Transport in Plants

Plants need to move water and food inside their body. They do not have blood or veins like animals. Instead, plants use special vascular tissues (xylem and phloem) to transport water, minerals, and food.

This movement of materials is called transport in plants. It helps in growth, repair, and making food.

Why Plants Need Transport

Roots take in water and minerals from the soil daily. This water travels to the leaves. Leaves use it to make food during photosynthesis.

The food made in the leaves also needs to travel to the other parts. It goes to the roots, stems, fruits, and growing parts of the plant.

Without a transport system, these materials will not reach where needed. This would stop plant growth and survival.

Main Transport Tissues in Plants

Plants have two types of transport tissues: Xylem and Phloem.

Xylem

Xylem carries water and dissolved minerals from roots to leaves. This movement goes only in one direction – upward.

It is mainly made of tracheids and vessel elements (dead cells) joined end to end, along with fibres and xylem parenchyma.

Phloem

Phloem moves food made in the leaves to all other parts. It carries sugar and nutrients up or down, based on where needed.

Phloem consists of sieve tube elements with sieve plates, companion cells, phloem fibres, and phloem parenchyma. The holes in sieve plates help food move throughout the plant.

How Plants Absorb Water

Roots have tiny hairs called root hairs near their tips. These hairs increase the surface area. More surface area helps absorb more water efficiently.

There are two main ways of water absorption:

Active Absorption

Uses energy from the root cells.
Slower process, works during low transpiration.
Water moves through cells using energy-based transport.

Passive Absorption

Happens because of transpiration from the leaves.
Water gets pulled up as water evaporates.
Faster process, common during high water loss.

How Food Moves Through Plants

Food made in leaves is mainly sugar. It moves to other parts of the plant through translocation.

Translocation takes place in the phloem. Food goes to roots, stems, fruits, or new growing areas.

Plants use different ways to move materials between cells:

Diffusion

Molecules move from high to low concentration naturally.
This process does not require energy.
It is slow but works well for small substances and gases.

Facilitated Diffusion

Uses helper proteins to carry molecules across cell membranes.
Still needs no energy from the plant.
Faster than normal diffusion.

Active Transport

Moves substances from low to high concentration.
Needs energy (ATP) from the plant cells.
Helps move nutrients where they are needed most.

How Water Travels Up the Plant

Water must move against gravity, from root to leaf. Several natural forces help this movement.

Transpiration Pull – evaporation from leaves pulls water upward.
Surface tension and capillary action help water rise.
Hydrogen bonding keeps water molecules together.
Water potential gradient moves water from soil to plant tissues.

Summary

Transport in plants helps move water, minerals, and food to all parts. Water moves from roots to leaves through xylem vessels. Food made in leaves travels through phloem. Root hairs absorb water efficiently. Transpiration pull and hydrogen bonding help water move upward.