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Plant Translocation

Mary Ellise Schiffer, Lauren Posey
  • Author
    Mary Ellise Schiffer

    Mary Ellise has a M.S. in Environmental Science and Policy and a B.A. in Earth Systems Science from Clark University. She has taught science and writing to students in grades kindergarten through college.

  • Instructor
    Lauren Posey

    Lauren has taught intermediate reading in an English Language Institute, and she has her Master's degree in Linguistics.

Understand translocation in plants. Comprehend the process plants use to translocate glucose to where they need it. Find out about translocation in biology. Updated: 01/27/2022

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What is Translocation in Plants?

Humans gain energy from nutrients in food. Once the food is eaten, the body needs to move those nutrients to other parts of the body to be processed and used for energy. Plants also need to move nutrients around their "body."

What is translocation? Translocation has a simple definition: the transport of materials from one place to another. Translocation in plants would be defined as the transport of materials from the leaves to other parts of the plant.

Plants do not eat food. Instead, plants gain energy from the sun and nutrients in the soil. Specifically, photosynthesis is the process by which plants create glucose (sugars) using energy from the sun.

The balanced equation for photosynthesis is as follows:

{eq}6CO2 + 6H2O \to C6H12O6 + 6O2 + 6H2O {/eq}

A plant uses carbon dioxide, water, and sun energy to create byproducts of glucose and oxygen.

Photosynthetic cells can be found in chlorophyll, the green coloring on plant leaves. Therefore photosynthesis occurs in the leaves.

But how do plants grow? Sugars created in photosynthesis are transported throughout the plant to fuel other non-photosynthetic parts such as seeds, fruits, roots, and new growth. The transportation of glucose from the leaves is an example of plant translocation.

Terms of Translocation in Plants

Just as humans have organs and blood vessels that run through the body, plants have transport tubes that run through the plant. The main transport tubes in plants are phloem. Phloem extend from the leaves throughout the entire plant, including stems, roots, and other parts. As a plant grows, phloem grows too.


400x magnified image of xylem and phloem cells within vascular bundles of a yucca plant

400x magnified image of xylem and phloem cells within vascular bundles of a Yucca plant.


Phloem are not hollow tubes. Phloem are a series of tissue-filled cells connected by sieve-like walls. The connecting walls allow water and dissolved nutrients to pass through. Phloem transport sugars that act as energy for the plant.

The counterpart to phloem is xylem, which helps carry water and dissolved nutrients from the soil through the plant. The two are often found close together within the same vascular bundle. Phloem are on the outer side, while xylem are in the center.

The movement of phloem is bidirectional, as it can move sugars up or down the plant. The movement of xylem is unidirectional, from the soil to the leaf to the atmosphere.

Through the phloem, materials are moved from sugar sources to sugar sinks. Sugar sources refer to photosynthetic sugar-producing parts of the plant, most notably leaves. Sugar sinks are non-photosynthetic sugar-using parts of the plant, such as new growth. In sugar sink cells, sugars are broken down to power metabolic and storage processes.

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The Process of Plant Translocation

Leaves and storage locations in plants can be either sources or sinks depending on the season and plant's stage of development.

In the growing season, leaves are sugar sources, actively photosynthesizing and creating sugars. Excess sugars are transported to sinks, such as areas of new growth. Sugars can also be used to grow storage locations such as roots and bulbs. When the growing season ends, the plant drops leaves and does not photosynthesize.

Storage locations in plants, such as roots, tubers, and bulbs, are initially sugar sinks because they need sugar to grow. However, once fully developed, roots, tubers, and bulbs then act as sugar sources because they have accumulated stores of sugar. When the growing season begins, the plant has no leaves to photosynthesize and produce sugar. Instead, the plant must use the sugar stored in its roots, tubers, or bulbs to fuel new growth.

Pressure Flow Model in Plant Translocation


Example of osmosis. Osmosis occurs when water moves through a semipermeable membrane from an area of lower solute concentration to higher solute concentration in order to achieve equal concentrations of solute on both sides. Osmosis is crucial for creating turgor pressure in the pressure flow model of plant translocation.

Osmosis occurring through a semipermeable membrane, with liquid transferred from the low solute to high solute solution.


Materials move (translocate) from source to sink. The mass flow hypothesis, or pressure flow model, is the main theory explaining the movement of materials throughout the plant. This theory was proposed by German plant physiologist Ernst Munch in 1930.

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Frequently Asked Questions

What is an example of translocation in plants?

An example of translocation in plants is the movement of sugars from sugar sources to sugar sinks. Sugar sources include sugars either created through photosynthesis or stored in plant parts such as roots, bulbs, and tubers.

What is translocation in DNA?

DNA translocation can cause a chromosomal abnormality when a piece of one chromosome breaks and fuses with a different chromosome. This abnormality is a common cause of leukemia.

What is a simple definition of translocation?

A simple definition of translocation is the movement of materials from one area to another. In plants, plant translocation involves the movement of sugars from sources to sinks.

How is translocation done in plants?

Translocation in plants is achieved by the movement of sugars through the phloem. The mass flow hypothesis, or pressure flow model, explains that sugars are able to move from sugar sources to sugar sinks through a pressure differential.

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