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Nelumbo Indica
''Nelumbo'' is a genus of aquatic plants with large, showy flowers. Members are commonly called lotus, though the name is also applied to various other plants and plant groups, including the unrelated genus '' Lotus''. Members outwardly resemble those in the family Nymphaeaceae ("water lilies"), but ''Nelumbo'' is actually very distant to that family. There are only two known living species of lotus; ''Nelumbo nucifera'' is native to East Asia, South Asia, Southeast Asia and probably Australia, and is better-known. It is commonly cultivated; it is eaten and used in traditional Chinese medicine. The other lotus is ''Nelumbo lutea'', which is native to North America and the Caribbean. Horticultural hybrids have been produced between these two allopatric species. Description Ultrahydrophobicity The leaves of ''Nelumbo'' are highly water-repellent (i.e. they exhibit ultrahydrophobicity) and have given the name to what is called the lotus effect. Ultrahydrophobicity in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nelumbo Nucifera
''Nelumbo nucifera'', also known as sacred lotus, Laxmi lotus, Indian lotus, or simply lotus, is one of two extant taxon, extant species of aquatic plant in the Family (Biology), family Nelumbonaceae. It is sometimes colloquially called a water lily, though this more often refers to members of the family Nymphaeaceae. Lotus plants are adapted to grow in the flood plains of slow-moving rivers and delta areas. Stands of lotus drop hundreds of thousands of seeds every year to the bottom of the pond. While some sprout immediately, and most are eaten by wildlife, the remaining seeds can remain dormant for an extensive period of time as the pond silts in and dries out. During flood conditions, sediments containing these seeds are broken open, and the dormant seeds rehydrate and begin a new lotus colony. Under favorable circumstances, the seeds of this aquatic perennial may remain viable for many years, with the oldest recorded lotus germination being from seeds 1,300 years old re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southeast Asia
Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical south-eastern region of Asia, consisting of the regions that are situated south of mainland China, east of the Indian subcontinent, and north-west of mainland Australia. Southeast Asia is bordered to the north by East Asia, to the west by South Asia and the Bay of Bengal, to the east by Oceania and the Pacific Ocean, and to the south by Australia and the Indian Ocean. Apart from the British Indian Ocean Territory and two out of 26 atolls of Maldives in South Asia, Maritime Southeast Asia is the only other subregion of Asia that lies partly within the Southern Hemisphere. Mainland Southeast Asia is completely in the Northern Hemisphere. East Timor and the southern portion of Indonesia are the only parts that are south of the Equator. The region lies near the intersection of geological plates, with both heavy seismi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidermis (botany)
The epidermis (from the Greek ''ἐπιδερμίς'', meaning "over-skin") is a single layer of cells that covers the leaves, flowers, roots and stems of plants. It forms a boundary between the plant and the external environment. The epidermis serves several functions: it protects against water loss, regulates gas exchange, secretes metabolic compounds, and (especially in roots) absorbs water and mineral nutrients. The epidermis of most leaves shows dorsoventral anatomy: the upper (adaxial) and lower (abaxial) surfaces have somewhat different construction and may serve different functions. Woody stems and some other stem structures such as potato tubers produce a secondary covering called the periderm that replaces the epidermis as the protective covering. Description The epidermis is the outermost cell layer of the primary plant body. In some older works the cells of the leaf epidermis have been regarded as specialized parenchyma cells,Hill, J. Ben; Overholts, Lee O; Popp, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stoma
In botany, a stoma (from Greek ''στόμα'', "mouth", plural "stomata"), also called a stomate (plural "stomates"), is a pore found in the epidermis of leaves, stems, and other organs, that controls the rate of gas exchange. The pore is bordered by a pair of specialized parenchyma cells known as guard cells that are responsible for regulating the size of the stomatal opening. The term is usually used collectively to refer to the entire stomatal complex, consisting of the paired guard cells and the pore itself, which is referred to as the stomatal aperture. Air, containing oxygen, which is used in respiration, and carbon dioxide, which is used in photosynthesis, passes through stomata by gaseous diffusion. Water vapour diffuses through the stomata into the atmosphere in a process called transpiration. Stomata are present in the sporophyte generation of all land plant groups except liverworts. In vascular plants the number, size and distribution of stomata varies wide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolution
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation tends to exist within any given population as a result of genetic mutation and recombination. Evolution occurs when evolutionary processes such as natural selection (including sexual selection) and genetic drift act on this variation, resulting in certain characteristics becoming more common or more rare within a population. The evolutionary pressures that determine whether a characteristic is common or rare within a population constantly change, resulting in a change in heritable characteristics arising over successive generations. It is this process of evolution that has given rise to biodiversity at every level of biological organisation, including the levels of species, individual organisms, and molecules. The theory of evolut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lotus Effect
The lotus effect refers to self-cleaning properties that are a result of ultrahydrophobicity as exhibited by the leaves of ''Nelumbo'', the lotus flower. Dirt particles are picked up by water droplets due to the micro- and nanoscopic architecture on the surface, which minimizes the droplet's adhesion to that surface. Ultrahydrophobicity and self-cleaning properties are also found in other plants, such as '' Tropaeolum'' (nasturtium), ''Opuntia'' (prickly pear), '' Alchemilla'', cane, and also on the wings of certain insects. The phenomenon of ultrahydrophobicity was first studied by Dettre and Johnson in 1964 using rough hydrophobic surfaces. Their work developed a theoretical model based on experiments with glass beads coated with paraffin or PTFE telomer. The self-cleaning property of ultrahydrophobic micro- nanostructured surfaces was studied by Wilhelm Barthlott and Ehler in 1977, who described such self-cleaning and ultrahydrophobic properties for the first time as the " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultrahydrophobicity
Ultrahydrophobic (or superhydrophobic) surfaces are highly hydrophobic, i.e., extremely difficult to wet. The contact angles of a water droplet on an ultrahydrophobic material exceed 150°. This is also referred to as the lotus effect, after the superhydrophobic leaves of the lotus plant. A droplet striking these kinds of surfaces can fully rebound like an elastic ball. Interactions of bouncing drops can be further reduced using special superhydrophobic surfaces that promote symmetry breaking, pancake bouncing or waterbowl bouncing. Theory In 1805, Thomas Young defined the contact angle ''θ'' by analysing the forces acting on a fluid droplet resting on a smooth solid surface surrounded by a gas. :\gamma_\ =\gamma_+\gamma_\cos where :\gamma_\ = Interfacial tension between the solid and gas :\gamma_\ = Interfacial tension between the solid and liquid :\gamma_\ = Interfacial tension between the liquid and gas ''θ'' can be measured using a contact angle goniometer. Wenze ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leaves
A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, flower, and fruit collectively form the shoot system. In most leaves, the primary photosynthetic tissue is the palisade mesophyll and is located on the upper side of the blade or lamina of the leaf but in some species, including the mature foliage of ''Eucalyptus'', palisade mesophyll is present on both sides and the leaves are said to be isobilateral. Most leaves are flattened and have distinct upper ( adaxial) and lower (abaxial) surfaces that differ in color, hairiness, the number of stomata (pores that intake and output gases), the amount and structure of epicuticular wax and other features. Leaves are mostly green in color due to the presence of a compound called chlorophyll that is essential for photosynthesis as it absorbs lig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nelumbo Nucifera (Indian Lotus)- Water Drops W IMG 8657
''Nelumbo nucifera'', also known as sacred lotus, Laxmi lotus, Indian lotus, or simply lotus, is one of two extant species of aquatic plant in the family Nelumbonaceae. It is sometimes colloquially called a water lily, though this more often refers to members of the family Nymphaeaceae. Lotus plants are adapted to grow in the flood plains of slow-moving rivers and delta areas. Stands of lotus drop hundreds of thousands of seeds every year to the bottom of the pond. While some sprout immediately, and most are eaten by wildlife, the remaining seeds can remain dormant for an extensive period of time as the pond silts in and dries out. During flood conditions, sediments containing these seeds are broken open, and the dormant seeds rehydrate and begin a new lotus colony. Under favorable circumstances, the seeds of this aquatic perennial may remain viable for many years, with the oldest recorded lotus germination being from seeds 1,300 years old recovered from a dry lakebed in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allopatric Speciation
Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from each other to an extent that prevents or interferes with gene flow. Various geographic changes can arise such as the movement of continents, and the formation of mountains, islands, bodies of water, or glaciers. Human activity such as agriculture or developments can also change the distribution of species populations. These factors can substantially alter a region's geography, resulting in the separation of a species population into isolated subpopulations. The vicariant populations then undergo genetic changes as they become subjected to different selective pressures, experience genetic drift, and accumulate different mutations in the separated populations' gene pools. The barriers prevent the exchange of genetic information betwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caribbean
The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean Sea and the North Atlantic Ocean) and the surrounding coasts. The region is southeast of the Gulf of Mexico and the North American mainland, east of Central America, and north of South America. Situated largely on the Caribbean Plate, the region has more than 700 islands, islets, reefs and cays (see the list of Caribbean islands). Island arcs delineate the eastern and northern edges of the Caribbean Sea: The Greater Antilles and the Lucayan Archipelago on the north and the Lesser Antilles and the on the south and east (which includes the Leeward Antilles). They form the West Indies with the nearby Lucayan Archipelago (the Bahamas and Turks and Caicos Islands), which are considered to be part of the Caribbean despite not bordering the Caribbe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Caribbean Sea, and to the west and south by the Pacific Ocean. Because it is on the North American Plate, North American Tectonic Plate, Greenland is included as a part of North America geographically. North America covers an area of about , about 16.5% of Earth's land area and about 4.8% of its total surface. North America is the third-largest continent by area, following Asia and Africa, and the list of continents and continental subregions by population, fourth by population after Asia, Africa, and Europe. In 2013, its population was estimated at nearly 579 million people in List of sovereign states and dependent territories in North America, 23 independent states, or about 7.5% of the world's population. In Americas (terminology)#Human ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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