Plants are the most important organisms that help make our planet habitable. Vegetation is all around us and provides us with fresh oxygen that we all need to breathe.
While plants are essential for all human beings, they are much more special for us plant lovers. But alongside affection for these green guys, we must also have proper knowledge about them to care for them better.
We love to see our plants grow, but what is the underlying process for plant growth?
How Do Plants Grow?
All 300,000+ plant species need the same four elements to grow—water, air, light, and nutrients. Plants grow via photosynthesis. Water and Carbon dioxide absorbed through the roots and leaves, respectively, are broken down in the presence of sunlight. This process occurs in the chloroplasts and results in complex sugars. These complex sugars, along with water and other nutrients, form the basic building blocks known as plant cells.
What Are Chloroplasts?
Chloroplasts are the powerhouses of a plant. They are structures in plant cells that allow the plant to capture energy from sunlight and convert it to food.
The green pigment chlorophyll present in the chloroplast gives plants their green color and is responsible for trapping sunlight.
The greener the color of a plant, the more chlorophyll there is in its leaves. This is why leaves that are dark in color need less light than leaves that are lighter in color.
When we say chloroplasts are the powerhouses of plants, we say they are directly responsible for putting together all the inputs to make plant food. Photosynthesis takes place inside the chloroplasts.
What Is Photosynthesis?
The word ‘photosynthesis’ is a Greek word derived from ‘photo’ (light) and ‘synthesis’ (to make). When put together, it means ‘to make with the help of light.’
It is a remarkable process whereby energy in the form of light is converted to chemical energy that can be stored in the plant.
Out of all the organisms in the world, only plants have the ability to make their food by converting light energy into chemical form. Here is how photosynthesis takes place inside the leaves of your plants.
- The roots absorb water, and Carbon di Oxide is drawn in through the leaves.
- Water and CO2 are transported into the chloroplast.
- Chlorophyll uses light energy to split water into its constituent elements, oxygen, and hydrogen.
- While the oxygen escapes back into the atmosphere, the chlorophyll uses light energy to combine CO2 and hydrogen to form complex sugars, also known as carbohydrates.
This is only a simplified version of the more intricate process of photosynthesis. The resulting carbohydrates then combine with water and nutrients such as nitrogen and phosphorous to make different types of plant cells.
The Role of Nutrients in Plant Growth
Researchers have identified up to 16 different nutrients that plants require in different quantities to thrive. They have grouped them into the following groups.
- Primary nutrients (carbon, hydrogen, nitrogen, oxygen, phosphorus, and potassium)
- Secondary nutrients (calcium, magnesium, and sulfur)
- Trace nutrients (boron, chlorine, copper, iron, manganese, molybdenum, and zinc)
Nitrogen, phosphorous, and potassium are the primary nutrients that are absolutely essential for all plants. These nutrients are absorbed by the roots in large quantities.
Here is what the three nutrients do to help plants grow.
- Nitrogen is needed to produce amino acids, and in turn, proteins. It is needed for chlorophyll, cell formation.
- Phosphorous is required for cell formation and sugar/fat metabolism.
- Potassium is needed for water regulation and enzyme activity.
How the Different Parts of a Plant Grow
Now that we know how photosynthesis works, let us look at how the newly created cells form different plant tissues and make a plant grow.
All parts of the plant grow upward except the roots. Roots grow downward, as far deep as they can go into the ground.
Roots grow in the downward direction to counter the upward growth of the foliage. They anchor the plant into position.
There is a layer of hardened root cells known as the root cap at the tips of roots. The hard root cap allows the roots to tunnel through the ground as they spread.
The roots grow both sideways and downwards, trying to cover as much area as possible in search of nutrients. Not only do roots grow in a particular direction, but they also tend to split up into numerous fine roots.
Because leaves need to absorb sunlight, they grow in a pattern that maximizes the surface area of leaves facing the light source.
The leaves produce the complex sugars needed for cell growth. Hence the sugars needed by the leaves to grow are used right there.
The extra complex sugars are transported to the roots and other parts of the plants via leaf veins. New leaf growth always happens in the direction that fronts the leaves’ upper surface directly to the light source.
Magnesium is an essential element that forms chlorophyll and helps give the leaves their green color. If a plant suffers from magnesium deficiency, the leaves may grow pale or yellow.
The stems are the primary supporting structures of a plant. The growth of branches determines the general growing direction of a plant.
So if the branches tend to grow towards a particular direction, you might soon notice that the significant part of the plant is now right where the branches were growing to.
The new growth takes place at the tip of stems. This area is also called apical meristem. This is where sugars from photosynthesis combine with water and nutrients to produce new leaves.
A branch may also produce buds that grow into another branch or stay dormant.
If the apical meristem is cut, the dormant buds are activated, and the branch is forced to grow into multiple branches. The pattern of stem growth depends on the living condition of a plant.
For instance, in the absence of adequate light, a plant may grow long leafless branches searching for light.
Importance of Temperature
The four basic elements for growth aren’t all that a plant needs. Temperature, too, has to play a crucial role.
We see that some plants shed all their leaves, and some stop growing in winters. This is because the temperatures drop too low for the plants to carry on growing.
Plants stop growing in low temperatures because there are multiple chemical reactions needed for growth.
These chemical reactions involve the functioning of enzymes, something which is only possible when the temperature level is just right. When it is too cold, enzymes cannot function, and hence no growth takes place, or the pace of growth is reduced significantly.
Frequently Asked Questions About Plant Growth
What do plants need to grow other than water, light, nutrients, air, and the right temperature?
Space and time. A plant needs ample space above and below the ground to develop properly. In case a plant is too crowded, its growth is stunted, and it may develop diseases easily. Time is the other crucial requirement, and you should let your plant take their time that can be multiple weeks or often months.
Why is my plant not growing?
The basic requirements for growth need to be met for a plant to grow, so check if a particular plant species is getting all that it requires. For instance, a tropical plant will not grow in a cold climate even if all other requirements are being met. If all requisites are being fulfilled, you might need to wait and see.
Marcel runs the place around here. He has a deep passion for houseplants & gardening and is constantly on the lookout for yet another special plant to add to his arsenal of houseplants, succulents & cacti.
Marcel is also the founder of Iseli International Commerce, a sole proprietorship company that publishes a variety of websites and online magazines.