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Vacuolar Pathway
{{unreferenced, date=August 2009 Vacuolar pathway: Movement of water molecules in plant cells via the vacuoles located in the cytoplasm of the cell. The water molecules encounter high resistance however and as a result little flow usually occurs making this pathway insignificant, the Apoplast, Apoplast pathway and Symplast, Symplast pathway being the major pathways for movement of water in plants. Water moves by osmosis across the vacuoles of the cells of the root system. The water moves down a concentration gradient from the soil solution to the xylem. The vacuolar pathway can also be considered a symplast pathway. Plant physiology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Cell
Plant cells are the cells present in green plants, photosynthetic eukaryotes of the kingdom Plantae. Their distinctive features include primary cell walls containing cellulose, hemicelluloses and pectin, the presence of plastids with the capability to perform photosynthesis and store starch, a large vacuole that regulates turgor pressure, the absence of flagella or centrioles, except in the gametes, and a unique method of cell division involving the formation of a cell plate or phragmoplast that separates the new daughter cells. Characteristics of plant cells * Plant cells have cell walls, constructed outside the cell membrane and composed of cellulose, hemicelluloses, and pectin. Their composition contrasts with the cell walls of fungi, which are made of chitin, of bacteria, which are made of peptidoglycan and of archaea, which are made of pseudopeptidoglycan. In many cases lignin or suberin are secreted by the protoplast as secondary wall layers inside the primary cell wall. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vacuoles
A vacuole () is a membrane-bound organelle which is present in plant and fungal cells and some protist, animal, and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic molecules including enzymes in solution, though in certain cases they may contain solids which have been engulfed. Vacuoles are formed by the fusion of multiple membrane vesicles and are effectively just larger forms of these. The organelle has no basic shape or size; its structure varies according to the requirements of the cell. Discovery Contractile vacuoles ("stars") were first observed by Spallanzani (1776) in protozoa, although mistaken for respiratory organs. Dujardin (1841) named these "stars" as ''vacuoles''. In 1842, Schleiden applied the term for plant cells, to distinguish the structure with cell sap from the rest of the protoplasm. In 1885, de Vries named the vacuole membrane as tonoplast. Function The function and significa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytoplasm
In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The main components of the cytoplasm are cytosol (a gel-like substance), the organelles (the cell's internal sub-structures), and various cytoplasmic inclusions. The cytoplasm is about 80% water and is usually colorless. The submicroscopic ground cell substance or cytoplasmic matrix which remains after exclusion of the cell organelles and particles is groundplasm. It is the hyaloplasm of light microscopy, a highly complex, polyphasic system in which all resolvable cytoplasmic elements are suspended, including the larger organelles such as the ribosomes, mitochondria, the plant plastids, lipid droplets, and vacuoles. Most cellular activities take place within the cytoplasm, such as many metabolic pathways including glycolysis, and proces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apoplast
Inside a plant, the apoplast can mean the space outside of cell membranes, where material can diffuse freely; that is, the extracellular spaces. ''Apoplast '' can also refer especially to the continuum of cell walls of adjacent cells; fluid and material flows occurring there or in any extacellular space are called ''apoplastic'' flow or apoplastic transport. The apoplastic route is one way by which water and solutes are transported and distributed to different places through tissues and organs; another way is symplastic flow. To prevent uncontrolled leakage to unwanted places, in certain areas there are barriers to the apoplastic flow: in roots the Casparian strip has this function larification needed On the outside of the skin of certain plant parts is a protective waxy film called plant cuticle to achieve this (protection against e.g. drying out, but also waterproofing against soaking). Air bubbles occupying extracellular spaces can also hinder apoplastic transport. The a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symplast
The symplast of a plant is the inner side of a cell membrane in which water and low-molecular-weight solutes can freely diffuse. Symplast cells have more than one nucleus. ''Symplast'' could also refer to the connection of the inner contents (cytoplasm) of neighbouring cells made by the microscopic channels that traverse the cell walls. These channels, which are called plasmodesmata, allow the direct flow of small molecules such as sugars, amino acids, and ions between cells (from the inner part of one cell to the inner partof the next cell). Larger molecules, including transcription factors and plant viruses, can also be transported through with the help of actin structures. This allows direct cytoplasm-to-cytoplasm flow of water and other nutrients along concentration gradients. In particular, symplastic flow is used in the root systems to bring in nutrients from soil. Nutrient solutes move in this way through three skin layers of the roots: from cells of the ''epidermis'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symplast Pathway
The symplast of a plant is the inner side of a cell membrane in which water and low-molecular-weight solutes can freely diffuse. Symplast cells have more than one nucleus. ''Symplast'' could also refer to the connection of the inner contents (cytoplasm) of neighbouring cells made by the microscopic channels that traverse the cell walls. These channels, which are called plasmodesmata, allow the direct flow of small molecules such as sugars, amino acids, and ions between cells (from the inner part of one cell to the inner partof the next cell). Larger molecules, including transcription factors and plant viruses, can also be transported through with the help of actin structures. This allows direct cytoplasm-to-cytoplasm flow of water and other nutrients along concentration gradients. In particular, symplastic flow is used in the root systems to bring in nutrients from soil. Nutrient solutes move in this way through three skin layers of the roots: from cells of the ''epidermi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
