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30 Cards in this Set
- Front
- Back
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Essential element |
A chemical element that is required for a plant to complete its life cycle and produce another generation. |
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Hydroponic culture |
A plant is grown in a mineral solution instead of soil to determine which chemical elements are essential. |
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Maceonutrients |
Essential elements that plants require in relatively large amounts. |
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Micronutrients |
Essential elements that a plant needs only in small quantities. |
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Chlorosis |
Yellowing of leaves. |
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Rhizosphere
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The soil closely surrounding the plant's roots.
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Endophytes
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Nonpathogenic bacteria that live between cells within the plant itself but do not form deep, intimate associations with the cells or alter their morphology.
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Nitrogen cycle
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Describes transformations of nitrogen and nitrogenous compounds in nature.
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Nitrogen fixing bacteria
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Bacteria that convert gaseous nitrogen (N₂) to NH3; which then picks up another proton in the soil solution, forming NH4+.
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Nitrification
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The oxidation of ammonia (NH3) to nitrite (NO2-) followed by oxidation of nitrite to nitrate (NO3-).
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Nodules
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Swellings that exist along a legume's roots composed of plant cells "infected" with Rhizobium bacteria.
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Bacteroids
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The form that the Rhizobium bacteria assume inside each nodule. They are contained within vesicles formed in the root cells.
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Crop rotation
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The farming practice where a non-legume such as maize is planted one year, and the following year alfalfa or some other legume is planted to restore the concentration of fixed nitrogen in the soil.
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Ectomycorrhizae
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A type of mycorrhizae that forms a dense sheath, or mantle, over the surface of the root. They are found in 10% of plant species.
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Arbuscular mycorrhizae
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A type of mycorrhizae that do not form a dense mantle ensheathing the root, but rather enter the cell walls of root cells. They are found in 85% of plant species.
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Epiphyte
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A plant that grows on another plant.
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Parasitic plants
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Plants that absorb water, minerals, and sometimes products of photosynthesis from their living hosts.
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Carnivorous plants |
Photosynthetic plants that supplement their mineral diet by capturing insects and other small animals. |
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Humus
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The remains of dead organisms and other organic matter.
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Soil horizons
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The topsoil and other soil layers.
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Loams
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The most fertile topsoils, composed of equal amounts of sand, silt, and clay.
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Cation exchange
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The process by which protons replace the cations that are attached to the negatively charged soil particles. The roots then absorb these replaced cations.
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Sustainable agriculture
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A commitment embracing a variety of farming methods that are conservation minded, environmentally safe, and profitable.
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Aquifers
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Underground water reserves that are the primary source of irrigation water.
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Land subsidence
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A gradual settling or sudden sinking of Earth's surface.
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Salinization
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The addition of salts to the soil that make it too salty for cultivating plants.
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Drip irrigation
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The slow release of water to soil and plants from perforated plastic tubing placed directly at the root zone.
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Fertilization
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The addition of mineral nutrients to the soil.
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No-till agriculture
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A plowing technique that creates a narrow farrow for seeds and fertilizer that reduces erosion.
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Phytoremediation |
A nondestructive biotechnology that harnesses the ability of some plants to extract soil pollutants and concentrate them in portions of the plant that can be easily removed for safe disposal. |
