Parts Of Plants And Their Functions

Parts Of Plants And Their Functions

All living beings depend on the Sun to exist. We are on a planet that is at the exact distance from the sun, where it receives solar rays with the right intensity, which allows an average temperature of 14 degrees Celsius: ideal for life. From our origins and until today, it seems that the vegetal beings are very different, but the reality is that the dividing line that separates both realms every time becomes more diffuse.

Why? Well, it is true that they cannot talk or walk, but to survive they have to perform a series of plant functions, which are basic to their survival. Let’s see which are the main ones.

parts of plants and their functions


Like any animal, plants need to breathe, and they do it in a similar way to us: absorbing oxygen and expelling carbon dioxide and water in the form of vapor. Where do they breathe? For three parts:

  • Stomata or pores : they are found in all their green parts, such as leaves, stems not lignified, green bracts (modified leaves that protect the flower).
  • Lenticelas : they are very small protuberances, with a circular or elongated shape, found in the woody stems. They are visible to the naked eye, since they can measure from 1 to 5cm.
  • Roots : by the radical hairs.

The question that you may be asking now is, do you breathe all day? Only at night? Well the answer is …: breathe 24 hours . And, if it were not like that, they could not perform photosynthesis.


This is the function that only they, the plants, do. Animals can hunt prey, or feed on herbs and / or fruits, but plant beings, from the time the seed germinates until it dies, remain anchored in the same place. In order to grow and develop, they need to be able to do photosynthesis; that is, transform the energy of the sun into food .

Where is it made? In the leaves . These, as we know, are green, since they contain chlorophyll. Thanks to it, they can absorb the adequate light, which together with carbon dioxide, becomes raw sap (water and minerals that absorb the roots and that is directed towards the leaves) in elaborated sap (the food of the plant, composed mainly of amino acids and sugars).

As a result, plants release oxygen into the atmosphere through stomata. But only during the day, which is when they are exposed to sunlight.


The plants, without food, could not grow, but without water they would not even be able to germinate. In the soil there are a number of nutrients , mainly nitrogen, phosphorus and potassium (or NPK), which will only be available once they are dissolved in the water . Once they do, the roots can absorb them without much trouble.

What is NPK useful for? For the following:

  • Nitrogen : it is essential for them to grow, develop chlorophyll and carry out photosynthesis.
  • Phosphorus : it serves so that they can develop their root system and for the growth of the fruits.
  • Potassium : it is very important, since it intervenes in plant respiration and food transport.

Once the roots obtain the water and minerals dissolved in it from the earth, a mixture called crude sap , it circulates upwards through the woody vessels until it reaches the leaves. There, by means of photosynthesis, it is transformed into elaborated sap , which is conducted in a descending way by the Liberian vessels to all parts of the plant being. The excess material is stored and remains as reserves.

Grow in the direction of sunlight

As we have seen, the Sun is fundamental for plants. They need it to, basically, everything. Since the seed germinates, what they do is grow in the direction of their light. But how do they do it? That is, how can the stem know that it has to grow up and the roots down?

These responses to the solar stimulus are known as phototropism . This stimulus causes a hormonal reaction in the plant whose consequence is a differential growth caused by auxin. It acts in a very unique way: when there is a negative phototropic response, that is, when it grows in the opposite direction to the Sun, it concentrates in the region of the plant opposite to the incidence of light. On the contrary, when the phototropic response is positive, the auxins concentrate in greater numbers and, consequently, the cells of these regions proliferate more than in those where the concentration is lower.

Positive phototropism IN THE STEMS

Thus, the roots present a negative phototropism, while the stems have a positive phototropism.

Did you know what were the main functions of the plants?

Don Burke

I am Don Burke, one of the authors at My Garden Guide.  I am a horticulturist that cultivates, grows, and cares for plants, ranging from shrubs and fruits to flowers. I do it in my own garden and in my nursery. I show you how to take care of your garden and how to perform garden landscaping in an easy way, step by step.I am originally from Sydney and I wrote in local magazines. Later on, I have decided, more than two decades ago, to create my own blog. My area of specialization is related to orchid care, succulent care, and the study of the substrate and the soil. Therefore, you will see many articles dedicated to these disciplines. I also provide advice about how to improve the landscape design of your garden.

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