structure and distribution of vascular bundles

Question 1

what is a vascular bundle

Answer 1

the tissues which transport materials around the plant consisting of the xylem and phloem which are found adjacent to each other in vascular bundles

Question 2

outline the distribution of the vascular bundle in the roots

Answer 2

• the xylem is central and start shaped with the phloem between groups of xylem cells
• this arrangement resists vertical stress and anchors plant in the soil

Question 3

outline the distribution of vascular bundles in the stem

Answer 3

• sit in a ring in the periphery of the plant with the xylem towards the centre and phloem towards the outside which gives flexible support and helps resist bending

Question 4

outline the distribution of the vascular bundle in the leaves

Answer 4

• sits in the midrib and in a network of veins giving flexible strength and resistance to tearing

Question 5

what are the two types of xylem

Answer 5

1) vessels

2) tracheid’s

Question 6

outline a tracheid

Answer 6

• occurs in ferns, conifers and flowering plants but not in mosses

Question 7

outline the structure of a vessel

Answer 7

• as lignin builds up in their walls the contents die leaving and empty space called the lumen
• as tissue develops the end walls break down leaving a long hollow tube through which water climbs straight upwards

Question 8

what is the function of the xylem

Answer 8

1) transport of water and dissolved minerals

2) provide mechanical strength and support