This is the simplest method for identifying and quantifying key pigments in a given sample based on differential absorbance spectra of distinct plant pigments. Fluorescence spectroscopy: with changeable wavelength settings, this approach enables for the specific identification of pigments. High-performance liquid chromatography (HPLC) is used to quantify the amount of each pigment present in the sample.
Pigments are responsible for colors that we see in flowers, fruits, leaves, and other parts of plants. They are also important for protecting photosynthetic machinery during exposure to light energy such as sunlight. In addition, plants use pigments for communication and as antioxidants. There are several different classes of plant pigments including carotenoids, chlorophylls, and anthocyanins. This article focuses on the first two; details on anthocyanins can be found here: How do plants make red wines and blueberries?
Carotenoids are fat-soluble compounds that occur naturally in plants and provide color to fruit and vegetables. The human body cannot produce carotenoids so they must be obtained from the diet. They may have antioxidant properties which help protect cells against damage caused by free radicals - molecules with an odd number of electrons. Carotenoids include beta-carotene, alpha-carotene, gamma-carotene, lycopene, lutein, and zeaxanthin.
Light is absorbed by pigments as a source of energy for photosynthesis. The wavelengths of light absorbed by each pigment are shown by the absorption spectrum (e.g., chlorophyll). The action spectrum represents the total rate of photosynthesis at each wavelength of light. The efficiency with which light is converted into chemical energy is called the quantum yield.
The color of a pigment is determined by the selective absorption of distinct wavelengths. Higher plant chlorophylls, for example, absorb red and blue wavelengths but not green wavelengths, giving leaves their distinctive green hue. The absorption spectrum of a pigment is determined by its molecular structure. Changes in the chemical composition of the pigment can change its absorption spectrum.
Pigments are usually classified according to their absorption maximum in the visible region of the spectrum. This classification is based on the peak wavelength of the pigment: chlorophyll A (436 nm), chlorophyll B (464 nm), carotenoids (470-490 nm). Other classes include phycobiliproteins (630-680 nm) which contain both pigment types and act as light-harvesting antennas for photosynthetic organisms, and xanthophylls which only occur in certain plants but have an absorption maximum at about 400 nm. Xanthophylls do not contribute significantly to the leaf color but rather serve as photoprotectors in response to high light levels. They are found in large quantities in dark-green vegetables such as kale and spinach.
The most important pigments for the plant growth process are chlorophylls. These are responsible for the green color of plants. Carotenoids also play a role in plant coloration. They are responsible for producing fruits and vegetables of different colors, including yellow, orange, and red.
The absorption spectrum, which identifies each kind of pigment, is a unique pattern of wavelengths that it absorbs from visible light. Figure 4 depicts the absorption spectra of chlorophyll a, chlorophyll b, and b-carotene, a form of carotenoid pigment (which absorbs blue and green light). Each pigment has its own unique pattern of wavelengths that it can't be replaced by any other pigment in plants. The absorption patterns are what allow scientists to identify the different pigments found in plants.
Pigments play a major role in the coloration of flowers and fruits, as well as leaves and stems. They also help plants to absorb light energy during photosynthesis, allowing them to grow and produce seeds. In addition, certain colored compounds called anthocyanins are produced by some plants in response to stress. These colors are responsible for the red, purple, and blue tones seen in berries, grapes, and other fruit bodies. Finally, plants use chlorophyll to capture sunlight energy and transform it into chemical energy that they can use to make their own food. Because chlorophyll only absorbs specific wavelengths of light, when it does so it produces a color that can be seen with the human eye: green.
Plants need three main types of nutrients to function properly: carbon, hydrogen, and oxygen. They get these elements from their environment, using the roots to explore their soil for those elements that are not present in large quantities.
The majority of pigments function by absorbing specific wavelengths of light. Other wavelengths are reflected or dispersed, causing you to see the colors you perceive. Certain wavelengths of light have the necessary energy to activate certain electron transitions in molecules or solids at the atomic level. When this occurs, the pigment will become colored.
Pigments are divided into two main groups based on how they function: dispersive and absorptive. Dispersive pigments spread out light of various colors that hits it, causing it to be seen as white. Absorptive pigments absorb all or most of the light that falls on them. The color may come from particles within the pigment that react with each other or with substances such as acids or bases to form a darker-colored compound. These dark compounds then reflect light of other colors, so the pigment doesn't show up red, for example.
Some pigments act as both dispersers and absorbers of light. For example, titanium dioxide is used because it has good reflecting properties which mean that lots of light is bounced off it. However, it also absorbs light that hits it, preventing it from reaching the eye. This effect is useful when trying to paint something that is supposed to look gray or white.
There are many different types of pigments, but they can be divided into three main groups: organic, inorganic, and synthetic.
Multiple pigments absorb different wavelengths of light, allowing the plant to get the most energy from the sun. Plants with several pigments can have varied colored leaves, allowing them to collect the most energy from the sun. These same colors may help predators identify plants that are toxic or otherwise not desirable.
Plants need sunlight to make food and grow, so they must capture some of the sun's energy to live. Leaves contain many tiny holes called pores that allow gas exchange with the atmosphere. The amount of sunlight that reaches the leaf determines how much carbon dioxide is absorbed through these pores. Energy from the sun also drives chemical reactions that produce nutrients for the plant to use as fuel for growth and reproduction. Most photosynthesis takes place in leaves; therefore, they need to be able to absorb more light than other parts of the plant.
Some plants, such as redwood trees, retain their mature color throughout their lifespan. This allows them to spread their energy budget over many more years than plants that turn green in summer and fall back in the spring. Also, because redwoods are slow growing it gives them time to gather resources from surrounding areas in order to increase their chance of survival. For example, they may take advantage of high-carbon-dioxide environments that others cannot access due to its toxicity for other organisms.