Plant pigments, also known as biochromes, are compounds that absorb specific light wavelengths and “give” plants, fruits, and vegetables their colors. The most common plant pigments are chlorophyll, carotenoids, flavonoids, and betalains with chlorophyll being the most important pigment. Apart from giving color to the plant, pigments also influence photosynthesis and development.
Carotenoids are pigments that absorb violet-green light and cause fruits and vegetables to have a red, orange, or yellow color. These pigments exist throughout the whole plant, from roots to its fruit. Carotenoids help absorb photon (light) energy to be used in photosynthesis and they help protect the plant by acting as antioxidants and by protecting the plant from excessive heat. There are over 500-1000 different types of carotenoids. The two best known carotenoids are beta-carotene and lycopene. In the human body, carotenoids act as antioxidants, they fight cancer, are anti-inflammatory, and can be converted into vitamin A.
Chlorophyll is a compound that absorbs and reflects specific wavelengths of light. This light is converted into energy used for photosynthesis. Chlorophyll A and chlorophyll B are the main types. Chlorophyll A is the most important type, since it is necessary for photosynthesis. Chlorophyll B is not necessary and that’s why not all plants that assimilate contain chlorophyll B, but they all do contain chlorophyll A. Chlorophyll reflect green light, making plants appear green to the human eye. Chlorophyll A absorbs orange-red and violet-blue light. They transfer the photon (light) energy within the plant to the point where it is converted into energy for photosynthesis. Chlorophyll B absorbs blue light and therefore mainly widens the spectrum plants can absorb and consequently use for photosynthesis.
Flavonoids are water soluble plant pigments which are usually orange, red, or blue. The most common flavonoid classes are the flavonols, flavones, and anthocyanins. Flavonoids help attract animals and insects that can help the plant reproduce (by eating the fruits and spreading the seeds or pollination). Flavonoids mainly absorb Ultraviolet (UV) light for protection and to form special UV patterns to attract bees for pollination.
Betalains are yellow and red pigments commonly found in beets, in which they were first found. Like anthocyanins, betalains are water soluble and have the same color. Betanin is the most studied betalain and it is found in red beet roots. Betalains are anti-inflammatory, anti-cancerous, and antioxidant. Betalains help attract animals and insects that can help the plant reproduce (by eating the fruits and spreading the seeds or pollination).
Other plant elements
Phytochrome are photoreceptors that respond to light. Phytochrome Type I are activated by Far-Red light (Pfr) and Type II are activated by Red light (Pr). They may also act as temperature sensors. Phytochromes control many aspects of plant development (such as germination, leaves building, timing of flowering, elongation of the stem, plant growth, and production of chlorophyll).
Terpenes are aromatic compounds, responsible for the smell of the plant (in leaves as well as fruits or vegetables that grow on a plant). Terpenes protect the plant against animals by deterring herbivores and attracting predators or parasites that attack or infect those herbivores. Terpenes can also lure pollinators and thus contribute to plant reproduction or help the plant recover from damage. The weather, age of the plant, soil type, climate, and even time of day influence terpenes development, but also the presence of other compounds. Terpenes can promote different things in humans, such as relaxation or stress-relief. Terpenes occur in live plants and become terpenoids when the plant is dried and cured.
Trichomes are outgrowths, or “hairs” that can be found on all parts of the plant. These hairs come in many variations, some can be spotted by the human eye, but others need a microscope to see. Trichomes protect the plant against insects and herbivores, but also solar radiation, and even against wind or extreme temperatures (thereby regulating transpiration and the amount of water a plant needs). Trichomes can be defined by their various features, such as: (I) stinging hairs, that contain (poisonous) liquid, are sharp, and can sting or cut; (II) glandular hairs, that secrete oil or other substances; and (III) peltate hairs, that look like shields and are often attached to the stalk or base of the plant; (IV) non-glandular, that provide protection against Ultraviolet (UV) light, and many more features make up all the different trichomes.