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Chalazal Spot
The chalaza (; from Greek "hailstone"; plural ''chalazas'' or ''chalazae'', ) is a structure inside bird eggs and plant ovules. It attaches or suspends the yolk or nucellus within the larger structure. In animals In the eggs of most birds (not of the reptiles), the chalazae are two spiral bands of tissue that suspend the yolk in the center of the white (the albumen). The function of the chalazae is to hold the yolk in place. In baking, the chalazae are sometimes removed in order to ensure a uniform texture. In plants In plant ovules, the chalaza is located opposite the micropyle opening of the integuments. It is the tissue where the integuments and nucellus are joined. Nutrients from the plant travel through vascular tissue in the funiculus and outer integument through the chalaza into the nucellus. During the development of the embryo sac inside a flowering plant ovule, the three cells at the chalazal end become the antipodal cells. Chalazogamy In most flowering plants, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greek Language
Greek ( el, label=Modern Greek, Ελληνικά, Elliniká, ; grc, Ἑλληνική, Hellēnikḗ) is an independent branch of the Indo-European family of languages, native to Greece, Cyprus, southern Italy (Calabria and Salento), southern Albania, and other regions of the Balkans, the Black Sea coast, Asia Minor, and the Eastern Mediterranean. It has the longest documented history of any Indo-European language, spanning at least 3,400 years of written records. Its writing system is the Greek alphabet, which has been used for approximately 2,800 years; previously, Greek was recorded in writing systems such as Linear B and the Cypriot syllabary. The alphabet arose from the Phoenician script and was in turn the basis of the Latin, Cyrillic, Armenian, Coptic, Gothic, and many other writing systems. The Greek language holds a very important place in the history of the Western world. Beginning with the epics of Homer, ancient Greek literature includes many works of lasting impo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoecious
Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system alongside gynomonoecy, andromonoecy and trimonoecy. Monoecy is connected to anemophily. It can prevent self-pollination in an individual flower but cannot prevent self-pollination between male and female flowers on the same plant. Monoecy in angiosperms has been of interest for evolutionary biologists since Charles Darwin. Terminology Monoecious comes from the Greek words for one house. History The term monoecy was first introduced in 1735 by Carl Linnaeus. Darwin noted that the flowers of monoecious species sometimes showed traces of the opposite sex function. Monoecious hemp was first reported in 1929. Occurrence Monoecy is most common in temperate climates and is often associated with inefficient pollinators or wind-pollinated plants. It may be beneficial to reducing pollen-stigma interferenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Morphology
Phytomorphology is the study of the morphology (biology), physical form and external structure of plants.Raven, P. H., R. F. Evert, & S. E. Eichhorn. ''Biology of Plants'', 7th ed., page 9. (New York: W. H. Freeman, 2005). . This is usually considered distinct from plant anatomy, which is the study of the internal Anatomy, structure of plants, especially at the microscopic level. Plant morphology is useful in the visual identification of plants. Recent studies in molecular biology started to investigate the molecular processes involved in determining the conservation and diversification of plant morphologies. In these studies transcriptome conservation patterns were found to mark crucial ontogenetic transitions during the plant life cycle which may result in evolutionary constraints limiting diversification. Scope Plant morphology "represents a study of the development, form, and structure of plants, and, by implication, an attempt to interpret these on the basis of similarit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oology
Oology (or oölogy) is a branch of ornithology studying bird eggs, nests and breeding behaviour. The word is derived from the Greek ''oion'', meaning egg. Oology can also refer to the hobby of collecting wild birds' eggs, sometimes called egg collecting, birdnesting or egging, which is now illegal in many jurisdictions. History As a science Oology became increasingly popular in Britain and the United States during the 1800s. Observing birds from afar was difficult because high quality binoculars were not readily available. Thus it was often more practical to shoot the birds or collect their eggs. While the collection of the eggs of wild birds by amateurs was considered a respectable scientific pursuit in the 19th century and early 20th century, from the mid 20th century onwards it was increasingly regarded as being a hobby rather than a scientific discipline. In the 1960s, the naturalist Derek Ratcliffe compared peregrine falcon eggs from historical collections with more rec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walnut
A walnut is the edible seed of a drupe of any tree of the genus ''Juglans'' (family Juglandaceae), particularly the Persian or English walnut, '' Juglans regia''. Although culinarily considered a "nut" and used as such, it is not a true botanical nut. After full ripening, the shell is discarded and the kernel is eaten. Nuts of the eastern black walnut (''Juglans nigra'') and butternuts ('' Juglans cinerea'') are less commonly consumed. Characteristics Walnuts are rounded, single-seeded stone fruits of the walnut tree commonly used for food after fully ripening between September and November, in which the removal of the husk at this stage reveals a browning wrinkly walnut shell, which is usually commercially found in two segments (three or four-segment shells can also form). During the ripening process, the husk will become brittle and the shell hard. The shell encloses the kernel or meat, which is usually made up of two halves separated by a membranous partition. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pistachio
The pistachio (, ''Pistacia vera''), a member of the cashew family, is a small tree originating from Central Asia and the Middle East. The tree produces seeds that are widely consumed as food. ''Pistacia vera'' is often confused with other species in the genus ''Pistacia'' that are also known as pistachio. These other species can be distinguished by their geographic distributions (in the wild) and their seeds which are much smaller and have a soft shell. Etymology Pistachio is from late Middle English ''pistace'', from Old French, superseded in the 16th century by forms from Italian ''pistacchio'', via Latin from Greek ''pistákion'', and from Middle Persian ''pistakē''. History The pistachio tree is native to regions of Central Asia, including present-day Iran and Afghanistan. Archaeology shows that pistachio seeds were a common food as early as 6750 BC. So far, the earliest evidence of pistachio consumption goes back to the Bronze Age Central Asia and comes from Djarkuta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melchior Treub
Melchior Treub (26 December 1851 – 3 October 1910) was a Dutch botanist. He worked at the Bogor Botanical Gardens in Buitenzorg on the island of Java, south of Batavia, Dutch East Indies, gaining renown for his work on tropical flora. He also founded the Bogor Agricultural Institute. He traveled and collected across many areas of Southeast Asia. He was born in Voorschoten, and in 1873 he graduated in biology from the University of Leiden. Subsequently, he remained in Leiden as a botanical assistant. From 1880 to 1909 he was a botanist based in the Dutch East Indies. In 1879 he was appointed a member of the Royal Dutch Academy of Sciences (KNAW) and was appointed as director of Bogor Botanical Gardens' Lands Plantentuin in Buitenzorg (Bogor) in the year 1880. Treub worked on tropical flora on Java and organized the Botanical Garden as a world-renowned scientific institution of botany. Under his leadership many crucial researches were successfully completed on plant diseases o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Casuarinaceae
The Casuarinaceae are a family of dicotyledonous flowering plants placed in the order Fagales, consisting of four genera and 91 species of trees and shrubs native to eastern Africa, Australia, Southeast Asia, Malesia, Papuasia, and the Pacific Islands. At one time, all species were placed in the genus ''Casuarina''. Lawrence Alexander Sidney Johnson separated out many of those species and renamed them into the new genera of ''Gymnostoma'' in 1980 and 1982, ''Allocasuarina'' in 1982, and ''Ceuthostoma'' in 1988, with some additional formal descriptions of new species in each other genus. At the time, it was somewhat controversial. The monophyly of these genera was later supported in a 2003 genetics study of the family. In the Wettstein system, this family was the only one placed in the order Verticillatae. Likewise, in the Engler, Cronquist, and Kubitzki systems, the Casuarinaceae were the only family placed in the order Casuarinales. Members of this family are characterized ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollen Tube
A pollen tube is a tubular structure produced by the male gametophyte of seed plants when it germinates. Pollen tube elongation is an integral stage in the plant life cycle. The pollen tube acts as a conduit to transport the male gamete cells from the pollen grain—either from the stigma (in flowering plants) to the ovules at the base of the pistil or directly through ovule tissue in some gymnosperms. In maize, this single cell can grow longer than to traverse the length of the pistil. Pollen tubes were first discovered by Giovanni Battista Amici in the 19th century. They are used as a model for understanding plant cell behavior. Research is ongoing to comprehend how the pollen tube responds to extracellular guidance signals to achieve fertilization. Description Pollen tubes are produced by the male gametophytes of seed plants. Pollen tubes act as conduits to transport the male gamete cells from the pollen grain—either from the stigma (in flowering plants) to the ovule ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird Egg
Bird eggs are laid by the females and range in quantity from one (as in condors) to up to seventeen (the grey partridge). Clutch size may vary latitudinally within a species. Some birds lay eggs even when the eggs have not been fertilized; it is not uncommon for pet owners to find their lone bird nesting on a clutch of infertile eggs, which are sometimes called wind-eggs. Anatomy All bird eggs contain the following components: * The embryo is the immature developing chick * The amnion is a membrane that initially covers the embryo and eventually fills with amniotic fluid, provides the embryo with protection against shock from movement * The allantois helps the embryo obtain oxygen and handles metabolic waste * The chorion, together with the amnion, forms the amniotic sac and encloses the amnion, vitellus, and the embryo * The vitellus, or yolk, is the nutrient-bearing portion of the egg, containing most of its fat, minerals, and many of its proteins and blood vessels * The alb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flowering Plant
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants that produce their seeds enclosed within a fruit. They are by far the most diverse group of land plants with 64 orders, 416 families, approximately 13,000 known genera and 300,000 known species. Angiosperms were formerly called Magnoliophyta (). Like gymnosperms, angiosperms are seed-producing plants. They are distinguished from gymnosperms by characteristics including flowers, endosperm within their seeds, and the production of fruits that contain the seeds. The ancestors of flowering plants diverged from the common ancestor of all living gymnosperms before the end of the Carboniferous, over 300 million years ago. The closest fossil relatives of flowering plants are uncertain and contentious. The earliest angiosperm fossils ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integument
In biology, an integument is the tissue surrounding an organism's body or an organ within, such as skin, a husk, shell, germ or rind. Etymology The term is derived from ''integumentum'', which is Latin for "a covering". In a transferred, or figurative sense, it could mean a cloak or a disguise. In English, "integument" is a fairly modern word, its origin having been traced back to the early seventeenth century; and refers to a material or layer with which anything is enclosed, clothed, or covered in the sense of "clad" or "coated", as with a skin or husk. Botanical usage In botany, the term "integument" may be used as it is in zoology, referring to the covering of an organ. When the context indicates nothing to the contrary, the word commonly refers to an envelope covering the nucellus of the ovule. The integument may consist of one layer (unitegmic) or two layers (bitegmic), each of which consisting of two or more layers of cells. The integument is perforated by a pore, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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