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Light interaction with plants: Reflection, Emission and Absorption

Light interaction with plants: Reflection, Emission and Absorption

In the context of commercial farming, particularly in greenhouse environments, the role of light is paramount for ensuring optimal plant growth and development. Light influences not just photosynthesis, the process through which plants convert water and carbon dioxide into oxygen and glucose, but also affects plant morphology—shaping their form and structure. For crops to photosynthesize effectively, they require a sufficient quantity of light; without it, they cannot produce the chemical energy necessary for growth. Moreover, the spectrum of light, or its color mix, plays a crucial role in determining the desired shape and development of plants.

But how exactly do plants interact with light? This interaction can be categorized into three main types: absorption, reflection, and emission. Absorption is crucial for plant light absorption, as it directly influences photosynthesis. When light is absorbed by plants, it is used to convert carbon dioxide and water into essential sugars and oxygen, a process fundamental to plant growth. On the other hand, reflection and emission play different roles in the plant’s interaction with light, with reflection often influencing the light that is not absorbed and used for growth.

Understanding these interactions is vital for optimizing light conditions to promote healthy plant development. This is where technologies like UbiGro films come into play. These films are designed to enhance the optimal light for plant growth by altering the light spectrum that reaches the plants, thereby affecting their photosynthetic efficiency and growth patterns. By optimizing the light’s effect on plants, UbiGro films can significantly contribute to achieving better growth outcomes in greenhouse farming.

In summary, the absorption of light is fundamental to photosynthesis, making it a critical aspect of plant growth. The proper spectrum of light ensures that plants not only grow but also achieve the desired shape and structure. Technologies that can manipulate the light spectrum, such as UbiGro films, represent a significant advancement in agricultural science, offering commercial farmers tools to enhance plant growth and development efficiently.

Reflected light

To explain how plants reflect light and the type of light they reflect, it helps to understand why plant tissue is green in the first place. An essential chemical known as chlorophyll is responsible for the green hue of leaves and plants. What is the role of this chemical in green plants? 

Chlorophyll absorbs solar light energy and converts carbon dioxide and water into glucose and oxygen; it is the main ingredient behind photosynthesis. Chlorophyll is referred to as an essential pigment because it is the only pigment capable of taking in light energy and transforming it into chemical energy. Among its various roles are:

  • absorbing and trapping solar radiation within the plant
  • aiding in the production of carbohydrates, which are essential for the plant as a whole, and
  • facilitating the uptake and assimilation of soil minerals.

Chlorophyll absorbs a broad spectrum of wavelengths of light, but most strongly absorbs red and blue light (99% absorption). Blue and red light is reported to be the most ideal for assimilating carbon dioxide. However, the green wavelength band (495–570 nm) is not absorbed as strongly (only ~85% absorption) as other colors, and so most of the reflected light from plants is green.

While chlorophyll is the primary pigment responsible for the green color of plants, other pigments like carotenoids (which reflect red, orange, and yellow light) and anthocyanins (which reflect red, purple, and blue light) can also be present in plants and contribute to their coloration, which is a product of the plants’ reflection properties.

Emitted light

Light emission from plants refers to light that originates from the plant itself, as opposed to reflected light whose origination is not from the plant.

Bioluminescence in plants

Living organisms, including plants, can emit light through a process known as bioluminescence, which is produced by biochemical reactions within the plant. This phenomenon is most commonly seen in certain species of algae and fungi, but some plants also have bioluminescent properties, such as the “shining” plants in the genus Kalanchoe. However, bioluminescence in plants is relatively uncommon. However, the development of knowledge about bioluminescence has led to the development of genetically altered plants with biological luminescence. 

Bioluminescent genes from bacteria and fungi, for example, Shewanellaceae, Vibrionaceae, and Mycena have been employed by scientists to create plants that can glow. A plant typically used by scientists in testing bioluminescence is tobacco, with leaves that produce a neon green glow from budding to maturity.

Light interaction with plants: Reflection, Emission and Absorption

Chlorophyl fluorescence

Another light emission mechanism from plants is chlorophyll fluorescence, a process where plants emit light in the visible spectrum as a byproduct of photosynthesis. It occurs when chlorophyll molecules absorb light energy, and then release some of that energy as a faint glow.

Chlorophyll fluorescence is caused by the absorption of light energy by chlorophyll molecules within the photosynthetic apparatus of plant cells. When chlorophyll molecules absorb light energy, they become excited and enter a higher energy state. Some of this excess energy is then emitted as fluorescence, which can be detected using specialized equipment.

The amount and pattern of chlorophyll fluorescence emitted by a plant can provide valuable information about its physiological state, including its photosynthetic activity, stress levels, and overall health. For example, changes in chlorophyll fluorescence can be used to monitor the effects of environmental stressors, such as drought or pollution, on plants, or to track the development and maturation of crops.

Absorbed light

Unlike emitted or reflected light, which is light coming off plants, absorbed light is the light taken in by plants. Light is absorbed by plants primarily for photosynthesis. However, not all wavelengths of light are used by plants in converting carbon dioxide and water to glucose and oxygen. Plants are only able to use visible light from 400 – 700 nm to drive photosynthesis. This range of wavelengths is known as photosynthetically active radiation, or PAR. Recent studies have shown that the active range should be extended to ~750 nm, to include some far-red light, and this regions is known as extended PAR, or ePAR.

Light interaction with plants: Reflection, Emission and Absorption

Light-dependent reactions

During the light-dependent reactions of photosynthesis, light energy is captured by chlorophyll and other pigments in the thylakoid membranes of the chloroplasts, and this energy is used to power a series of electron transport chains. Light-dependent reactions include the following: 

  • Light energy stimulating photosystems.
  • Water photolysis and reduction of NADP+(nicotinamide adenine dinucleotide phosphate).
  • Adenosine triphosphate (ATP) synthesis using the electron transportation chain.

Light-dependent reactions transform sunlight into glucose, the carbohydrate form of chemical energy. Energy for all green plants comes exclusively from photosynthesis. 

The light reaction occurs within the granules of the cells’ chloroplasts, releasing ATP, NADPH, and oxygen. Although the leaf is a plant’s primary organ for photosynthesis, chloroplasts are found in all of the plant’s green parts.

A grana (plural: granum) is a stack of flattened thylakoid membranes found within the chloroplasts, which are specialized organelles responsible for photosynthesis. Grana are found in the stroma, enclosed by a double membrane surrounding the chloroplasts. Chlorophyll is one of the pigments present in the granum and is the most vital element of photosynthesis, which occurs in two phases: the light stage and the dark stage. The biosynthetic phase of photosynthesis takes place in the dark stage, while the photochemical phase occurs in the light-dependent stage.

Factors that affect light absorption by plants

For photosynthesis to occur effectively, several factors must first be met. The following are some elements that influence a plant’s ability to absorb light:

  • Leaf structure: Leaves have varying levels of thickness. The thinner the leaf, the better it is at absorption.
  • Light intensity: A leaf’s ability to absorb light increases with its exposure to light.
  • Light wavelength: Specific wavelengths, for example, red and blue, are absorbed more efficiently by plants.
  • Duration: The longer leaves are exposed to light, the more of it they absorb.
  • Environmental conditions: Low humidity levels can result in water loss through transpiration, hindering a plant’s capacity to absorb light. 

Why is understanding reflected, emitted and absorbed light important?

Light, whether reflected, emitted or absorbed by plants, is essential for the growth and production of crops. Understanding the various types of lights that affect plants is important for serious home growers and cultivation directors alike. It enables you to optimize your farming conditions for the highest quality yield possible.

As mentioned above, various factors affect the amount of light absorbed by plants which in turn affects the amount of food and energy produced. For instance, plants absorb more light in less humid environmental conditions, and you could therefore provide an optimal environment with low humidity to enhance photosynthesis, especially in a greenhouse. 

Enhancing light absorption with UbiGro

A crucial aspect of commercial farming is improving the quality of sunlight your plants receive. If you’re invested in cultivating cannabis, vegetables, leafy greens, or ornamentals, insufficient light exposure or improper light spectrum will lead to stunted growth and, ultimately, low yield. 

An ideal solution to improving the spectrum of sunlight in your greenhouse environment without the use of electrical lighting is UbiGro’s quantum dot greenhouse film. To enhance the quality of the light in the greenhouse, our luminescent layer makes use of advanced nanotechnology called quantum dots, providing the necessary lighting conditions for your crops to thrive without adding energy costs.

UbiGro’s adaptable hardware is compatible with every greenhouse, regardless of size, façade material, shape, etc. UbiGro’s cutting-edge greenhouse Inner layer has led to a 16% boost in dry-trimmed cannabis yield, a 21% improvement in tomato production, and a 28% boost in strawberry production. Reap the fruits of quality farming and get a free quote today!

Light interaction with plants: Reflection, Emission and Absorption

Dr. Damon Hebert

Dr. Damon Hebert serves as Director of Agriculture Research for UbiQD, Inc., with a background in solar materials and controlled environment cannabis cultivation. He is an advocate for the use of advanced materials to further the industry’s push towards sustainable farming practices. He can be reached at [email protected].


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The Impact of Color on your plants
Hunter McDaniel CEO & Founder UbiGro

Hunter McDaniel, PhD

Founder & CEO

 Hunter earned a Ph.D. in Materials Science and Engineering at the University of Illinois at Urbana-Champaign, before joining Los Alamos National Laboratory in the Chemistry Division. Ultimately the value proposition of UbiGro is about boosting crop yields and quality without the cost or energy impact of lighting. Hunter has more than fifty publications and patents, and more than 2000 total citations, h-index: 20. Hunter fundamentally believes that novel materials underpin every significant technology advancement, and he is focused on leveraging new materials to have a lasting and sustainable impact.

Meet The Team

Damon Hebert, PhD

Director of Agriculture

Damon brings a wide range of experience in agriculture, materials science, spectroscopy, and small business. During his time in Prof. Angus Rockett’s research group at The University of Illinois at Urbana-Champaign (UIUC), Hebert authored a doctoral thesis and multiple papers on the materials science of CIGS semiconductor materials, which is closely related to the materials developed at UbiQD. He also served as a consultant to Nanosolar, a CIGS nanocrystal solar cell manufacturing company. Hebert has industry experience having co-founded Dr. Jolly’s, a leading cultivation and distribution operation in Bend, OR.

Meet The Team

Tania Lafaille

Sales Representative

Tania is a UbiGro Sales Representative, with over 7 years of experience in product sales (specifically berries and avocados) covering all of North America and parts of South America. While in agriculture, Tania has cultivated strong relationships with growers and distributors, granting her a unique insight into both perspectives. That understanding, paired with her fierce dedication to results, drives her fun and fiery commitment to her craft. Tania is based in Gilroy, CA.

Meet The Team

Tyler Veyna

Sales Representative​

Tyler brings 15 years of experience in Greenhouse production and facility management of a wide range of crops in multiple states to the UbiGro team. Based in Salinas, California. “Being a fourth-generation farmer, I look to improve and empower the grower, and with UbiGro, we can do just that.”

Meet The Team

Jim Gideon

Sales Manager

Jim Gideon is an UbiGro Sales Manager, with over 25 years of greenhouse industry sales experience covering all of North America. Previously Jim has worked for Green Tek, Plazit-Polygal, Texel, Cherry Creek, and Nexus. He is based in Montgomery, AL, and Jim believes that “light is everything to the grower.”

Meet The Team

Eric Moody

Director of Sales

Eric Moody is UbiQD’s Director of UbiGro Sales. Eric has more than 6 years of experience in horticulture lighting industry, building relationships with greenhouse growers of all sizes and crops on optimal lighting for their growing operation, and most recently managed a North American sales team for PL Light Systems. Overall, Eric has been in sales leadership positions for more than 13 years. Eric brings with him a great understanding of the market and available technologies for growers, greenhouse facilities, and sales leadership. Reach Eric by phone at 541-490-6421 or by email at [email protected].

Meet The Team

Mike Burrows, PhD

VP of Business Development

Dr. Michael Burrows is UbiQd’s Vice President of Business Development. His educational background includes a Materials Science doctorate from the University of Delaware and an MBA from Duke University Fuqua School of Business. His career has specialized in the commercialization of novel electronic materials in venture-run programs for different industries including solar, biosensors, and the automotive industry. In both start-up and corporate environments, he has extensive experience in global market development, foraging supply chain partnerships, productization, and brand building. He is currently leading UbiQD’s partnership efforts in luminescent greenhouse technology, smart windows, and security ventures.

Meet The Team

Matt Bergern, PhD

Cheif Product Officer

As Chief Product Officer at UbiQD, Dr. Matt Bergren leads the company’s product development efforts, sales, and product manufacturing, including the company’s first commercial agriculture product, UbiGro. He plays a critical role in continuing the company’s path of technology development and vision of powering product innovations in agriculture, clean energy, and security.

He serves as the principal investigator for UbiQD’s contract with NASA, focused on tailoring the solar spectrum for enhanced crop production for space missions. Dr. Bergren’s leadership experience includes serving on the board of directors for the New Mexico Energy Manufacturing Institute, focused on job creation in New Mexico’s energy, and related manufacturing community.