Transportation in Plants
In this article, we are going to learn about the transportation in plant and how plants transport water and nutrients to all parts to grow and survive.
We already know that the leaves produce food by using water, sunlight, and carbon dioxide through a process known as photosynthesis. Have you ever wondered how plants transport food and water to other parts of the plant? The transportation system of a plant is like a human’s circulatory system—just without all the blood. Instead of the blood, the transportation system helps distribute water and nutrients.
Plants have a transport system:
- To carry water and minerals absorbed by the roots up to the leaves, and
- To carry food (sugar and amino acids) from the leaves to all parts of the plant.
In simple words, plants have a transport system to carry water and nutrients to all parts of the plant.
Transportation in plants is made up of two vascular tissues. They are called the xylem, which transports water and minerals, and the phloem, which is responsible for food distribution. Let’s have a deeper look into both of the vascular tissues.
A tissue is a group of cells that perform specialized functions in an organism.
Water and food transportation in plant
What is xylem?
Xylem is a tissue in vascular plants that transports water and dissolved minerals from the roots to the leaves through the stem and branches. Xylem transports water in only one direction: upwards.
Now you may wonder, Why do plants even need a xylem? They can just absorb water from their leaves, right? Well, the answer is that they can’t. Plants don’t have the ability to absorb water from the environment. They can only get it from the roots.
So plants use the xylem vessels to transport water from the roots to the leaves to produce food through the process of photosynthesis.
- xylem parenchyma
- xylem fibres
- xylem tracheids
- xylem vessels
Why is xylem called dead tissue?
- All the elements of xylem tissue are dead except the parenchyma, which are living cells with thin walls.
- The xylem tissues have no organelles (mitochondria, nucleus, chloroplast, vacuole, and cytoplasm).
- Since the conduction of water is the primary job of xylem, it’s elements need to form a narrow pipe-like structure so that water can rise in the pipe through capillary action.
What is phloem?
Phloem is a vascular tissue that transports food from the leaves to all the other parts of the plant, including the roots.
The food produced in the leaves during photosynthesis consists of glucose. The phloem vessel transports food to all parts of the plant in the form of glucose solution. The transportation of food in phloem is called translocation.
Phloem is known as bi-directional because it carries food in both directions, upward and downward.
Phloem is composed of various cells:
- sieve elements,
- phloem fibres,
- phloem parenchyma cells.
Unlike xylem, phloem consists of living cells that carry sap. Sieve elements are living cells that contain little cytoplasm and no nucleus.
Sap is a liquid that contains water and dissolved substances such as sugars and minerals.
What is transipiration?
Transpiration is the process by which water is lost as water vapor from the upper parts of a plant through the stomata (the tiny pores of leaves). Leaves continuously lose water to the environment by evaporation.
Stomata open during the day to allow gas exchange and close at night to limit transpiration. The opening and closing of the stomata are due to specialized cells called guard cells. When water enters the guard cells, they become turgid or swollen, and the stoma opens. When the guard cells lose water, they become flaccid and straight, and the stoma closes.
What are the benefits of transpiration?
- Supply water for photosynthesis.
- Creates transpiration pull for transport of water
- Transports water and minerals from soil to all parts of the plant
- Removes the excess water.
- Control the temperature of the plant to keep it cool.
What is translocation?
What is a vascular bundle?
A group of xylem and phloem vessels is called a vascular bundle. You can also learn from this.