Download Plant Nutrition and Water Absorption: A Deep Dive into Soil, Roots, and Transpiration and more Quizzes Biology in PDF only on Docsity! TERM 1 From where do plants get the nutrients they require? DEFINITION 1 Plants require nine macronutrients and seven micronutrients, all elements. All are available from water, air, and soil.Soil consists of mainly mineral particles: sand, silt, and clay. Clay attracts and reversibly binds dissolved mineral ions.Soil contains humus, a reservoir of organic material rich in organic acids.Most plants grow best in loams and between 10 and 20 percent humus.Leaching and erosion remove nutrients from soil. TERM 2 How do roots take up water and nutrients? DEFINITION 2 Root hairs, mycorrhizae, and root nodules greatly enhance a root's ability to take up water and nutrients.Transport proteins in root cell plasma membranes control the uptake of water and ions into the vascular cylinder. TERM 3 What makes water move inside plants? DEFINITION 3 Transpiration is the evaporation of water from leaves, stems, and other plants parts.By cohesion-tension theory, transpiration puts water in xylem into a continuous state of tension from leaves to roots.Tension pulls columns of water in xylem upward through the plant. The collective strength of many hydrogen bonds (cohesion) keeps water from breaking into droplets as it rises. TERM 4 How do land plants conserve water? DEFINITION 4 A waxy cuticle covers all epidermal surfaces of the plant exposed to air. It restricts water loss from plant surfaces.Plants conserve water by closing their many stomata. Closed stomata also prevent gas exchanges necessary for photosynthesis and aerobic respiration.A stoma stays open when the guard cells that define it are plump with water. It closes when the cels lose water and collapse against each other. TERM 5 How do organic molecules move through plants? DEFINITION 5 Plants store carbohydrates as starch, and distribute them as sucrose and other small, water-soluble molecules.Concentration and pressure gradients in the sieve-tube system of phloem force organic compounds to flow to different parts of the plant.The gradients are set up by companion cells moving organic molecules into sieve tubes at sources and the unloading of the molecules at sinks. TERM 6 Nutrients DEFINITION 6 an element or molecule with an essential role in an organism's growth and survival TERM 7 Soil DEFINITION 7 consists of mineral particles mixed with variable amounts of decomposing organic material; types differ in their proportions of sand, silt, and clay TERM 8 Humus DEFINITION 8 decomposing organic material; form from organic litter and dead organisms TERM 9 Loams DEFINITION 9 soils with roughly equal proportions of sand, silt, and clay; have the best oxygen and water penetration TERM 10 Topsoil DEFINITION 10 contains the greatest amount of organic matter, so the roots of most plants grow densely in it; horizon A TERM 21 Translocation DEFINITION 21 the process by which water moves sucrose and other organic compounds through phloem of vascular plants TERM 22 Source DEFINITION 22 any location of the plant where organic compounds are loaded into sieve tubes; companion cells actively load photosynthesis products into sieve tubes of phloem TERM 23 Sink DEFINITION 23 any location of the plant where organic compounds are being used or stored TERM 24 Pressure flow theory DEFINITION 24 the movement of fluid through phloem is driven by internal pressure and solute gradients; pressure builds up at sieve tube sources and the pressure gradient pushes solute-rich fluid to a sink TERM 25 Guard cells DEFINITION 25 a pair of specialized epidermal cells that define each stoma; when they swell with water they bend slightly, opening the stoma; when they lose water they collapse against each otheraffected by environmental cues that trigger osmotic pressure changes in their cytoplasm TERM 26 Cuticle DEFINITION 26 water-conversing layer on all plant cells exposed to air; consists of epidermal cell secretions (waxes, pectin, and cellulose fibers) TERM 27 Closed stomata limit __, but also prevent __ DEFINITION 27 fill in the blank:the loss of waterthe gas exchange required for photosynthesis and aerobic respiration
