Food on the move

The idea

Translocation is the transport of soluble products of photosynthesis, along with amino acids and other substances, in the phloem's sieve tubes aided by companion cells, upward and downward, to storage and growing organs.

Sugar to the roots

Leaves make sugar in sunlight. Roots, deep in the soil, have no leaves of their own.

How do you think the roots get food?

• It is carried from the leaves
• They make it in the dark
• They need none

Follow the food

Open each tab.

Food in both directions

The soluble products of photosynthesis, made in the leaves, are moved to the rest of the plant. This is translocation, and it takes place in the phloem. The sieve tubes carry the material, helped by companion cells next to them. The movement is both upward and downward, and the food is delivered especially to storage organs and growing organs.

Translocation is the transport of soluble products of photosynthesis, along with amino acids and other substances, in the phloem's sieve tubes aided by companion cells, upward and downward, to storage and growing organs.

Notes

Translocation: soluble products of photosynthesis (with amino acids and others) move in the phloem's sieve tubes with companion cells, up and down, to storage and growing organs.

Check yourself

What is translocation?

In which tubes does translocation take place?

In which directions does translocation take place?

To which parts are the substances especially delivered?

• The loss of water as vapour from the aerial parts. That is transpiration.
• The movement of water into the root. That happens when root cells take up ions; it is not translocation.
• The transport of the soluble products of photosynthesis in the phloem — correct. Yes!
• Sieve tubes, with the help of companion cells — correct. Yes!
• Xylem vessels and tracheids. Xylem vessels and tracheids conduct water.
• Stomata. Stomata are tiny pores on the leaves where gases are exchanged.
• Only upward. The book says it takes place both in upward and downward directions.
• Both upward and downward — correct. Yes!
• Only downward. The book says it takes place both in upward and downward directions.
• The stomata. Stomata are pores on the leaves; they are not storage or growing organs.
• The dead cells of the xylem. The substances are delivered to storage organs and growing organs.
• Storage organs of roots, fruits and seeds, and growing organs — correct. Yes!