11.4 LED for Plant Breeding
247
light compensation points of tomato, cucumber and pepper are 3000 lx, 2000 lx and
1500 lx, respectively, and the light saturation points are 70,000 lx, 55,000 lx and
30,000 lx, respectively. Therefore, the light intensity of greenhouse light supplement
is generally required to reach 1000–3000 lx. Secondly, as far as the optical quality
requirements is concerned, the plant uses sunlight for photosynthesis. Its absorption
spectrum lies between 380 and 760 nm [17]. Hence according to the type of the crop,
there are specific requirements for spectral morphology. Finally, the requirements of
the photoperiod, the natural day and night, alternating and recurring phenomena form
the cycle of light and dark and spectral morphology. Crops adapt to this change during
the long evolutionary process. However, before or after the winter solstice or even
cloudy days, the illumination time often fails to meet the growth and development
needs of the crop. Artificial light is therefore needed to increase the illumination
time. In recent years, artificial light supplementation in greenhouses has become an
important means of facility agricultural production. Various artificial light sources
have also been developed rapidly.
The LED light source system includes a plant growth system that is an LED light
source, growth control software, signal conditioner, and data collection software. The
system can control the LED illumination through the growth control software, and
collect the growth environment information measured by the sensor into the database
through the data collection software, and at the same time realize automatic control
of different light qualities.
11.4.4 Systematic Design Trend
Light is one of the most important environmental factors for crop growth. Some
scholars have pointed out that “1% of light is 1% of production”. This statement
clearly indicates the importance of visible light in crop production. The illumination
of the greenhouse itself is much lower than that of the open field. Especially in the
winter and spring seasons and under rain and snow, the situation of insufficient light
will become more obvious. It has become an important factor limiting the yield of
vegetables. Artificial light supplementation in the greenhouse will be an inevitable
choice.
A large number of studies has successfully proved that LED can be used as
an artificial light source for tissue culture, greenhouse, and closed plant factories.
One can utilize various light qualities of various LED radiations to study the light
quality response characteristics of different crops. One can also combine different
proportions and different light spectrum of the LED to generate special lighting
condition. Due to the easy selection of LED wavelengths and compact structure
[20–23], it will be more and more widely used in the field of facility agriculture
in the future. However, further improvement of light efficiency and cost reduction
of the device need to be improved urgently. With the continuous maturity of LED
technology, the reduction of manufacturing costs, LED will be the most promising
247
light compensation points of tomato, cucumber and pepper are 3000 lx, 2000 lx and
1500 lx, respectively, and the light saturation points are 70,000 lx, 55,000 lx and
30,000 lx, respectively. Therefore, the light intensity of greenhouse light supplement
is generally required to reach 1000–3000 lx. Secondly, as far as the optical quality
requirements is concerned, the plant uses sunlight for photosynthesis. Its absorption
spectrum lies between 380 and 760 nm [17]. Hence according to the type of the crop,
there are specific requirements for spectral morphology. Finally, the requirements of
the photoperiod, the natural day and night, alternating and recurring phenomena form
the cycle of light and dark and spectral morphology. Crops adapt to this change during
the long evolutionary process. However, before or after the winter solstice or even
cloudy days, the illumination time often fails to meet the growth and development
needs of the crop. Artificial light is therefore needed to increase the illumination
time. In recent years, artificial light supplementation in greenhouses has become an
important means of facility agricultural production. Various artificial light sources
have also been developed rapidly.
The LED light source system includes a plant growth system that is an LED light
source, growth control software, signal conditioner, and data collection software. The
system can control the LED illumination through the growth control software, and
collect the growth environment information measured by the sensor into the database
through the data collection software, and at the same time realize automatic control
of different light qualities.
11.4.4 Systematic Design Trend
Light is one of the most important environmental factors for crop growth. Some
scholars have pointed out that “1% of light is 1% of production”. This statement
clearly indicates the importance of visible light in crop production. The illumination
of the greenhouse itself is much lower than that of the open field. Especially in the
winter and spring seasons and under rain and snow, the situation of insufficient light
will become more obvious. It has become an important factor limiting the yield of
vegetables. Artificial light supplementation in the greenhouse will be an inevitable
choice.
A large number of studies has successfully proved that LED can be used as
an artificial light source for tissue culture, greenhouse, and closed plant factories.
One can utilize various light qualities of various LED radiations to study the light
quality response characteristics of different crops. One can also combine different
proportions and different light spectrum of the LED to generate special lighting
condition. Due to the easy selection of LED wavelengths and compact structure
[20–23], it will be more and more widely used in the field of facility agriculture
in the future. However, further improvement of light efficiency and cost reduction
of the device need to be improved urgently. With the continuous maturity of LED
technology, the reduction of manufacturing costs, LED will be the most promising