Comparation Pholem and Xylem

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• Essay on xylem bio

  ...(k) Describe current theories about processes responsible for the movement of materials through plants in xylem and phloem tissue. Parts of Plants: Roots  Structural support & transports by taking in water & nutrients, process of diffusion Root Hairs – Increase S/A, are extension of epidermal cells Stems in vascular tissue, which is made of xylem & phloem. Xylem – transports water & dissolved minerals Long tubes made up of series of cells. From roots upwards to leaves; useable for tree with maximum height. Phloem – transport sucrose, produced in photosynthetic tissue to other regions of plant, as well as hormones & any other organic material made by plan. Role begins at leaves Transports ‘sap’ to rest of plant Phloem cells linked by sieve plates for continuity. Sugar moved using turgor pressure How Materials Move in Vascular Tissue: Xylem: Water absorbed by root hairs  moves through the cortex into xylem (small xylem vessels) in vascular tissue  (transported throughout plant) into mesophyll cells in leaf Water absorbed by root hairs (via osmosis & root pressure)  Move through cortex into xylem (small xylem vessels) via symplastic loading (movement through cell) & apoplastic loading (movement through cell wall)  Water movement up xylem by capillarity  Stomata controls transpiration allowing water to leave xylem...

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• Xylem cell Essay

  ...The Xylem is part of a plant, which is a hollow tube with spiral thickening of lignin around the wall giving strength, which is continuous throughout the whole plant. The difference between the Xylem cell and other cells is that the Xylem is dead and has no cytoplasm. The Xylem is responsible for transporting water and certain nutrients form root to plant. Phloem carries soluble organic material i.e. food for the plant. The top of the plant is in the light, conducting photosynthesis and helping the plant reproduce. There are two types of vascular tissues, together they for vascular bundles and are responsible for the survival of the plant. Xylem flows only from bottom up to the top and Phloem flows both ways. Phloem is the innermost layer of the bark in most trees. Outer Phloem is dead cells and inner Phloem is living cells, when the primary Xylem cells become dead, losing their conducting function and forming a hard skeleton that serves support to the plant. Xylem is part of a vascular tissue. The vascular tissue transports fluids and nutrients internally. Between the Xylem and Phloem is a meristem called vascular cambium. The tissue divides cells that will become additional Xylem and Phloem cells, as long as the vascular cambium produces new cells, the plant will grow bigger. Xylem is orientated near the adaxial system of the...

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• Importance of Xylem and Phloem Tissues Essay

  ...The primary xylem and primary phloem tissues are pushed inward into the] pith and outwards respectively by the continuous production of secondary tissues cut I off by the cambium ring. The primary xylem is gradually pushed inward and is found at the centre of the axis; whereas, the primary phloem, being soft in nature, gets completely crushed. These activities in the stelar region exert a great pressure outwardly. The cortex cells, the pericycle and the epidermis divide anticlinally to cope with the production of tissues in the stelar region. Formation of annual ring or growth ring The activity of the cambium ring is under the control of series of physiological and environmental factors. For example, in spring the cambium becomes more active and forms a greater number of vessels with wider cavities. In winter, the temperature is low due to which the cambium also becomes less active and forms narrow pitted vessels, tracheids and wood fibers. The xylem (wood) formed during the spring is known as spring wood or early wood and which is formed in winter is called autumn wood or late wood. The spring wood is lighter in color and exhibits low density where as the autumn (or winter) wood is darker and has higher density. These two kinds of wood appear together, in a transverse section of the stem, as a concentric ring known as the annual ring or growth ring. Successive annual rings are formed year after year by the...

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• Essay about Xylem and Phloem

  ...Xylem and Phloem Research Task 3/8/2014 Xylem and phloem are the conducting elements of vascular plants. They function in the transport of water, nutrients, sugars, proteins and RNA throughout the plant. The xylem and phloem are generally found together in vascular bundles and can lie in various positions relative to each other. (Plant Vascular System Development) The term phloem originates from the Greek word, phloios, meaning “bark”. (Merriam-Webster) In vascular plants, phloem is the living tissue that carries organic nutrients, particularly sucrose, to all parts of the plant where needed. (Lalonde S, 2004) Phloem’s main job is to move sugars from the source tissue (ex. photosynthetic leaf cells) to sink tissues (ex. non-photosynthetic root cells or developing flowers). Molecules like proteins and mRNAs also are transported to parts of the plant by the phloem. (WiseGEEK) Phloem is composed of several cell types including sclerenchyma, parenchyma, sieve elements and companion cells. The sieve element and companion cell are found closely associated with each other in what is referred to as the sieve element/companion cell complex. (MSU) It is believed that when phloem is damaged, P-proteins quickly aggregate at the sieve plate to form a “clot” which prevents the leakage of phloem exudates. Callose is a carbohydrate which is also placed at the sieve plate in response to injury. (MSU) Xylem is...

  659  Words | 2  Pages

• comparison of the xylem and phloem Essay

  ...The phloem and the xylem are complex tissues that perform the transportation of food and water in a plant, They are both vascular tissues of the plant that together form vascular bundles, they work together as a unit to make the transportation of food, nutrients, minerals and water effective. The xylem is a tubular shape that has no cross walls which allows a continuous column of water and minerals a more rapid transport within the xylem, there are two types protoxylem first formed xylem and metaxylem mature xylem which depends on pattern of lignin, the phloem is an elongated tubular shape with thin walled sieve tubes. The sieve tubes have pores at each end in the cross walls and microtubules that extend between sieve elements allowing longitudinal flow of material. Xylem sap contains water, inorganic ions and a few organic chemicals whereas phloem sap contains water and sugars. Both the phloem and xylem are tubular structures that give easy transportation, in xylem vessels water travels by bulk flow rather than cell diffusions, the phloem’s create a diffusion gradient by the concentration of organic substance inside the phloem cell, water flows into cells and the phloem sap moves from the source to sugar sinks by the cell diffusion gradient. Negative pressure helps the movement of water and minerals in xylem while in phloem positive...

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• Compare the structure and function of the xylem and phloem Essay

  ...Plants have two separate transport systems. A network of xylem vessels transports water and mineral ions from the roots to all other parts of the plant. Phloem tubes transport food made in the leaves to all other parts of the plant. Neither of these systems has a pump, this is because they are not as active as animals and do not need such rapid supplies of food. Neither xylem nor phloem transports oxygen as oxygen gets to a plants cell by diffusion. Both stems and roots contain xylem vessels and phloem tubes. In a stem these are grouped into vascular bundles arranged in a ring. In a root these are arranged in the centre forming a structure called the stele. Xylem tissue has the dual functions of support and transport. It contains several different types of cells these are vessel elements, traceids, fibres and parenchyma cells. In contrast to this phloem tissue is living and comprises of sieve tubes, phloem parenchyma (also known as companion cells) and phloem fibres. In the xylem tissue the vessel elements and tracheids are the cells that are involved with the transport of water. Fibres are elongated with lignified walls that help to support the plant. They are dead cells; they have no living contents at all. Parenchyma cells are plant cells they have unthickened cellulose cell walls and contain all the organelles you would expect to see. However the parenchyma cells in xylem tissue do...

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• Compare and Contrast Xylem Tissue and Phloem Tissue, Including Their Respective Structures and Functions. Essay

  ...Compare and contrast xylem tissue and phloem tissue, including their respective structures and functions. The stems and roots of plants contain two separate transport systems; xylem vessels and phloem tubes, of which neither transport oxygen as it is transported to cells by diffusion. The network of xylem vessels transports water and mineral ions from the roots to all other parts of the plant whereas phloem tubes transport food made in the leaves to all other parts of the plant. In the stems the tissue is collectively known as vascular tissue, within the roots they form a structure called the stele. The movement of water from roots to shoots is conducted via the xylem using mass flow. The force of cohesion - a force produced by the xylem, increases the attraction between the molecules which make up the water in the xylem. The xylem is composed of different kinds of cells; tracheids, vessels, fibres and unthickended xylem parenchyma. Both tracheids and vessels form pipes through which liquid can be moved, conducting water and supporting tissues. Fibres simply play a support role and parenchyma have a storage function. The xylem pipework in all living plants consists entirely of dead cells; composed of lignin rich tissues that once have reached maturity promptly die via a process known as apoptosis. This cell death creates a hollow tube...

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• Transpiration Xylem and Plant Essay

  ...water from the plant surface. They also lose much of their water through guttation which is the loss of liquids from the ends of vascular tissues at the margins of the leaves. It is imperative that this water lost is replaced; otherwise the plant will wilt and most likely die. Water from the roots in the xylem travels up from cell to cell and over long distances in the plant to replace lost water. This process is governed by the differences in water potential. More water potential means that there are more free water molecules available, and thus more potential energy. The factors contributing to water potential are gravity, pressure and solute concentration. Water always moves from an area of higher water potential to an area of lower water potential. The movement of water is able to occur due to the properties of water, osmosis, adhesion and cohesion, and root pressure. Cohesion is when water molecules are attracted to each other due to hydrogen bond formation. Adhesion is when water molecules stick to something, in this case he walls of the xylem cells, which offsets the forces of gravity. Within the root, minerals are actively transported in accumulating in the xylem. As a result, water potential is lowered because the solute (minerals) leave less water available. Water moves into the root by osmosis (the movement of water from a higher concentration to a lower concentration). The stomata are small pores in the...

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