Transportation in plants
Plants have slow
transport systems because of their low
energy needs. In plants the materials are
mainly transported in two pathways.
1. Food materials from the site of
production to the site of storage
that is from leaf to stem or root.
This conductive tissue is called Phloem.
The transport of this soluble product of
photosynthesis from the leaf to other
parts is called translocation.
The translocation of food and other
substances take place in the sieve tubes
with the help of adjacent companion
cells both in upward and downward
directions. The translocation in phloem
is achieved by utilizing energy
materials like sucrose is transferred in
phloem tissue using energy from ATP.
This increases the osmotic pressure of
the tissue causing water to move into it
This pressure moves the material in the
phloem to tissues which have less
pressure.
This allows the phloem to move
material according to the plants needs
For example in the spring sugar stored
in root or stem tissue would be
transported to the buds which need energy to grow
2: Water and minerals are
conducted from root to other body parts
through a specialized tissue called Xylem.
It consists of vessels and  trachieds, through which roots, stems and leaves are interconnected to
form a continuous system of water
conducting channels.
At the roots cells in contact with the soil
actively take up ions this creates a difference in the
concentration of these ions between the
root and the soil. Water therefore moves
into the root from the soil to eliminate
this difference. The effect of root
pressure in transport of water is more
important at night. During the day
when stomata are open the
transpiration pull becomes the major
driving force in the movement of water
in the xylem
