5 minutes 15-02-2022

Plant biochemistry – the foundation

Plants are found nearly everywhere in the world and are integral to the existence of most life on earth. Therefore, understanding how growth mechanisms work in plants is vital to scientific research and development. With this article, we are beginning to dive into the world of ‘plant biochemistry’. The subject matter under this segment of plant science is incredibly complex and wide ranging, as it pertains explicitly to plants yet it also includes plants’ interaction with the environment and organisms around them.

Our mission is to share this complex scientific knowledge in an easy-to-understand manner for everyone out there.

To begin, let us first understand what general biochemistry encompasses:

What is biochemistry?

Biochemistry is the study of the chemical and physiological processes as well as substances that occur within living organisms. Reading this, you might think, “so…what does that mean?” Basically, biochemistry is the study of the elements that make up an organism, and the processes that keep them alive, such as breathing, eating, growing, etc. The study of biochemistry began in 1833 with the discovery of amylase (an enzyme that breaks down starch).

To begin, living matter is split into two categories of substances: inorganic and organic. Inorganic substances are not synthesized by the organism and must be taken up from the environment, such as water and minerals. Organic substances are the main compounds of a living body which include a variety of substances such as carbohydrates, proteins, and fats; nucleic acids for DNA; enzymes; hormones and antibodies; and other metabolism products.

Further to that, plants and animals are primarily made up of varying combinations of carbon (C), hydrogen (H), and oxygen (O), and a handful of other elements. The elements, or nutrients, are separated into two categories: macroelements (needed in large amounts), and microelements (equally crucial, but needed in minute amounts). Through reactions of decomposition (breaking down) or catabolization (adding together), bodies grow and change. Like animals, plants require nutrition and a diverse “diet”. Unlike animals, plants take up nutrients mostly through the roots and sometimes through leaves. For both plants and animals, if they have too much or too little of each of these nutrients, toxicity or deficiency diseases can occur.

What is plant biochemistry?

A plant is a living organism that typically grows in a permanent site, that absorbs water and minerals through roots, and synthesizes nutrients through photosynthesis within chlorophyll (the green pigment). Plants are “producers” or “autotrophs”. An autotroph is an organism able to form organic substances (nutrition) from simple inorganic substances (like water, carbon dioxide, and minerals). This means all plants are autotrophs. Algae and some bacteria are also autotrophs.

Plant biochemistry looks at everything that we talked about in general biochemistry, specifically in the context of autotrophic organisms and plant specific processes like plant “breathing” (photosynthesis and respiration) and “digestion” (pathways such as the Kreb’s cycle). There are too many plant processes to discuss in one article, so here is a brief introduction to two basic, daily processes that produces gas that humans literally cannot live without.

When the sun is high in the sky, photosynthesis occurs, which is comparable to a human breathing in. The plant absorbs carbon dioxide and photons (packets of light) from the sun through its leaves, and water through its roots. A chemical reaction occurs that produces sugar molecules and oxygen. The sugars are transported throughout the plant, and oxygen is released back into the environment. When the sun goes down, photosynthesis stops. If you want to learn more about this process, you can read our in depth article on photosynthesis.

Respiration is the opposite of photosynthesis and is comparable to a human breathing out. This process is constantly occurring and is where the plant uses oxygen and the sugar molecules from photosynthesis in different parts of the plant to grow and change (for instance, producing seeds and flowers, or growing new leaves). A by-product of this reaction is the production of carbon dioxide, which is released back into the environment. And so, the cycle continues! Learn more about this process by reading our in depth article on photorespiration.

Why care about plant biochemistry?

If you think biochemistry is boring and doesn’t impact you, think again! Biochemistry is everywhere. Examples of plant biochemistry range from photosynthesis and the production of oxygen to the alcoholic fermentation of yeast in the production of beer to the growth of corn to produce ethanol!

Plant biochemistry is crucial for human activity in areas like food supply and processing raw materials for industrial or pharmaceutical use. Understanding and utilizing biochemistry pathways in plants help in obtaining higher yields, better quality, and economics of harvest and production. For instance, providing plants the right nutrients at the right time can change the plants growth. A macroelement key for plant growth is nitrogen (N). N is also a major component of amino acids, the building block of protein. If N is added earlier in the plant lifecycle, the plant will grow thicker and taller. If N is added later, the plant will have higher protein content in their seeds. Understanding plant biochemistry is essential for maximizing yield and quality production, depending on the end use of the plant.

Plant biochemistry is still crucial after the harvest and during their transformation into agricultural or industrial products. An example where this knowledge is important is for certain forages (plant species used for grazing or livestock feed). When a forage plant freezes, their cell membranes can rupture. Some biochemical compounds within the cells can react with compounds outside the cells, thereby producing a poisonous acid. When consumed in a high enough dose, animals can suffer from serious health problems, or even die. This is a higher risk in certain forage plant species, but also in certain growing conditions. This is just one example where understanding plant biochemistry enables humans to produce better and safer products.

Plant biochemistry offers plenty of exciting potential in the future too! Scientists are using plant biochemistry to improve food quality and nutrition, improve plant genetics to mitigate climate change impacts, and to create renewable resources to replace fossil fuels. Plant biochemistry has nearly endless potential and opportunities!

Conclusion

Biochemistry is a fascinating and complex science, and this article barely scratches the surface. Plants may initially seem less exciting than furry animals, however their biochemistry is equally complex and special. All you need to do is look around to enjoy the benefits of plant biochemistry, from your disposable coffee cup to your ice cream to your cotton shirt! Plants are crucial to human activities and understanding their biochemistry is essential for the efficient and safe production of plant-based products. 

For more interesting articles diving into the fascinating sphere of plant science, keep checking this space!

By Stacy Berry | 15-February-2022

About the author

Stacy Berry was born and raised on a farm in Alberta, Canada. She graduated in 2016 from the University of Alberta with a Bachelor of Science in Agriculture, major in Crop Science. Stacy has mostly worked in municipal government (vegetation management), and primary agriculture production (including horses, cows, and bees). She currently works for Nutrien Ag Services and is excited to be writing for Lab Associates! She is an animal lover who enjoys reading good books, eating good food, travelling, nature, the outdoors, and spending time with friends.

References

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