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87-431: "Liners" is a horticultural term referring to very young plants , usually grown for sale to retailers or wholesalers , who then grow them to a larger size before selling them to consumers. Liners are usually grown from seed , but may also be grown from cuttings or tissue culture . They are grown in plastic trays with many "cells," each of which contains a single liner plant. Liners will typically range in size from

174-489: A coleoptile that forms the first leaf while the radicle is covered with a coleorhiza that connects to the primary root and adventitious roots form the sides. Here the hypocotyl is a rudimentary axis between radicle and plumule. The seeds of corn are constructed with these structures; pericarp, scutellum (single large cotyledon) that absorbs nutrients from the endosperm, plumule, radicle, coleoptile, and coleorhiza – these last two structures are sheath-like and enclose

261-401: A seed is a plant embryo and nutrient reserve enclosed in a seed coat, a protective outer covering called a testa. More generally, the term "seed" means anything that can be sown , which may include seed and husk or tuber . Seeds are the product of the ripened ovule , after the embryo sac is fertilized by sperm from pollen , forming a zygote . The embryo within a seed develops from

348-431: A 36 cell tray up to a 288 cell tray. The most common size used in commercial nurseries is between 50 and 72 cells. The term "liner", is typically used for perennial, ornamental, and woody seedlings. Annuals in this form are usually referred to as plugs . According to the U.S. Department of Agriculture , plants can only be defined as "liners" if they are at least an inch in diameter but not more than 3 inches in diameter at

435-422: A curved megagametophyte often giving the seed a tight "C" shape. The last ovule shape is called amphitropous , where the ovule is partly inverted and turned back 90 degrees on its stalk (the funicle or funiculus ). In the majority of flowering plants, the zygote's first division is transversely oriented in regards to the long axis, and this establishes the polarity of the embryo. The upper or chalazal pole becomes

522-412: A distinct field from agriculture when humans sought to cultivate plants for pleasure on a smaller scale rather than for mere sustenance. Emerging technologies are moving the industry forward, especially in the way of altering plants to be more adverse to parasites, disease and drought. Modifying technologies such as Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR/Cas9), are also improving

609-411: A few will end in a favorable place for growth. Herbaceous perennials and woody plants often have larger seeds; they can produce seeds over many years, and larger seeds have more energy reserves for germination and seedling growth and produce larger, more established seedlings after germination. Seeds serve several functions for the plants that produce them. Key among these functions are nourishment of

696-454: A highly efficient, simplified, precise, and low cost method of altering the genomes of species. Since 2013, CRISPR has been used to enhance a variety of species of grains, fruits, and vegetables. Crops are modified to increase their resistance to biotic and abiotic stressors such as parasites, disease, and drought as well as increase yield, nutrition, and flavour. Additionally, CRISPR has been used to edit undesirable traits, for example, reducing

783-451: A horticulturist may consider aspects based on the plants intended use and can include plant morphology, rarity, and utility. When selecting plants for the landscape, there are necessary observations of the location that must be made first. Considerations as to soil-type, temperature/climate, light, moisture, and pre-existing plants are made. These evaluations of the given environment are taken into consideration when selecting plant material for

870-415: A location and be there at a time favorable for germination and growth. When the fruits open and release their seeds in a regular way, it is called dehiscent , which is often distinctive for related groups of plants; these fruits include capsules , follicles , legumes , silicles and siliques . When fruits do not open and release their seeds in a regular fashion, they are called indehiscent, which include

957-502: A special focus on horticulture for development (H4D), which involves using horticulture to reduce poverty and improve nutrition worldwide. GlobalHort is organized in a consortium of national and international organizations which collaborate in research, training, and technology-generating activities designed to meet mutually-agreed-upon objectives. GlobalHort is a non-profit organization registered in Belgium. Seed In botany ,

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1044-435: A supply of nutrients for the embryo in most monocotyledons and the endospermic dicotyledons. Seeds have been considered to occur in many structurally different types (Martin 1946). These are based on a number of criteria, of which the dominant one is the embryo-to-seed size ratio. This reflects the degree to which the developing cotyledons absorb the nutrients of the endosperm, and thus obliterate it. Six types occur amongst

1131-550: A tegmen from the inner integument while unitegmic seeds have only one integument. Usually, parts of the testa or tegmen form a hard protective mechanical layer. The mechanical layer may prevent water penetration and germination. Amongst the barriers may be the presence of lignified sclereids . The outer integument has a number of layers, generally between four and eight organised into three layers: (a) outer epidermis, (b) outer pigmented zone of two to five layers containing tannin and starch, and (c) inner epidermis. The endotegmen

1218-464: A variety of methods. Covering plants with plastic in the form of cones - called hot caps, or tunnels, can help to manipulate the surrounding temperature. Mulching is also an effective method to protect outdoor plants from frost during the wintertime. Inside, other frost prevention methods include the use of wind machines, heaters, and sprinklers. Plants have evolved to require different amounts of light, and lengths of daytime; their growth and development

1305-405: A way for the species to survive dry or cold seasons. Ephemeral plants are usually annuals that can go from seed to seed in as few as six weeks. Seed germination is a process by which a seed embryo develops into a seedling. It involves the reactivation of the metabolic pathways that lead to growth and the emergence of the radicle or seed root and plumule or shoot. The emergence of the seedling above

1392-565: Is a charity in United Kingdom that leads on the encouragement and improvement of the science, art, and practice of horticulture in all its branches. The organization shares the knowledge of horticulture through its community, learning programs, and world-class gardens and shows. The Chartered Institute of Horticulture (CIH) is the Chartered professional body for horticulturists and horticultural scientists representing all sectors of

1479-509: Is at a suitable temperature with proper soil moisture. This true dormancy or innate dormancy is therefore caused by conditions within the seed that prevent germination. Thus dormancy is a state of the seed, not of the environment. Induced dormancy, enforced dormancy or seed quiescence occurs when a seed fails to germinate because the external environmental conditions are inappropriate for germination, mostly in response to conditions being too dark or light, too cold or hot, or too dry. Seed dormancy

1566-503: Is because plants are grown for many different reasons. Some of the divisions in horticulture include: It includes the cultivation of all plants including, but not limited to: ornamental trees/shrubs/plants , fruits , vegetables , flowers , turf , nuts , seeds , herbs and other medicinal/edible plants. This cultivation may occur in garden spaces, nurseries , greenhouses , vineyards , orchards , parks , recreation areas, etc. Horticulturists, are those who study and practice

1653-481: Is caused by conditions outside the embryo, including: Endogenous dormancy is caused by conditions within the embryo itself, including: The following types of seed dormancy do not involve seed dormancy, strictly speaking, as lack of germination is prevented by the environment, not by characteristics of the seed itself (see Germination ): Not all seeds undergo a period of dormancy. Seeds of some mangroves are viviparous; they begin to germinate while still attached to

1740-402: Is derived from the inner epidermis of the inner integument, the exotegmen from the outer surface of the inner integument. The endotesta is derived from the inner epidermis of the outer integument, and the outer layer of the testa from the outer surface of the outer integument is referred to as the exotesta . If the exotesta is also the mechanical layer, this is called an exotestal seed, but if

1827-457: Is determined by the amount of light/light intensity that they receive. Control of this may be achieved artificially through the use of fluorescent lights in an indoor setting. Manipulating the amount of light also controls flowering. Lengthening the day encourages the flowering of long-day plants and discourages the flowering of short-day plants. Water management methods involve employing irrigation/drainage systems, and controlling soil moisture to

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1914-644: Is extrapolated as evapotranspiration is increased, soils are degraded of their nutrients, and oxygen levels are depleted, resulting in up to a 70% loss in crop yield. Living organisms such as bacteria, viruses, fungi, parasites, insects, weeds and native plants are sources of biotics stresses and can deprive the host of its nutrients. Plants respond to these stresses using defence mechanisms such as morphological and structural barriers, chemical compounds, proteins, enzymes and hormones. The impact of biotic stresses can be prevented using practices such as incorporate tilling, spraying or Integrated Pest Management (IPM). Care

2001-723: Is no soil used. Growers within a greenhouse setting will often opt for a soilless mix which does not include any actual components of naturally occurring soil. These mixes offer advantages such as water absorption, sterility, and are generally very available within the industry. Soil management methods are broad, but includes the use of fertilizers, planned crop rotation to prevent the degradation of soils that are seen in monocultures, applying fertilizers, and soil analysis. Abiotic factors such as weather, light and temperature are all things that can be manipulated with enclosed environments such as cold frames, greenhouses , conservatories , poly houses and shade houses. Materials that are used in

2088-444: Is not the same as seed persistence in the soil or on the plant, though even in scientific publications dormancy and persistence are often confused or used as synonyms. Often, seed dormancy is divided into four major categories: exogenous; endogenous; combinational; and secondary. A more recent system distinguishes five classes: morphological, physiological, morphophysiological, physical, and combinational dormancy. Exogenous dormancy

2175-535: Is protection against disease. Seeds protect and nourish the embryo or young plant. They usually give a seedling a faster start than a sporeling from a spore, because of the larger food reserves in the seed and the multicellularity of the enclosed embryo. Unlike animals, plants are limited in their ability to seek out favorable conditions for life and growth. As a result, plants have evolved many ways to disperse their offspring by dispersing their seeds (see also vegetative reproduction ). A seed must somehow "arrive" at

2262-429: Is required to reduce damages and losses to horticultural crops during harvest. Compression forces occur during harvesting, and horticultural goods can be hit in a series of impacts during transport and packhouse operations. Different techniques are used to minimize mechanical injuries and wounding to plants such as: Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR/Cas9) has recently gained recognition as

2349-407: Is required to support a rapidly growing population with demands for its products. Due to global climate change, extremes in temperatures, strength of precipitation events, flood frequency, and drought length and frequency are increasing. Together with other abiotic stressors such salinity, heavy metal toxicity , UV damage, and air pollution, stressful environments are created for crop production. This

2436-446: Is the ability of the embryo to germinate and is affected by a number of different conditions. Some plants do not produce seeds that have functional complete embryos, or the seed may have no embryo at all, often called empty seeds. Predators and pathogens can damage or kill the seed while it is still in the fruit or after it is dispersed. Environmental conditions like flooding or heat can kill the seed before or during germination. The age of

2523-411: Is then aborted or absorbed during early development. The seed is composed of the embryo (the result of fertilization) and tissue from the mother plant, which also form a cone around the seed in coniferous plants such as pine and spruce . Seeds are very diverse, and as such there are many terms are used to describe them. A typical seed includes two basic parts: In addition, the endosperm forms

2610-419: Is usually triploid , and is rich in oil or starch , and protein . In gymnosperms, such as conifers , the food storage tissue (also called endosperm) is part of the female gametophyte , a haploid tissue. The endosperm is surrounded by the aleurone layer (peripheral endosperm), filled with proteinaceous aleurone grains. Originally, by analogy with the animal ovum , the outer nucellus layer ( perisperm )

2697-638: The International Society for Horticultural Science and the American Society of Horticultural Science . In the United Kingdom, there are two main horticulture societies. The Ancient Society of York Florists is the oldest horticultural society in the world and was founded in 1768; this organization continues to host four horticultural shows annually in York , England. Additionally, The Royal Horticultural Society , established in 1804,

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2784-417: The cone scales as they develop in some species of conifer . Angiosperm (flowering plants) seeds consist of three genetically distinct constituents: (1) the embryo formed from the zygote, (2) the endosperm, which is normally triploid, (3) the seed coat from tissue derived from the maternal tissue of the ovule. In angiosperms, the process of seed development begins with double fertilization , which involves

2871-412: The embryo , dispersal to a new location, and dormancy during unfavorable conditions. Seeds fundamentally are means of reproduction, and most seeds are the product of sexual reproduction which produces a remixing of genetic material and phenotype variability on which natural selection acts. Plant seeds hold endophytic microorganisms that can perform various functions, the most important of which

2958-421: The flowering plants , the ovary ripens into a fruit which contains the seed and serves to disseminate it. Many structures commonly referred to as "seeds" are actually dry fruits. Sunflower seeds are sometimes sold commercially while still enclosed within the hard wall of the fruit, which must be split open to reach the seed. Different groups of plants have other modifications, the so-called stone fruits (such as

3045-424: The legumes (such as beans and peas ), trees such as the oak and walnut , vegetables such as squash and radish , and sunflowers . According to Bewley and Black (1978), Brazil nut storage is in hypocotyl and this place of storage is uncommon among seeds. All gymnosperm seeds are albuminous. The seed coat develops from the maternal tissue, the integuments , originally surrounding the ovule. The seed coat in

3132-416: The peach ) have a hardened fruit layer (the endocarp ) fused to and surrounding the actual seed. Nuts are the one-seeded, hard-shelled fruit of some plants with an indehiscent seed, such as an acorn or hazelnut . The first land plants evolved around 468 million years ago, and reproduced using spores. The earliest seed bearing plants to appear were the gymnosperms , which have no ovaries to contain

3219-599: The Gods, as well as were given in ceremonies to leaders to demonstrate their connection to the Gods. Plant propagation in horticulture is the process in which the multiplication of a species is performed, increasing the number of individual plants. Propagation involves both sexual and asexual methods. In sexual propagation seeds are used, while asexual propagation involves the division of plants, separation of tubers, corms, and bulbs - by use of techniques such as cutting, layering, grafting. When selecting plants to cultivate,

3306-833: The Middle Ages. Early practices in horticulture include a number of various ways that people managed the land (using an assortment of tools), with a variety of methods and types of plants cultivated for a number of uses. Methods, tools and plants grown, have always depended on the culture and climate. There are a number of traditional horticultural practices that we know of today: such as the Indigenous peoples of pre-colonized North America using biochar to enhance soil productivity by smoldering plant waste - European settlers called this soil Terra Preta de Indio . In North America, Indigenous people grew maize, squash, and sunflower - among other crops. Mesoamerican cultures focused on

3393-830: The New Zealand Horticulture Institute is another known horticultural organization. In India, the Horticultural Society of India (now Indian Academy of Horticultural Sciences) is the oldest society which was established in 1941 at Lyallpur, Punjab (now in Pakistan) but was later shifted to Delhi in 1949. The other notable organization in operation since 2005 is the Society for Promotion of Horticulture based at Bengaluru. Both these societies publish scholarly journals – Indian Journal of Horticulture and Journal of Horticultural Sciences for

3480-679: The advancement of horticultural sciences. Horticulture in the Indian state of Kerala is spearheaded by Kerala State Horticulture Mission . The National Junior Horticultural Association (NJHA) was established in 1934 and was the first organization in the world dedicated solely to youth and horticulture. NJHA programs are designed to help young people obtain a basic understanding of horticulture and develop skills in this ever-expanding art and science. The Global Horticulture Initiative (GlobalHort) fosters partnerships and collective action among different stakeholders in horticulture. This organization has

3567-468: The aesthetic care and maintenance of plants in gardens or landscapes. However, there are aspects of horticulture that are industrialized/commercial such as greenhouse production or CEA. Horticulture began with the domestication of plants around 10,000-20,000 years ago. At first, only plants for sustenance were grown and maintained, but eventually as humanity became increasingly sedentary, plants were grown for their ornamental value. Horticulture emerged as

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3654-473: The browning and production of toxic and bitter substances of potatoes. CRISPR has also been employed to solve issues of low pollination rates and low fruit yield common in greenhouses. As compared to Genetically Modified Organisms (GMO), CRISPR does not add any alien DNA to the plant's genes. There are various organizations worldwide that focus on promoting and encouraging research and education in all branches of horticultural science; such organizations include

3741-636: The cells are filled with starch , as for instance cereal grains , or not (non-farinaceous). The endosperm may also be referred to as "fleshy" or "cartilaginous" with thicker soft cells such as coconut , but may also be oily as in Ricinus (castor oil), Croton and Poppy . The endosperm is called "horny" when the cell walls are thicker such as date and coffee , or "ruminated" if mottled, as in nutmeg , palms and Annonaceae . In most monocotyledons (such as grasses and palms ) and some ( endospermic or albuminous ) dicotyledons (such as castor beans )

3828-405: The cells of the outer epidermis enlarge radially and their walls thicken, with nucleus and cytoplasm compressed into the outer layer. these cells which are broader on their inner surface are called palisade cells. In the inner epidermis, the cells also enlarge radially with plate like thickening of the walls. The mature inner integument has a palisade layer, a pigmented zone with 15–20 layers, while

3915-407: The construction of these buildings are chosen based on the climate, purpose and budget. Cold frames provide an enclosed environment, they are built close to the ground and with a top made of glass or plastic. The glass or plastic allows sunlight into the frame during the day and prevents heat loss that would have been lost as long-wave radiation at night. This allows plants to start to be grown before

4002-591: The cultivating of crops on a small scale, such as the milpa or maize field, around their dwellings or in specialized plots which were visited occasionally during migrations from one area to the next. In Central America, the Maya involved augmentation of the forest with useful trees such as papaya , avocado , cacao , ceiba and sapodilla . In the fields, multiple crops such as beans, squash, pumpkins and chili peppers were grown. The first horticulturists in many cultures, were mainly or exclusively women. In addition to

4089-679: The cultivation of plant material professionally. There are many different types of horticulturists with different job-titles, including: gardener , grower, farmer , arborist , floriculturist , landscaper , agronomist, designer, landscape architect, lawn-care specialist, nursery manager, botanical garden curator, horticulture therapist, and much more. They may be hired by a variety of companies/institutions including, but not limited to: botanical gardens, private/public gardens, parks, cemeteries, greenhouses, golf courses, vineyards, estates, landscaping companies, nurseries, educational institutions, etc. They may also be self-employed. Horticulture began with

4176-458: The domestication of plants 10,000-20,000 years ago, and has since, been deeply integrated into humanity's history. The domestication of plants occurred independently within various civilizations across the globe. The history of horticulture overlaps with the history of agriculture and history of botany , as all three originated with the domestication of various plants for food. In Europe, agriculture and horticulture diverged at some point during

4263-407: The early 19th century, influential works being: Angiosperm seeds are "enclosed seeds", produced in a hard or fleshy structure called a fruit that encloses them for protection. Some fruits have layers of both hard and fleshy material. In gymnosperms, no special structure develops to enclose the seeds, which begin their development "naked" on the bracts of cones. However, the seeds do become covered by

4350-440: The elaiosomes are eaten. The remainder of the seed, which is hard and inedible to the ants, then germinates either within the nest or at a removal site where the seed has been discarded by the ants. This dispersal relationship is an example of mutualism , since the plants depend upon the ants to disperse seeds, while the ants depend upon the plants seeds for food. As a result, a drop in numbers of one partner can reduce success of

4437-429: The embryo is embedded in the endosperm (and nucellus), which the seedling will use upon germination . In the non-endospermic dicotyledons the endosperm is absorbed by the embryo as the latter grows within the developing seed, and the cotyledons of the embryo become filled with stored food. At maturity, seeds of these species have no endosperm and are also referred to as exalbuminous seeds. The exalbuminous seeds include

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4524-452: The fertilised ovule, an immature plant from which a new plant will grow under proper conditions. The embryo has one cotyledon or seed leaf in monocotyledons , two cotyledons in almost all dicotyledons and two or more in gymnosperms. In the fruit of grains (caryopses) the single monocotyledon is shield shaped and hence called a scutellum . The scutellum is pressed closely against the endosperm from which it absorbs food and passes it to

4611-439: The field. This horticulture article is a stub . You can help Misplaced Pages by expanding it . Horticultural Typically, horticulture is characterized as the ornamental, small-scale/non-industrial cultivation of plants; horticulture is distinct from gardening by its emphasis on scientific methods, plant breeding, and technical cultivation practices, while gardening, even at a professional level, tends to focus more on

4698-645: The first few years of their lives deriving energy from the fungi and do not produce green leaves. At up to 55 pounds (25 kilograms) the largest seed is the coco de mer (Lodoicea maldivica). This indicates a 25 Billion fold difference in seed weight. Plants that produce smaller seeds can generate many more seeds per flower, while plants with larger seeds invest more resources into those seeds and normally produce fewer seeds. Small seeds are quicker to ripen and can be dispersed sooner, so autumn all blooming plants often have small seeds. Many annual plants produce great quantities of smaller seeds; this helps to ensure at least

4785-507: The fruits achenes , caryopses , nuts , samaras , and utricles . Other seeds are enclosed in fruit structures that aid wind dispersal in similar ways: Myrmecochory is the dispersal of seeds by ants . Foraging ants disperse seeds which have appendages called elaiosomes (e.g. bloodroot , trilliums , acacias , and many species of Proteaceae ). Elaiosomes are soft, fleshy structures that contain nutrients for animals that eat them. The ants carry such seeds back to their nest, where

4872-408: The fusion of two male gametes with the egg cell and the central cell to form the primary endosperm and the zygote. Right after fertilization, the zygote is mostly inactive, but the primary endosperm divides rapidly to form the endosperm tissue. This tissue becomes the food the young plant will consume until the roots have developed after germination . After fertilization, the ovules develop into

4959-446: The grasses, are not distinct structures, but are fused with the fruit wall to form a pericarp .) The testae of both monocots and dicots are often marked with patterns and textured markings, or have wings or tufts of hair. When the seed coat forms from only one layer, it is also called the testa, though not all such testae are homologous from one species to the next. The funiculus abscisses (detaches at fixed point – abscission zone),

5046-613: The ground or in containers. A liner traditionally refers to lining out nursery stock in a field row. The term has evolved to mean a small plant produced from a rooted cutting, seedling, plug, or tissue culture plantlet. Direct sticking or direct rooting into smaller liner pots is commonly done in United States propagation nurseries. Seedlings and rooted cuttings can also be transplanted into small liner pots and allowed to become established during liner production, before being transplanted to larger containers (upcanned) or outplanted into

5133-431: The growing parts. Embryo descriptors include small, straight, bent, curved, and curled. Within the seed, there usually is a store of nutrients for the seedling that will grow from the embryo. The form of the stored nutrition varies depending on the kind of plant. In angiosperms, the stored food begins as a tissue called the endosperm , which is derived from the mother plant and the pollen via double fertilization . It

5220-494: The growing season starts. Greenhouses/conservatories are similar in function, but are larger in construction and heated with an external energy source. They can be built out of glass, although they are now primarily made from plastic sheets. More expensive and modern greenhouses can include temperature control through shade and light control or air-conditioning as well as automatic watering. Shade houses provide shading to limit water loss by evapotranspiration. Commercial horticulture

5307-442: The horticultural industry across Great Britain, Ireland and overseas.  It is the only horticultural professional body where its top professionals can achieve Chartered status and become a Chartered Horticulturist. The Australian Institute of Horticulture and Australian Society of Horticultural Science was established in 1990 as a professional society to promote and enhance Australian horticultural science and industry. Finally,

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5394-434: The inner epidermis may remain a single layer, it may also divide to produce two to three layers and accumulates starch, and is referred to as the colourless layer. By contrast, the outer epidermis becomes tanniferous . The inner integument may consist of eight to fifteen layers. As the cells enlarge, and starch is deposited in the outer layers of the pigmented zone below the outer epidermis, this zone begins to lignify, while

5481-444: The innermost layer is known as the fringe layer. In gymnosperms, which do not form ovaries, the ovules and hence the seeds are exposed. This is the basis for their nomenclature – naked seeded plants. Two sperm cells transferred from the pollen do not develop the seed by double fertilization, but one sperm nucleus unites with the egg nucleus and the other sperm is not used. Sometimes each sperm fertilizes an egg cell and one zygote

5568-424: The latter example these hairs are the source of the textile crop cotton . Other seed appendages include the raphe (a ridge), wings, caruncles (a soft spongy outgrowth from the outer integument in the vicinity of the micropyle), spines, or tubercles. A scar also may remain on the seed coat, called the hilum , where the seed was attached to the ovary wall by the funicle. Just below it is a small pore, representing

5655-775: The location. Plant selection may be for annual displays, or they may be for more permanent plantings. Characteristics of the plant such as mature height/size, colour, growth habit, ornamental value, flowering time and invasive potential are what finalizes the plant selection process. Environmental factors that effect plant development include: temperature, light, water, pH, nutrient availability, weather events (rain, snow, sleet, hail and freezing rain, dew, wind and frost) humidity, elevation, terrain, and micro-climate effects. In horticulture, these environmental variables may be avoided, controlled or manipulated in an indoor growing environment. Plants require specific temperatures to grow and develop properly. Temperature control can be done through

5742-402: The main area of growth of the embryo, while the lower or micropylar pole produces the stalk-like suspensor that attaches to the micropyle. The suspensor absorbs and manufactures nutrients from the endosperm that are used during the embryo's growth. The main components of the embryo are: Monocotyledonous plants have two additional structures in the form of sheaths. The plumule is covered with

5829-422: The mature seed can be a paper-thin layer (e.g. peanut ) or something more substantial (e.g. thick and hard in honey locust and coconut ), or fleshy as in the sarcotesta of pomegranate . The seed coat helps protect the embryo from mechanical injury, predators, and drying out. Depending on its development, the seed coat is either bitegmic or unitegmic . Bitegmic seeds form a testa from the outer integument and

5916-514: The mechanical layer is the endotegmen, then the seed is endotestal. The exotesta may consist of one or more rows of cells that are elongated and pallisade like (e.g. Fabaceae ), hence 'palisade exotesta'. In addition to the three basic seed parts, some seeds have an appendage, an aril , a fleshy outgrowth of the funicle ( funiculus ), (as in yew and nutmeg ) or an oily appendage, an elaiosome (as in Corydalis ), or hairs (trichomes). In

6003-652: The medicinal and nutritional values that plants hold, plants have also been grown for their beauty, and to impress and demonstrate power, knowledge, status and even wealth of those in-control of the cultivated plant material. This symbolic power that plants hold has existed even before the beginnings of their cultivation. There is evidence that various gardens maintained by the Aztecs were sacred, as they grew plants that held religious value. Plants were grown for their metaphorical relation to Gods and Goddesses. Flowers held symbolic power in religious rites, as they were offered to

6090-456: The micropyle of the ovule. Seeds are very diverse in size. The dust-like orchid seeds are the smallest, with about one million seeds per gram; they are often embryonic seeds with immature embryos and no significant energy reserves. Orchids and a few other groups of plants are mycoheterotrophs which depend on mycorrhizal fungi for nutrition during germination and the early growth of the seedling. Some terrestrial orchid seedlings, in fact, spend

6177-399: The monocotyledons, ten in the dicotyledons, and two in the gymnosperms (linear and spatulate). This classification is based on three characteristics: embryo morphology, amount of endosperm and the position of the embryo relative to the endosperm. In endospermic seeds, there are two distinct regions inside the seed coat, an upper and larger endosperm and a lower smaller embryo. The embryo is

6264-469: The needs of the species. Methods of irrigation include surface irrigation, sprinkler irrigation, sub-irrigation, and trickle irrigation. Volume of water, pressure, and frequency are changed to optimize the growing environment. On a small scale watering can be done manually. The choice of growing media and components to the media help support plant life. Within a greenhouse environment, growers may choose to grow their plants in an aquaponic system where there

6351-494: The nutrition, taste and yield of crops. There are many horticultural organizations and societies found around the world, that are formed by horticulturists and those within the industry. These include the Royal Horticultural Society , the International Society for Horticultural Science , and the American Society of Horticultural Science . There are divisions and sub-divisions within horticulture, this

6438-403: The optimal conditions for survival of the resulting seedling; the second is spreading germination of a batch of seeds over time so a catastrophe (e.g. late frosts, drought, herbivory ) does not result in the death of all offspring of a plant ( bet-hedging ). Seed dormancy is defined as a seed failing to germinate under environmental conditions optimal for germination, normally when the environment

6525-477: The other. In South Africa , the Argentine ant ( Linepithema humile ) has invaded and displaced native species of ants. Unlike the native ant species, Argentine ants do not collect the seeds of Mimetes cucullatus or eat the elaiosomes. In areas where these ants have invaded, the numbers of Mimetes seedlings have dropped. Seed dormancy has two main functions: the first is synchronizing germination with

6612-410: The parent. The large, heavy root allows the seed to penetrate into the ground when it falls. Many garden plant seeds will germinate readily as soon as they have water and are warm enough; though their wild ancestors may have had dormancy, these cultivated plants lack it. After many generations of selective pressure by plant breeders and gardeners, dormancy has been selected out. For annuals , seeds are

6699-455: The plumule and radicle, acting as a protective covering. The maturing ovule undergoes marked changes in the integuments, generally a reduction and disorganization but occasionally a thickening. The seed coat forms from the two integuments or outer layers of cells of the ovule, which derive from tissue from the mother plant, the inner integument forms the tegmen and the outer forms the testa . (The seed coats of some monocotyledon plants, such as

6786-405: The rate of germination. This is given as a percent of germination over a certain amount of time, 90% germination in 20 days, for example. 'Dormancy' is covered above; many plants produce seeds with varying degrees of dormancy, and different seeds from the same fruit can have different degrees of dormancy. It's possible to have seeds with no dormancy if they are dispersed right away and do not dry (if

6873-415: The scar forming an oval depression, the hilum . Anatropous ovules have a portion of the funiculus that is adnate (fused to the seed coat), and which forms a longitudinal ridge, or raphe , just above the hilum. In bitegmic ovules (e.g. Gossypium described here) both inner and outer integuments contribute to the seed coat formation. With continuing maturation the cells enlarge in the outer integument. While

6960-413: The seed affects its health and germination ability: since the seed has a living embryo, over time cells die and cannot be replaced. Some seeds can live for a long time before germination, while others can only survive for a short period after dispersal before they die. Seed vigor is a measure of the quality of seed, and involves the viability of the seed, the germination percentage, germination rate, and

7047-405: The seeds. The ovule consists of a number of components: The shape of the ovules as they develop often affects the final shape of the seeds. Plants generally produce ovules of four shapes: the most common shape is called anatropous , with a curved shape. Orthotropous ovules are straight with all the parts of the ovule lined up in a long row producing an uncurved seed. Campylotropous ovules have

7134-507: The seeds. They arose during the late Devonian period (416 million to 358 million years ago). From these early gymnosperms, seed ferns evolved during the Carboniferous period (359 to 299 million years ago); they had ovules that were borne in a cupule, which consisted of groups of enclosing branches likely used to protect the developing seed. Published literature about seed storage, viability and its hygrometric dependence began in

7221-420: The soil surface is the next phase of the plant's growth and is called seedling establishment. Three fundamental conditions must exist before germination can occur. (1) The embryo must be alive, called seed viability. (2) Any dormancy requirements that prevent germination must be overcome. (3) The proper environmental conditions must exist for germination. Far red light can prevent germination. Seed viability

7308-507: The strength of the seedlings produced. The germination percentage is simply the proportion of seeds that germinate from all seeds subject to the right conditions for growth. The germination rate is the length of time it takes for the seeds to germinate. Germination percentages and rates are affected by seed viability, dormancy and environmental effects that impact on the seed and seedling. In agriculture and horticulture quality seeds have high viability, measured by germination percentage plus

7395-504: The widest point. Plant liners must also have established root systems that touch the outer edges of the container and stay intact when lifted from the container. The U.S. Department of Agriculture 's National Plant Materials Manual defines "liner" as plant material which is grown in one location and then “lined-out” in another location for finishing off. Plants may be started in seedbeds and lifted bare-root or grown in containers. Either type of these liners may finish their production cycle in

7482-457: The zygote and grows within the mother plant to a certain size before growth is halted. The formation of the seed is the defining part of the process of reproduction in seed plants ( spermatophytes ). Other plants such as ferns , mosses and liverworts , do not have seeds and use water-dependent means to propagate themselves. Seed plants now dominate biological niches on land, from forests to grasslands both in hot and cold climates . In

7569-426: Was referred to as albumen , and the inner endosperm layer as vitellus. Although misleading, the term began to be applied to all the nutrient matter. This terminology persists in referring to endospermic seeds as "albuminous". The nature of this material is used in both describing and classifying seeds, in addition to the embryo to endosperm size ratio. The endosperm may be considered to be farinaceous (or mealy) in which

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