xyelm and phloem

Why do plants need a transport system?

-SA:V

-metabolic rate

-plants have a small SA:V ratio, which means they have a longer diffusion distance. This means diffusion will be too slow to meet their metabolic demands.

-have a high metabolic rate so their cells need a constant supply of glucose and oxygen for respiration

name of plant transport system

what does it consist of and their function (2)

-vascular system

-xylem→transport water and minerals up the plant from the roots to the leaves

phloem→transports assimilates both up and down the plant

what do germinating seeds contain?

herbaceous dicotyledonous plant?

contain an embryonic leaf called a cotyledon

plants that produce seeds that contain two cotyledons and do not have a woody stem

[check freesciencelesson #1]

where do we find vascular tissue in the plant? (3)

-roots
-stem
-leaf

-describe the structure and function of the vascular system in the roots

-what surrounds vascular bundle?

-the xylem vessels are arranged in an x-shape in the center, surrounded by phloem.This provides support as the root grows through soil. It provides resistance against force.

-endodermis

describe the structure and function of the vascular system in the stem

→ arrangement

→ layer

(where are xylem and phloem located)

-the vascular bundles are arranged in a ring around the edge of the stem. (Xylem is on the inside of bundle and phloem is on the outside). This arrangement provides support and helps reduce bending due to wind.

-the vascular cambium is found between the xylem and phloem which contains meristem cells. They divide to produce new xylem and phloem.

describe the structure and function of the vascular system in the leaves

(where are xylem and phloem located)

-the xylem and phloem forms the midrib and a network of veins of a leaf.(xylem is on the upper side of vascular bunder and phloem is on the lower side) This provides support for thin leaves.

what are xylems?

how are xylems adapted for their function?

-long continuous tubes made from dead cells joined end to end

-have no end walls→so water can flow easily

-cell walls are strengthened with lignin→ helps support the walls

-contain pits→allow water to move between vessels

how is lignin arranged and how what does this allow?

is arranged in spiral or rings to allow flexibility and prevents stem from collapsing

what are phloems?

what are phloem made up of?

how are phloems adapted for their function?

-long tubes made from living cells joined end to end

-sieve tube elements and companion cells.

-sieve plates->allow phloem sap to pass through

-companion cells→[have a large nucleus] have lots of mitochondria→provides energy for active transport of sugars.

-plasmodesmata→ allows flow of sugar between companion cells and sieve tube elements in the phloem