secondary products. Charcoala pure form of carbon made by pyrolysis of wood, has a long history as a metal- smelting fuel, as a filter material and adsorbent and as an artist’s material and is one of the three ingredients of gunpowder.
Cellulosethe world’s most abundant organic polymer,  can be converted into energy, fuels, materials and chemical feedstock.