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Portulacaria Afra
''Portulacaria afra'' (known as elephant bush, porkbush, purslane tree and ' in Afrikaans) is a small-leaved succulent plant found in South Africa. These succulents commonly have a reddish stem and leaves that are green, but also a variegated cultivar is often seen in cultivation. They are simple to care for and make easy houseplants for a sunny location. In frost-free regions they may be used in outdoor landscaping. Description It is a soft-wooded, semi-evergreen upright shrub or small tree, usually tall. It is sometimes confused with ''Crassula ovata'' (Jade plant), which it is not closely related to. ''P. afra'' has smaller and rounder pads and more compact growth (shorter internodal spaces, down to ). It is much hardier, faster growing, more loosely branched, and has more limber tapering branches than ''Crassula'' once established. The genus ''Portulacaria'' has been shown to be an outlier, relatively unrelated to the other genera in the family, which are all restricte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nikolaus Joseph Von Jacquin
Nikolaus Joseph Freiherr von Jacquin (16 February 172726 October 1817) was a scientist who studied medicine, chemistry and botany. Biography Born in Leiden in the Netherlands, he studied medicine at Leiden University, then moved first to Paris and afterward to Vienna. In 1752, he studied under Gerard van Swieten in Vienna. Between 1755 and 1759, Jacquin was sent to the West Indies, Central America, Venezuela and New Granada by Francis I to collect plants for the Schönbrunn Palace, and amassed a large collection of animal, plant and mineral samples. In 1797, Alexander von Humboldt profited from studying these collections and conversing with Jacquin in preparation of his own journey to the Americas. In 1763, Jacquin became professor of chemistry and mineralogy at the Bergakademie Schemnitz (now Banská Štiavnica in Slovakia). In 1768, he was appointed Professor of Botany and Chemistry and became director of the botanical gardens of the University of Vienna. For his work ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Rhinoceros
The black rhinoceros, black rhino or hook-lipped rhinoceros (''Diceros bicornis'') is a species of rhinoceros, native to eastern and southern Africa including Angola, Botswana, Kenya, Malawi, Mozambique, Namibia, South Africa, Eswatini, Tanzania, Zambia, and Zimbabwe. Although the rhinoceros is referred to as ''black'', its colours vary from brown to grey. The other African rhinoceros is the white rhinoceros (''Ceratotherium simum''). The word "white" in the name "white rhinoceros" is often said to be a misinterpretation of the Afrikaans word ' (Dutch ') meaning wide, referring to its square upper lip, as opposed to the pointed or hooked lip of the black rhinoceros. These species are now sometimes referred to as the square-lipped (for white) or hook-lipped (for black) rhinoceros. The species overall is classified as critically endangered (even though the south-western black rhinoceros is classified as near threatened). Three subspecies have been declared extinct, including the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Physiology (journal)
''Plant Physiology'' is a monthly peer-reviewed scientific journal that covers research on physiology, biochemistry, cellular and molecular biology, genetics, biophysics, and environmental biology of plants. The journal has been published since 1926 by the American Society of Plant Biologists. The current editor-in-chief is Yunde Zhao (University of California San Diego. According to the ''Journal Citation Reports'', the journal has a 2021 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as i ... of 8.005. References External links * {{Authority control Botany journals Publications established in 1926 Monthly journals English-language journals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desertification
Desertification is a type of land degradation in drylands in which biological productivity is lost due to natural processes or induced by human activities whereby fertile areas become increasingly arid. It is the spread of arid areas caused by a variety of factors, such as climate change and overexploitation of soil as a result of human activity. Throughout geological history, the development of deserts has occurred naturally. In recent times, the potential influences of human activity, improper land management, deforestation and climate change on desertification is the subject of many scientific investigations. Definitions of words As recently as 2005, considerable controversy existed over the proper definition of the term "desertification." Helmut Geist (2005) identified more than 100 formal definitions. The most widely acceptedGeist (2005)p. 2/ref> of these was that of the Princeton University Dictionary which defined it as "the process of fertile land ''transforming into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overgrazing
Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, game reserves, or nature reserves. It can also be caused by immobile, travel restricted populations of native or non-native wild animals. Overgrazing reduces the usefulness, productivity, and biodiversity of the land and is one cause of desertification and erosion. Overgrazing is also seen as a cause of the spread of invasive species of non-native plants and of weeds. Degrading land, emissions from animal agriculture and reducing the biomass in a ecosystem contribute directly to climate change. Overgrazing can be reversed or prevented by removing grazers in order to give plants time to recover between grazing events. Successful planned grazing strategies have been support in the American bison of the Great Plains, or migratory Wildebeests of the African savann ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Fixation
Biological carbon fixation or сarbon assimilation is the process by which inorganic carbon (particularly in the form of carbon dioxide) is converted to organic compounds by living organisms. The compounds are then used to store energy and as structure for other biomolecules. Carbon is primarily fixed through photosynthesis, but some organisms use a process called chemosynthesis in the absence of sunlight. Organisms that grow by fixing carbon are called autotrophs, which include photoautotrophs (which use sunlight), and lithoautotrophs (which use inorganic oxidation). Heterotrophs are not themselves capable of carbon fixation but are able to grow by consuming the carbon fixed by autotrophs or other heterotrophs. "Fixed carbon", "reduced carbon", and "organic carbon" may all be used interchangeably to refer to various organic compounds. Chemosynthesis is carbon fixation driven by chemical energy, rather than from sunlight. Sulfur- and hydrogen-oxidizing bacteria often use the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crassulacean Acid Metabolism
Crassulacean acid metabolism, also known as CAM photosynthesis, is a carbon fixation pathway that evolved in some plants as an adaptation to arid conditions that allows a plant to photosynthesize during the day, but only exchange gases at night. In a plant using full CAM, the stomata in the leaves remain shut during the day to reduce evapotranspiration, but they open at night to collect carbon dioxide () and allow it to diffuse into the mesophyll cells. The is stored as four-carbon malic acid in vacuoles at night, and then in the daytime, the malate is transported to chloroplasts where it is converted back to , which is then used during photosynthesis. The pre-collected is concentrated around the enzyme RuBisCO, increasing photosynthetic efficiency. This mechanism of acid metabolism was first discovered in plants of the family Crassulaceae. Historical background Observations relating to CAM were first made by de Saussure in 1804 in his ''Recherches Chimiques sur la Végétatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C3 Carbon Fixation
carbon fixation is the most common of three metabolic pathways for carbon fixation in photosynthesis, along with and CAM. This process converts carbon dioxide and ribulose bisphosphate (RuBP, a 5-carbon sugar) into two molecules of 3-phosphoglycerate through the following reaction: :CO2 + H2O + RuBP → (2) 3-phosphoglycerate This reaction was first discovered by Melvin Calvin, Andrew Benson and James Bassham in 1950. C3 carbon fixation occurs in all plants as the first step of the Calvin–Benson cycle. (In and CAM plants, carbon dioxide is drawn out of malate and into this reaction rather than directly from the air.) Plants that survive solely on fixation ( plants) tend to thrive in areas where sunlight intensity is moderate, temperatures are moderate, carbon dioxide concentrations are around 200 ppm or higher, and groundwater is plentiful. The plants, originating during Mesozoic and Paleozoic eras, predate the plants and still represent approximately 95% of Eart ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Succulents
In botany, succulent plants, also known as succulents, are plants with parts that are thickened, fleshy, and engorged, usually to retain water in arid climates or soil conditions. The word ''succulent'' comes from the Latin word ''sucus'', meaning "juice" or "sap". Succulent plants may store water in various structures, such as leaves and stems. The water content of some succulent organs can get up to 90–95%, such as '' Glottiphyllum semicyllindricum'' and '' Mesembryanthemum barkleyii''. Some definitions also include roots, thus geophytes that survive unfavorable periods by dying back to underground storage organs may be regarded as succulents. The habitats of these water-preserving plants are often in areas with high temperatures and low rainfall, such as deserts, but succulents may be found even in alpine ecosystems growing in rocky soil. Succulents are characterized by their ability to thrive on limited water sources, such as mist and dew, which makes them equipped to s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jade Plant
''Crassula ovata'', commonly known as jade plant, lucky plant, money plant or money tree, is a succulent plant with small pink or white flowers that is native to the KwaZulu-Natal and Eastern Cape provinces of South Africa, and Mozambique; it is common as a houseplant worldwide. Much of its popularity stems from the low levels of care needed; the jade plant requires little water and can survive in most indoor conditions. It is sometimes referred to as the money tree; however, ''Pachira aquatica'' also has this nickname. Description The jade plant is an evergreen with thick branches. It has thick, shiny, smooth leaves that grow in opposing pairs along the branches. Leaves are a rich jade green, although some may appear to be more of a yellow-green. Some varieties may develop a red tinge on the edges of leaves when exposed to high levels of sunlight. New stem growth is the same colour and texture as the leaves, becoming woody and brown with age. It grows as an upright, rounded, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xeriscaping
Xeriscaping is the process of Garden design, landscaping, or gardening, that reduces or eliminates the need for irrigation. It is promoted in regions that do not have accessible, plentiful, or reliable supplies of fresh water and has gained acceptance in other regions as access to irrigation water has become limited, though it is not limited to such climates. Xeriscaping may be an alternative to various types of traditional gardening. In some areas, terms such as ''water conservation, water-conserving landscaping'', ''drought-tolerant landscaping'', and ''smart scaping'' are used instead. The use of plants whose natural requirements are appropriate to the local climate is emphasized, and care is taken to avoid losing water to evaporation and surface runoff, runoff. However, the specific plants used in xeriscaping vary based on climate as this strategy can be used in xeric, mesic, and hydric environments. Xeriscaping is different from natural landscaping, because the emphasis in x ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portulacaria Afra 2
''Portulacaria'' is a genus of succulent plant, classified in its own subfamily Portulacarioideae in the family Didiereaceae. It is indigenous to southern Africa. Taxonomy The genus was previously placed in the family Portulacaceae, but according to molecular studies is part of Didiereaceae. It has further been revised when phylogenetic tests showed conclusively that genus ''Ceraria'' was located within ''Portulacaria'', and all ''Ceraria'' species have consequently been renamed and moved into this genus. Species Species include: * ''Portulacaria afra'' Jacq. * '' Portulacaria armiana'' E. J. Van Jaarsveld * '' Portulacaria carrissoana''. Previously '' Ceraria carrissoana'' Excell & Mendonca * '' Portulacaria fruticulosa''. Previously '' Ceraria fruticulosa'' Pearson & Stephens * '' Portulacaria longipedunculata''. Previously '' Ceraria longipedunculata'' Merxm & Podlech * '' Portulacaria namaquensis''. Previously ''Ceraria namaquensis'' Sond. * '' Portulacaria pygmaea''. Prev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
