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Chalazal Spot
The chalaza (; ; : 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 (though not in eggs of 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, the pollen tube enters th ... [...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). Avian clutch size, 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 Yolk, vitellus, or yolk, is the nutrient-bearing portion of the egg, containing most of its fat, minerals, and many of its proteins and bl ... [...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 comparable with gynomonoecy, andromonoecy and trimonoecy, and contrasted with dioecy where individual plants produce cones or flowers of only one sex and with bisexual or hermaphroditic plants in which male and female gametes are produced in the same flower. Monoecy often co-occurs with anemophily, because it prevents self-pollination of individual flowers and reduces the probability of self-pollination between male and female flowers on the same plant. Monoecy in Flowering plant, 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, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Morphology
Phytomorphology is the study of the 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 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 similarity of plan and origin". There ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oology
Oology (; also oölogy) is a branch of ornithology studying bird eggs, Bird nest, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walnut
A walnut is the edible seed of any tree of the genus '' Juglans'' (family Juglandaceae), particularly the Persian or English walnut, '' Juglans regia''. They are accessory fruit because the outer covering of the fruit is technically an involucre and thus not morphologically part of the carpel; this means it cannot be a drupe but is instead a drupe-like 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. Description Walnuts are the round, single-seed stone fruits of the walnut tree. They ripen between September and November in the northern hemisphere. The brown, wrinkly walnut shell is enclosed in a husk. Shells of walnuts available in commerce usually have two segments (but three or four-segment shells can also form). During the bumming process, the husk becomes brittle and the shell hard. The shell encloses the kernel or meat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pistachio
The pistachio (, ; ''Pistacia vera'') is a small to medium-sized tree of the Anacardiaceae, cashew family, originating in Iran. The tree produces nut (fruit)#Culinary definition and uses, seeds that are widely consumed as food. In 2022, world production of pistachios was one million tonnes, with the United States, Iran, and Turkey combined accounting for 88% of the total. Description The tree grows up to tall. It has deciduous, pinnate leaves long. The plants are dioecious, with separate male and female trees. The flowers are apetalous and unisexual and borne in panicles. The fruit is a drupe, containing an elongated seed, which is the edible portion. The seed, commonly thought of as a nut, is a nut (food), culinary nut, not a nut (fruit)#Botanical definition, botanical nut. The fruit has a hard, cream-colored exterior shell. The seed has a mauve-colored skin and light green flesh, with a distinctive flavor. When the fruit ripens, the shell changes from green to an autu ... [...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 attention 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 scientific institution of botany. Under his leadership many crucial researches were successfully completed on plant diseases of econom ... [...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 phylogenetic 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 charac ... [...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. Pollen tubes are unique to seed plants and their structures have evolved over their history since the Carboniferous period. Pollen tube formation is complex and the mechanism is not fully understood. Angiosperms The male ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ovule
In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the ''integument'', forming its outer layer, the ''nucellus'' (or remnant of the sporangium, megasporangium), and the female gametophyte (formed from a haploid megaspore) in its center. The female gametophyte — specifically termed a ''megagametophyte'' — is also called the ''embryo sac'' in Flowering plant, angiosperms. The megagametophyte produces an ovum, egg cell for the purpose of fertilization. The ovule is a small structure present in the ovary. It is attached to the placenta by a stalk called a funicle. The funicle provides nourishment to the ovule. On the basis of the relative position of micropyle, body of the ovule, chalaza and funicle, there are six types of ovules. Location within the plant In flowering plants, the ovule is located inside the portion of the flower called the gynoecium. The Ovary (plants), ovary of the gynoecium p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flowering Plant
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed within a fruit. The group was formerly called Magnoliophyta. Angiosperms are by far the most diverse group of Embryophyte, land plants with 64 Order (biology), orders, 416 Family (biology), families, approximately 13,000 known Genus, genera and 300,000 known species. They include all forbs (flowering plants without a woody Plant stem, stem), grasses and grass-like plants, a vast majority of broad-leaved trees, shrubs and vines, and most aquatic plants. Angiosperms are distinguished from the other major seed plant clade, the gymnosperms, by having flowers, xylem consisting of vessel elements instead of tracheids, endosperm within their seeds, and fruits that completely envelop the seeds. The ancestors of flowering plants diverged from the commo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
