Indicators LED Grow Light LED industry can be said to be the most copied. A variety of plants in the unique geographical environment to survive, including sunlight, temperature, altitude and soil, etc., they form a unique breeding flowering response strategy in the last million years of evolution in the life of the natural environment, and that is the flowering season is limited to a suitable period to ensure that the offspring can smoothly growth and development, which is the phenomenon of light cycle of a plant. Most plants in natural selection and evolution have gradually adapted to the natural rhythm of light environment, to form a clear reproduction of the best seasonal. Studies have shown that photoperiodic induction of flowering plants important environmental factors, analyzed the performance of the plant breeding laws in order to improve output efficiency of agricultural facilities, and promote healthy development of the farming industry.
Photoperiod is an important factor inducing flowering plants. Based on the flowering photoperiod physiological pathway analysis, an overview of the photoperiod specific application in plant flowering, it pointed out the application to consider other effects of environmental factors for agricultural facilities flower planting and efficient development of a useful ideas, but also for LED grow light manufacturers and control designed to provide a scientific basis.
Flowering photoperiod physiological pathways
Leaf feel photoperiod signal, this flowering stimulant conducted to the tip of the stem growing point. Phytochrome and Cryptochromes as a light receptor is involved in this pathway, through gene expression, and the completion of flowering control the formation of floral organs. At least three types of photoreceptors in higher plants: Feel the red and far-red phytochrome, absorbs ultraviolet (UV-A) and Blu-ray Cryptochrome and phototaxis factors.
Plant photoperiodic response types
Plant Nutrition and transferred from a purely vegetative growth to reproductive growth is double the plant life in a major turning point, and its importance for the continuation of the plant species itself. United States Gardner (W.W.Garner) and Arad (H.A.Allard) proposed a “plant itself can measure the day length and season accordingly perceived” concept in 1920, which is now called photoperiodism.
Within a certain period of development, based on length of day type of reaction can be divided into the plant long-day plant (long-dayplant, abbreviated as LDP), short-day plants (short-dayplant, abbreviated as SDP), Day-neutral plants ( day-neutralplant, abbreviated as DNP). LDP refers to the exposure time must be longer than a certain number of hours per day and after a certain number of days to flowering plants. Such as wheat, barley, canola, henbane, osmanthus and sugar beet, and the longer the exposure time, the earlier flowering. SDP refers to the illumination time of day must be shorter than a certain number of plants when to flower. As appropriate to shorten the light, flowering earlier, but the extension of the light, the delay flowering or not flowering. Such as rice, cotton, soybeans, tobacco, begonia, chrysanthemum, morning glory and cocklebur like. DNP refers to any day conditions can flowering plants, such as tomatoes, cucumbers, roses and Clivia and so on.
Flowering light cycle regulatory application of key issues
1 plant critical day length
Plants critical day length refers to the circadian cycle, inducing short-day flowering plants can endure the longest sunshine or inducing long-day flowering plants must shortest sunshine. For the LDP, the Japanese grew up in the critical day long, even 24 hours can blossom. But for SDP, the date must be smaller than the critical day length to flower, but not too short flowering.
2 key manual control flowering and photoperiod
SDP flowering decide on the length of the dark period does not depend on the length of time illumination. LDP flowering sunshine required length longer than the SDP is not necessarily required day length flowering.
We learned flowering photoperiodic response and key type, you can extend or shorten the length of day in a greenhouse, control flowering, flowering time to solve the problem. Artificial light can accelerate the extension of long-day plants flowering, appropriate to shorten the light, can promote short-day plants flowering early. It intends to delay flowering or non-flowering, setting operation can be reversed. If the long-day plant cultivation in the tropics, due to lack of light, they will not bloom, the same short-day plants cultivated in temperate and boreal also because exposure time is too long to blossom.
3 introduction, breeding
Artificial plants photoperiodic control of this has very important implications for the introduction, breeding plants. SDP is introduced to northern South seed to bloom early, late-maturing varieties need. Similarly south species northward, to be early-maturing varieties; seed for LDP is introduced north south, to delay flowering, to be early-maturing varieties. Similarly south species northward, to be late-maturing varieties. For example, the genus Malvaceae Hibiscus Roselle is SDP, if south species northward extension of the vegetative growth stage. Budding, flowering, seed of lag, early frost was easily hurt, then you should know that need shade treatment.
4 red and far-red floral induction
The main receiving Photofrin red (Pr) and far-red (Pfr) signal, the impact of flowering induction. Flower effect is not determined by the absolute amount of Pr and Pfr, but affected Pfr / Pr ratio. SDP in the lower Pfr / Pr ratio under the flower, while LDP flowering stimulate the formation of substances requires a relatively high Pfr / Pr ratio. If the dark period is interrupted red light, the ratio Pfr / Pr increases, so SDP flowering is inhibited. LDP to Pfr / Pr ratio stringent requirements better than SDP, but long enough illumination time, relatively high irradiance and far-red light to induce flowering LDP is essential.
LED lighting effects and control system
Photoperiodic control of light and dark is a state within a day range, can be artificially set automatically change. LED control technology has been controlled by a single initial constant current, the current development of SCR dimming, PWM dimming, DMX512, DALI, ZigBee protocols such as dimming. Control mode is also developed from the first wire technology to IR, FR, Wi-Fi short-range wireless control. The controller uses an embedded structure, the optical parameters can be real-time monitoring data via the Internet to communicate with a remote server, the system can easily achieve the brightness regulation time.
In fact, even for one door outline families have different segments. Their needs are not the same light. Light cycle regulation environmentally safe, low cost LED lamps and labor-saving features and simple in agricultural facilities. Therefore, rational and effective use of light can break the cycle of seasonal restrictions factory cultivated plants within certain limits, to achieve anti-season to stimulate or inhibit, in order to achieve the purpose of efficient production of agricultural products. With the continuous development of science and technology, the photoperiod phenomenon is bound to a more profound understanding. The photoperiodic regulation of flowering plant breeding applied to industrialized species colonization industry, will promote the steady and rapid development of agricultural facilities and LED lighting applications Plant Industry.