사용자:Raccoon Dog/Sandbox 4

위키백과, 우리 모두의 백과사전.

생장등(grow light, plant light)은 광합성에 적절한 빛을 발하여 식물의 성장을 촉진하기 위해 고안된 인공적인 광원이며 일반적으로 전등이 사용된다. 생장등은 자연광이 없거나 보조광원이 필요한 곳에서 사용한다. 예를 들어 햇빛이 비추는 시간이 식물이 충분히 성장하기에는 모자란 겨울에 식물이 빛을 받는 시간을 늘리기 위해 사용할 수 있다. 식물이 빛을 충분히 받지 못하면 웃자랄 수 있다.[출처 필요]

생장등은 태양과 비슷한 빛띠를 비추기 위해서, 경작되는 식물의 Grow lights either attempt to provide a light spectrum similar to that of the sun, or to provide a spectrum that is more tailored to the needs of the plants being cultivated. Outdoor conditions are mimicked with varying colour, temperatures and spectral outputs from the grow light, as well as varying the lumen output (intensity) of the lamps. Depending on the type of plant being cultivated, the stage of cultivation (e.g. the germination/vegetative phase or the flowering/fruiting phase), and the photoperiod required by the plants, specific ranges of spectrum, luminous efficacy and colour temperature are desirable for use with specific plants and time periods.

러시아의 식물학자 Andrei Famintsyn 은 식물의 성장과 연구에 인공광원을 최초로 사용하였다 (1868)

일반적인 사용[편집]

생장등은 원예, 실내정원, 식물번식, 음식생산, 실내 수경재배, 수생식물 재배 등에 사용된다. 생장등은 대개 산업 분야에서 사용되지만, 집에서도 사용할 수 있다.

역제곱 법칙에 따르면, (전구의 경우) 광원에서 방사되어 표면에 도달하는 빛의 강도는 광원과의 거리의 제곱에 반비례하는데 (대상이 두 배 멀어지면, 빛은 반의 반 밖에 쬐지 못한다) According to the inverse-square law, the intensity of light radiating from a point source (in this case a bulb) that reaches a surface is inversely proportional to the square of the surface's distance from the source (if an object is twice as far away, it receives only a quarter the light) which is a serious hurdle for indoor growers, and many techniques are employed to use light as efficiently as possible. Reflectors are thus often used in the lights to maximize light efficiency. Plants or lights are moved as close together as possible so that they receive equal lighting and that all light coming from the lights falls on the plants rather than on the surrounding area.

생장 텐트에 설치된 HPS 생장등의 예시. 악취를 제거하기 위한 탄소 필터, 환기팬을 통해 노폐 가스를 제거하는 배관이 설치되어 있다.

A range of bulb types can be used as grow lights, such as incandescents, fluorescent lights, high-intensity discharge lamps (HID), and light-emitting diodes (LED). Today, the most widely used lights for professional use are HIDs and fluorescents. Indoor flower and vegetable growers typically use high-pressure sodium (HPS/SON) and metal halide (MH) HID lights, but fluorescents and LEDs are replacing metal halides due to their efficiency and economy.[1]

Metal halide lights are regularly used for the vegetative phase of plant growth, as they emit larger amounts of blue and ultraviolet radiation.[2][3] With the introduction of ceramic metal halide lighting and full-spectrum metal halide lighting, they are increasingly being utilized as an exclusive source of light for both vegetative and reproductive growth stages. Blue spectrum light may trigger a greater vegetative response in plants.[4][5][6]

고압소듐광은 생장기, 번식기에 단일 광원으로 사용되기도 한다. As well, they may be used as an amendment to full-spectrum lighting during the reproductive stage. 적색 스펙트럼 광을 쪼여주면 더욱 훌륭한 개화를 촉발할 수 있다.[7] 고압 소듐 광이 생장기에 사용되면 식물은 좀 더 빠르게 자라며, 마디 사이가 길어져서 전반적으로 더 길어질 것이다.

2010년대 이후에 LED 기술이 생장등 시장에 도입되었다. 다이오드를 실내 생장등에 이용하면 특정한 파장을 만들어낼 수 있다. NASA는 우주를 식민화하기 위해 우주공간에서 식물을 높은 효율로 생장시키기 위해 LED 생장등을 시험했다. 이를 통해 식물은 가시광선 중에 적색, 녹색, 청색의 빛에 영향을 받는다는 것을 밝혀냈다.[8][9]

종류[편집]

고강도방전 등 (HID)[편집]

한때 형광등이 실내 생장등에 제일 흔하게 사용되었지만, 오늘날은 고강도 방전등이 제일 인기 있다.[10] 고강도방전등은 와트 당 루멘 효율이 높다.[11] HID 등에는 수은증기, 금속 할로겐화물, 고압 소듐, 전환형 전구가 있다. 금속 할로겐화물, 고압 소듬 등은 태양과 다소 비슷한 파장 스펙트럼을 만들어내어서 식물 생장에 사용할 수 있다. 수은 증기 등은 최초의 고강도방전 등이며 가로등에 널리 사용되었지만, 식물 생장에는 다소 적합하지 않기 때문에 오늘날에는 생장등 분야에서는 대부분 다른 유형의 고강도방전 등으로 대체되었다.[11]

HID 생장등을 운용하기 위해서는 안정기가 필요하며, 각각의 안정기는 grow lights require a ballast to operate, and each ballast has a particular wattage. 인기 있는 HID wattages 는 150W, 250W, 400W, 600W, 1000W 등이 있다. 모든 . Of all the sizes, 600W HID 등이 제일 광량 대비 효율적이며 그 다음은 1000W 이다. A 600W HPS 등은 1000W HPS 보다 와트 당 7% 더 많은 빛을 생산한다.[11]

Although all HID lamps work on the same principle, the different types of bulbs have different starting and voltage requirements, as well as different operating characteristics and physical shape. Because of this a bulb won't work properly unless it's using a matching ballast, even if the bulb will physically screw in. In addition to producing lower levels of light, mismatched bulbs and ballasts will stop working early, or may even burn out immediately.[11]

금속 할로겐화물 (MH)[편집]

작은 백열들 전구와 400W 금속 할로겐화물 전구.

Metal halide bulbs are a type of HID light that emit light in the blue and violet parts of the light spectrum, which is similar to the light that is available outdoors during spring.[12] Because their light mimics the color spectrum of the sun, some growers find that plants look more pleasing under a metal halide than other types of HID lights such as the HPS which distort the color of plants. Therefore, it's more common for a metal halide to be used when the plants are on display in the home (for example with ornamental plants) and natural color is preferred.[13] Metal halide bulbs need to be replaced about once a year, compared to HPS lights which last twice as long.[13]

금속 할로겐화물 등은 원예업계에서 널리 사용되며 Metal halide lamps are widely used in the horticultural industry and are well-suited to supporting plants in earlier developmental stages by promoting stronger roots, better resistance against disease and more compact growth.[12] 청색 파장을 띄는 빛은 성장 속도를 증진시키며 이파리를 많이 만들어내도록 한다. The blue spectrum of light encourages compact, leafy growth and may be better suited to growing vegetative plants with lots of foliage.[13]

A metal halide bulb produces 60-125 lumens/watt, depending on the wattage of the bulb.[14]

They are now being made for digital ballasts in a pulse start version, which have higher electrical efficiency (up to 110 lumens per watt) and faster warmup.[15] One common example of a pulse start metal halide is the ceramic metal halide (CMH). Pulse start metal halide bulbs can come in any desired spectrum from cool white (7000 K) to warm white (3000 K) and even ultraviolet-heavy (10,000 K).[출처 필요]

세라믹메탈핼라이드 (CMH, CDM)[편집]

Ceramic metal halide (CMH) lamps are a relatively new type of HID lighting, and the technology is referred to by a few names when it comes to grow lights, including ceramic discharge metal halide (CDM),[16] ceramic arc metal halide.

Ceramic metal halide lights are started with a pulse-starter, just like other "pulse-start" metal halides.[16] The discharge of a ceramic metal halide bulb is contained in a type of ceramic material known as polycrystalline alumina (PCA), which is similar to the material used for an HPS. PCA reduces sodium loss, which in turn reduces color shift and variation compared to standard MH bulbs.[15] Horticultural CDM offerings from companies such as Philips have proven to be effective sources of growth light for medium-wattage applications.[17]

MH & HPS 조합 ("이중 아크")[편집]

Combination HPS/MH lights combine a metal halide and a high-pressure sodium in the same bulb, providing both red and blue spectrums in a single HID lamp. The combination of blue metal halide light and red high-pressure sodium light is an attempt to provide a very wide spectrum within a single lamp. This allows for a single bulb solution throughout the entire life cycle of the plant, from vegetative growth through flowering. There are potential tradeoffs for the convenience of a single bulb in terms of yield. There are however some qualitative benefits that come for the wider light spectrum.

고압소듐 (HPS)[편집]

공기로 식혀지는 반사기 안에 설치된 HPS (고압소듐) 생장등. grow light bulb in an air-cooled reflector with hammer finish. 노란빛은 HPS 전등의 상징이다.

High-pressure sodium lights are a more efficient type of HID lighting than metal halides. HPS bulbs emit light in the yellow/red visible light as well as small portions of all other visible light. Since HPS grow lights deliver more energy in the red part of the light spectrum, they may promote blooming and fruiting.[10] They are used as a supplement to natural daylight in greenhouse lighting and full-spectrum lighting(metal halide) or, as a standalone source of light for indoors/grow chambers.

HPS grow lights are sold in the following sizes: 150W, 250W, 400W, 600W and 1000W.[10] Of all the sizes, 600W HID lights are the most electrically efficient as far as light produced, followed by 1000W. A 600W HPS produces 7% more light (watt-for-watt) than a 1000W HPS.[11]

600W 고압소듐전등

HPS 전구는 전구의 와트량에 따라 60-140 lumens/watt 를 생산한다.[18]

HPS의 빛 아래에서 자라는 식물은 tend to elongate from the lack of blue/ultraviolet radiation. 현대적인 원예용 HPS 등은 식물 생장에 상당히 최적화되어있다.lamps have a much better adjusted spectrum for plant growth. The majority of HPS 등의 대부분은 생장률이 좋지만 lamps while providing good growth, offer poor color rendering index (CRI) rendering. As a result, the yellowish light of an HPS can make monitoring plant health indoors more difficult. CRI isn't an issue when HPS lamps are used as supplemental lighting in greenhouses which make use of natural daylight (which offsets the yellow light of the HPS).

High-pressure sodium lights have a long usable bulb life, and six times more light output per watt of energy consumed than a standard incandescent grow light. Due to their high efficiency and the fact that plants grown in greenhouses get all the blue light they need naturally, these lights are the preferred supplemental greenhouse lights. But, in the higher latitudes, there are periods of the year where sunlight is scarce, and additional sources of light are indicated for proper growth. HPS lights may cause distinctive infrared and optical signatures, which can attract insects or other species of pests; these may in turn threaten the plants being grown. High-pressure sodium lights emit a lot of heat, which can cause leggier growth, although this can be controlled by using special air-cooled bulb reflectors or enclosures.

전환형 전등[편집]

Conversion bulb는 MH나 HPS 안정기와 함께 작동하도록 제조되었다. 업자는 MH 안정기에 HPS conversion bulb를, 또는 HPS 안정기에 MH conversion bulb를 연결하여 운용할 수 있다. The difference between the ballasts is an HPS ballast has an igniter which ignites the sodium in an HPS bulb, while a MH ballast does not. Because of this, all electrical ballasts can fire MH bulbs, but only a Switchable or HPS ballast can fire an HPS bulb without a conversion bulb.[19] Usually a metal halide conversion bulb will be used in an HPS ballast since the MH conversion bulbs are more common.

전환형 안정기[편집]

A switchable ballast is an HID ballast can be used with either a metal halide or an HPS bulb of equivalent wattage. So a 600W Switchable ballast would work with either a 600W MH or HPS.[10] Growers use these fixtures for propagating and vegetatively growing plants under the metal halide, then switching to a high-pressure sodium bulb for the fruiting or flowering stage of plant growth. To change between the lights, only the bulb needs changing and a switch needs to be set to the appropriate setting.

발광다이오드 (LED)[편집]

LED 생장등 아래서 자라는 두 식물

LED 생장등은 발광다이오드로 구성되어있으며, 대개 히트 싱크와 내장형 송풍기가 장착된 케이스에 설치된다. LED 생장등은 일반적으로 개별적인 안정기가 필요하지 않으며 표준적인 콘센트에 직접 연결될 수 있다.

LED 생장등은 용도에 따라 색상이 다양하다. 광형태형성에 대한 연구를 통하여 녹색, 적색, 근적외선, 청색의 스펙트럼이 뿌리 형성, 식물 생장, 개화에 효과를 보인다고 알려져있지만, LED 생장등으로 식물이 최적으로 생장한다는 특정 파장대를 쏘여줬을 때에 대한 과학적인 연구나 현장 실증은 충분히 이루어지지 않았다.[20] 청색, 적색광을 쏘일 때 대부분의 식물이 정상적으로 자라는 것으로 보인다.[21][22][23] 하지만 수많은 연구를 통해 청색, 적색광만을 쏘이는 것은 단지 비용대비 제일 효율적인 방식일 뿐이고 녹색을 섞어줬을 때 식물이 더 잘 자란다는 것을 보여준다.[24][25][26]

백색 LED 생장등은 자연광을 모방하기 위해 청, 적, 녹이 균형잡힌 모든 자연광 스펙트럼을 제공한다. 하지만 The spectrum used varies, however, white LED grow lights are designed to emit similar amounts of red and blue light with the added green light to appear white. White LED grow lights are often used for supplemental lighting in home and office spaces.

A large number of plant species have been assessed in greenhouse trials to make sure plants have higher quality in biomass and biochemical ingredients even higher or comparable with field conditions. Plant performance of mint, basil, lentil, lettuce, cabbage, parsley, carrot were measured by assessing health and vigor of plants and success in promoting growth. Promoting in profuse flowering of select ornamentals including primula, marigold, stock were also noticed.[27]

In tests conducted by Philips Lighting on LED grow lights to find an optimal light recipe for growing various vegetables in greenhouses, they found that the following aspects of light affects both plant growth (photosynthesis) and plant development (morphology): light intensity, total light over time, light at which moment of the day, light/dark period per day, light quality (spectrum), light direction and light distribution over the plants. However it's noted that in tests between tomatoes, mini cucumbers and bell peppers, the optimal light recipe was not the same for all plants, and varied depending on both the crop and the region, so currently they must optimize LED lighting in greenhouses based on trial and error. They've shown that LED light affects disease resistance, taste and nutritional levels, but as of 2014 they haven't found a practical way to use that information.[28]

A small ficus plant being grown under a black LED light fixture emitting warm white light.
흰색 LED 생장등 아래서 자라는 Ficus 식물

The diodes used in initial LED grow light designs were usually 1/3 watt to 1 watt in power. However, higher wattage diodes such as 3 watt and 5 watt diodes are now commonly used in LED grow lights. for highly compacted areas, COB chips between 10 watts and 100 watts can be used. Because of heat dissipation, these chips are often less efficient.

LED grow lights should be kept at least 12 인치 (30 cm) away from plants to prevent leaf burn.[13]

역사적으로 LED 조광은 굉장히 값비쌌지만, 시간이 지나면서 비용은 급격히 줄어들어왔고, 특유의 긴 수명 덕분에 점점 인기가 높아졌다. LED 생장등은 대개 여타의 LED 등보다 와트당 가격이 높은데, 더욱 에너지 효율이 높고 오래 가도록 설계하기 때문이다. 특히 LED 생장등은 상대적으로 출력이 강하기 때문에 일반적으로 냉각 체계가 설치되는데, 온도가 낮으면 밝기와 수명이 향상되기 때문이다. LED는 일반적으로 last for 50,000 - 90,000 hours until LM-70 is reached.[출처 필요]

형광등[편집]

형광생장등

형광등은 길쭉한 형광등, 전구형광등 등의 다양한 형태로 존재한다.Fluorescent lights come in many form factors, including long, thin bulbs as well as smaller spiral shaped bulbs (compact fluorescent lights). Fluorescent lights are available in color temperatures ranging from 2700 K to 10,000 K. 발광효율은 30 lm/W 에서 90 lm/W 에 이른다. 생장등으로 주로 사용되는 형광등의 유형에는 tube-style lights 와 compact fluorescent lights 가 있다.

튜브형 형광등[편집]

형광생장등은 HID 조명만큼 Fluorescent grow lights are not as intense as HID lights 대개 실내에서 채소와 허브를 기르거나 봄에 심을 묘목을 빨리 키우는 데 사용된다. 이러한 유형의 형광등을 가동하기 위해서는 조정기가 필요하다.[18]

Standard fluorescent lighting comes in multiple form factors, including the T5, T8 and T12. The brightest version is the T5. The T8 and T12 are less powerful and are more suited to plants with lower light needs. High-output fluorescent lights produce twice as much light as standard fluorescent lights. A high-output fluorescent fixture has a very thin profile, making it useful in vertically limited areas.

Fluorescents have an average usable life span of up to 20,000 hours. A fluorescent grow light produces 33-100 lumens/watt, depending on the form factor and wattage.[14]

소형형광등 (CFL)[편집]

Dual spectrum compact fluorescent grow light. Actual length is about 40 cm (16 in)
표준형 소형형광등

소형형광등 (Compact Fluorescent lights, CFLs) 은 본래 pre-heat lamp로서 설계되었지만 오늘날 available in rapid-start form 작은 버전의 형광등이다. 소형형광등은 수명이 길고 에너지 효율이 훨씬 높아 백열등을 거의 대체하였다.[18] 소형형광등은 어떤 경우 생장등으로 사용되기도 한다. 일반적인 형광등과 마찬가지로 증식시킬 때나 상대적으로 낮은 광량을 쬐여줄 때 유용하다.

일반적인 소형형광등이 생장등으로 사용될 수도 있지만, 생장등에 최적으로 설계된 소형형광등도 있다. Often these larger compact fluorescent bulbs are sold with specially designed reflectors that direct light to plants, much like HID lights. 일반적인 소형형광등 생장등의 크기로는 125W, 200W, 250W, 300W 등이 있다.

소형형광등은 HID 등과는 달리 fit in a standard mogul light socket 개별적인 안정기가 필요하지 않다. and don't need a separate ballast.[10]

밝은 적색 (2700 K), 햇빛의 모든 파장대 (5000 K), 어두운 파란색 (6500 K) 을 발하는 소형형광등을 구할 수 있다. 밝은 적색 파장대는 개화에, 어두운 파란색은 초목의 생장에 적합하다.[10]

소형형광등 생장등으로 적절한 수명주기는 10,000 시간 이상이다.[18] 소형형광등은 전구의 와트수에 따라 44-80 lumens/watt 의 광량을 발한다.[14]

Examples of lumens and lumens/watt for different size CFLs:

CFL Wattage Initial Lumens Lumens/watt
23W 1,600 70
42W 2,800 67
85W 4,250 50
125W 7,000 56
200W 10,000 50

Cold Cathode Fluorescent Light (CCFL)

A cold cathode is a cathode that is not electrically heated by a filament. A cathode may be considered "cold" if it emits more electrons than can be supplied by thermionic emissionalone. It is used in gas-discharge lamps, such as neon lamps, discharge tubes, and some types of vacuum tube. The other type of cathode is a hot cathode, which is heated by electric current passing through a filament. A cold cathode does not necessarily operate at a low temperature: it is often heated to its operating temperature by other methods, such as the current passing from the cathode into the gas.

색상 파장[편집]

The color temperatures of different grow lights

생장등에 따라 다양한 빛의 스펙트럼을 만들어낸다. 식물의 성장 패턴은 빛의 색상 파장에 따라 달라지며 이는 광합성과는 전혀 별개의 과정인 광형태형성에 따라 조절된다.[29]

자연광은 높은 색온도 (대략 5000-5800 K) 를 가진다. Visible light color varies according to the weather and the angle of the Sun, and specific quantities of light (measured in lumens) stimulate photosynthesis. Distance from the sun has little effect on seasonal changes in the quality and quantity of light and the resulting plant behavior during those seasons. The axis of the Earth is not perpendicular to the plane of its orbit around the sun. During half of the year the north pole is tilted towards sun so the northern hemisphere gets nearly direct sunlight and the southern hemisphere gets oblique sunlight that must travel through more atmosphere before it reaches the Earth's surface. In the other half of the year, this is reversed. The color spectrum of visible light that the sun emits does not change, only the quantity (more during the summer and less in winter) and quality of overall light reaching the Earth's surface. Some supplemental LED grow lights in vertical greenhouses produce a combination of only red and blue wavelengths.[30] The color rendering index facilitates comparison of how closely the light matches the natural color of regular sunlight.

The ability of a plant to absorb light varies with species and environment, however, the general measurement for the light quality as it affects plants is the PAR value, or Photosynthetically Active Radiation.

LED를 생장등으로 사용한 몇 차례 실험이 있었고, 식물이 건강하게 자라기 위해서는 청색광, 적색광이 모두 필요하다는 것이 밝혀졌다. 이러한 실험을 통해 LED의 적색 파장만을 쬐여준 식물은 , 여기에 약간의 청색광을 더해주면 대부분의 식물이 정상적으로 자랄 수 있게 되었다. There have been several experiments using LEDs to grow plants, and it has been shown that plants need both red and blue light for healthy growth. From experiments it has been consistently found that the plants that are growing only under LEDs red (660 nm, long waves) spectrum growing poorly with leaf deformities, though adding a small amount of blue allows most plants to grow normally.[24]

Several reports suggest that a minimum blue light requirement of 15-30 µmol·m−2·s−1 is necessary for normal development in several plant species.[23][31][32]

LED panel light source used in an experiment on potato plant growth by NASA

Many studies indicate that even with blue light added to red LEDs, plant growth is still better under white light, or light supplemented with green.[24][25][26] Neil C Yorio demonstrated that by adding 10% blue light (400 to 500 nm) to the red light (660 nm) in LEDs, certain plants like lettuce[21] and wheat[22] grow normally, producing the same dry weight as control plants grown under full spectrum light. However, other plants like radish and spinach grow poorly, and although they did better under 10% blue light than red-only light, they still produced significantly lower dry weights compared to control plants under a full spectrum light. Yorio speculates there may be additional spectra of light that some plants need for optimal growth.[21]

Greg D. Goins examined the growth and seed yield of Arabidopsis plants grown from seed to seed under red LED lights with 0%, 1%, or 10% blue spectrum light. Arabidopsis plants grown under only red LEDS alone produced seeds, but had unhealthy leaves, and plants took twice as long to start flowering compared to the other plants in the experiment that had access to blue light. Plants grown with 10% blue light produced half the seeds of those grown under full spectrum, and those with 0% or 1% blue light produced one-tenth the seeds of the full spectrum plants. The seeds all germinated at a high rate under all light types tested.[23]

Hyeon-Hye Kim demonstrated that the addition of 24% green light (500-600 nm) to red and blue LEDs enhanced the growth of lettuce plants. These RGB treated plants not only produced higher dry and wet weight and greater leaf area than plants grown under just red and blue LEDs, they also produced more than control plants grown under cool white fluorescent lamps, which are the typical standard for full spectrum light in plant research.[25][26] She reported that the addition of green light also makes it easier to see if the plant is healthy since leaves appear green and normal. However, giving nearly all green light (86%) to lettuce produced lower yields than all the other groups.[25]

The National Aeronautics and Space Administration’s (NASA) Biological Sciences research group has concluded that light sources consisting of more than 50% green cause reductions in plant growth, whereas combinations including up to 24% green enhance growth for some species.[33] Green light has been shown to affect plant processes via both cryptochrome-dependent and cryptochrome-independent means. Generally, the effects of green light are the opposite of those directed by red and blue wavebands, and it's speculated that green light works in orchestration with red and blue.[34]

빛의 파장에 따른 생장효율[편집]

<nowiki /> 광합성방사조도곡선 문서를 참고하십시오.
Absorbance spectra of free chlorophyll a (blue) and b (red) in a solvent. The action spectra of chlorophyll molecules are slightly modified in vivo depending on specific pigment-protein interactions.

A plant's specific needs determine which lighting is most appropriate for optimum growth. If a plant does not get enough light, it will not grow, regardless of other conditions. Most plants use chlorophyll which mostly reflects green light, but absorbs red and blue light well. Vegetables grow best in strong sunlight, and to flourish indoors they need sufficient light levels, whereas foliage plants (e.g. Philodendron) grow in full shade and can grow normally with much lower light levels.

Grow lights usage is dependent on the plant's phase of growth. Generally speaking, during the seedling/clone phase, plants should receive 16+ hours on, 8- hours off. The vegetative phase typically requires 18 hours on, and 6 hours off. During the final, flower stage of growth, keeping grow lights on for 12 hours on and 12 hours off is recommended.[출처 필요]

광주기성[편집]

게다가 대부분의 식물들은 개화를 촉발하기 위해 어두운 시기와 밝은 시기를 번갈아 맞이해야 한다.(광주기성) 따라서 In addition, many plants also require both dark and light periods, an effect known as photoperiodism, to trigger flowering. Therefore, lights may be turned on or off at set times. The optimum photo/dark period ratio depends on the species and variety of plant, as some prefer long days and short nights and others prefer the opposite or intermediate "day lengths".

Much emphasis is placed on photoperiod when discussing plant development. However, it is the number of hours of darkness that affects a plant’s response to day length.[35] In general, a “short-day” is one in which the photoperiod is no more than 12 hours. A “long-day” is one in which the photoperiod is no less than 14 hours. Short-day plants are those that flower when the day length is less than a critical duration. Long-day plants are those that only flower when the photoperiod is greater than a critical duration. Day-neutral plants are those that flower regardless of photoperiod.[36]

Plants that flower in response to photoperiod may have a facultative or obligate response. A facultative response means that a plant will eventually flower regardless of photoperiod, but will flower faster if grown under a particular photoperiod. An obligate response means that the plant will only flower if grown under a certain photoperiod.[37]

광합성유효방사 (PAR)[편집]

<nowiki /> 이 부분의 본문은 광합성유효방사입니다.
Weighting factor for photosynthesis. The photon-weighted curve is for converting PPFD to YPF; the energy-weighted curve is for weighting PAR expressed in watts or joules.

Lux and lumens are commonly used to measure light levels, but they are photometric units which measure the intensity of light as perceived by the human eye.

The spectral levels of light that can be used by plants for photosynthesis is similar to, but not the same as what's measured by lumens. Therefore, when it comes to measuring the amount of light available to plants for photosynthesis, biologists often measure the amount of photosynthetically active radiation (PAR) received by a plant.[38] PAR designates the spectral range of solar radiation from 400 to 700 nanometers, which generally corresponds to the spectral range that photosynthetic organisms are able to use in the process of photosynthesis.

The irradiance of PAR can be expressed in units of energy flux (W/m2), which is relevant in energy-balance considerations for photosynthetic organisms. However, photosynthesis is a quantum process and the chemical reactions of photosynthesis are more dependent on the number of photons than the amount of energy contained in the photons.[38] Therefore, plant biologists often quantify PAR using the number of photons in the 400-700 nm range received by a surface for a specified amount of time, or the Photosynthetic Photon Flux Density (PPFD).[38] This is normally measured using mol m−2s−1.

According to one manufacturer of grow lights, plants require at least light levels between 100 and 800 μmol m−2s−1.[39] For daylight-spectrum (5800 K) lamps, this would be equivalent to 5800 to 46,000 lm/m2.

참고 문서[편집]

각주[편집]

  1. ↑ “Are LED Grow Lights Really That Efficient?” (영어). Growgear. September 21, 2013. 2016년 11월 17일에 원본 문서에서 보존된 문서. November 16, 2016에 확인함. 
  2. ↑ http://hortsci.ashspublications.org/content/30/2/374.full.pdf
  3. ↑ Learning centre 보관됨 2013-09-07 - 웨이백 머신
  4. ↑ Plant Growth Factors: Light 보관됨 2013-12-04 - 웨이백 머신
  5. ↑ http://www.mv.helsinki.fi/aphalo/photobio/pdf/notes1.pdf
  6. ↑ Phototropins Promote Plant Growth in Response to Blue Light in Low Light Environments
  7. ↑ http://hortsci.ashspublications.org/content/45/2/236.full.pdf
  8. ↑ Green-light Supplementation for Enhanced Lettuce Growth under Red- and Blue-light-emitting Diodes
  9. ↑ Green Light Drives Leaf Photosynthesis More Efficiently than Red Light in Strong White Light: Revisiting the Enigmatic Question of Why Leaves are Green
  10. ↑ 가 나 다 라 마 바 Howard Resh (2013년 1월 16일). 《Hobby Hydroponics, Second Edition》. CRC Press. 23–28쪽. ISBN 978-1-4665-6942-3. 
  11. ↑ 가 나 다 라 마 George F. Van Patten (2002). 《Gardening Indoors: The Indoor Gardener's Bible》. Van Patten Publishing. 47–50쪽. ISBN 978-1-878823-31-1. 
  12. ↑ 가 나 Max Clarke (2013년 3월 13일). 《The Complete Guide to Building Your Own Greenhouse》. Lulu.com. 53쪽. ISBN 978-1-105-91367-9. 
  13. ↑ 가 나 다 라 Ellen Zachos (2014년 12월 16일). 《Growing Healthy Houseplants: Choose the Right Plant, Water Wisely, and Control Pests》. Storey Publishing, LLC. 12–13쪽. ISBN 978-1-61212-440-7. 
  14. ↑ 가 나 다 Sue Reed (2013년 10월 18일). 《Energy-Wise Landscape Design: A New Approach for Your Home and Garden》. New Society Publishers. 247–250쪽. ISBN 978-1-55092-443-5. 
  15. ↑ 가 나 Wayne C. Turner; Steve Doty (2007). 《Energy Management Handbook》. The Fairmont Press, Inc. 376–378쪽. ISBN 978-0-88173-543-7. 
  16. ↑ 가 나 Turner, Wayne C.; Doty, Steve (2007년 1월 1일). 《Energy Management Handbook》 (영어). The Fairmont Press, Inc. 376쪽. ISBN 9780881735437. 
  17. ↑ http://www.cycloptics.com/sites/default/files/initial_testing_results.pdf
  18. ↑ 가 나 다 라 Anil Ahuja (2013년 3월 9일). 《Integrated M/E Design: Building Systems Engineering》. Springer Science & Business Media. 28–31쪽. ISBN 978-1-4757-5514-5. 
  19. ↑ “Conversion (MH<-->HPS)”. 《Growers House》. Growers House. 2015년 12월 15일에 확인함. 
  20. ↑ “Frequently Asked Questions”. 《leds.hrt.msu.edu》. 2015년 9월 19일에 확인함. 
  21. ↑ 가 나 다 Yorio, Neil C.; Goins, Gregory D.; Kagie, Hollie R.; Wheeler, Raymond M.; Sager, John C. (2001년 4월 1일). “Improving Spinach, Radish, and Lettuce Growth under Red Light-emitting Diodes (LEDs) with Blue Light Supplementation”. 《HortScience》 (영어) 36 (2): 380–383. ISSN 0018-5345. 
  22. ↑ 가 나 Goins, G. D.; Yorio, N. C.; Sanwo, M. M.; Brown, C. S. (1997년 7월 1일). “Photomorphogenesis, photosynthesis, and seed yield of wheat plants grown under red light-emitting diodes (LEDs) with and without supplemental blue lighting”. 《Journal of Experimental Botany》 48 (312): 1407–1413. doi:10.1093/jxb/48.7.1407. ISSN 0022-0957. PMID 11541074. 
  23. ↑ 가 나 다 Goins, G. D.; Yorio, N. C.; Sanwo-Lewandowski, M. M.; Brown, C. S. (1998년 1월 1일). “Life cycle experiments with Arabidopsis grown under red light-emitting diodes (LEDs)”. 《Life Support & Biosphere Science: International Journal of Earth Space》 5 (2): 143–149. ISSN 1069-9422. PMID 11541670. 
  24. ↑ 가 나 다 Massa, Gioia D.; Kim, Hyeon-Hye; Wheeler, Raymond M.; Mitchell, Cary A. (2008년 12월 1일). “Plant Productivity in Response to LED Lighting”. 《HortScience》 (영어) 43 (7): 1951–1956. ISSN 0018-5345. 
  25. ↑ 가 나 다 라 Kim, Hyeon-Hye; Wheeler, Raymond M.; Sager, John C.; Yorio, Neil C.; Goins, Gregory D. (2005년 1월 1일). “Light-emitting diodes as an illumination source for plants: a review of research at Kennedy Space Center”. 《Habitation (Elmsford, N.Y.)》 10 (2): 71–78. doi:10.3727/154296605774791232. ISSN 1542-9660. PMID 15751143. 
  26. ↑ 가 나 다 Kim, Hyeon-Hye; Goins, Gregory D.; Wheeler, Raymond M.; Sager, John C. (2004년 12월 1일). “Green-light Supplementation for Enhanced Lettuce Growth under Red- and Blue-light-emitting Diodes”. 《HortScience》 (영어) 39 (7): 1617–1622. ISSN 0018-5345. 
  27. ↑ Sabzalian, Mohammad R., Parisa Heydarizadeh, Morteza Zahedi, Amin Boroomand, Mehran Agharokh, Mohammad R. Sahba, and Benoît Schoefs. "High performance of vegetables, flowers, and medicinal plants in a red-blue LED incubator for indoor plant production." Agronomy for Sustainable Development 34, no. 4 (2014): 879-886.
  28. ↑ Abhay Thosar, Ph.D., Esther Hogeveen van Echtelt (July 29, 2014). 《LED: the New Fast-track to Growth: Recipe Development and Practical Applications in Horticulture - Part 1: Global Examples LED Recipes and Development》 (Video) (영어). Orlando, FL. 00:03:15, 00:13:05에 발생. February 16, 2016에 원본 문서에서 보존된 문서. February 12, 2015에 확인함. 
  29. ↑ Parks, Brian M. (2003년 12월 1일). “The Red Side of Photomorphogenesis”. 《Plant Physiology》 (영어) 133 (4): 1437–1444. doi:10.1104/pp.103.029702. ISSN 1532-2548. PMC 1540344. PMID 14681526. 
  30. ↑ “Vertical 'Pinkhouses:' The Future Of Urban Farming?”. 《NPR.org》. 2016년 2월 8일에 확인함. 
  31. ↑ Hoenecke, M. E.; Bula, R. J.; Tibbitts, T. W. (1992년 5월 1일). “Importance of 'blue' photon levels for lettuce seedlings grown under red-light-emitting diodes”. 《HortScience: A Publication of the American Society for Horticultural Science》 27 (5): 427–430. ISSN 0018-5345. PMID 11537611. 
  32. ↑ Wheeler, R. M.; Mackowiak, C. L.; Sager, J. C. (1991년 10월 1일). “Soybean stem growth under high-pressure sodium with supplemental blue lighting”. 《Agronomy Journal》 83 (5): 903–906. doi:10.2134/agronj1991.00021962008300050024x. ISSN 0002-1962. PMID 11537676. 
  33. ↑ “Evaluation of lettuce growth using supplemental green light with red and blue light-emitting diodes in a controlled environment - a review of research at kennedy space center”. 《www.actahort.org》. 2016년 2월 12일에 확인함. 
  34. ↑ Folta, Kevin; Maruhnich, Stefanie A. (2007년 9월 1일). “Green light: a signal to slow down or stop”. 《Journal of Experimental Botany》 (영어) 58 (12): 3099–3111. doi:10.1093/jxb/erm130. ISSN 0022-0957. PMID 17630292. 
  35. ↑ Managing Photoperiodic Lighting
  36. ↑ http://flor.hrt.msu.edu/assets/Uploads/Controllingphotoperiod.pdf
  37. ↑ http://www.hrt.msu.edu/energy/Notebook/pdf/Sec1/Runkle%20and%20Blanchard,%20Use_of_Lighting.pdf 보관됨 2015-05-01 - 웨이백 머신
  38. ↑ 가 나 다 Hall, David O.; Rao, Krishna (1999년 6월 24일). 《Photosynthesis》 (영어). Cambridge University Press. 8–9쪽. ISBN 9780521644976. 
  39. ↑ Growing your profits: horticultural lighting. [깨진 링크] Philips (2010).

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