B2.2.4 Flashcards
What does the xylem tissue do
The xylem tissue transports minerals ions and water from the roots to the stem, leaves and flowers. Water diffuses into the roots and minerals are taken in via active transport.
What does the phloem do
The phloem tissue transports dissolved sugars produced during photosynthesis and other soluble food molecules, from the leaves to all other areas of the plant. This is called translocation.
Where do the sugars go
Sugars go to the meristems where they are needed for making new plant cells, and to storage tissues in roots.
What are xylem vessels made from
The xylem vessels are made from dead xylem cells. There are no cell walls at the end of these cells. This forms tubes through which the water and dissolved minerals can flow. The rest of the xylem cellulose cell wall is thickened.
In what plants do xylem tissues make up the bulk of the plant
In woody plants
What are phloem vessels made up of
Phloem vessels are made of living cells. The cell walls of these do not completely break down. Instead sieve plates are formed - small holes in the end wall allow for dissolved sugars to pass through. The connection of phloem cells forms a tube which allows dissolved sugars to be transported.
What do the location of vascular bundles help
They help to provide support for the plant:
In the leaf they form a network that supports the softer leaf tissue
In the stem they are located around the outer edge, providing the stem with strength to resist bending during breeze.
In the root they are found in the centre, enabling the root to act as an anchor - the root can bend as the plant moves in the wind.
What does the xylem look like and characteristics
One-way flow only
water and minerals
No end walls between cells
Thick walls stiffened with lignin
What does the phloem look like and characteristics
Transports water and food
Sieve plates
Two way flow
