Xylem

GCSE RECAP:

What is the role of Xylem?

What is the role of phloem?

What is the equivalent to vascular tissues in animals?

a) helps with transport of water and dissolves minerals and is made of dead cells

b) helps with transport of sugar and water

c) Blood

Xylem

Tissue in plants conducting water and dissolved materials upwards

Parenchyma:

• Often have a large vacuole for storage

• Association with photosynthetic sections of plants.

• Living tissue - made of cellulose

Collenchyma

• growing sections of plants,

• the cell wall is thickened with cellulose and pectin to resist bending

• living tissue

Sclerenchyma:

• composed of dead cells with very thick cell walls

• support tissue in plants

  • lignified - make them waterproof.

Root:

Xylem vessels are arranged in an x-shape in centre of ________ ________, surrounded by phloem. This provides support to withstand pulling forces which roots are exposed. Vascular bundle surrounded by ___________ which is an out layer of cells which supply xylem vessels with ________. Inside layer of the endodermis is a layer of meristem cells called ________.

vascular bundle

endodermis

water

pericycle

Stem:

Vascular bundles located near _______ ______ of stem. Xylem found towards _________ of each vascular bundle & phloem towards __________. Arrangement provides _________ & _________ to withstand bending forces that stems & branches are exposed. Layer of __________ in between xylem and phloem which is a layer of __________ cells that divide to produce new xylem & phloem tissue.

outer edge

inside

outer

strength

flexibility

cambium

meristem

Leaf:

Vascular bundles form _______ and _______ of a leaf. ______________ leaves have a branching network of _______ that starting at midrib and spreading outwards. These are involved in transport and support of leaves.

midribs veins

Dicotyledonous

veins

Apoplast

space between cells

Symplast:

space inside cells

Casparian Strip

impermeable to water and mineral ions

XYLEM:

Xylems carry _______

• Thick walls lined by ___________.

• Lignin walls proofs the walls and ______________ the vessel.

• Lignin deposit in walls in spiral. __________ or reticulate.

water

lignin

strengthens

annular

Vessels are found in ______________ plants (angiosperms). Lignin tends to laid down in _______ patterns. As tissue develops, the end walls _______ _______ leaving a hollow tube.

flowering

spiral

break down

Tracheid - found in ferns, conifers, and ______________.

They are not found in _______ as this _______ how tall mosses as they can’t transport ______________ any distance.

angiosperms

mosses, limits

water

What are the xylem adaptations:

• Lignin in cell walls

• Narrow tubes

• Pits in lignified cells

• Dead cells end to make a continuous column

• Lignin in spiral, annular or reticulate patterns

• No end walls, no cell contents.

Lignin in cell walls:

strength, support, waterproofing

Narrow tubes:

Allows adhesion with walls of xylem

Pits in lignified cells:

Water can travel to other vessels.

Dead cells end to make a continuous column:

cohesion of water molecules

Lignin in spiral, annular or reticulate patterns

stems can bend without breaking

No end walls, no cell contents

No resistance to upward flow of water