| 单词 | xylem |
| 例句 | And lifting water is just one of the many jobs that the phloem, xylem, and cambium perform. A Walk in the Woods 1997-11-01T00:00:00Z All of its internal life exists within three paper-thin layers of tissue—the phloem, xylem, and cambium—just beneath the bark, which together form a moist sleeve around the dead heartwood. A Walk in the Woods 1997-11-01T00:00:00Z Most sap-sucking insects drill into a nutrient-dense plant tissue called phloem, but spittlebugs specialize in the much more dilute sap from another tissue, xylem. Meet the world’s least picky insect—a spreader of deadly crop disease 2023-10-06T04:00:00Z More research is needed, but the scientists suspect it's due to the bugs' preference for sap from the xylem, which is the main water-carrying structure of the plant. Meadow Spittlebug's record-breaking diet also makes it top disease carrier for plants 2023-10-04T04:00:00Z The leading theory is that these insects have an internal molecular clock synced to the seasonal flow of fluid, or xylem, that passes through a tree’s roots each spring, which cicadas sip on as food. Noticing more cicadas this year in the U.S.? There may be a reason 2023-09-05T04:00:00Z With their rigid cell walls, the xylem cells provide support to the plant and allow it to achieve impressive heights. Fundamentals of Biology 2015-01-01T00:00:00Z The vascular system contains xylem and phloem tissues. Concepts of Biology 2013-04-25T00:00:00Z Researchers said the noises are the sound of popping air bubbles, which plants produce in their xylem, a tissue that moves water. Plants make ultrasonic popping sounds. They might be cries for help. 2023-04-04T04:00:00Z Unlike sap from the phloem, the liquid in the xylem is similar across a diverse range of host plants. Meadow Spittlebug's record-breaking diet also makes it top disease carrier for plants 2023-10-04T04:00:00Z Hadany says the current theory for how plants make noises centers on their xylem, the tubes that transport water and nutrients from their roots to their stems and leaves. Stressed Plants ‘Cry’—and Some Animals Can Probably Hear Them 2023-03-31T04:00:00Z There are four teardrop-shaped vascular bundles, with the narrow point of the teardrop meeting at a round xylem vessel. Fundamentals of Biology 2015-01-01T00:00:00Z Like angiosperms, but unlike other gymnosperms, all gnetophytes possess vessel elements in their xylem. Concepts of Biology 2013-04-25T00:00:00Z They use their strawlike mouth to siphon water and minerals from plants’ xylem, the system of tubes that transports both substances from the roots through growing tissues. Sharpshooter Insects Use ‘Superpropulsion’ to Catapult Their Pee 2023-02-28T05:00:00Z Towering redwoods and lanky jungle vines hoist water from the soil to their lofty leaves through a tubelike tissue called the xylem. How Plants’ Plumbing Let Them Conquer the World 2023-01-27T05:00:00Z Water in the the xylem is held together by surface tension, just like water sucked through a drinking straw. Stressed Plants ‘Cry’—and Some Animals Can Probably Hear Them 2023-03-31T04:00:00Z The bundles are smaller than in the dicot stem, and distinct layers of xylem, phloem and sclerenchyma cannot be discerned. Fundamentals of Biology 2015-01-01T00:00:00Z Vascular systems consist of xylem tissue, which transports water and minerals, and phloem tissue, which transports sugars and proteins. Concepts of Biology 2013-04-25T00:00:00Z Dots inside that outline mark where the plant’s vascular tissues, the xylem and phloem, were connected, and conducted fluids between stem and leaf. How to read tree leaves — the science of plants 2022-12-02T05:00:00Z But smaller-scale tweaks to xylem cells and tissue organization can protect against drought, too, says Cornell University evolutionary biologist Jacob Suissa, who was not involved in the new study. How Plants’ Plumbing Let Them Conquer the World 2023-01-27T05:00:00Z When an air bubble forms or breaks in the xylem, it might make a little popping noise; bubble formation is more likely during drought stress. Stressed Plants ‘Cry’—and Some Animals Can Probably Hear Them 2023-03-31T04:00:00Z Vessel elements are xylem cells with thinner walls; they are shorter than tracheids. Fundamentals of Biology 2015-01-01T00:00:00Z Gnetophyta are considered the closest group to angiosperms because they produce true xylem tissue that contains both tracheids and vessel elements. Concepts of Biology 2013-04-25T00:00:00Z So a negative pressure created by water evaporation must be present to pull the sap up through the xylem vessels. College Physics for AP Courses 2015-08-12T00:00:00Z Many modern xylems have intricate cross sections that look like gappy rings, crosses, diamonds or hearts, with dead space called pith separating bundles of xylem tissue. How Plants’ Plumbing Let Them Conquer the World 2023-01-27T05:00:00Z It is partly by capillary action occurring in plant cells called xylem that water and dissolved nutrients are brought from the soil up through the roots and into a plant. Chemistry 2019-02-14T00:00:00Z Surrounding the pith is a ring of xylem cells about 75 microns across and four cells deep. Fundamentals of Biology 2015-01-01T00:00:00Z Together, xylem and phloem tissues form the vascular system of plants. Concepts of Biology 2013-04-25T00:00:00Z Vascular tissue is an example of a complex tissue, and is made of two specialized conducting tissues: xylem and phloem. Biology for AP Courses 2022-06-09T00:00:00Z Trying to do so strains the xylem, introducing air bubbles that clog the tubes and starve tissues of water—similar to the way that deadly air embolisms cut off animals’ blood flow. How Plants’ Plumbing Let Them Conquer the World 2023-01-27T05:00:00Z The combination of transpiration and capillary action lifts water upward through the xylem tissues of a plant. Miller & Levine Biology 2018-01-01T00:00:00Z Rows of green-staining phloem cells radiate out from the xylem cells. Fundamentals of Biology 2015-01-01T00:00:00Z The simplest arrangement of conductive cells shows a pattern of xylem at the center surrounded by phloem. Concepts of Biology 2013-04-25T00:00:00Z In stems, the xylem and the phloem form a structure called a vascular bundle; in roots, this is termed the vascular stele or vascular cylinder. Biology for AP Courses 2022-06-09T00:00:00Z When a network of rigid, vascular tissue, called xylem pressurizes, sap starts to flow. Why maple syrup prices are so low despite inflation 2022-07-13T04:00:00Z Tracheids are found in xylem, a tissue that carries water upward from the roots to every part of a plant. Miller & Levine Biology 2018-01-01T00:00:00Z Phloem cells are about half the size of xylem cells. Fundamentals of Biology 2015-01-01T00:00:00Z Like a plunger inside a syringe, a diaphragm is pulled by muscles to increase the volume of the chamber and draw in xylem sap. This Insect Drinks Your Milkshake 2021-07-13T04:00:00Z Xylem tissue has three types of cells: xylem parenchyma, tracheids, and vessel elements. Biology for AP Courses 2022-06-09T00:00:00Z Some think immature cicadas, called nymphs, measure the 17-year time underground through the sap in a tree’s xylem. Marching to the Beat of the 17-Year Cicada Clock 2021-06-14T04:00:00Z Vascular tissues—xylem and phloem—make it possible for vascular plants to move fluids through their bodies against the force of gravity. Miller & Levine Biology 2018-01-01T00:00:00Z Outside the pith is a layer of xylem. Fundamentals of Biology 2015-01-01T00:00:00Z Their calculations suggested froghoppers might be able to generate up to 1.6 megapascals, a pressure greater than the tension inside many xylem vessels. This Insect Drinks Your Milkshake 2021-07-13T04:00:00Z The vascular cambium is located just outside the primary xylem and to the interior of the primary phloem. Biology for AP Courses 2022-06-09T00:00:00Z Cicadas get all their nutrients from tree xylem, a very watery sap that contains minerals and amino acids. What is Brood X? When do cicadas come out in 2021? Answering your buggiest questions. 2021-04-01T04:00:00Z Tree sap, the sticky liquid from trees, is formed in the xylem and phloem. Miller & Levine Biology 2018-01-01T00:00:00Z The inner xylem cells are large, while ones further out are smaller. Fundamentals of Biology 2015-01-01T00:00:00Z Our tall conifers might grow so tall and live so long because of their narrower xylem. Science offers compelling theories for the mysteries of our tallest trees, but their majesty requires no research — just appreciation 2020-09-19T04:00:00Z This supplies oxygen to the living and metabolically active cells of the cortex, xylem and phloem. Biology for AP Courses 2022-06-09T00:00:00Z The xylem hydrates and cools them in addition to providing nutrients. What is Brood X? When do cicadas come out in 2021? Answering your buggiest questions. 2021-04-01T04:00:00Z Based upon what you’ve learned about xylem and phloem, what do you think causes the sweet taste of maple syrup? Miller & Levine Biology 2018-01-01T00:00:00Z The smaller xylem cells radiate out from the center, like spokes on a wheel. Fundamentals of Biology 2015-01-01T00:00:00Z The xylem is like a never-ending production line in a factory. Science offers compelling theories for the mysteries of our tallest trees, but their majesty requires no research — just appreciation 2020-09-19T04:00:00Z During the spring growing season, cells of the secondary xylem have a large internal diameter and their primary cell walls are not extensively thickened. Biology for AP Courses 2022-06-09T00:00:00Z Trees move water from the ground to their crowns by continuous vertical piping in their trunks in cells called xylem. Death of the giants: Forests getting shorter, younger, in Northwest and elsewhere 2020-06-05T04:00:00Z Water inside the Casparian strip travels upward as root pressure forces it through the vascular cylinder and into the xylem. Miller & Levine Biology 2018-01-01T00:00:00Z A blowup of the root indicates that negative water potential draws water from the soil into the root hairs, then into the root xylem. Fundamentals of Biology 2015-01-01T00:00:00Z "Conflicting functional effects of xylem pit structure relate to the growth-longevity trade-off in a conifer species." How a Tiny Pit Decides a Pine Tree’s Fate 2019-10-20T04:00:00Z During the fall season, the secondary xylem develops thickened cell walls, forming late wood, or autumn wood, which is denser than early wood. Biology for AP Courses 2022-06-09T00:00:00Z The xylem and phloem were not flowing properly. Yosemite's Sequoias have a vital message. Listen to them, urges Terry Tempest Williams 2019-10-07T04:00:00Z As more water is forced up, water in the xylem is forced into the roots. Miller & Levine Biology 2018-01-01T00:00:00Z The cork found on stems, and the water-conducting tissue of the xylem, for example, are composed of dead cells. Fundamentals of Biology 2015-01-01T00:00:00Z But ultimately, they, too, succumb because of damage to two key tree components: vascular tissues called xylem and phloem. Why Amazon Trees Are Especially Vulnerable to This Year’s Fires 2019-09-13T04:00:00Z The xylem consists of tracheids and vessels, which transport water and minerals to the leaves. Biology for AP Courses 2022-06-09T00:00:00Z The plan is to analyze water flowing in the xylem, the water-carrying layers of wood, for tracers suggesting it came from the melting glacier. Global warming has made iconic Andean peak unrecognizable 2019-09-11T04:00:00Z In monocots, clusters of xylem and phloem tissue, called vascular bundles, are scattered through stem ground tissue. Miller & Levine Biology 2018-01-01T00:00:00Z Outside the xylem is a ring of phloem cells. Fundamentals of Biology 2015-01-01T00:00:00Z An outer sapwood layer holds vessels called xylem tubes that siphon water and minerals up the plant. Tree sleuths are using DNA tests and machine vision to crack timber crimes 2019-04-02T04:00:00Z The high percentage of sugar decreases Ψs, which decreases the total water potential and causes water to move by osmosis from the adjacent xylem into the phloem tubes, thereby increasing pressure. Biology for AP Courses 2022-06-09T00:00:00Z Plant vascular tissue is comprised of water-transporting xylem cells and nutrient-transporting phloem cells, both of which are typically located in a central region of the mature root and stem. Plant-thickening mechanisms revealed 2019-01-08T05:00:00Z Transpiration is the loss of water through leaves, which may be replaced by water drawn into the leaf through xylem in the vascular tissue. Miller & Levine Biology 2018-01-01T00:00:00Z Small phloem cells make up the bottom of the bundle, and larger xylem cells make up the top. Fundamentals of Biology 2015-01-01T00:00:00Z In the inner layer, of heartwood, resin blocks much of the xylem. Tree sleuths are using DNA tests and machine vision to crack timber crimes 2019-04-02T04:00:00Z This reduces the water potential, which causes water to enter the phloem from the xylem. Biology for AP Courses 2022-06-09T00:00:00Z Smetana and colleagues report that cambial stem cells need to receive signals from neighbouring xylem cells that are acting as organizers. Plant-thickening mechanisms revealed 2019-01-08T05:00:00Z Modern trees add new layers of multiple xylem as they grow, creating a woody trunk with a single set of concentric rings. Ancient Tree Structure Is Like a Forest unto Itself 2018-01-04T05:00:00Z Rounded bundles of primary xylem tissue project from this ring into the pith. Fundamentals of Biology 2015-01-01T00:00:00Z New xylem grow in rings at the periphery of the trunk just behind the bark, adding girth so the tree can get taller. The world’s first trees grew by splitting their guts 2017-10-23T04:00:00Z Transpiration causes water to return to the leaves through the xylem vessels. Biology for AP Courses 2022-06-09T00:00:00Z The division of cambial stem cells leads to the generation of xylem and phloem daughter cells towards the root interior and periphery, respectively. Plant-thickening mechanisms revealed 2019-01-08T05:00:00Z In 2014, MIT researchers made a filter from sapwood, the outermost layer of a tree that contains xylem tissue for transporting sap up a trunk. Nature’s Brita filters: Scientists are using wood, sunlight and even human waste to solve drinking water shortages 2017-04-02T04:00:00Z Outside the secondary xylem is a ring of secondary phloem tissue. Fundamentals of Biology 2015-01-01T00:00:00Z A network of crisscrossing strands connected the vertical xylem—much like a chain-link fence spreads from pole to pole—and soft tissue filled the spaces between all these strands. The world’s first trees grew by splitting their guts 2017-10-23T04:00:00Z Vascular tissue, for example, is made up of xylem and phloem cells. Biology for AP Courses 2022-06-09T00:00:00Z This means that xylem cells acting as organizers do so only transiently, before another cell replaces them in the position adjacent to the cambial stem cell and assumes organizer function. Plant-thickening mechanisms revealed 2019-01-08T05:00:00Z Scientists are studying which types of plant xylem are most suitable. Nature’s Brita filters: Scientists are using wood, sunlight and even human waste to solve drinking water shortages 2017-04-02T04:00:00Z The vascular cambium separates the xylem from the phloem. Fundamentals of Biology 2015-01-01T00:00:00Z New growth formed in rings around each of the xylem columns while an increasing volume of soft tissue forced the strands to spread out. The world’s first trees grew by splitting their guts 2017-10-23T04:00:00Z Water potential and transpiration influence how water is transported through the xylem in plants. Biology for AP Courses 2022-06-09T00:00:00Z The disease is believed to kill plants by dehydration, as it blocks the delivery of sap in the xylem tissue. Italy halts EU-ordered olive tree cull - BBC News 2015-12-19T05:00:00Z Capillary action pulls the polymer up into the rose’s vascular tissue or xylem. Bionic roses implanted with electronic circuits 2015-11-19T05:00:00Z The inner part of the vascular bundle is xylem tissue, and the outer part is sclerenchyma tissue. Fundamentals of Biology 2015-01-01T00:00:00Z But it also split apart the tree’s xylem skeleton, which required the tree to continually repair itself, the team reports today in the Proceedings of the National Academy of Sciences. The world’s first trees grew by splitting their guts 2017-10-23T04:00:00Z The tracheids in the xylem contain mostly lipid droplets stained with Sudan Red. Biology for AP Courses 2022-06-09T00:00:00Z The disease kills plants by dehydration, as it blocks the delivery of sap in the xylem tissue. France acts against olive disease outbreak in Corsica - BBC News 2015-07-30T04:00:00Z The risk assessment report observed: "All xylem fluid-feeding insects in Europe are considered to be potential vectors." Disease 'major threat' to EU olives 2015-01-09T05:00:00Z Apical meristems differentiate into the three basic types of meristem tissue which correspond to the three types of tissue: protoderm produces new epidermis, ground meristem produces ground tissue, and procambium produces new xylem and phloem. Fundamentals of Biology 2015-01-01T00:00:00Z The researchers focused on the secondary cell walls in a type of plant tissue called xylem from the Arabidopsis plant's roots. How to Manipulate Plants to Build a Better Biofuel 2015-01-09T05:00:00Z Unlike xylem conducting cells, phloem conducting cells are alive at maturity. Biology for AP Courses 2022-06-09T00:00:00Z They modeled the veins, called xylem, as a network of pipes with varying flow and pressure. In Natural Networks, Strength in Loops 2013-08-20T17:15:00.780Z Tree rings are made of tissue called xylem. Dendrochronology: Not always the ring of truth 2013-06-20T15:05:37Z Attached to the vascular cambium are primary phloem and primary xylem. Fundamentals of Biology 2015-01-01T00:00:00Z Over two to three weeks, periodical cicada nymphs, which have the longest developmental cycle of any insect, emerge from the ground after 17 years of sucking xylem from tree roots to molt into adults. One Place Cicadas Get a Warm Welcome 2013-06-02T20:01:41Z Tracheids are xylem cells with thick secondary cell walls that are lignified. Biology for AP Courses 2022-06-09T00:00:00Z The xylem tissue of most gymnosperms comprises a single water-transporting cell type, tracheids. The Norway spruce genome sequence and conifer genome evolution 2013-05-29T17:21:22.577Z Juveniles subsist on xylem, or root fluid, for food. They're back: 17-year cicadas to swarm from Georgia to New York 2013-05-05T14:18:40Z Plant roots absorb water from the soil through root hairs and transport it up to the leaves through the xylem. Fundamentals of Biology 2015-01-01T00:00:00Z Water transport up trees occurs through the xylem, a set of tiny channels that extends from the roots to the top of the tree, working like a giant straw. Trees Living on the Edge 2012-11-21T18:00:00Z In dicot roots, the xylem and phloem of the stele are arranged alternately in an X shape, whereas in monocot roots, the vascular tissue is arranged in a ring around the pith. Biology for AP Courses 2022-06-09T00:00:00Z Two major differences between angiosperms and gymnosperms are their contrasting reproductive development and the development of water-conducting xylem cells. The Norway spruce genome sequence and conifer genome evolution 2013-05-29T17:21:22.577Z Trees in the East that experience these weather extremes, therefore, restrict their height to keep the xylem narrow, which prevents cavitation. Climate explains why West Coast trees are much taller than those in the East 2012-04-30T19:06:32Z A single unbranched vein—a bundle of vascular tissue made of xylem and phloem—runs through the center of the leaf. Fundamentals of Biology 2015-01-01T00:00:00Z Finally, in the pinnae of the frond the centrifugal xylem may disappear, the protoxylem being now exarch in position and abutting on the phloem. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 7 "Gyantse" to "Hallel" 2011-12-26T03:00:11.613Z A single vascular bundle, no matter how large or small, always contains both xylem and phloem tissues. Biology for AP Courses 2022-06-09T00:00:00Z So do the blood vessels of animals and the sap-carrying xylem and phloem of plants. 2010-02-11T10:38:00Z A vascular bundle consists of only xylem and phloëm, without the cambium, and so no secondary thickening can take place in the stems of grasses. A Handbook of Some South Indian Grasses Gnetophyta are considered the closest group to angiosperms because they produce true xylem tissue. Fundamentals of Biology 2015-01-01T00:00:00Z When tracheids occur in the medullary rays of the xylem these are replaced in the phloem-region by irregular parenchymatous cells known as albuminous cells. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 7 "Gyantse" to "Hallel" 2011-12-26T03:00:11.613Z Water potential and transpiration influence how water is transported through the xylem. Biology for AP Courses 2022-06-09T00:00:00Z Unlike the xylem and phloem, the veins in a leaf cross-link and loop. 2010-02-11T10:38:00Z Just above the xylem there is a group of large and small thin-walled cells. A Handbook of Some South Indian Grasses Within each teardrop near the center are two to four more xylem vessels. Fundamentals of Biology 2015-01-01T00:00:00Z Resin-canals, which occur abundantly in the xylem, phloem or cortex, are not found in the wood of the yew. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 7 "Gyantse" to "Hallel" 2011-12-26T03:00:11.613Z It is the main driver of water movement in the xylem. Biology for AP Courses 2022-06-09T00:00:00Z On examining the xylem, where two growth rings are in contact, the reason of the sharply marked line seen when the stem is examined with the naked eye is obvious. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses All round the xylem and the phloëm there are many thick-walled cells. A Handbook of Some South Indian Grasses To the outside of the xylem vessels are much smaller phloem cells. Fundamentals of Biology 2015-01-01T00:00:00Z The vascular bundles of the stem belong to the collateral type, that is to say, the elements of the wood or xylem and the bast or phloem stand side by side on the same radius. Encyclopaedia Britannica, 11th Edition, Volume 2, Part 1, Slice 1 The xylem vessels and tracheids are structurally adapted to cope with large changes in pressure. Biology for AP Courses 2022-06-09T00:00:00Z The xylem, as in the pine, is toward the outside of the stem, but the boundary between xylem and phloem is not well defined, there being no cambium present. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses The arrangement of the xylem and the phloëm is different from that of the stem. A Handbook of Some South Indian Grasses Lateral sieve areas on the side of the column allow different phloem tubes to interact.Part b shows the transpiration of water up the tubes of the xylem from a root sink cell. Fundamentals of Biology 2015-01-01T00:00:00Z In larger trees, the resulting embolisms can plug xylem vessels, making them non-functional. Transpiration is a passive process, meaning that metabolic energy in the form of ATP is not required for water movement. Fundamentals of Biology 2015-01-01T00:00:00Z The formation of gas bubbles in xylem interrupts the continuous stream of water from the base to the top of the plant, causing a break termed an embolism in the flow of xylem sap. Biology for AP Courses 2022-06-09T00:00:00Z The rest of the xylem cells, as well as those of the phloem, are not noticeably different from the cells of the ground tissue, except for their much smaller size, and absence of intercellular spaces. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses The number of xylem groups is fairly large and the development of the xylem is from the pericycle towards the centre of the stele. A Handbook of Some South Indian Grasses Phloem cells fill the space between the X. A ring of cells called the pericycle surrounds the xylem and phloem. Fundamentals of Biology 2015-01-01T00:00:00Z Outside the pith is a ring of secondary xylem. Fundamentals of Biology 2015-01-01T00:00:00Z In larger trees, the resulting embolisms can plug xylem vessels, making them non-functional. Biology for AP Courses 2022-06-09T00:00:00Z The tracheary tissue of the xylem is made up of small, spirally-marked vessels, and larger ones with thickened rings or with pits in the walls. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses The larger vascular bundles consist of xylem and phloëm surrounded by a bundle sheath of a single layer of cells. A Handbook of Some South Indian Grasses A blowup of the trunk indicates that cohesion and adhesion draws water up the xylem. Fundamentals of Biology 2015-01-01T00:00:00Z In dicots, the phloem and xylem cells are scattered in the pith. Biology for AP Courses 2022-06-09T00:00:00Z Strengthening tissue, especially xylem, is produced to add stiffness to resist the wind’s force. Biology for AP Courses 2022-06-09T00:00:00Z Water and minerals must cross the tracheids of the xylem. Biology for AP Courses 2022-06-09T00:00:00Z In the smaller bundles the xylem is very much reduced. A Handbook of Some South Indian Grasses A cross section at the top of the root reveals xylem tissue interspersed by four ovals containing phloem at the periphery. Fundamentals of Biology 2015-01-01T00:00:00Z Apoptosis, or programmed cell death, is an important step in the development of xylem. Biology for AP Courses 2022-06-09T00:00:00Z Vascular tissue is made up of xylem and phloem tissues and conducts water, minerals, and photosynthetic products. Biology for AP Courses 2022-06-09T00:00:00Z Fluid dynamic models predict that increasing the diameter, d, of the xylem greatly increases the rate of flow of water, leading to greater productivity when water is abundant. Biology for AP Courses 2022-06-09T00:00:00Z The larger bundles are normal in every way, while in the smaller ones the xylem elements are considerably reduced. A Handbook of Some South Indian Grasses Patches of phloem cells, stained blue, are located at the edge of the ring of xylem cells. Fundamentals of Biology 2015-01-01T00:00:00Z The cells of the secondary xylem contain lignin, which provides hardiness and strength. Biology for AP Courses 2022-06-09T00:00:00Z The increased solute concentration causes water to move by osmosis from the xylem into the phloem. Biology for AP Courses 2022-06-09T00:00:00Z For example, water is absorbed through the root system and travels upward through xylem to the leaves, where it is used in photosynthesis. Biology for AP Courses 2022-06-09T00:00:00Z The physical separation of xylem and phloem permits plants to move different nutrients simultaneously from roots to shoots and vice versa. Biology for AP Courses 2022-06-09T00:00:00Z The pericycle is a ring of cells on the outer edge of the xylem and phloem. Fundamentals of Biology 2015-01-01T00:00:00Z Sucrose produced in the Calvin cycle is loaded into the sieve-tube elements of the phloem, and the increased solute concentration causes water to move by osmosis from the xylem into the phloem. Biology for AP Courses 2022-06-09T00:00:00Z The sucrose is unloaded into the sink, and the water returns to the xylem vessels. Biology for AP Courses 2022-06-09T00:00:00Z The phloem and xylem are the main tissues responsible for this movement. Biology for AP Courses 2022-06-09T00:00:00Z Water diffuses from the phloem by osmosis and is then transpired or recycled via the xylem back into the phloem sap. Biology for AP Courses 2022-06-09T00:00:00Z The X is made up of many xylem cells. Fundamentals of Biology 2015-01-01T00:00:00Z The vascular bundles divide into primary xylem and primary phloem. Biology for AP Courses 2022-06-09T00:00:00Z Phloem tissue would show the presence of labeled minerals and xylem tissue would show the presence of radioactive sucrose. Biology for AP Courses 2022-06-09T00:00:00Z The vascular bundles divide into secondary xylem and primary phloem. Biology for AP Courses 2022-06-09T00:00:00Z Describe a model of the evolution of xylem in trees in terms of selection under conditions of unlimited and limited water resources. Biology for AP Courses 2022-06-09T00:00:00Z Round clusters of xylem cells are embedded in the phloem, symmetrically arranged around the central pith. Fundamentals of Biology 2015-01-01T00:00:00Z |
| 随便看 |
英语例句辞典收录了117811条英语例句在线翻译词条，基本涵盖了全部常用单词及词组的例句翻译及用法，是英语学习的有利工具。