Republic of the Philippines LEYTE NATIONAL HIGH SCHOOL Science, Technology, Engineering, and Mathematics Strand Tacloban City GENERAL BIOLOGY 2 FOR STEM Name of members:Alzate, Nathalie Shaene Badidles, Raul De Arao, Mariza Jenelle Erandio, Sean Benedict Labay, Kassandra Cloe Macapiot, John Ray Mendoza, Gwyette Jane Olino, Princess Joy Ortega, Abigail Pedrosa, Ramil Matthew Salvador, Princess Acce Grade and Section: 12- L. Belardo Subject Teacher: Princess Michelle B. Gabornes TITLE: Chapter 36. Resource Acquisition and Transport in Vascular Plants DISCUSSION: 36.1. Adaptations for acquiring resources were key steps in the evolution of vascular plants In this chapter, we'll look at some adaptations that help plants collect water, nutrients, carbon dioxide, and light more efficiently. However, obtaining these resources is only the beginning of the story. Resources must be moved to their final destination. As a result, we'll look at how water, minerals, and carbohydrates move through the plant. Adaptations make it easier for plants to live and reproduce in their specific habitat, passing on those features to their offspring. Temperature, accessible water, soil type, and interactions with animals and other organisms are all factors that plants adapt to, regardless of where they grow. - The evolution of vascular tissue (xylem and phloem) enabled the development of large root and shoot systems capable of long-distance transport. Water and minerals are transported from roots to shoots via the xylem. The phloem transfers photosynthetic products from where they are produced or stored to where they are required. Figure 36.2 depicts the acquisition and transport of resources in a vascular plant. In this section, we'll look at how the basic architecture of shoots and roots helps plants collect resources like water, minerals, and sunlight. Shoot Architecture and Light Capture - Shoot architecture is determined by the arrangement and activity of apical, axillary, intercalary, secondary, and inflorescence meristems, as well as the development of stems, leaves, shoot branches, and inflorescences. Typically, shoot architecture facilitates light capture for photosynthesis. - Water availability and leaf size were shown to be related. The largest leaves are frequently found in tropical rain forests, whereas the smallest are typically found in dry or very cold regions where liquid water is rare and evaporative loss is more issue. - Stems support the leaves and act as channels for the transmission of water and nutrients. Two architectural characteristics that influence light capture are stem length and branching patterns. Phyllotaxy - is the arrangement of leaves on a stem - is an architectural characteristic significant in light capture. The shoot apical meristem (see Figure 35.16) determines phyllotaxy and is unique to each species. One leaf per node (alternate, or spiral, phyllotaxy), two leaves per node (opposite phyllotaxy), or more (whorled phyllotaxy) can be found in a species. The leaves of most angiosperms are arranged in an ascending spiral around the stem, with each succeeding leaf emerging 137.5° from the previous one's location. Why 137.5°? One theory is that this angle reduces the shade of the lower leaves by those above. - If there are multiple layers of vegetation, shade from lower leaves is so great that they respire more than they photosynthesize. When this occurs, the inactive leaves or branches are programmed to die and are eventually shed The technique is known as self-pruning. - Self-pruning is the shedding of branches that are shaded or diseased. - Leaf orientation is another aspect that influences light capture. In low-light settings, horizontal leaves capture far more sunlight than vertical leaves. However, in grasslands or other sunny areas, horizontal orientation may expose upper leaves to excessively bright light, damaging plants and limiting photosynthesis. However, if a plant's leaves are almost vertical, light beams are practically parallel to the leaf surfaces, ensuring that no leaf receives too much light and that light penetrates deeper to the lower leaves. Root Architecture and Acquisition of Water and Minerals - Plants develop a more inquisitive root system when nitrogen (N) is deficient, increasing main and lateral root length. - Plants will need nitrogen in form of nitrate, and for the production of chlorophyll, plants will also need magnesium. For the production of nucleic acids and phospholipids(basic building components of cell membrane, plants need phosphorus in the form of phosphate. The evolution of mycorrhizae - Mutualistic relationships between roots and fungi - was a vital phase in plant colonization of land's success. Mycorrhizal hyphae - provide a huge surface area for absorbing water and minerals, particularly phosphate, to the root systems of many plants. - When resources are gathered, they must be transferred to other portions of the plant that require them. *The role of mycorrhizal associations in plant nutrition will be examined more fully in Chapter 37. CONCEPT 36.2 DIFFERENT MECHANISMS TRANSPORT SUBSTANCES OVER SHORT AND LONG DISTANCE THE APOPLAST AND SYMPLAST: TRANSPORT CONTINUUMS - The two primary compartments of plant tissues are assumed to be the APOPLAST and the SYMPLAST. APOPLAST- The apoplast anything that is not contained inside the plasma membranes. Comprises living cells, cell walls and extracellular spaces, and dead cells interiors, including vascular components, tracheids. SYMPLAST - The symplast consists of the majority of the cytosol in a plant’s living cells is made up of plasmodesmata, or the cytoplasmic channels that connect living cells. The three transport pathways that the compartmental structure of plants provides within a plant tissue or organ are the APOPLASTIC, SYMPLASTIC, and TRANSMEMBRANE ROUTES. APOPLASTIC - During the apoplastic route, water and solutes ( dissolved materials) move over a continuum of cell walls and extracellular matrix spaces. SYMPLASTIC - symplastic route are solutes and water. The variety of cytosol. This route requires components to go via plasma membrane when they first enter the plant. After entering one cell. Substances can move via plasmodesmata from one cell to the next. Water and solutes depart one cell, traverse the cell wall, and enter the next cell in the transmembrane route. TRANSMEMBRANE PATHWAY - is a two-way door through which water and solutes can flow to enter and exit a plant cell. •SHORT-DISTANCE TRANSPORT OF SOLUTES ACROSS PLASMA MEMBRANE In all animals, including plants, the plasma membrane's selective permeability governs the short-distance transport of chemicals into and out of cells. The basic types of pumps and transport proteins (channel proteins, carrier proteins, and cotransporters) found in other cell membranes are also present in plant cell membranes. The methods are the main topic of this section. that the way in which solutes permeate plasma membranes in plants and animals is different. In contrast to animal cells, hydrogen ions (H+) rather than sodium ions (Na+) are principally responsible for basic transport processes in plant cells. to create the membrane potential (the voltage across the membrane), for instance, proton pumps in plant cells predominantly pump H+ across the membrane. (Figure 36,6a). instead of the pumping via sodium-potassium pumps of Na+. Furthermore, Na+ is commonly cotransported in animals, whereas H+ is most frequently cotransported in plants. Plant cells employ the energy from the H+ gradient and membrane potential to power the active transport of numerous distinct solutes during cotransport. As an illustration, cotransport Phloem cells and other plant cells absorb neutral solutes, such as the sugar sucrose, thanks to H+. An H+/sucrose cotransporter, which combines the movement of sucrose against its concentration gradient with the movement of H+ down its electrochemical gradient ( Figure 36,6b). facilitates the uptake of nitrate (NO3-) by root cells. (Figure 36.6c).The membranes of plant cells also include ion channels, which alone allow for the passage of particular ions.(Figure 36,6d) like a creature.The majority of cells' channels are gated, and they respond by opening or closing. Next in this chapter, we'll go through how K+ works. To open and close stomata, guard cells' ion channels are functional. Additionally, ion channels are involved in the production of electrical signals similar to the action animal potentials Nevertheless, these signals are 1000 times slower, and use Ca2+ anion channels that are activated as opposed to Na+ animal cells that use ion channels. • SHORT-DISTANCE TRANSPORT OF WATER ACROSS PLASMA MEMBRANES The process through which a cell gains or loses water is known as OSMOSIS. crossing of a membrane by free water, or water that isn't bound to surfaces or solutes. The physical property that predicts the water's flow direction The measure of WATER POTENTIAL, which includes flowability, the effects of solute concentration and physical pressure. Higher water potential areas divert free water to Areas with less potential for water, assuming no barrier along its path flow. The term "water potential" uses the word "potential" to refer to the potential energy—or capability—of water migrate from an area with a higher water potential to an area with less water possibilities. For illustration, if a plant a seed or cell is submerged in a solution with a greater water content Water may potentially enter the cell or seed, causing it to to increase.The word "potential" is used in the phrase "water potential" to water's potential energy—or capability move from a region with more water potential to a location with less access to water. As an example, if a plant A seed or cell is immersed in a more water-rich solution. It's possible that water will get inside the cell or seed, causing it to get bigger.The development of seedlings and plant cells can both be a powerful force:The growth of tree roots' cells walkways made of broken concrete and the swelling of moist grain seeds the holds of wrecked ships may inflict catastrophic devastation.The ships' hulls failing and sinking. It's interesting to think about what happens when seeds swell because of the strong forces they produce. causes seeds to absorb water. Plant cells can develop and seedlings can as well. a powerful force: The cell expansion in tree roots cracked concrete walkways and the swelling of wet grain seeds potential. The holds of sinking ships could cause catastrophic destruction. hulls of the ships breaking down and sinking. The enormous forces that seeds produce when they swell make it interesting to consider what occurs. water to be absorbed by seedlings. • HOW SOLUTES AND PRESSURE AFFECT WATER POTENTIAL Physical pressure and solute concentration both have an impact on water potential. as demonstrated by water potential equation: ψ = ψS + ψP where ψ is the water potential, ψS is the solute potential (osmotic potential), and ψP is the pressure potential. The SOLUTE POTENTIAL (ψS) of a solution is directly proportional to its molarity. Solute potential is also called osmotic potential because solutes affect the direction of osmosis. The solutes in plants are typically mineral ions and sugars. By definition, the ψS of pure water is 0. When solutes are added, they bind water molecules. where denotes the water potential and S denotes the osmotic potential for a solute, and Pressure potential is denoted by P. The element A solution's potential (S) is closely related to in accordance with its molarity. Osmotic potential is another name for solute potential.considering that solutes alter the direction of osmosis. Mineral ions and sugars are the two main types of solutes found in plants. The S of pure water is 0 by definition. Water molecules are bound when solutes are introduced. Because fewer free water molecules are present as a result, the ability of the water to move and perform work is diminished. This is why the S of a solution is always stated as a negative number because an increase in solute concentration has a negative impact on water potential. A 0.1 M solution, as an illustration, has a S of -0.23 MPa for a sugar. As the concentration of solutes rises, S will turn more negative. The PRESSURE POTENTIAL (ψP) denotes the actual external force acting on a solution. Unlike ψS, ψP could be relative either positively or negatively. the atmospheric pressure. •WATER MOVEMENT ACROSS PLANT CELL MEMBRANES the protoplast of the cell experiences In other words, it contracts and pushes away from the cell membrane. The same flaccid cell will have a lower water potential in pure water (ψ = 0 MPa) than it does in the cell because of the solutes it contains (Figure 36.7b). arrives in the cell via osmosis. The cell's contents start to increase in size and push the plasma membrane up against the cell wall. By exerting turgor pressure, the slightly elastic wall holds the compressed protoplast in place. P and S are equal, and = 0, when this pressure is sufficient to prevent the solutes' tendency to force water to enter the cell. This is consistent with the water potential of the extracellular environment, which in this instance is 0 MPa. There is no longer any net water flow because a dynamic equilibrium has been reached. In contrast to a flaccid cell, a walled cell with a higher solute concentration than its surroundings is TURGID, or very hard. When the turgid tissue cells rub up against one another, a non woody tissue becomes stiffened. The effects of turgor loss are evident during WILTING, when leaves and stems droop as a result of cells losing water. Aquaporins: Facilitating Diffusion of Water The direction of water transport across membranes is determined by a difference in water potential, but how can water molecules traverse the membranes? Small enough to diffuse across the phospholipid bilayer are water molecules. despite the hydrophobic core of the bilayer. However, they travel too quickly across biological membranes to be explained by unaided diffusion. be accounted for by spontaneous diffusion. termed transport proteins aquaporins. assist in the movement of water molecules across the plasma membranes of plant cells. Aquaporin channels that can open and close have an impact on the speed at which water crosses the membrane osmotically. Increases in cytosolic Ca2+ diminish their permeability.or falls in the cytosolic pH. • LONG-DISTANCE TRANSPORT: THE ROLE OF BULK FLOW Diffusion is a successful transport method over the typical spatial scales found at the cellular level. However, Diffusion is far too slow for long-distance transport within a plant to function. Although diffusion from one end of a cell to the other is only just a few seconds, diffusion from the massive redwood's growth from the base to the top would take eons. Instead, long distances are covered by BULK transportation. Flow is the term used to describe how a liquid moves in response to a pressure gradient. The bulk flow of material always originates higher to minimize the strain. Osmosis is dependent, whereas bulk flow is independent. the solutes' concentration. The tracheids have long-distance bulk flow. Sieve tubes and xylem vessels contain various parts of the phloem, respectively. These conducting's skeletal systems Bulk flow is aided by cells. Since mature tracheids and vessel components are dead cells without cytoplasm, The majority of the cytoplasm insieve-tube components is Internal organelles. If you've ever transacted. When a drain is partially clogged, you are aware of the volume of The diameter of the pipe affects the flow. The effective diameter of the drainpipe is decreased by clogs. CONCEPT 36.3 CONCEPT 36.4 THE RATE OF TRANSPIRATION IS REGULATED BY STOMATA • STOMATA: MAJOR PATHWAYS FOR WATER LOSS Stomata allow around 95% of the water a plant loses to escape, although only making up 1%–2% of the total volume of a plant's pore. external surface of a leaf. The waxy cuticle limits water loss through the remaining surface of the leaf. All stomata are two guard cells, one on each side. To manage the stoma's diameter, guard cells widen their shape. or closing the gap between the two guard cells. The amount of water lost under the same environmental circumstances by a leaf is mostly determined by the quantity and typical size of its pores, or stomata. A leaf's stomatal density, which could be as high as 20,000 square centimeters, are influenced by both genetics and environment. • MECHANISMS OF STOMATAL OPENING AND CLOSING When guard cells consume water from adjacent cells They get more turgid through osmosis. The thickness of guard cells' cell walls varies among most angiosperm species, and the cellulose microfibrils are orientated in one direction. that, when turgid, forces the guard cells to bow outward (Figure 36.13a). The extent of this leaning outward rises because of a hole that exists between the guard cells. The pore closes when the cells become less bent as they dry out and become flaccid. Guard cells' turgor pressure variations are principally caused by the reversible absorption and loss of K+. When guard cells actively assemble K+ from, the stomata open. adjacent epidermal cells (Figure 36.13b). Proton pumps generate a membrane potential in conjunction with the flow of K+ through the guard cell's plasma membrane. Active stomatal opening is related to H+ transportation from the guardhouse. The voltage that results K+ is driven by (membrane potential). particular membrane channels into the cell. K+ absorption results in the As water enters by osmosis, its potential changes inside the guard cells, making the cells more rigid and negative. Because the vacuole is where most of the K+ and water are kept, the vacuolar membrane also affects how guard cells behave. A loss causes stomatal closure. of K+ to nearby cells from guard cells, which results in a loss of water due to osmosis. Aquaporins also support the regulation of shrinkage and osmotic swelling of guard cells. •STIMULI FOR STOMATAL OPENING AND CLOSING Stomata typically open during the day and are largely closed at night to stop water loss to the plant in circumstances where photosynthesis is impossible. At least three stimuli influence stomatal opening in the early morning: Guard cells have a "clock" inside them, light, and CO2 depletion. Guard cells are stimulated by light to collect K+. and start becoming turgid. This reaction is brought on by the illumination of Guard cells' plasma membranes containing blue-light sensors. The action of the proton pumps in the guard cells' plasma membrane is stimulated by the activation of these receptors. thereby encouraging K+ absorption. In response to the internal CO2 being depleted, stomata also open. photosynthesis causes the air pockets in the leaf to expand. If enough water is provided to the leaf, the stomata will gradually open as CO2 levels drop throughout the day. Stomata maintain their daily regularity of opening and closing thanks to a third cue: the internal "clock" in the guard cells. Even if a plant is housed in an enclosed space, this rhythm is a dim environment. Guard cells appear when the plant is lacking in water. Stomata might seal and turgor disappear. Moreover, a hormone generated in roots and leaves, is referred to as ABSCISIC ACID (ABA). a lack of water triggers the closure of the guard cells. stomata. This reaction lessens wilting but also limits absorption of CO2, which slows photosynthesis. Growth stops throughout the plant because turgor is required for cell elongation. These are a few explanations for why droughts lessen yields of crops. Guard cells include a photosynthesistranspiration compromise control into their moment-to-moment operation. Different impulses from the inside and outside. Even after the passage A brief beam of sunlight through a cloud or a woodland can impact the transpiration rate. • EFFECTS OF TRANSPIRATION ON WILTING AND LEAF TEMPERATURE Transpiration's effects on wilting the Leaf Temperature, and the majority of stomata must be open for transpiration to occur. Best when conditions are sunny, warm, dry, and windy since these conditions boost evaporation. If the leaves cannot absorb enough water through transpiration, as cells lose turgor pressure, the shoot begins to somewhat wilt. Evaporative cooling is another effect of transpiration, which can reduce a leaf's temperature by up to 10°C in comparison to the air around it. •ADAPTATIONS THAT REDUCE EVAPORATIVE WATER LOSS Plant productivity is significantly influenced by water availability. The primary factor linking water availability to plant productivity is not connected to the direct requirement for water for photosynthesis. Water as a substrate, but more so because water is readily available. permits plants to maintain open stomata and absorb more CO2. Reduced water loss is a particularly pressing issue for Desert plants. Plants adapted to arid environments are called XEROPHYTES (from the Greek xero, dry). Other xerophytes have extraordinary morphological or physiological adaptations to withstand severe conditions. setting in the desert. The stems of many xerophytes are fleshy. because they store water for use during extended dry periods. Cacti have leaves that are drastically shrunk and resist excessive water. loss; the majority of their stems' photosynthesis is performed. The crassulacean is another adaptation that is typical of arid settings. Succulents in the Crassulaceae family and other plants that use the specialized form of photosynthesis known as acid metabolism (CAM) many additional families. COCEPT 36.5 Sugars are transported from sources to sinks via the phloem Translocation - The movement of photosynthetic products from leaves to different tissues throughout the plant. is carried out by another tissue, the phloem. Movement from Sugar Sources to Sugar Sinks - The sieve-tube elements are specialized cells in angiosperms that act as translocation channels. - Between these cells are sieve plates, structures that allow the flow of sap along the sieve tube. Phloem sap - the watery solution that passes through the sap delivered by sieve tubes differs significantly from the sap transported by tracheids and vessel components - the most prevalent solute in phloem sap is sugar, typically sucrose in most species - Sucrose concentrations can reach 30% by weight, giving the sap a syrupy consistency - may also contain amino acids, hormones, and minerals - Unlike xylem sap, which flows unidirectionally from roots to leaves, phloem sap goes from sites of sugar production to sites of sugar utilization or storage Sugar Source - organ that is a net generator of sugar, either through photosynthesis or starch breakdown. Sugar Sink - an organ that is a net sugar consumer or repository Sugar sinks include growing roots, buds, stems, and fruits. Although expanding leaves are sugar sinks, mature leaves are sugar sources if well illuminated. Depending on the season, a storage organ, such as a tuber or a bulb, can be a source or a sink. When stockpiling carbohydrates in the summer, it is a sugar sink. It is a sugar source after breaking dormancy in the spring because its starch is broken down to sugar, which is carried to the growing shoot tips. Sinks usually receive sugar from the nearest sugar sources. For example - upper leaves on a branch➡️ growing shoot tip - whereas, lower leaves➡️ roots. Sugar movement into the phloem requires active transport in many plants because sucrose is more concentrated in sieve-tube elements and companion cells than in mesophyll. Sucrose is transported from mesophyll cells to sieve-tube elements or companion cells via proton pumping and H+/sucrose cotransport (Figure 36.15b). Bulk Flow by Positive Pressure: The Mechanism of Translocation in Angiosperms Researchers have concluded that phloem sap moves through angiosperm sieve tubes via bulk flow driven by positive pressure, also known as pressure flow. Sap flows from source to sink due to pressure buildup at the source and pressure reduction at the sink. There are sometimes more sinks than sources can support. In such cases, a plant may abort some flowers, seeds, or fruits, which is known as self-thinning. CONCEPT 36.6 THE SYMPLAST IS HIGHLY DYNAMIC - Symplast is the protoplasts present in plants, which are interconnected by the plasmodesmata. It is the inner part of the plasma membrane, which plays a vital role in transporting or free movement of water and other low-molecular-weight solutes such as sugars, amino acids, and other ions in between cells. Changes in Plasmodesmatal Number and Pore Size - More recent studies have revealed that plasmodesmata are highly dynamic. They can open or close rapidly in response to changes in turgor pressure, cytosolic Ca2+ levels, or cytosolic pH. - Based on these observations, they concluded that the pore sizes were approximately 2.5 nm—too small for macromolecules such as proteins to pass. - Pathologists provided electron micrographs showing evidence of the passage of virus particles with diameters of 10 nm or greater. - It was learned that plant viruses produce viral movement proteins that cause the plasmodesmata to dilate, enabling the viral RNA to pass between cells. A high degree of cytosolic interconnectedness exists only within certain groups of cells and tissues, which are known as symplastic domains. Informational molecules, such as proteins and RNAs, coordinate development between cells within each symplastic domain. If symplastic communication is disrupted, development can be grossly affected. Phloem: An Information Superhighway - The phloem is a “superhighway” for the transport of macromolecules and viruses. - Systemic communication through the phloem helps integrate the functions of the whole plant. - It is a defensive response to localized infection, in which chemical signals traveling through the phloem activate defense genes in non infected tissues. Electrical Signaling in the Phloem - Electrical signaling has been studied extensively in plants that have rapid leaf movements, such as the sensitive plant (Mimosa pudica) and Venus flytrap (Dionaea muscipula). - Studies have revealed that a stimulus in one part of a plant can trigger an electrical signal in the phloem that affects another part, where it may elicit a change in gene transcription, respiration, photosynthesis, phloem unloading, or hormonal levels. - The phloem can serve a nerve-like function, allowing for swift electrical communication between widely separated organs. - The coordinated transport of materials and information is central to plant survival. Plants can acquire only so many resources in the course of their lifetimes. c. Soil and Plant Nutrition CONCEPT 37.1 ●SOIL TEXTURE Soil contains a living, complex ecosystem The texture of soil depends on the sizes of its particles. Soil particles can range from coarse sand (0.02–2 mm in diameter) to silt (0.002–0.02 mm) to microscopic clay particles (less than 0.002 mm). These particles of varying sizes appear eventually from the weathering of rock. When mineral particles released by weathering combine with living things, humus, the remains of dead things, and other organic stuff, topsoil is created. The most fertile topsoils- enabling the most abundant growth- are Loams. Loams -made up of a mixture of clay, silt, and sand in about equal amounts. -have enough small silt and clay particles to offer a sufficient amount of surface area for the adsorption and retention of minerals and water. -the big spaces between sand particles allows effective oxygen trasport to the roots. The pores in the most productive topsoils are typically about half air and half water, creating a favorable balance between water storage capacity, drainage, and aeration. ●TOPSOIL COMPOSITION -Inorganic Composition •Most soil particles are negatively charged. Positively charged ions (cations), such potassium (K+), calcium (Ca2+), and magnesium (Mg2+), attach to these particles and are more resistant to leaching, the process by which water percolates or flows through soil. Roots, however, do not absorb mineral cations directly from soil particles; they absorb them from the soil solution. These mineral cations enter the soil solution by cation exchange, a process in which cations are displaced from soil particles by other cations. Cation Exchange -Plants produce hydrogen cations (H+) that they can exchange. One hydrogen for one potassium cation. -For nutrients with a positive charge of two like calcium, two hydrogen cations are needed •Negatively charged ions (anions)—such as the plant nutrients nitrate (NO3−), phosphate (H2PO4−), and sulfate (SO42−), are more easily lost by leaching since they are unable to bind to the negatively charged soil particles that are normally present in the most productive soils. -Organic Composition •Humus -consists of organic material that is created when bacteria and fungi break down organic matter like dead organisms, fallen leaves, and feces. -Humus prevents clay particles from compressing together and forms crumbly soil that holds water while being able to aerate and allow roots to breathe. •Variety of Organisms -About 5 billion bacteria live in a teaspoon of topsoil, together with fungi, algae, and other protists, insects, earthworms, nematodes, and plant roots. -The physical and chemical properties of the soil are impacted by the activities of all these organisms. For example: Earthworms -expel wastes and transport significant amounts of material to the soil's surface. -By mixing and clumping the soil particles, earthworms improve water retention and air transport. ●SOIL CONSERVATION AND SUSTAINABLE AGRICULTURE -Irrigation Farmers must understand the soil's capacity to retain water, the crops' water requirements, and the best irrigation technology if they are to utilise water in an effective manner. In a lot of arid agricultural regions, drip irrigation is used since it uses less water and lessens salinization. Drip irrigation is a common technology that uses perforated plastic tubing that is put right at the root zone to slowly distribute water to the soil and plants. -Fertilization The majority of farmers in industrialized countries now use fertilizers that contain minerals that are either mined or processed in ways that require a lot of energy. The three nutrients that are most frequently deficient in impoverished soils—nitrogen (N), phosphorus (P), and potassium (K)—are usually enhanced in these fertilizers. The minerals a plant receives can come from chemical factories or organic fertilizers. However, organic fertilizers release them gradually, whereas minerals in commercial fertilizers are immediately, however they might not stay in the soil for very long. -Adjusting Soil PH The pH of the soil should be set to a mineral requirements of the crop. If soil is too alkaline, it can have its pH adjusted by adding sulfate, and a too acidic soil can have its pH adjusted by adding lime (Calcium carbonate or carbon hydroxide). -Controlling Erosion Farmers place windbreak trees in rows, terrace crops on hillsides, and grow crops in a contour pattern to prevent erosion. Erosion can also be reduced by a plowing technique called no-till agriculture. A particular plough is used in no-till farming to make shallow furrows for seeds and fertiliser. In this manner, the field is seeded with the least amount of soil disturbance and the least amount of fertilizer. -Phytoremediation Phytoremediation is a nondestructive biotechnology that makes use of some plants' capacity to collect soil pollutants and concentrate them in areas of the plant that are easy to remove for proper disposal. CONCEPT 37.2 PLANTS REQUIRE ESSENTIAL ELEMENTS TO COMPLETE LIFE CYCLE •Essential Elements -Essential elements in plants are vital for their growth, nutrient uptake, photosynthesis, reproduction, enzyme function, disease resistance, and maintaining water balance. •Hydroponic culture -In which plants are grown in mineral solutions instead of soil. •Macronutrients -Essential elements that plants need in relatively large amounts to support their growth and development. •Micronutrients -Essential elements that plants require in smaller amounts but are just as crucial for their overall growth and well-being. •Mineral deficiency symptoms -A mineral deficiency that affects young portions of the plant is largely immobile. first. -The mineral requirements of a plant may also change with the time of the year and the age of the plant. -Experts and farmers can identify plant deficits, often by analyzing the mineral composition of plants or soil. Improving Plant Nutrition by Genetic Modification •Resistance to Aluminum Toxicity -Acidic soils with high aluminum harm roots and crop yields. To resist aluminum, roots release organic acids (like malic and citric acids) that bind to aluminum ions, reducing soil aluminum. •Smart Plants -Researchers seek to enhance crop yields by creating genetically engineered "smart plants" that turn leaves blue when they detect nutrient deficiencies, signaling farmers to use phosphate-containing fertilizers. SUMMARY & CONCLUSION: EVALUATION: insert 10-item multiple choice questions here (NOTE: do not provide the answer key) Reference:
