Abstract
Imagine your legs were buried in the ground and you were not able to move or to talk. What would you do to eat, grow, and defend yourself? This situation is more common than you think: It is part of the daily life of plants. Plants have developed many strategies not only to survive, but also to interact with other plants, animals, and microorganisms around them. Some of these strategies involve using chemical compounds that work as messages from the plant to its surroundings. Scientists have developed creative methods to estimate what and how much of a chemical is inside a plant. If we can identify the great diversity of plant compounds, in the future we might be able to better understand how plants grow and interact with their environments. Also, we may be able to use those compounds to make medicines and to produce healthier, tastier vegetables.
Plants Produce Chemicals to Grow and Interact With Their Surroundings
Plants are sessile, which means they cannot move and are permanently restricted to the spot where they germinate. As plants grow, they must cope with an environment that changes all the time (sometimes too dry, some others too wet). Think of the changes in seasons, or the different weather conditions throughout the day and night. As if that is not enough, plants also need to have strategies to interact with their neighbors, to attract animals that help them move their seeds or pollen from one place to another, and to defend themselves from animals that want to eat them. One of the strategies that plants use to do all of that is to produce a great number of chemicals, known asmetabolites. Plant metabolites are small chemical compounds that help plants grow and interact with other organisms.
It is estimated that, taken together, all plants produce between 100,000 and 1 million metabolites [1]. To study them, scientists have classified the metabolites into two groups: primary and specialized metabolites. Primary metabolites are found in all plants and help the plants grow, develop and reproduce. One of the most well-known groups of primary metabolites are carbohydrates, which provide plants with energy to grow. Specialized metabolites are unique to different plants and they help plants interact with other organisms. We will focus on specialized metabolites in the remainder of this article.
Have you ever wondered how a plant can defend itself? Plants and herbivore (plant-eating) insects have lived together for millions of years, and during this long time, plants have developed toxic defense compounds. For example, when an insect starts eating the leaves of a cabbage, the plant increases the amounts of toxic specialized metabolites calledglucosinolates, which are then converted into even more toxic compounds [2]. These compounds make the cabbage’s leaves taste very unpleasant, discouraging the insects from eating them (Figure 1A). Glucosinolates are very familiar to us, as they give broccoli and radishes their characteristic flavors. At the same time, insects have created ways to tolerate those toxic compounds, allowing them to keep eating those “poisonous” plants. This continuous battle between plants and insects has resulted in the evolution of new specialized metabolites.
In other cases, plants need to attract animals to pollinate their flowers so that they can produce seeds to secure their reproduction (Figure 1A). Pollinators are not only essential for plant reproduction, but they are also important for humans, as 75% of the world’s food crops depend on pollinators for successful production [3]. One of the strategies plants use to attract pollinators is to produce a sugary liquid called nectar. Bees and other insects visit plants to drink the nectar and while doing so, pollen attaches to their bodies. When the same insect visits other flowers, the pollen from the previous plants is released in the new flower, securing future seed production. In this way, plants use the visiting insects for their own benefit. Interesting fact: scientists have found that nectar does not only contain sugar, but also small amounts of caffeine [4]. In high amounts, caffeine is bitter, and it works as a plant defense compound. However, in low amounts, it acts as a memory enhancer, stimulating insects to remember to come back for more nectar and further ensuring the plant’s pollination process.
Humans (And Other Animals) Use Chemicals Produced by Plants
Humans and other animals have learned to use chemicals produced by plants for their own benefit. Since ancient times, people have used plant metabolites as medicines, natural dyes, and ingredients in food and cosmetics, amongst many other uses (Figure 1B).
One of the oldest plant extracts is opium, a mix of chemical compounds extracted from the plantPapaver somniferum, commonly known as the poppy, which was used as an antidote against snake and spider bites and scorpion stings. Today, morphine, one of the many chemicals found in opium, is prescribed to alleviate pain.Saponinsare another well-known example of plant compounds used by humans. Saponins are present in a variety of different plants and trees, where they work as nasty compounds that keep insects away from eating plants’ leaves (Figure 1A) [5]. Also, indigenous people from around the world have commonly use saponin-rich plant extracts as natural soap.
Plant metabolites can also influence the behavior of other animals. Catnip (Nepeta cataria) produces a compound known asnepetalactone. When cats sniff this plant, they become very playful and relaxed (Figure 1C). Nepetalactone is commonly associated with plant defense; however scientists do not yet fully understand its role. Future research on how plants make nepetalactone could help scientists develop new medicines with sedative and relaxant properties, or new bio-insecticides for agriculture.
We are still far from identifying all plant metabolites and even further from understanding how plants produce them. However, in the last decades, technological developments have allowed scientists to discover more plant metabolites. In the next section, we will explore how scientists isolate and identify these substances.
How Do Scientists Identify and Study Plant Chemicals?
Since specialized metabolites are so important for plants and quite useful for us, scientists have developed several ways to measure them. Humans have extracted specialized metabolites from plants for a very long time. Brewing coffee is one example ofextraction. The concept is simple: plant material, for example ground coffee beans, is mixed with a liquid called asolvent(hot water, in the case of coffee) to allow the extraction of metabolites. After some time, the solvent takes up the flavor and color of the metabolites contained in the coffee beans. The mixture is then filtered and the solid plant materials are discarded, while the liquid solvent contains an extract of plant metabolites.
Scientists have applied this same principle to extract and study many plant metabolites. To identify specific metabolites, scientists must consider their chemical and physical properties, such as whether the metabolites can dissolve in water or whether a different solvent is needed. Obtaining the filtered extract is the last step of the extraction process (Figure 2A). The next steps are the separation and identification of the chemical compounds present in the extract.
Chromatographyis a technique used to separate chemical compounds (Figure 2B). The liquid mixture of metabolites to be separated is called the mobile phase (contained in the tube inFigure 2A). The mobile phase is then flowed through a second substance called the stationary phase (colored blue inFigure 2B). The metabolites in the mobile phase (plant extract) will interact with the stationary phase in different ways. Some metabolites will move slowly through the stationary phase and others will move more quickly, causing the various metabolites to separate. The different travel time of each metabolite is one of the signatures that scientists use to identify them.
Some plant metabolites can be easily identified using chromatography alone. However, plant metabolites can be extremely complex. This complexity makes their identification difficult, and other methods are sometimes required to identify them.Mass spectrometryis a technique that breaks metabolites down further and then separates the different parts (called ions) to detect how many of them are present in a chemical compound (Figure 2C). A mass spectrometer is usually composed of three main chambers. In the first chamber, the metabolite is disintegrated into its essential parts, called ions. The ions race through the second chamber, called the mass analyzer, to reach the third chamber, called the detector. The mass of each ion and the time taken to travel through the mass analyzer is recorded by the detector, providing extremely specific information about the ion’s identity. Chromatography and mass spectrometry can be combined in a single, powerful machine to detect very small amounts of specialized metabolites.
What is Next?
We have shown you just a few examples of the great diversity and uses of plant metabolites and explained how scientists isolate and identify them. Many plant metabolites have already been discovered and, in addition to being important to the plants that make them, some of the compounds are also useful to humans1. There are still plenty more plant metabolites to be discovered and explored, and every year scientists discover new ones. Understanding plant chemicals is not only exciting, but it also helps us to develop new medicines and agricultural resources. Although the functions of many plant metabolites are still not understood, these compounds represent a huge reservoir of potential applications. This great diversity of chemical compounds makes plants the master chemists of our planet.
Glossary
Metabolite:↑Small chemical compound that helps plants grow and interact with other organisms.
Glucosinolates:↑Specialized metabolites with pungent taste, present in plants, such as broccoli, radish, and mustard.
Saponins:↑Specialized metabolites traditionally used as natural detergents. The name comes from the Latin word “sapo” which means soap. A very important saponin mix, called QS-21, comes from the Chilean treeQuillaja soapwort, and it is used as an ingredient in formulation of vaccines.
Nepetalactone:↑Specialized metabolite found in the catnip plant,Nepetaspp. that attracts and alters the behavior of cats making them relaxed and playful.
Extraction:↑The process by which plant metabolites are separated and isolated from any other compounds present in plant material.
Solvent:↑In chromatography the solvent is the liquid where plant metabolites are placed. This solution (solvent plus metabolites) flows through chromatography for separation.
Chromatography:↑A separation technique commonly used to separate a mix of compounds.
Mass Spectrometry:↑A technique to measure the mass and charge of ions from molecules present in a solution.
Conflict of Interest
NC-Q is employed by Keygene N.V.
The remaining author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Acknowledgments
PC's work was supported by the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 752437. We thank Matias Aravena-Calvo for his help with the illustrations, and Javiera Aravena-Calvo and Marina Arias for their comments and suggestions.
Footnote
1.↑If plant metabolites interest you, check out taxol, artemisinin, and betalains.
References
[1]↑Fang, C., Fernie, A. R., and Luo, J. 2019. Exploring the diversity of plant metabolism.Trends Plant Sci.24:83–98. doi: 10.1016/j.tplants.2018.09.006
[2]↑Halkier, B. A., and Gershenzon, J. 2006. Biology and biochemistry of glucosinolates.Annu. Rev. Plant Biol.57:303–33. doi: 10.1146/annurev.arplant.57.032905.105228
[3]↑FAO. 2018.Why Bees Matter: The Importance of Bees and Other Pollinators for Food and Agriculture. Available online at:http://www.fao.org/publications/card/en/c/I9527EN/
[4]↑Wright, G. A., Baker, D. D., Palmer, M. J., Stabler, D., Mustard, J. A., Power, E. F., et al. 2013. Caffeine in floral nectar enhances a pollinator’s memory of reward.Science. 339:1202–4. doi: 10.1126/science.1228806
[5]↑Cárdenas, P. D., Almeida, A., and Bak, S. 2019. Evolution of structural diversity of triterpenoids.Front. Plant Sci.10:1523. two: 10.3389/fpls.2019.01523
FAQs
Plants: The Master Chemists of Our Planet? ›
Although the functions of many plant metabolites are still not understood, these compounds represent a huge reservoir of potential applications. This great diversity of chemical compounds makes plants the master chemists of our planet.
What is a plant chemist called? ›Botanists interested in ecology study interactions of plants with other organisms and the environment.
How are plants related to chemistry? ›Plant chemistry is included within the domain of plant physiology. To function and survive, plants produce a wide array of chemical compounds not found in other organisms. Photosynthesis requires a large array of pigments, enzymes, and other compounds to function.
What chemicals are made from plants? ›Many higher plants produce economically important organic compounds such as oils, resins, tannins, natural rubber, gums, waxes, dyes, flavors and fragrances, pharmaceuticals, and pesticides.
What chemical is found in most plants? ›chlorophyll, any member of the most important class of pigments involved in photosynthesis, the process by which light energy is converted to chemical energy through the synthesis of organic compounds. Chlorophyll is found in virtually all photosynthetic organisms, including green plants, cyanobacteria, and algae.
What is the word for a plant scientist? ›A botanist, plant scientist or phytologist is a scientist who specialises in this field.
Why are plants known as the master chemists of the natural world? ›Although the functions of many plant metabolites are still not understood, these compounds represent a huge reservoir of potential applications. This great diversity of chemical compounds makes plants the master chemists of our planet.
Why are plants called protectors? ›Trees remove carbon dioxide from the atmosphere, helping to lower greenhouse gas levels and slow climate change. The roots also anchor the soil and help prevent erosion during extreme weather events. The roots can also remove environmental toxins through a process called phytoremediation.
Do plants have chemical messengers? ›In higher plants, such as in animals, the intercellular communication is fulfilled through chemical messengers. These specific compounds in plants are called phytohormones, or in a wide sense, bioregulators.
Is chemistry the study of plants? ›Answer and Explanation: Botany is the study of plants and chemistry is the study of atoms, molecules, and the physical nature of compounds. Plants are living things and chemistry is the foundation for all matter, both living and nonliving.
What are the most toxic chemicals for plants? ›
The major pollutants toxic to plants are sulfur dioxide, fluorine, ozone, and peroxyacetyl nitrate.
What is the main chemical in plants? ›The most important chemicals that plants need, without which they won't thrive, are the three macronutrients: potassium, nitrogen and phosphorus. The reason for this is that the basic building blocks of every plant are ATP, cell membranes and amino acids.
What is the main ingredient in plants? ›1) Alkaloids
The most active ingredient found in plants, these (normally nitrogen bearing) molecules have various medicinal and even cancer fighting effects on the body (e.g. Madagascar periwinkle - Vinca rosea) but are also toxic in high doses. Most plants contain some alkaloids.
Glyphosate is a non-selective herbicide, meaning it will kill most plants. It prevents the plants from making certain proteins that are needed for plant growth. Glyphosate stops a specific enzyme pathway, the shikimic acid pathway.
Which is the most strong biological substance in plants? ›Due to its high stability and chemical inertness, sporopollenin is the most resistant biological substance. It is a component of the strong outer wall of plant spores and aids in the cell wall's resistance to chemicals and enzymes that can dissolve plant cell spores.
What 3 chemicals do plants need to grow? ›Soil is a major source of nutrients needed by plants for growth. The three main nutrients are nitrogen (N), phosphorus (P) and potassium (K). Together they make up the trio known as NPK. Other important nutrients are calcium, magnesium and sulfur.
Who is father of botany? ›Theophrastus, a Greek naturalist is known as the Father of Botany, the Father of Zoology, and the Father of Embryology. Botany deals with the study of plants and their characteristics.
What are the 5 branches of botany? ›- Plant Pathology. It is the study of organisms and environmental conditions that are responsible for causing diseases in plants, the mechanisms by which the disease occurs, and the methods of controlling plant diseases.
- Plant Ecology. ...
- Palaeobotany. ...
- Archaeobotany. ...
- Forensic Botany.
botany, branch of biology that deals with the study of plants, including their structure, properties, and biochemical processes.
Who is the father of plant chemistry? ›Nicolas-Théodore de Saussure (14 October 1767 – 18 April 1845) was a Swiss chemist and student of plant physiology who made seminal advances in phytochemistry.
Who is the father of modern plant chemistry? ›
Considered the father of modern chemistry, Lavoisier promoted the Chemical Revolution, naming oxygen and helping systematize chemical nomenclature.
Who is the greatest organic chemist? ›Robert Robinson (1886–1975) — The Quintessential Organic Chemist. Christopher Kelk Ingold (1893–1970) — Founder of Physical Organic Chemistry.
What is control over plants called? ›ability to create, control, manipulate or animate plant life. chlorokinesis.
Why are plants called lungs of the earth? ›Tropical rainforests are often called the “lungs of the planet” because they generally draw in carbon dioxide and breathe out oxygen.
What is the flower of protection? ›| Flower | Meaning | |
|---|---|---|
| Hawthorn | Hope, fertility | |
| Heather | purple | Solitude, beauty, admiration |
| white | Protection | |
| Heliotrope | Devotion | |
Plants do not. Plants may exhibit reactions to stimuli, and we sometimes interpret these responses as defensive behavior, but we're really talking about successful adaptations to their environment. Plants have neither nervous systems nor neuro-transmitting pain receptors.
Can plants sense us? ›Summary: Plants lack eyes and ears, but they can still see, hear, smell and respond to environmental cues and dangers. They do this with the aid of hundreds of membrane proteins that sense microbes or other stresses. Researchers now have created the first network map for 200 of these proteins.
Are plants aware they exist? ›All organisms in natural circumstances, animals, plants and bacteria, are aware of changes in their environment and respond by changing behaviour.
What does a plant chemist do? ›A plant chemist is a scientist who researches and experiments with the properties of chemical substances and plants. They measure the effects of chemical compounds in various situations and study inter-chemical reactions.
Are plants considered science? ›Research. The branch of science that studies plants is called botany (or plant biology). An expert in this field is called a botanist. Some of the areas of study are morphoanatomy, cytology, histology, physiology, ecology, evolution, taxonomy, and pathology.
Do plants make oxygen? ›
Through a process called photosynthesis, leaves pull in carbon dioxide and water and use the energy of the sun to convert this into chemical compounds such as sugars that feed the tree. But as a by-product of that chemical reaction oxygen is produced and released by the tree.
What plant removes formaldehyde? ›Philodendrons, spider plants and golden pothos are the most effective at removing formaldehyde molecules. Flowering plants such as gerbera daisies and chrysanthemums are most effective at removing benzene.
What plants remove toxins from water? ›Plants That Filter Water
Cattail, typically growing between 5 and 10 feet tall, can remove metals such as zinc, cadmium, lead and nitrate from water. Water mint, or Mentha aquatica, grows up to 6 inches high with light purple flowers and should be first planted in a container before being moved to the water.
And though they may be aesthetically pleasing, are houseplants good or bad for your health? “Houseplants in moderation are fine for most of the population,” says Alan Redding, M.D., an allergist at Piedmont. In fact, Dr. Redding admits to having several houseplants in his own home.
What liquids help plants grow best? ›Spring water contains natural minerals that are essential for optimal growth in your plants. Distilled water will keep your plants alive, but won't add any nutrients to help them thrive.
What fertilizer makes plants grow faster? ›High-nitrogen fertilizers are known for causing huge growth in plants, which is why many types are rich in nitrogen or include it as the main component. Fertilizers high in nitrogen will also restore bright green hues to your foliage.
What plant converts the most CO2 to oxygen? ›1. Pothos. Pothos is the number one indoor plant for oxygen due to its fast conversion rate. In an experiment, it was able to show a 6.5% reduction in carbon dioxide, where it decreased the CO2 content from 454PPM to 425PPM, thereby increasing the oxygen levels.
Which plant gives oxygen 24 hours? ›Areca Palm plant is a popular ornamental houseplant in every Indian household. But not many are aware that it provides oxygen 24*7. This way, it not only adds to the good looks of your space but also turns the surrounding air breathable by working as a natural air purifier.
What do plants turn those 3 ingredients into? ›Explanation: In photosynthesis, plants take in carbon dioxide from the air and combine it with water absorbed through their roots. They use energy from sunlight to turn these ingredients into carbohydrates (sugars) and oxygen, and they release extra oxygen to the air.
What is a career in plants called? ›Horticulture is the art, technology, business, education and science of plants.
What is the difference between apothecary and chemist? ›
Apothecary (/əˈpɒθɪkəri/) is an archaic English term for a medical professional who formulates and dispenses materia medica (medicine) to physicians, surgeons, and patients. The modern terms 'pharmacist' and 'chemist' (British English) have taken over this role.
What is the difference between a botanist and a horticulturist? ›Botanists are theorists who prefer working on the science of plants. Horticulturists make their changes to the plants themselves, working on breeding crop rotation and cultivation. Botanists usually make their changes to the genetics of the plants using laboratory techniques to make changes.
Is a botanist a plant scientist or phytologist? ›Botanists are scientists who study plants. They are also known as plant scientists, plant biologists or 'phytologists'.
What is the highest paying job in a plant? ›- Horticulturist. National average salary : $50,752 per year. ...
- Interior designer. National average salary: $54,585 per year. ...
- Gardener. National average salary: $55,776 per year. ...
- Landscape designer. ...
- Plant videographer. ...
- Conservation scientist. ...
- Zoologist. ...
- Garden writer.
Stanford Health Care has the highest average salary for horticulturists.
What does a floriculturist do? ›A floriculturist cultivates flowering and ornamental plants for gardens and for the floral industry. Floriculturists with advanced degrees are often found in universities and in the horticulture industry in research and teaching positions developing and breeding new varieties of flowers.
What is a modern day apothecary called? ›"Pharmacist" is a more common synonym for apothecary. Some contemporary companies and drugstore owners use the old-fashioned charm of the term apothecary to label products they sell.
What do Americans call a chemist? ›In British English, a person who is qualified to prepare and sell drugs and medicines can be referred to as a chemist or a pharmacist. ... the pills the chemist had given him. You can ask the pharmacist for advice on common illnesses. In American English, someone like this can only be referred to as a pharmacist.
Is an apothecary a healer? ›"Apothecary" is an ancient term for those who produce healing remedies from raw materials.
What type of botanist makes the most money? ›Forest has the highest average salary for botanists.
Do botanists make money? ›
How much does a Botanist make in the United States? The average Botanist salary in the United States is $72,913 as of May 25, 2023, but the range typically falls between $60,225 and $89,992.
Who is the most famous botanist? ›1. Carl Linnaeus. Often regarded as the father of taxonomy, Carl Linnaeus is certainly one of the most famous botanists in history.
What is a professional gardener called? ›Horticulturists are professional gardeners with an academic degree who are trained in horticulture, gardening, and land management (other related degrees include landscape design and landscaping, which are often distributed by a university's horticulture department).
Who is considered the father of botany? ›Theophrastus (c. 371–286 BC), known as the 'father of botany', wrote many books, including the 10-volume set, Historia Plantarum ('Enquiry into Plants').