Transport in Plant

R A T U F A T I M A H

Cambridge IGCSE Biology

How does water move through plants to get the top of tall trees?

Structure and function of xylem and phloemPathway taken by water into and through the plant

Root hairs and surface area, linked to osmosis and active transport

Transport in Plants

Why do plants need water?

• For growth and photosynthesis• To distribute organic and inorganic compounds• Cell expansion

Vascular Bundles

Xylem Phloem

• Elongated tubes in xylem called vessels

• The cell walls are thickened and impregnated with lignin

• Died cells (without nucleus and cytoplasm)

• Having supporting cells called fibres

• Conducting cells remain alive and form sieve tubes

• The cell walls are not lignified

• The cells loss their nuclei, but the cell do not die (alive).

• Having supporting cells as well as sieve tubes

Xylem and Phloem

Root

Water Uptake

• The water is absorbed by osmosis• The water enters the root hair cells

and is then passed on to cells in the root cortex.

• It enters the xylem vessels to be transported up the stem and into the leaves

• Some salts may be carried in with the water drawn up by transpiration

• Diffusion and active transport plays an important part in the uptake of salts

Transport of water through the plantLoss by evaporation through plant leavesCauses of changes in transpiration rate

Transpiration

A single irrigated corn plant growing in

Kansas can use 200 L of water during a

typical summer

Some large rainforest trees can use

nearly 1200 L of water in a single day!

The amount of water lost via transpiration can be incredibly high

Transpiration

• The loss of water vapour from plant leaves by evaporation of water at the surfaces of the mesophyll cells followed by the diffusion of water vapor through the stomata

• Water vapor can diffuse out the leaf when the stomata are open

• Water travels up the xylem vessels in the vascular bundles and the flow of water is called the transpiration stream

Movement of water through a leaf

The turgor pressure forces some water out of the cells. Hundreds stomata is enabling water vapour to diffuse

To replace the loss of water, the cell walls draws water from the nearest vein without actually going inside the cells

Rates of Transpiration

1 Light Intensity

Humidity 2

Air movements 3

Temperature 4

Structure and Function of Phloem Pathway taken by sucrose and amino acids from sources to sinks

Translocation

Translocation

• The movement of sucrose and amino acids in the

phloem, from the source to the sink

• Sources are areas where sugars and amino acids

are loaded into phloem tubes, and sinks are

known as areas where sugars and amino acids

from the sources are unloaded and used.

• Some parts of a plant can act as a source and a

sink at different times during the life of plant

• Translocation depends on living processes (cell

metabolism)

Transpiration Vs Translocation

JazakumullahThank You

“Sesungguhnya Allah SWT menyukai orang-orang yang berjuang di jalan-Nya dalam barisan yang teratur seakan-akan mereka seperti bangunan kokoh”.

(As Shaff: 4)