|
Stele (biology)
In a vascular plant, the stele is the central part of the root or Plant stem, stem containing the tissues derived from the procambium. These include vascular tissue, in some cases ground tissue (pith) and a pericycle, which, if present, defines the outermost boundary of the stele. Outside the stele lies the endodermis, which is the innermost cell layer of the cortex. The concept of the stele was developed in the late 19th century by France, French botanists Phillippe Édouard Léon van Tieghem, P. E. L. van Tieghem and H. Doultion as a model for understanding the relationship between the Shoot (botany), shoot and root, and for discussing the evolution of vascular plant morphology. Now, at the beginning of the 21st century, plant molecular biologists are coming to understand the genetics and developmental pathways that govern tissue patterns in the stele. Moreover, physiologists are examining how the anatomy (sizes and shapes) of different steles affect the function of organs. Proto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vascular Plant
Vascular plants (), also called tracheophytes (, ) or collectively tracheophyta (; ), are plants that have lignin, lignified tissues (the xylem) for conducting water and minerals throughout the plant. They also have a specialized non-lignified Tissue (biology), tissue (the phloem) to conduct products of photosynthesis. The group includes most embryophyte, land plants ( accepted known species) excluding mosses. Vascular plants include the clubmosses, Equisetum, horsetails, ferns, gymnosperms (including conifers), and angiosperms (flowering plants). They are contrasted with nonvascular plants such as mosses and green algae. Scientific names for the vascular plants group include Tracheophyta, Tracheobionta and Equisetopsida sensu lato, Equisetopsida ''sensu lato''. Some early land plants (the rhyniophytes) had less developed vascular tissue; the term eutracheophyte has been used for all other vascular plants, including all living ones. Historically, vascular plants were known as "hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phloem
Phloem (, ) is the living tissue in vascular plants that transports the soluble organic compounds made during photosynthesis and known as ''photosynthates'', in particular the sugar sucrose, to the rest of the plant. This transport process is called translocation. In trees, the phloem is the innermost layer of the bark, hence the name, derived from the Ancient Greek word (''phloiós''), meaning "bark". The term was introduced by Carl Nägeli in 1858. Different types of phloem can be distinguished. The early phloem formed in the growth apices is called protophloem. Protophloem eventually becomes obliterated once it connects to the durable phloem in mature organs, the metaphloem. Further, secondary phloem is formed during the thickening of stem structures. Structure Phloem tissue consists of conducting cells, generally called sieve elements, parenchyma cells, including both specialized companion cells or albuminous cells and unspecialized cells and supportive cells, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Botanic Gardens, Kew
Royal Botanic Gardens, Kew is a non-departmental public body in the United Kingdom sponsored by the Department for Environment, Food and Rural Affairs. An internationally important botanical research and education institution, it employs 1,100 staff. Its board of trustees is chaired by Dame Amelia Fawcett. The organisation manages botanic gardens at Kew in Richmond upon Thames in south-west London, and at Wakehurst, a National Trust property in Sussex which is home to the internationally important Millennium Seed Bank, whose scientists work with partner organisations in more than 95 countries. Kew, jointly with the Forestry Commission, founded Bedgebury National Pinetum in Kent in 1923, specialising in growing conifers. In 1994, the Castle Howard Arboretum Trust, which runs the Yorkshire Arboretum, was formed as a partnership between Kew and the Castle Howard Estate. In 2019, the organisation had 2,316,699 public visitors at Kew, and 312,813 at Wakehurst. Its site ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vascular Bundle
A vascular bundle is a part of the transport system in vascular plants. The transport itself happens in the stem, which exists in two forms: xylem and phloem. Both these tissues are present in a vascular bundle, which in addition will include supporting and protective tissues. There is also a tissue between xylem and phloem, which is the cambium. The xylem typically lies towards the axis ( adaxial) with phloem positioned away from the axis ( abaxial). In a stem or root this means that the xylem is closer to the centre of the stem or root while the phloem is closer to the exterior. In a leaf, the adaxial surface of the leaf will usually be the upper side, with the abaxial surface the lower side. The sugars synthesized by the plant with sun light are transported by the phloem, which is closer to the lower surface. Aphids and leaf hoppers feed off of these sugars by tapping into the phloem. This is why aphids and leaf hoppers are typically found on the underside of a l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vascular Tissue
Vascular tissue is a complex transporting tissue, formed of more than one cell type, found in vascular plants. The primary components of vascular tissue are the xylem and phloem. These two tissues transport fluid and nutrients internally. There are also two meristems associated with vascular tissue: the vascular cambium and the cork cambium. All the vascular tissues within a particular plant together constitute the vascular tissue system of that plant. The cells in vascular tissue are typically long and slender. Since the xylem and phloem function in the conduction of water, minerals, and nutrients throughout the plant, it is not surprising that their form should be similar to pipes. The individual cells of phloem are connected end-to-end, just as the sections of a pipe might be. As the plant grows, new vascular tissue differentiates in the growing tips of the plant. The new tissue is aligned with existing vascular tissue, maintaining its connection throughout the plant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maize
Maize (; ''Zea mays''), also known as corn in North American English, is a tall stout grass that produces cereal grain. It was domesticated by indigenous peoples in southern Mexico about 9,000 years ago from wild teosinte. Native Americans planted it alongside beans and squashes in the Three Sisters polyculture. The leafy stalk of the plant gives rise to male inflorescences or tassels which produce pollen, and female inflorescences called ears. The ears yield grain, known as kernels or seeds. In modern commercial varieties, these are usually yellow or white; other varieties can be of many colors. Maize relies on humans for its propagation. Since the Columbian exchange, it has become a staple food in many parts of the world, with the total production of maize surpassing that of wheat and rice. Much maize is used for animal feed, whether as grain or as the whole plant, which can either be baled or made into the more palatable silage. Sugar-rich varieties called sw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monocot
Monocotyledons (), commonly referred to as monocots, (Lilianae ''sensu'' Chase & Reveal) are flowering plants whose seeds contain only one Embryo#Plant embryos, embryonic leaf, or cotyledon. A monocot taxon has been in use for several decades, but with various ranks and under several different names. The APG IV system recognises its monophyly but does not assign it to a taxonomic rank, and instead uses the term "monocots" to refer to the group. Monocotyledons are contrasted with the Dicotyledon, dicotyledons, which have two cotyledons. Unlike the monocots however, the dicots are not Monophyly, monophyletic and the two cotyledons are instead the ancestral characteristic of all flowering plants. Botanists now classify dicots into the eudicots ("true dicots") and several Basal (phylogenetics), basal lineages from which the monocots emerged. The monocots are extremely important economically, culturally, and ecologically, and make up a majority of plant biomass used in agriculture. Com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fern
The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissues that conduct water and nutrients, and in having life cycles in which the branched sporophyte is the dominant phase. Ferns have complex leaf, leaves called megaphylls that are more complex than the microphylls of clubmosses. Most ferns are leptosporangiate ferns. They produce coiled Fiddlehead fern, fiddleheads that uncoil and expand into fronds. The group includes about 10,560 known extant species. Ferns are defined here in the broad sense, being all of the Polypodiopsida, comprising both the leptosporangiate (Polypodiidae (plant), Polypodiidae) and eusporangiate ferns, the latter group including horsetails, Psilotaceae, whisk ferns, marattioid ferns, and ophioglossoid ferns. The fern crown group, consisting of the leptosporangiates and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asterid
Asterids are a large clade (monophyletic group) of flowering plants, composed of 17 orders and more than 80,000 species, about a third of the total flowering plant species. The asterids are divided into the unranked clades lamiids (8 orders) and campanulids (7 orders), and the single orders Cornales and Ericales. Well-known asterids include dogwoods and hydrangeas (order Cornales), tea, blueberries, cranberries, kiwifruit, Brazil nuts, argan, sapote, and azaleas (order Ericales), sunflowers, lettuce, common daisy, yacon, carrots, celery, parsley, parsnips, ginseng, ivies, holly, honeysuckle, elder, and valerian (clade campanulids), borage, forget-me-nots, comfrey, coffee, frangipani, gentian, pong-pong, oleander, periwinkle, basil, mint, rosemary, sage, oregano, thyme, lavender, wild dagga, olives, ash, teak, foxgloves, lilac, jasmine, snapdragons, African violets, butterfly bushes, sesame, psyllium, potatoes, eggplants, tomatoes, chilli peppers, tobacco, petuni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siphonostele
In a vascular plant, the stele is the central part of the root or stem containing the tissues derived from the procambium. These include vascular tissue, in some cases ground tissue (pith) and a pericycle, which, if present, defines the outermost boundary of the stele. Outside the stele lies the endodermis, which is the innermost cell layer of the cortex. The concept of the stele was developed in the late 19th century by French botanists P. E. L. van Tieghem and H. Doultion as a model for understanding the relationship between the shoot and root, and for discussing the evolution of vascular plant morphology. Now, at the beginning of the 21st century, plant molecular biologists are coming to understand the genetics and developmental pathways that govern tissue patterns in the stele. Moreover, physiologists are examining how the anatomy (sizes and shapes) of different steles affect the function of organs. Protostele The earliest vascular plants had stems with a central core of v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lycopodium
''Lycopodium'' (from Ancient Greek ''lykos'', wolf and ''podion'', diminutive of ''pous'', foot) is a genus of clubmosses, also known as ground pines or creeping cedars, in the family Lycopodiaceae. Two very different circumscriptions of the genus are in use. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), ''Lycopodium'' is one of nine genera in the subfamily Lycopodioideae, and has from nine to 15 species. In other classifications, the genus is equivalent to the whole of the subfamily, since it includes all of the other genera. More than 40 species are accepted. Description They are flowerless, vascular, terrestrial or epiphytic plants, with widely branched, erect, prostrate, or creeping stems, with small, simple, needle-like or scale-like leaves that cover the stem and branches thickly. The stems usually creep along the ground, forking at intervals. The leaves contain a single, unbranched vascular strand, and are microphylls by definition. They are usually ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhynia
''Rhynia'' is a single-species genus of Devonian vascular plants. ''Rhynia gwynne-vaughanii'' was the sporophyte generation of a vascular, axial, free-sporing diplohaplontic embryophytic land plant of the Early Devonian that had anatomical features more advanced than those of the bryophytes. ''Rhynia gwynne-vaughanii'' was a member of a sister group to all other eutracheophytes, including modern vascular plants. Description ''Rhynia gwynne-vaughanii'' was first described as a new species by Robert Kidston and William H. Lang in 1917. The species is known only from the Rhynie chert in Aberdeenshire, Scotland, where it grew in the vicinity of a silica-rich hot spring. ''Rhynia'' was a vascular plant, and grew in association with other vascular plants such as '' Asteroxylon mackei'', a probable ancestor of modern clubmosses ( Lycopsida), and with pre-vascular plants such as '' Aglaophyton major'', which is interpreted as basal to true vascular plants. ''Rhynia'' is though ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
