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DIF (technique)
DIF is a greenhouse technique involving temperature control for the purpose of controlling plant Plant stem, internode length and thus elongation rates. DIF's effectiveness has led to a reduction in the need and use of chemical plant growth regulators. Although many common greenhouse plants do react strongly to -DIF, there are some plants which show little or no response to -DIF. Basics DIF refers to the difference between daytime and nighttime temperatures. DIF is calculated by subtracting the nighttime temperature from the daytime temperature to get a +DIF when the daytime is warmer, or a -DIF when the night time is warmer. When there is a +DIF, elongation rates are normal, but when there is a -DIF elongation rates are lowered. As nights are generally cooler than days, the DIF technique is only actively utilized to slow growth, not to increase growth. Instead of increasing heating all through the night, which can be very expensive, another approach to getting a -DIF response is to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenhouse
A greenhouse (also called a glasshouse, or, if with sufficient heating, a hothouse) is a structure with walls and roof made chiefly of Transparent ceramics, transparent material, such as glass, in which plants requiring regulated climatic conditions are grown.These structures range in size from small sheds to industrial-sized buildings. A miniature greenhouse is known as a cold frame. The interior of a greenhouse exposed to sunlight becomes significantly warmer than the external temperature, protecting its contents in cold weather. Many commercial glass greenhouses or hothouses are high tech production facilities for vegetables, flowers or fruits. The glass greenhouses are filled with equipment including screening installations, heating, cooling, and lighting, and may be controlled by a computer to optimize conditions for plant growth. Different techniques are then used to manage growing conditions, including air temperature, relative humidity and vapour-pressure deficit, in ord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Stem
A stem is one of two main structural axes of a vascular plant, the other being the root. It supports leaves, flowers and fruits, transports water and dissolved substances between the roots and the shoots in the xylem and phloem, stores nutrients, and produces new living tissue. The stem can also be called halm or haulm. The stem is normally divided into nodes and internodes: * The nodes hold one or more leaves, as well as buds which can grow into branches (with leaves, conifer cones, or flowers). Adventitious roots may also be produced from the nodes. * The internodes distance one node from another. The term "shoots" is often confused with "stems"; "shoots" generally refers to new fresh plant growth including both stems and other structures like leaves or flowers. In most plants stems are located above the soil surface but some plants have underground stems. Stems have four main functions which are: * Support for and the elevation of leaves, flowers, and fruits. The stems ke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Growth Regulators
Plant hormone (or phytohormones) are signal molecules, produced within plants, that occur in extremely low concentrations. Plant hormones control all aspects of plant growth and development, from embryogenesis, the regulation of organ size, pathogen defense, stress tolerance and through to reproductive development. Unlike in animals (in which hormone production is restricted to specialized glands) each plant cell is capable of producing hormones. Went and Thimann coined the term "phytohormone" and used it in the title of their 1937 book. Phytohormones occur across the plant kingdom, and even in algae, where they have similar functions to those seen in higher plants. Some phytohormones also occur in microorganisms, such as unicellular fungi and bacteria, however in these cases they do not play a hormonal role and can better be regarded as secondary metabolites. Characteristics The word hormone is derived from Greek, meaning ''set in motion''. Plant hormones affect gene ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Growing Degree-day
Growing degree days (GDD), also called growing degree units (GDUs), are a heuristic tool in phenology. GDD are a measure of heat accumulation used by horticulturists, gardeners, and farmers to predict plant and animal development rates such as the date that a flower will bloom, an insect will emerge from dormancy, or a crop will reach maturity. Introduction In the absence of extreme conditions such as unseasonal drought or disease, plants grow in a cumulative stepwise manner which is strongly influenced by the ambient temperature. Growing degree days take aspects of local weather into account and allow gardeners to predict (or, in greenhouses, even to control) the plants' pace toward maturity. Unless stressed by other environmental factors like moisture, the development rate from emergence to maturity for many plants depends upon the daily air temperature. Because many developmental events of plants and insects depend on the accumulation of specific quantities of heat, it is possib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorosis
In botany, chlorosis is a condition in which leaves produce insufficient chlorophyll. As chlorophyll is responsible for the green color of leaves, chlorotic leaves are pale, yellow, or yellow-white. The affected plant has little or no ability to manufacture carbohydrates through photosynthesis and may die unless the cause of its chlorophyll insufficiency is treated and this may lead to a plant diseases called rusts, although some chlorotic plants, such as the albino ''Arabidopsis thaliana'' mutant ''ppi2'', are viable if supplied with exogenous sucrose. The word ''chlorosis'' is derived from the Greek ''khloros'' meaning "greenish-yellow", "pale green", "pale", "pallid", or "fresh". In viticulture, the most common symptom of poor nutrition in grapevines is the yellowing of grape leaves caused by chlorosis and the subsequent loss of chlorophyll. This is often seen in vineyard soils that are high in limestone such as the Italian wine region of Barolo in the Piedmont, the Spanish wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lilium
''Lilium'' () is a genus of herbaceous flowering plants growing from bulbs, all with large prominent flowers. They are the true lilies. Lilies are a group of flowering plants which are important in culture and literature in much of the world. Most species are native to the northern hemisphere and their range is temperate climates and extends into the subtropics. Many other plants have "lily" in their common names, but do not belong to the same genus and are therefore not true lilies. Description Lilies are tall perennials ranging in height from . They form naked or tunicless scaly underground bulbs which are their organs of perennation. In some North American species the base of the bulb develops into rhizomes, on which numerous small bulbs are found. Some species develop stolons. Most bulbs are buried deep in the ground, but a few species form bulbs near the soil surface. Many species form stem-roots. With these, the bulb grows naturally at some depth in the soil, and each ye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
