Transportation in Plants

        

      Transportation in plants

All plants need water. Plant roots absorb

water and minerals from the soil

water absorption is mainly carried out

by root hairs

these narrow walled hairs greatly

increase the area over which water

absorption can take place.

By two pathways, water and minerals enter in the root. 

Apoplastic pathway

and Sim plastic pathway

through spaces between the cell

walls if water and minerals move from cell to

   cell  then it is known as apoplastic pathway.

In simplastic pathway the water and

minerals move across the cytoplasm and

finally reaches the xylem.

Xylem vessels are long

narrow hollow tubes containing no living

material.

The xylem transports water and soluble

mineral nutrients from the roots to

other parts of a plant.

About 95 percent of the water absorbed

is lost through the stomata present in

the leaves,

this process is known as transpiration.

The number of stomata is more

on the lower surface of leaves.

If transpiration happens throughout the

day

then there will be a great loss of water

this is controlled by the stomatal

opening and closing mechanism.

During the daytime

water enters into the guard cells along

with the potassium ions

this brings about  change in shape

of the guard cells

and the stoma opens

during the night the potassium ions and

water molecules leave the guard cells.

Thus,

the turgidity decreases

and the stoma closes

stomata also act as main sites of

gaseous exchange in plants

leaves make use of water

and the carbon dioxide for

photosynthesis.

Glucose formed during photosynthesis is

transported to the other parts of the

body through phloem cells

phloem tissue consists of less

specialized and nucleate parenchyma

cells

sieve tube cells

and companion cells.

Transport of food in phloem can be up or

down the stem to reach all parts of the

plant.

hence,

the transportation in plants is the

function of xylem and phloem cells.