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Dawsonia (plant)
''Dawsonia'' is a genus of acrocarpous mosses. ''Dawsonia'', along with other members of the order Polytrichales, are taller than most mosses and have thicker leaves. Their sporophytes have conducting systems analogous to those of vascular plants. '' Dawsonia superba'' is found in New Zealand, Australia and New Guinea. '' D. longifolia'' is found in the Philippines, Indonesia, Malaysia, and Australia. There is uncertainty as to whether ''D. superba'' and ''D. longifolia'' are actually distinct species. Etymology ''Dawsonia'' was named in honor of Dawson Turner (1775–1858), distinguished cryptogamist and friend of Robert Brown, who named the genus in 1811. Description Height Moss gametophytes lack internal transport tissues, which, coupled with the absence of cuticles, leads to the water-loss characteristic of bryophytes. As bryophytes can only grow when hydrated, the lack of conducting tissue restricts most mosses, even in relatively wet habitats, to a low stature. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abel Tasman National Park
Abel Tasman National Park is a national park at the north end of New Zealand's South Island. It covers of land between Golden Bay / Mohua and Tasman Bay / Te Tai-o-Aorere, making it the smallest of National parks of New Zealand, New Zealand's national parks. Despite this, the park is one of the most visited, partially due to the popularity of the Abel Tasman Coast Track which spans along the eastern and northern coastal areas of the park. The area of the park has seen human interaction for approximately 700 years, with evidence of habitation dating back to early Māori people, Māori iwi such as Waitaha (South Island iwi), Waitaha and Rapuwai during the early periods of Māori habitation in New Zealand. Following the arrival of Pākehā in the 19th century, the area saw widespread deforestation, farming, and quarrying, significantly modifying the area's environment. As a result of this, the park is one of the most modified landscapes of any of New Zealand's national parks, wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malaysia
Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and three federal territories, separated by the South China Sea into two regions: Peninsular Malaysia on the Mainland Southeast Asia, Indochinese Peninsula and East Malaysia on the island of Borneo. Peninsular Malaysia shares land and maritime Malaysia–Thailand border, borders with Thailand, as well as maritime borders with Singapore, Vietnam, and Indonesia; East Malaysia shares land borders with Brunei and Indonesia, and a maritime border with the Philippines and Vietnam. Kuala Lumpur is the country's national capital, List of cities and towns in Malaysia by population, largest city, and the seat of the Parliament of Malaysia, legislative branch of the Government of Malaysia, federal government, while Putrajaya is the federal administrative capi ... [...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] |
Xylem
Xylem is one of the two types of transport tissue (biology), tissue in vascular plants, the other being phloem; both of these are part of the vascular bundle. The basic function of the xylem is to transport water upward from the roots to parts of the plants such as stems and leaves, but it also transports plant nutrition, nutrients. The word ''xylem'' is derived from the Ancient Greek word (), meaning "wood"; the best-known wood organism is plants, though it is found throughout a plant. The term was introduced by Carl Nägeli in 1858. Structure The most distinctive xylem cell (biology), cells are the long tracheary elements that transport water. Tracheids and vessel elements are distinguished by their shape; vessel elements are shorter, and are connected together into long tubes that are called ''vessels''. Wood also contains two other type of cells: Ground tissue#Parenchyma, parenchyma and ground tissue#Fibres, fibers. Xylem can be found: * in vascular bundles, present in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dawsonia Stem
''Dawsonia'' is the scientific name of several genera of organisms and may refer to: * ''Dawsonia'' (plant), a genus of moss some reaching up to 65 cm (two feet) in length * ''Dawsonia'' (trilobite), an eodiscoid trilobite * ''Dawsonia'' (problematicum), a Palaeozoic problematicum {{Genus disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Wall
A cell wall is a structural layer that surrounds some Cell type, cell types, found immediately outside the cell membrane. It can be tough, flexible, and sometimes rigid. Primarily, it provides the cell with structural support, shape, protection, and functions as a selective barrier. Another vital role of the cell wall is to help the cell withstand osmotic pressure and mechanical stress. While absent in many eukaryotes, including animals, cell walls are prevalent in other organisms such as fungi, algae and plants, and are commonly found in most Prokaryote, prokaryotes, with the exception of Mollicutes, mollicute bacteria. The composition of cell walls varies across taxonomic groups, species, cell type, and the cell cycle. In Embryophyte, land plants, the primary cell wall comprises Polysaccharide, polysaccharides like cellulose, hemicelluloses, and pectin. Often, other Polymer, polymers such as lignin, suberin or cutin are anchored to or embedded in plant cell walls. Algae exhibit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leaf
A leaf (: leaves) is a principal appendage of the plant stem, stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, flower, and fruit collectively form the Shoot (botany), shoot system. In most leaves, the primary Photosynthesis, photosynthetic Tissue (biology), 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. The leaf is an integral part of the stem system, and most leaves are flattened and have distinct upper (Glossary of botanical terms#adaxial, adaxial) and lower (Glossary of botanical terms#abaxial, abaxial) surfaces that differ in color, Trichome, hairiness, the number of stomata (pores that intake and output gases), the amount and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lamella (cell Biology)
A lamella (: lamellae) in biology refers to a thin layer, membrane or plate of tissue. This is a very broad definition, and can refer to many different structures. Any thin layer of organic tissue can be called a lamella and there is a wide array of functions an individual layer can serve. For example, an intercellular lipid lamella is formed when lamellar disks fuse to form a lamellar sheet. It is believed that these disks are formed from vesicles, giving the lamellar sheet a lipid bilayer that plays a role in water diffusion. Another instance of cellular lamellae can be seen in chloroplasts. Thylakoid membranes are actually a system of lamellar membranes working together, and are differentiated into different lamellar domains. This lamellar system allows plants to convert light energy into chemical energy. Chloroplasts are characterized by a system of membranes embedded in a hydrophobic proteinaceous matrix, or stroma. The basic unit of the membrane system is a flattened s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gametophyte
A gametophyte () is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the sexual phase in the life cycle of plants and algae. It develops sex organs that produce gametes, haploid sex cells that participate in fertilization to form a diploid zygote which has a double set of chromosomes. Cell division of the zygote results in a new diploid multicellular organism, the second stage in the life cycle known as the sporophyte. The sporophyte can produce haploid spores by meiosis that on germination produce a new generation of gametophytes. Algae In some multicellular green algae ('' Ulva lactuca'' is one example), red algae and brown algae, sporophytes and gametophytes may be externally indistinguishable (isomorphic). In ''Ulva'', the gametes are isogamous, all of one size, shape and general morphology. Land plant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Stem
A stem is one of two main structural axes of a vascular plant, the other being the root. It supports leaf, leaves, flowers and fruits, transports water and dissolved substances between the roots and the shoots in the xylem and phloem, engages in photosynthesis, stores nutrients, and produces new living tissue. The stem can also be called the culm, halm, haulm, stalk, or thyrsus. The stem is normally divided into nodes and internodes: * The nodes are the points of attachment for leaves and can hold one or more leaves. There are sometimes axillary buds between the stem and leaf which can grow into branches (with leaf, leaves, conifer cones, or inflorescence, flowers). Adventitious roots (e.g. brace roots) may also be produced from the nodes. Vines may produce tendrils from nodes. * The internodes distance one node from another. The term "Shoot (botany), shoots" is often confused with "stems"; "shoots" generally refers to new fresh plant growth, including both stems and other str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bryophytes
Bryophytes () are a group of land plants ( embryophytes), sometimes treated as a taxonomic division referred to as Bryophyta '' sensu lato'', that contains three groups of non-vascular land plants: the liverworts, hornworts, and mosses. In the strict sense, the division Bryophyta consists of the mosses only. Bryophytes are characteristically limited in size and prefer moist habitats although some species can survive in drier environments. The bryophytes consist of about 20,000 plant species. Bryophytes produce enclosed reproductive structures ( gametangia and sporangia), but they do not produce flowers or seeds. They reproduce sexually by spores and asexually by fragmentation or the production of gemmae. Though bryophytes were considered a paraphyletic group in recent years, almost all of the most recent phylogenetic evidence supports the monophyly of this group, as originally classified by Wilhelm Schimper in 1879. The term ''bryophyte'' comes . Features The defining ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Cuticle
A plant cuticle is a protecting film covering the outermost skin layer (epidermis) of leaves, young shoots and other aerial plant organs (aerial here meaning all plant parts not embedded in soil or other substrate) that have no '' periderm''. The film consists of lipid and hydrocarbon polymers infused with wax, and is synthesized exclusively by the epidermal cells. Kolattukudy, PE (1996) Biosynthetic pathways of cutin and waxes, and their sensitivity to environmental stresses. In: Plant Cuticles. Ed. by G. Kerstiens, BIOS Scientific publishers Ltd., Oxford, pp 83-108 Description The plant cuticle is a layer of lipid polymers impregnated with waxes that is present on the outer surfaces of the primary organs of all vascular land plants. It is also present in the sporophyte generation of hornworts, and in both sporophyte and gametophyte generations of mosses. The plant cuticle forms a coherent outer covering of the plant that can be isolated intact by treating plant tissue with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
