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Musa Acuminata
''Musa acuminata'' is a species of banana native to Southern Asia, its range comprising the Indian Subcontinent and Southeast Asia. Many of the modern edible dessert bananas are from this species, although some are hybrids with ''Musa balbisiana''. First cultivated by humans around 10 kya (8000 BCE), it is one of the early examples of domesticated plants. Description ''Musa acuminata'' is an evergreen perennial, not a tree. The trunk (known as the pseudostem) is made of tightly packed layers of leaf sheaths emerging from completely or partially buried corms. The leaves are at the top of the leaf sheaths, or petioles and in the subspecies M. a. truncata the blade or lamina is up to22 feet (seven meters) in length and 39 inches (one meter) wide. The inflorescence grows horizontally or obliquely from the trunk. The individual flowers are white to yellowish-white in color and are negatively geotropic (that is, growing upwards and away from the ground). Both male and female flo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luigi Aloysius Colla
Luigi Aloysius Colla (30 April 1766 – 23 December 1848) was an Italian botanist of the late 18th and early 19th Centuries. He was a member of the Provisional Government of Savoy from December 12, 1798, to April 2, 1799, taking his turn as chairman of the government in rotation for a ten-day term. In 1820 Colla described two species, ''Musa balbisiana'' and ''Musa acuminata'', that are the basis for almost all cultivated bananas. Colla was a member of the Philadelphia Academy of Natural Sciences The Academy of Natural Sciences of Drexel University, formerly the Academy of Natural Sciences of Philadelphia, is the oldest natural science research institution and museum in the Americas. It was founded in 1812, by many of the leading natur .... Bibliography * ''L'antolegista botanico'' - Turin - Volume 1, Volume 5, Volume 6 * ''Memoria sul genere Musa e monografia del medesimo'' - Turin * ''Observations sur le Limodorum purpureum de M. de Lamarck et création d'un nouveau genre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petiole (botany)
In botany, the petiole () is the stalk that attaches the leaf blade to the stem, and is able to twist the leaf to face the sun. This gives a characteristic foliage arrangement to the plant. Outgrowths appearing on each side of the petiole in some species are called stipules. Leaves with a petiole are said to be petiolate, while leaves lacking a petiole are called sessile or apetiolate. Description The petiole is a stalk that attaches a leaf to the plant stem. In petiolate leaves, the leaf stalk may be long, as in the leaves of celery and rhubarb, or short. When completely absent, the blade attaches directly to the stem and is said to be sessile. Subpetiolate leaves have an extremely short petiole, and may appear sessile. The broomrape family Orobanchaceae is an example of a family in which the leaves are always sessile. In some other plant groups, such as the speedwell genus '' Veronica'', petiolate and sessile leaves may occur in different species. In the grasses ( Poacea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parthenocarpy
In botany and horticulture, parthenocarpy is the natural or artificially induced production of fruit without fertilisation of ovules, which makes the fruit seedless. Stenospermocarpy may also produce apparently seedless fruit, but the seeds are actually aborted while they are still small. Parthenocarpy (or stenospermocarpy) occasionally occurs as a mutation in nature; if it affects every flower, the plant can no longer sexually reproduce but might be able to propagate by apomixis or by vegetative means. Examples of this include many citrus varieties that undergo nucellar embryony for reproduction, instead of solely sexual reproduction, and can yield seedless fruits. However, parthenocarpy of some fruits on a plant may be of value. Up to 20% of the fruits of wild parsnip are parthenocarpic. The seedless wild parsnip fruit are preferred by certain herbivores and so serve as a "decoy defense" against seed predation. Utah juniper has a similar defense against bird feeding. The ab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyploid
Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei ( eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contains one or more chromosomes and comes from each of two parents, resulting in pairs of homologous chromosomes between sets. However, some organisms are polyploid. Polyploidy is especially common in plants. Most eukaryotes have diploid somatic cells, but produce haploid gametes (eggs and sperm) by meiosis. A monoploid has only one set of chromosomes, and the term is usually only applied to cells or organisms that are normally diploid. Males of bees and other Hymenoptera, for example, are monoploid. Unlike animals, plants and multicellular algae have life cycles with two alternating multicellular generations. The gametophyte generation is haploid, and produces gametes by mitosis, the sporophyte generation is diploid and produces spore ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cultivar
A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture, or carefully controlled seed production. Most cultivars arise from purposeful human manipulation, but some originate from wild plants that have distinctive characteristics. Cultivar names are chosen according to rules of the International Code of Nomenclature for Cultivated Plants (ICNCP), and not all cultivated plants qualify as cultivars. Horticulturists generally believe the word ''cultivar''''Cultivar'' () has two meanings, as explained in '' Formal definition'': it is a classification category and a taxonomic unit within the category. When referring to a taxon, the word does not apply to an individual plant but to all plants that share the unique characteristics that define the cultivar. was coined as a term meaning "cultivated var ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are the histones. These proteins, aided by chaperone proteins, bind to and condense the DNA molecule to maintain its integrity. These chromosomes display a complex three-dimensional structure, which plays a significant role in transcriptional regulation. Chromosomes are normally visible under a light microscope only during the metaphase of cell division (where all chromosomes are aligned in the center of the cell in their condensed form). Before this happens, each chromosome is duplicated ( S phase), and both copies are joined by a centromere, resulting either in an X-shaped structure (pictured above), if the centromere is located equatorially, or a two-arm structure, if the centromere is located distally. The joined copies are now c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diploid
Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectively, in each homologous chromosome pair, which chromosomes naturally exist as. Somatic cells, tissues, and individual organisms can be described according to the number of sets of chromosomes present (the "ploidy level"): monoploid (1 set), diploid (2 sets), triploid (3 sets), tetraploid (4 sets), pentaploid (5 sets), hexaploid (6 sets), heptaploid or septaploid (7 sets), etc. The generic term polyploid is often used to describe cells with three or more chromosome sets. Virtually all sexually reproducing organisms are made up of somatic cells that are diploid or greater, but ploidy level may vary widely between different organisms, between different tissues within the same organism, and at different stages in an organism's life cycle. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parenchyma
Parenchyma () is the bulk of functional substance in an animal organ or structure such as a tumour. In zoology it is the name for the tissue that fills the interior of flatworms. Etymology The term ''parenchyma'' is New Latin from the word παρέγχυμα ''parenchyma'' meaning 'visceral flesh', and from παρεγχεῖν ''parenchyma'' meaning 'to pour in' from παρα- ''para-'' 'beside' + ἐν ''en-'' 'in' + χεῖν ''chyma'' 'to pour'. Originally, Erasistratus and other anatomists used it to refer to certain human tissues. Later, it was also applied to plant tissues by Nehemiah Grew. Structure The parenchyma is the ''functional'' parts of an organ, or of a structure such as a tumour in the body. This is in contrast to the stroma, which refers to the ''structural'' tissue of organs or of structures, namely, the connective tissues. Brain The brain parenchyma refers to the functional tissue in the brain that is made up of the two types of brain cell, neurons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micropyle , a differentiated area of surface in an egg, through which a sperm enters
{{Disambiguation ...
Micropyle may refer to: * Micropyle (botany) a minute opening in the integument of an ovule of a seed plant. * Micropyle (zoology) A micropyle is a pore in the membrane covering the ovum, through which a sperm enters. Micropyles are also found in sporozoites of some digenetic microorganisms such as ''Plasmodium'' at the anterior part of the cell that ultimately leads towards t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Berry (botany)
In botany, a berry is a fleshy fruit without a stone (pit) produced from a single flower containing one ovary. Berries so defined include grapes, currants, and tomatoes, as well as cucumbers, eggplants (aubergines) and bananas, but exclude certain fruits that meet the culinary definition of berries, such as strawberries and raspberries. The berry is the most common type of fleshy fruit in which the entire outer layer of the ovary wall ripens into a potentially edible " pericarp". Berries may be formed from one or more carpels from the same flower (i.e. from a simple or a compound ovary). The seeds are usually embedded in the fleshy interior of the ovary, but there are some non-fleshy exceptions, such as peppers, with air rather than pulp around their seeds. Many berries are edible, but others, such as the fruits of the potato and the deadly nightshade, are poisonous to humans. A plant that bears berries is said to be bacciferous or baccate (a fruit that resembles a berry ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture. Typically, they also look different from the parts of the flower, such as the petals or sepals. A plant having bracts is referred to as bracteate or bracteolate, while one that lacks them is referred to as ebracteate and ebracteolate, without bracts. Variants Some bracts are brightly-coloured and serve the function of attracting pollinators, either together with the perianth or instead of it. Examples of this type of bract include those of '' Euphorbia pulcherrima'' (poinsettia) and ''Bougainvillea'': both of these have large colourful bracts surrounding much smaller, less colourful flowers. In grasses, each floret (flower) is enclosed in a pair of papery bracts, called the lemma (lower bract) and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geotropism
Gravitropism (also known as geotropism) is a coordinated process of differential growth by a plant in response to gravity pulling on it. It also occurs in fungi. Gravity can be either "artificial gravity" or natural gravity. It is a general feature of all higher and many lower plants as well as other organisms. Charles Darwin was one of the first to scientifically document that roots show ''positive gravitropism'' and stems show ''negative gravitropism''. That is, roots grow in the direction of gravitational pull (i.e., downward) and stems grow in the opposite direction (i.e., upwards). This behavior can be easily demonstrated with any potted plant. When laid onto its side, the growing parts of the stem begin to display negative gravitropism, growing (biologists say, turning; see tropism) upwards. Herbaceous (non-woody) stems are capable of a degree of actual bending, but most of the redirected movement occurs as a consequence of root or stem growth outside. The mechanism ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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