Xylem Tissue

Question 1

What is the xylem differentiated into?

Answer 1

A number of cell types but main type involved in water and ion transport is the xylem vessel

Question 2

What are the xylem vessels specilsed for?

Answer 2

Highly specialised for transport

Question 3

Describe xylem vessels

Answer 3

No end walls
No cell contents
And are dead when fully formed

Question 4

What does a column of vessels form?

Answer 4

Produces a long continuous tube up the plant, ideal for transport

Question 5

What happens to the cell walls

Answer 5

Secondary cell walls are specially thickened with lignin which is an impermeable substance

Question 6

What xylem firsts forms?

Answer 6

Protoxylem

Question 7

Where does protoxylem form

Answer 7

In region of ELONGATION behind root tip

Question 8

What jockeying does protoxylem have?

Answer 8

ANULAR or SPIRAL

Discrete loops or continuous spiral

Question 9

Why is ligngin laid down like this in protoxylem?

Answer 9

Does not restrict the elongation of the xylem vessels as growth of root tip takes place

Question 10

What are xylem vessels in more mature parts?

Answer 10

Metaxylem

Question 11

What do metaxylem often have?

Answer 11

More complete covering of lignin

Question 12

What patterns of lignin in metaxylem are there?

Answer 12

RETICULATE or PITTED pattern

Question 13

What I’m pitted pattern

Answer 13

Almost complete covering with pits that allows the SIDEWAYS movement of theatre between ADJACENT vessels and surrounding cells

Question 14

What are the properties of lignin?

Answer 14

1-Provides great strength that prevent the vessels from collapsing when under pressure exerted by the transpiration stream sucking water up the plant
1b- also important in providing structural support for plant
2- it is water proof which prevent leakage of water

Question 15

Where are new xylem CELLS produced?

Answer 15

A Meristematic region (the Cambium) (constantly undergoing division) between xylem and phloem

Question 16

What does that combine thig result it’s?

Answer 16

In root the protoxylem is pushed to the outer edge of the stele as the metaxylem forms behind it

Question 17

Protoxylem vs metaxylem

Answer 17

Protoxylem are normally smaller and less thicker walls

Question 18

Fun fact

Answer 18

Protoxylem and metaxylem can often occurs together

Question 19

Where do xylem vessels run form and to

Answer 19

Run from root of plant rigt up through the stem and branch out into each leaf

Question 20

Why do xylem vessels contain no nucleus or cytoplasm?

Answer 20

Nothing to obstruct flow of water

Question 21

What are the cell walls made of

Answer 21

Lignin and cellulose

Question 22

Why do xylem keep the plant upright

Answer 22

Due to the strong lignin in the cell walls

Question 23

Advantage of way lignin laid down in protoxylem

Answer 23

Does not restrict the elongation of of the xylem vessels as growth of the root tip takes place