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Duckweed
Lemnoideae is a subfamily of flowering aquatic plants, known as duckweeds, water lentils, or water lenses. They float on or just beneath the surface of still or slow-moving bodies of fresh water and wetlands. Also known as bayroot, they arose from within the arum or aroid family (Araceae), so often are classified as the subfamily Lemnoideae within the family Araceae. Other classifications, particularly those created prior to the end of the twentieth century, place them as a separate family, Lemnaceae. These plants have a simple structure, lacking an obvious stem or leaves. The greater part of each plant is a small organized " thallus" or "frond" structure only a few cells thick, often with air pockets (aerenchyma) that allow it to float on or just under the water surface. Depending on the species, each plant may have no root or may have one or more simple rootlets. Reproduction is mostly by asexual budding ( vegetative reproduction), which occurs from a meristem enclosed at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lemna
''Lemna'' is a genus of free-floating aquatic plants referred to by the common name "duckweed". They are morphologically divergent members of the arum family Araceae. These rapidly growing plants have found uses as a model system for studies in community ecology, basic plant biology, ecotoxicology, and production of biopharmaceuticals, and as a source of animal feeds for agriculture and aquaculture. Currently, 14 species of ''Lemna'' are recognised. Taxonomy These duckweeds were previously placed in a separate flowering plant family, the Lemnaceae, but they are now considered to be members of the Araceae. Description ''Lemna'' species grow as simple free-floating thalli on or just beneath the water surface. Most are small, not exceeding 5 mm in length, except ''Lemna trisulca'', which is elongated and has a branched structure. ''Lemna'' thalli have a single root, which distinguishes this genus from the related genera '' Wolffia'' (lacks roots), ''Spirodela'' and ''Lan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spirodela Polyrrhiza
''Spirodela polyrhiza'' ( ''S. polyrrhiza'') is a species of duckweed known by the common names common duckmeat, greater duckweed, great duckmeat, common duckweed, and duckmeat. It can be found nearly worldwide in many types of freshwater habitat. Description ''Spirodela polyrhiza'' is a perennial aquatic plant usually growing in dense colonies, forming a mat on the water surface. Each plant is a smooth, round, flat disc 0.5 to 1.0 cm wide. Its upper surface is mostly green, sometimes red, while the lower surface is dark red. It produces several minute roots and a pouch containing male and female flowers. The top part dies in the fall and the plant often overwinters as a turion. The turion sinks to the bottom of the water body and stays in a dormant phase, until water temperature reaches 15 °C. The turions then germinate on the bottom of the water body and start a new life cycle. As this species lives in ponds and slow-moving water bodies, differs developmentally fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wolffia
''Wolffia'' is a genus of aquatic plants with a cosmopolitan distribution. They include the smallest flowering plants on Earth. Commonly called watermeal or duckweed, these aquatic plants resemble specks of cornmeal floating on the water. Individuals often float together in pairs or form floating mats with related plants, such as ''Lemna'' and ''Spirodela'' species. Description ''Wolffia'' are free-floating aquatic plants with fronds that are nearly spherical to cylindrical in shape and lack airspaces or veins. They do not have roots. Their rarely seen flowers originate from a cavity on the upper surface of the frond, and each flower has one stamen and one pistil. Although ''Wolffia'' can reproduce by seed, they usually use vegetative reproduction. A mother frond has a terminal conical cavity from which it produces daughter fronds. Physiology The growth rate of ''Wolffia'' varies within and among species. The rates of photosynthesis and respiration also vary proportionate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spirodela
''Spirodela'' is a genus of aquatic plants, one of several genera containing plants commonly called duckweed. ''Spirodela'' species are members of the Araceae under the APG II system. They were formerly members of the Lemnaceae. ''Spirodela'' species are free-floating thalli; two to five plants may remain connected to each other. Plants are green, but may have a red or brown underside. Multiple root In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the su ...s (seven to 12) emerge from each thallus. ''Spirodela'' is larger () than '' Lemna'' ( – , one root per thallus). Certain species of ''Spirodela'' overwinter as turions, a dormant form that lacks air pockets, so sinks to the bottom of the pond. In spring, turions rise to the surface and germinate to start a new population. ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wetlands
A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The primary factor that distinguishes wetlands from terrestrial land forms or Body of water, water bodies is the characteristic vegetation of aquatic plants, adapted to the unique anoxic hydric soils. Wetlands are considered among the most biologically diverse of all ecosystems, serving as home to a wide range of plant and animal species. Methods for assessing wetland functions, wetland ecological health, and general wetland condition have been developed for many regions of the world. These methods have contributed to wetland conservation partly by raising public awareness of the functions some wetlands provide. Wetlands occur naturally on every continent. The water in wetlands is either freshwater, brackish or saltwater. The main wetland t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wolffia Globosa
''Wolffia globosa'' is a species of flowering plant known by the common names Asian watermeal and duckweed. It is native to Asia and is found in parts of the Americas and Africa, where it is an introduced species. It grows in mats on the surface of calm, freshwater bodies, such as ponds, lakes, and marshes. It is a very tiny, oval-shaped plant with no leaves, stems, or roots. The body of the plant, a transparent green frond, is less than a millimeter wide. In one human experiment, processed ''W. globosa'' was reported to provide dietary protein and vitamin B12. ''Wolffia globosa'' has been described as the world's smallest flowering plant, at in diameter. Known in Thai as ''Pham'' (ผํา), it is a popular item in Thai cuisine, especially in Isan Northeast Thailand or Isan (Isan/ th, อีสาน, ; lo, ອີສານ; also written as Isaan, Isarn, Issarn, Issan, Esan, or Esarn; from Pali ''īsānna'' or Sanskrit ईशान्य ''īśānya'' "northeast") cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Araceae
The Araceae are a family of monocotyledonous flowering plants in which flowers are borne on a type of inflorescence called a spadix. The spadix is usually accompanied by, and sometimes partially enclosed in, a spathe (or leaf-like bract). Also known as the arum family, members are often colloquially known as aroids. This family of 140 genera and about 4,075 known species is most diverse in the New World tropics, although also distributed in the Old World tropics and northern temperate regions. Many species display very decorative leaves and flowers, and they are widely used for gardening; popular as indoor plants and also outdoor plants where climates are mild, and winter freezes will not generally occur. However, some temperate species are also very popular in Mediterranean-climate gardening, or in moderately cool temperate zones, such as ''Zantedeschia''. Description Species within Araceae are often rhizomatous or tuberous, and the leaves nearly always contain calcium ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquatic Plant
Aquatic plants are plants that have adapted to living in aquatic environments ( saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that grows in or near water and is either emergent, submergent, or floating. In lakes and rivers macrophytes provide cover for fish, substrate for aquatic invertebrates, produce oxygen, and act as food for some fish and wildlife. Macrophytes are primary producers and are the basis of the food web for many organisms. They have a significant effect on soil chemistry and light levels as they slow down the flow of water and capture pollutants and trap sediments. Excess sediment will settle into the benthos aided by the reduction of flow rates caused by the presence of plant stems, leaves and roots. Some plants have the capability of absorbing pollutants into their tissue. Seaweeds are multicellular marine algae and, although their ecological ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wolffiella
''Wolffiella'' is a genus of aquatic plants commonly called duckweeds in the family Araceae The Araceae are a family of monocotyledonous flowering plants in which flowers are borne on a type of inflorescence called a spadix. The spadix is usually accompanied by, and sometimes partially enclosed in, a spathe (or leaf-like bract). Also .... Common names for plants in this genus include bogmat and mud-midget. They are rootless and have a keel that allows them to maintain their orientation in the water. They are small, measuring to in width. Selected species *'' Wolffiella caudata'' *'' Wolffiella denticulata'' *'' Wolffiella gladiata'' *'' Wolffiella hyalina'' *'' Wolffiella lingulata'' *'' Wolffiella neotropica'' *'' Wolffiella oblonga'' *'' Wolffiella repanda'' *'' Wolffiella rotunda'' *'' Wolffiella welwitschii'' References Further reading *Bown, Deni (2000). ''Aroids: Plants of the Arum Family''. Timber Press. . {{Taxonbar, from=Q9377653 Lemnoideae Araceae genera< ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fry (biology)
Fish go through various life stages between fertilization and adulthood. The life of a fish start as spawned eggs which hatch into immotile larvae. These larval hatchlings are not yet capable of feeding themselves and carry a yolk sac which provides stored nutrition. Before the yolk sac completely disappears, the young fish must mature enough to be able to forage independently. When they have developed to the point where they are capable of feeding by themselves, the fish are called fry. When, in addition, they have developed scales and working fins, the transition to a juvenile fish is complete and it is called a fingerling, so called as they are typically about the size of human fingers. The juvenile stage lasts until the fish is fully grown, sexually mature and interacting with other adult fish. Growth stages Ichthyoplankton ''(planktonic or drifting fish)'' are the eggs and larvae of fish. They are usually found in the sunlit zone of the water column, less than 200 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Reproduction
Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete ( haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote that develops into an organism composed of cells with two sets of chromosomes ( diploid). This is typical in animals, though the number of chromosome sets and how that number changes in sexual reproduction varies, especially among plants, fungi, and other eukaryotes. Sexual reproduction is the most common life cycle in multicellular eukaryotes, such as animals, fungi and plants. Sexual reproduction also occurs in some unicellular eukaryotes. Sexual reproduction does not occur in prokaryotes, unicellular organisms without cell nuclei, such bacteria and archaea. However, some process in bacteria may be considered analogous to sexual reproduction in that they incorporate new genetic information, including bacterial conjugation, transforma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waterfowl
Anseriformes is an order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae (three species of screamers), Anseranatidae (the magpie goose), and Anatidae, the largest family, which includes over 170 species of waterfowl, among them the ducks, geese, and swans. Most modern species in the order are highly adapted for an aquatic existence at the water surface. With the exception of screamers, males have penises, a trait that has been lost in the Neoaves. Due to their aquatic nature, most species are web-footed. Evolution Anseriformes are one of only two types of modern bird to be confirmed present during the Mesozoic alongside the other dinosaurs, and in fact were among the very few birds to survive their extinction, along with their cousins the galliformes. These two groups only occupied two ecological niches during the Mesozoic, living in water and on the ground, while the toothed enantiornithes were the domina ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
