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Plant Tissue Test
The nutrient content of a plant can be assessed by testing a sample of tissue from that plant. These tests are important in agriculture since fertilizer application can be fine-tuned if the plants nutrient status is known. Nitrogen most commonly limits plant growth and is the most managed nutrient. Most useful times Tissue tests are almost always useful, since they provide additional information about the physiology of the crop. Tissue tests are especially useful in certain situations; * For monitoring the nitrogen status of a crop throughout the growing season. Soil tests are commonly performed before planting. * In highly controlled environments, such as hydroponic production in greenhouses, crops require a constant feed of nutrients in their water supply. Even a transient lack of nutrients can reduce yields. Soil testing results cannot reveal actual nutrient uptake and nutrient mobility. Soil tests may be insufficient to manage crop nitrogen status. Soil testing may be more s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nutrient
A nutrient is a substance used by an organism to survive, grow and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi and protists. Nutrients can be incorporated into cells for metabolic purposes or excreted by cells to create non-cellular structures such as hair, scales, feathers, or exoskeletons. Some nutrients can be metabolically converted into smaller molecules in the process of releasing energy such as for carbohydrates, lipids, proteins and fermentation products ( ethanol or vinegar) leading to end-products of water and carbon dioxide. All organisms require water. Essential nutrients for animals are the energy sources, some of the amino acids that are combined to create proteins, a subset of fatty acids, vitamins and certain minerals. Plants require more diverse minerals absorbed through roots, plus carbon dioxide and oxygen absorbed through leaves. Fungi live on dead or living organic matter and meet nutrient needs from th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lettuce
Lettuce (''Lactuca sativa'') is an annual plant of the family Asteraceae mostly grown as a leaf vegetable. The leaves are most often used raw in Green salad, green salads, although lettuce is also seen in other kinds of food, such as sandwiches, wraps and soups; it can also be grilled. Its stem and seeds are sometimes used; celtuce (asparagus lettuce) is one variety grown for its stems, which are eaten either raw or cooked. In addition to its main use as a leafy green, it has also gathered religious and medicinal significance over centuries of human consumption. Europe and North America originally dominated the market for lettuce, but by the late 20th century the consumption of lettuce had spread throughout the world. , world production of lettuce (and chicory) was 27 million tonnes, 53percent of which came from China. Lettuce was originally farmed by the ancient Egyptians, who transformed it from a plant whose seeds were used to obtain oil into an important food crop raised fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fertilizer
A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Many sources of fertilizer exist, both natural and industrially produced. For most modern agricultural practices, fertilization focuses on three main macro nutrients: nitrogen (N), phosphorus (P), and potassium (K) with occasional addition of supplements like rock flour for micronutrients. Farmers apply these fertilizers in a variety of ways: through dry or pelletized or liquid application processes, using large agricultural equipment, or hand-tool methods. Historically, fertilization came from natural or organic sources: compost, animal manure, human manure, harvested minerals, crop rotations, and byproducts of human-nature industries (e.g. fish processing waste, or bloodmeal from animal slaughter). However, starting in the 19th cen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosystem II
Photosystem II (or water-plastoquinone oxidoreductase) is the first protein complex in the light-dependent reactions of oxygenic photosynthesis. It is located in the thylakoid membrane of plants, algae, and cyanobacteria. Within the photosystem, enzymes capture photons of light to energize electrons that are then transferred through a variety of coenzymes and cofactors to reduce plastoquinone to plastoquinol. The energized electrons are replaced by oxidizing water to form hydrogen ions and molecular oxygen. By replenishing lost electrons with electrons from the splitting of water, photosystem II provides the electrons for all of photosynthesis to occur. The hydrogen ions (protons) generated by the oxidation of water help to create a proton gradient that is used by ATP synthase to generate ATP. The energized electrons transferred to plastoquinone are ultimately used to reduce to NADPH or are used in non-cyclic electron flow. DCMU is a chemical often used in laboratory se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorophyll Fluorescence
Chlorophyll fluorescence is light re-emitted by chlorophyll molecules during return from Excited state, excited to non-excited states. It is used as an indicator of photosynthetic energy conversion in plants, algae and bacteria. Excited chlorophyll dissipates the absorbed light energy by driving photosynthesis (photochemical energy conversion), as heat in non-photochemical quenching or by emission as fluorescence radiation. As these processes are complementary processes, the analysis of chlorophyll fluorescence is an important tool in plant research with a wide spectrum of applications. The Kautsky effect Upon illumination of a dark-adapted leaf, there is a rapid rise in fluorescence from Photosystem II (PSII), followed by a slow decline. First observed by ''Kautsky et al., 1932'', this is called the Kautsky Effect. This variable rise in chlorophyll fluorescence is due to photosystem II. Fluorescence from photosystem I is not variable, but constant. The increase in fluoresce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecophysiology
Ecophysiology (from Greek , ''oikos'', "house(hold)"; , ''physis'', "nature, origin"; and , '' -logia''), environmental physiology or physiological ecology is a biological discipline that studies the response of an organism's physiology to environmental conditions. It is closely related to comparative physiology and evolutionary physiology. Ernst Haeckel's coinage bionomy is sometimes employed as a synonym. Plants Plant ecophysiology is concerned largely with two topics: mechanisms (how plants sense and respond to environmental change) and scaling or integration (how the responses to highly variable conditions—for example, gradients from full sunlight to 95% shade within tree canopies—are coordinated with one another), and how their collective effect on plant growth and gas exchange can be understood on this basis. In many cases, animals are able to escape unfavourable and changing environmental factors such as heat, cold, drought or floods, while plants are unable to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorophyll Fluorescence
Chlorophyll fluorescence is light re-emitted by chlorophyll molecules during return from Excited state, excited to non-excited states. It is used as an indicator of photosynthetic energy conversion in plants, algae and bacteria. Excited chlorophyll dissipates the absorbed light energy by driving photosynthesis (photochemical energy conversion), as heat in non-photochemical quenching or by emission as fluorescence radiation. As these processes are complementary processes, the analysis of chlorophyll fluorescence is an important tool in plant research with a wide spectrum of applications. The Kautsky effect Upon illumination of a dark-adapted leaf, there is a rapid rise in fluorescence from Photosystem II (PSII), followed by a slow decline. First observed by ''Kautsky et al., 1932'', this is called the Kautsky Effect. This variable rise in chlorophyll fluorescence is due to photosystem II. Fluorescence from photosystem I is not variable, but constant. The increase in fluoresce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kautsky Effect
In biophysics, the Kautsky effect (also fluorescence transient, fluorescence induction or fluorescence decay) is a phenomenon consisting of a typical variation in the behavior of a plant fluorescence when exposed to light. It was discovered in 1931 by H. Kautsky and A. Hirsch. When dark-adapted photosynthesising cells are illuminated with continuous light, chlorophyll fluorescence displays characteristic changes in intensity accompanying the induction of photosynthetic activity. Application of Kautsky effect The quantum yield of photosynthesis, which is also the photochemical quenching of fluorescence, is calculated through the following equation: Φp = (Fm-F0)/Fm = Fv/Fm F0 is the low fluorescence intensity, which is measured by a short light flash that is not strong enough to cause photochemistry, and thus induces fluorescence. Fm is the maximum fluorescence that can be obtained from a sample by measuring the highest intensity of fluorescence after a saturating flash. The differ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dualex
The Dualex is an optical sensor used in plant science and agriculture for the assessment of flavonol, anthocyanin, and chlorophyll contents in leaves. This device allows researchers to perform real-time and non-destructive measurements of these important plant metabolites, which are crucial indicators of plant health and stress responses. Developed by Force-A (now out of business), the sensor is a result of technology transfer from the CNRS (National Center for Scientific Research) and University of Paris-Sud Orsay. It allows to make instant measurements without damaging the leaves. The main applications are plant sciences and agricultural research. Calculated parameters The assessment of polyphenolic compounds in leaves is based on the absorbance of the leaf epidermis through the screening effect it procures to chlorophyll fluorescence. The parameters calculated by Dualex are: * Anth, for the anthocyanin index * Chl, for the chlorophyll content * Flav, for the flavonols index * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen Deficiency
Nitrogen deficiency is a deficiency of nitrogen in plants. This can occur when organic matter with high carbon content, such as sawdust, is added to soil. Soil organisms use any nitrogen available to break down carbon sources, making nitrogen unavailable to plants. This is known as "robbing" the soil of nitrogen. All vegetables apart from nitrogen-fixing legumes are prone to this disorder. Nitrogen deficiency can be prevented by using grass mowings as a mulch or foliar feeding with manure. Sowing green manure crops such as grazing rye to cover soil over the winter will help to prevent nitrogen leaching, while leguminous green manures such as winter tares will fix additional nitrogen from the atmosphere. Moreover, poor irrigation system in the field can lead to loss of nitrogen in plants as stagnant water in the field will cause the nitrogen to evaporate in the air. Symptoms Some symptoms of nitrogen deficiency (in absence or low supply) are given below: #The chlorophyll conte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorophyll
Chlorophyll is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words (, "pale green") and (, "leaf"). Chlorophyll allows plants to absorb energy from light. Those pigments are involved in oxygenic photosynthesis, as opposed to bacteriochlorophylls, related molecules found only in bacteria and involved in anoxygenic photosynthesis. Chlorophylls absorb light most strongly in the blue portion of the electromagnetic spectrum as well as the red portion. Conversely, it is a poor absorber of green and near-green portions of the spectrum. Hence chlorophyll-containing tissues appear green because green light, diffusively reflected by structures like cell walls, is less absorbed. Two types of chlorophyll exist in the photosystems of green plants: chlorophyll ''a'' and ''b''. History Chlorophyll was first isolated and named by Joseph Bienaimé Caventou and Pierre Joseph Pelletier in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinach
Spinach (''Spinacia oleracea'') is a leafy green flowering plant native to Central Asia, Central and Western Asia. It is of the order Caryophyllales, family Amaranthaceae, subfamily Chenopodioideae. Its leaves are a common vegetable consumed either fresh or after storage, using Food preservation, preservation techniques by canning, Freezing (food), freezing, or Dehydrated food, dehydration. It may be eaten cooked or raw, and the taste differs considerably; the high oxalate content may be reduced by steaming. It is an annual plant (rarely biennial plant, biennial), growing as tall as . Spinach may Overwintering, overwinter in temperate regions. The leaf, leaves are alternate, simple, ovate to triangular, and very variable in size: long and broad, with larger leaves at the base of the plant and small leaves higher on the flowering stem. The flowers are inconspicuous, yellow-green, in diameter, and mature into a small, hard, dry, lumpy fruit cluster across containing several see ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
