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Heliotropism
Heliotropism, a form of tropism, is the diurnal or seasonal motion of plant parts (flowers or leaves) in response to the direction of the Sun. The habit of some plants to move in the direction of the Sun, a form of tropism, was already known by the Ancient Greeks. They named one of those plants after that property '' Heliotropium'', meaning "sun turn". The Greeks assumed it to be a passive effect, presumably the loss of fluid on the illuminated side, that did not need further study. Aristotle's logic that plants are passive and immobile organisms prevailed. In the 19th century, however, botanists discovered that growth processes in the plant were involved, and conducted increasingly in-depth experiments. A. P. de Candolle called this phenomenon in ''any'' plant ''heliotropism'' (1832). It was renamed phototropism in 1892, because it is a response to light rather than to the sun, and because the phototropism of algae in lab studies at that time strongly depended on the brightness ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tropism
A tropism is a biological phenomenon, indicating growth or turning movement of a biological organism, usually a plant, in response to an environmental stimulus. In tropisms, this response is dependent on the direction of the stimulus (as opposed to nastic movements which are non-directional responses). Tropisms are usually named for the stimulus involved (for example, a phototropism is a reaction to sunlight). Tropisms occur in three sequential steps. First, there is a sensation to a stimulus. Next, signal transduction occurs. And finally, the directional growth response occurs. Tropisms are typically associated with plants (although not necessarily restricted to them). Where an organism is capable of directed physical movement (motility), movement or activity in response to a specific stimulus is more likely to be regarded by behaviorists as a '' taxis'' (directional response) or a '' kinesis'' (non-directional response). The Cholodny–Went model, proposed in 1927, is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bellis Perennis
''Bellis perennis'' (), the daisy, is a European species of the family (biology), family Asteraceae, often considered the archetypal species of the name daisy (other), daisy. To distinguish this species from other plants known as daisies, it is sometimes qualified as common daisy, lawn daisy or English daisy. Description ''Bellis perennis'' is a perennial herbaceous plant growing to in height. It has short creeping rhizomes and rosettes of small rounded or spoon-shaped leaves that are from long and grow flat to the ground. The species habitually colonises lawns, and is difficult to eradicate by mowing, hence the term 'lawn daisy'. It blooms from March to September and exhibits the phenomenon of heliotropism, in which the flowers follow the position of the sun in the sky. The inflorescence, flowerheads are composite, about in diameter, in the form of a pseudanthium, consisting of many sessile flowers with white Head (botany), ray florets (often tipped red) and yellow d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bellis Perennis
''Bellis perennis'', the daisy, is a European species of the family Asteraceae, often considered the archetypal species of that name. To distinguish this species from other plants known as daisies, it is sometimes qualified as common daisy, lawn daisy or English daisy. Historically, it has also been widely known as bruisewort, and occasionally woundwort (although the common name "woundwort" is now more closely associated with the genus ''Stachys''). ''B. perennis'' is native to western, central and northern Europe, including remote islands such as the Faroe Islands, but has become widely naturalised in most temperate regions, including the Americas and Australasia. Description ''B. perennis'' is a perennial herbaceous plant with short creeping rhizomes and rosettes of small rounded or spoon-shaped leaves that are from long and grow flat to the ground. The species habitually colonises lawns, and is difficult to eradicate by mowing, hence the term 'lawn daisy'. It exhibits the ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seed
A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm plants. Seeds are the product of the ripened ovule, after the embryo sac is fertilized by sperm from pollen, forming a zygote. The embryo within a seed develops from the zygote, and grows within the mother plant to a certain size before growth is halted. The seed coat arises from the integuments of the ovule. Seeds have been an important development in the reproduction and success of vegetable gymnosperm and angiosperm plants, relative to more primitive plants such as ferns, mosses and liverworts, which do not have seeds and use water-dependent means to propagate themselves. Seed plants now dominate biological niches on land, from forests to grasslands both in hot and cold climates. The term "seed" also has a general meaning t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollination
Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds, and bats; water; wind; and even plants themselves, when self-pollination occurs within a closed flower. Pollination often occurs within a species. When pollination occurs between species, it can produce hybrid offspring in nature and in plant breeding work. In angiosperms, after the pollen grain (gametophyte) has landed on the stigma, it germinates and develops a pollen tube which grows down the style until it reaches an ovary. Its two gametes travel down the tube to where the gametophyte(s) containing the female gametes are held within the carpel. After entering an ovum cell through the micropyle, one male nucleus fuses with the polar bodies to produce the endosperm tissues, while the other fuses with the ovule to produce the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fertilization
Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Processes such as insemination or pollination which happen before the fusion of gametes are also sometimes informally called fertilisation. The cycle of fertilisation and development of new individuals is called sexual reproduction. During double fertilisation in angiosperms the haploid male gamete combines with two haploid polar nuclei to form a triploid primary endosperm nucleus by the process of vegetative fertilisation. History In Antiquity, Aristotle conceived the formation of new individuals through fusion of male and female fluids, with form and function emerging gradually, in a mode called by him as epigenetic. In 1784, Spallanzani established the need of interaction between the female's ovum and male's sperm to form a zyg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tropical
The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to as the tropical zone and the torrid zone (see geographical zone). In terms of climate, the tropics receive sunlight that is more direct than the rest of Earth and are generally hotter and wetter as they aren't affected as much by the Season, solar seasons. The word "tropical" sometimes refers to this sort of climate in the zone rather than to the geographical zone itself. The tropical zone includes deserts and snow-capped mountains, which are not tropical in the climatic sense. The tropics are distinguished from the other climatic and biomatic regions of Earth, which are the middle latitudes and the polar regions of Earth, polar regions on either side of the equatorial zone. The tropics constitute 40% of Earth's surface area and contain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convolvulaceous
Convolvulaceae (), commonly called the bindweeds or morning glories, is a family of about 60 genera and more than 1,650 species. These species are primarily herbaceous vines, but also include trees, shrubs and herbs. The tubers of several species are edible, the best known of which is the sweet potato. Description Convolvulaceae can be recognized by their funnel-shaped, radially symmetrical corolla; the floral formula for the family has five sepals, five fused petals, five epipetalous stamens (stamens fused to the petals), and a two-part syncarpous and superior gynoecium. The stems of these plants are usually winding, hence their Latin name (from ''convolvere'', "to wind"). The leaves are simple and alternate, without stipules. In parasitic Cuscuta (dodder) they are reduced to scales. The fruit can be a capsule, berry, or nut, all containing only two seeds per one locule (one ovule/ovary). The leaves and starchy, tuberous roots of some species are used as foodstuffs (e.g. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A Gaenseblume4
A, or a, is the first letter and the first vowel of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''a'' (pronounced ), plural ''aes''. It is similar in shape to the Ancient Greek letter alpha, from which it derives. The uppercase version consists of the two slanting sides of a triangle, crossed in the middle by a horizontal bar. The lowercase version can be written in two forms: the double-storey a and single-storey ɑ. The latter is commonly used in handwriting and fonts based on it, especially fonts intended to be read by children, and is also found in italic type. In English grammar, " a", and its variant " an", are indefinite articles. History The earliest certain ancestor of "A" is aleph (also written 'aleph), the first letter of the Phoenician alphabet, which consisted entirely of consonants (for that reason, it is also called an abjad to distinguish it fr ... [...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 ov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seasonal
A season is a division of the year based on changes in weather, ecology, and the number of daylight hours in a given region. On Earth, seasons are the result of the axial parallelism of Earth's tilted orbit around the Sun. In temperate and polar regions, the seasons are marked by changes in the intensity of sunlight that reaches the Earth's surface, variations of which may cause animals to undergo hibernation or to migrate, and plants to be dormant. Various cultures define the number and nature of seasons based on regional variations, and as such there are a number of both modern and historical cultures whose number of seasons varies. The Northern Hemisphere experiences most direct sunlight during May, June, and July, as the hemisphere faces the Sun. The same is true of the Southern Hemisphere in November, December, and January. It is Earth's axial tilt that causes the Sun to be higher in the sky during the summer months, which increases the solar flux. However, due to s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corolla Tube
Petals are modified leaves that surround the reproductive parts of flowers. They are often brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corolla''. Petals are usually accompanied by another set of modified leaves called sepals, that collectively form the ''calyx'' and lie just beneath the corolla. The calyx and the corolla together make up the perianth, the non-reproductive portion of a flower. When the petals and sepals of a flower are difficult to distinguish, they are collectively called tepals. Examples of plants in which the term ''tepal'' is appropriate include genera such as '' Aloe'' and '' Tulipa''. Conversely, genera such as ''Rosa'' and ''Phaseolus'' have well-distinguished sepals and petals. When the undifferentiated tepals resemble petals, they are referred to as "petaloid", as in petaloid monocots, orders of monocots with brightly colored tepals. Since they include Liliales, an alternati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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