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| In plants, the continuum of cell walls plus the extracellular spaces. |
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| A transport protein in the plasma membrane of a plant or animal cell that specifically facilitates the diffusion of water across the membrane (osmosis). |
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| The movement of water due to a difference in pressure between two locations. |
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| A water-impermeable ring of wax in the endodermal cells of plants that blocks the passive flow of water and solutes into the stele by way of cell walls. |
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| An energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP. Most ATP synthesis in cells occurs by chemiosmosis. |
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| A physiological cycle of about 24 hours that is present in all eukaryotic organisms and that persists even in the absence of external cues. |
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| The coupling of the downhilldiffusion of one substance to the uphilltransport of another against its own concentration gradient. |
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| Limp. A walled cell is flaccid in surroundings where there is no tendency for water to enter. |
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| The exudation of water droplets, caused by root pressure in certain plants. |
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| The diffusion of water across a selectively permeable membrane. |
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| To shrink and pull away from a cell wall, or when a plant cell protoplast pulls away from the cell wall as a result of water loss. |
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| An active transport mechanism in cell membranes that uses ATP to force hydrogen ions out of a cell, generating a membrane potential in the process. |
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| The upward push of xylem sap in the vascular tissue of roots. |
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| selective passageway across a cell membrane, formed by specialized membrane transport proteins |
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| process where positively charged minerals are made available when hydrogen ions in the soil displace mineral ions from the clay particles |
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| a chemical element that is required for a plant to grow |
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| A plant organ that is a net consumer or storer of sugar. Growing roots, shoot tips, stems, and fruits are sugar sinks supplied by phloem. |
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| A plant organ in which sugar is being produced by either photosynthesis or the breakdown of starch. Mature leaves are the primary sugar sources of plants. |
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| negative pressure on water or solutions |
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| A membrane that encloses the central vacuole in a plant cell, separating the cytosol from the vacuolar contents, called cell sap; also known as the vacuolar membrane. |
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| The transport of organic nutrients in the phloem of vascular plants |
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| In plants, the continuum of cytoplasm connected by plasmodesmata between cells. |
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| The evaporative loss of water from a plant. |
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| A transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane. |
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| The force directed against a cell wall after the influx of water and the swelling of a walled cell due to osmosis. |
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| The physical property predicting the direction in which water will flow, governed by solute concentration and applied pressure. |
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| A plant adapted to an arid climate. |
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| Decomposing organic material found in topsoil. |
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| The most fertile of all soils, made up of roughly equal amounts of sand, silt, and clay. |
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| A chemical substance that an organism must obtain in relatively large amounts. See also micronutrient. |
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| An element that an organism needs in very small amounts and that functions as a component or cofactor of enzymes. See also macronutrient. |
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| An essential chemical element absorbed from the soil in the form of inorganic ions. |
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| The assimilation of atmospheric nitrogen by certain prokaryotes into nitrogenous compounds that can be directly used by plants. |
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| Microorganisms that restock nitrogenous minerals in the soil by converting nitrogen to ammonia. |
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| An enzyme complex, unique to certain prokaryotes, that reduces N2 to NH3. |
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| A swelling on the root of a legume. Nodules are composed of plant cells that contain nitrogen-fixing bacteria of the genus Rhizobium. |
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| An emerging nondestructive technology that seeks to cheaply reclaim contaminated areas by taking advantage of the remarkable ability of some plant species to extract heavy metals and other pollutants from the soil and to concentrate them in easily harvested portions of the plant. |
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| Long-term productive farming methods that are environmentally safe. |
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| A mixture of particles derived from rock, living organisms, and humus. |
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