Take in substances from the environment and remove wastes
1 of 28
Larger plants need what & why?
Specialised exchange surfaces + a transport system as they have a small SA:V
2 of 28
Why do plants have a low demand of oxygen?
They aren't active so have a low respiratory rate
3 of 28
How is this demand met?
By diffusion
4 of 28
However, what do plants have a high demand for?
Water + sugars (nutrients and minerals)
5 of 28
How do they meet this demand?
Roots absorb water and minerals from the soil & leaves synthesise sugars by photo. + perform gaseous exchange
6 of 28
What can't leaves do?
Absorb water from air
7 of 28
A transport system is thus needed to move what?
Water + minerals from the roots to the leaves, and sugars from the leaves to the rest of the plant
8 of 28
The transport system consists of what?
Vascular tissue
9 of 28
What is vascular tissue?
A group of cells specialised for transporting fluids by mass flow
10 of 28
What happens in the xylem vessel?
Water and minerals travel upwards from the roots to the leaves
11 of 28
What happens in the phloem vessel?
Assimilates such as sugars, move downwards from the leaves to the rest of the plant
12 of 28
What are dicotyledonous plants?
Plants with 2 seed leaves and a branching pattern of veins in their leaves
13 of 28
How is vascular tissue distributed in dicotyledonous leaves?
It's distributed throughout the plant
14 of 28
How are the phloem and xylem found?
In a vascular bundle
15 of 28
What other tissues may the bundle contain? Why?
Collenchyma + sclerenchyma that give the bundle strength and support
16 of 28
Where is the vascular bundle found in young root?
At the centre
17 of 28
How are the vascular tissues vessels arranged in young root?
They form a central core; the xylem forms an X-shape and the phloem is between the arms
18 of 28
What does arrangement provide?
Strength to withstand pulling forces exposed to roots
19 of 28
Where is vascular bundle found in the stem?
Near the edge of the stem
20 of 28
What are bundles like in non-woody plants?
Separate and distinct
21 of 28
What are the bundles like in woody plants?
Separate in young stems, but become a continuous ring in older stems
22 of 28
What does this mean?
That there is a complete ring of vascular tissue under the bark of a tree, providing strength and flexibility to withstand bending forces that stems and branches are exposed to
23 of 28
What is the arrangement of the xylem + phloem tissue in stems?
Xylem: found towards the inside, Phloem: found towards the outside
24 of 28
What lays between the xylem and phloem?
A layer of cambium
25 of 28
What is cambium?
A layer of meristem cells that divide to produce new xylem/phloem
26 of 28
How is the vascular bundle arranged in leaves?
They form the midrib and veins of a leaf.
27 of 28
How are the xylem and phloem vessels arranged in the vascular bundle of a leaf?
The xylem is on top, then ploem on the bottom
28 of 28
Other cards in this set
Card 2
Front
Larger plants need what & why?
Back
Specialised exchange surfaces + a transport system as they have a small SA:V
Comments
No comments have yet been made