1. Transportation

The process of movement of water and nutrients throughout the plant for its survival is known as transportation.

 

 

Xylem:

Xylem is a dead, lignified tissue made of tracheids and vessels that conducts water and minerals unidirectionally from roots to the plant tips, providing mechanical support through passive transport.

 

1. Cohesion and adhesion: Cohesion (attraction between water molecules) and adhesion (attraction between water and xylem walls) together help maintain a continuous water column and enable the upward movement of water in plants.

 

2. Transpirational pull: Transpirational pull is a suction force that drives the upward movement of water from roots to leaves through xylem (ascent of sap), where transpiration creates negative pressure in the leaves that pulls a continuous water column upward due to cohesion and adhesion, thereby supplying water for photosynthesis, replacing lost water through stomata, and acting as the main force for water transport during the day.

 

 

 

 

Two pots (one with a plant and one with a stick) are covered with plastic and kept in sunlight; only the plant setup shows water droplets due to transpiration. This demonstrates that transpiration creates transpirational pull, which helps in absorption and upward movement of water and minerals in plants.

 

Imbibition:

Imbibition is the absorption of water by solid adsorbent materials (imbibants) without forming a solution, causing them to swell. It occurs due to a water potential gradient and affinity between the imbibant and the imbibed liquid (imbibate), generating imbibitional pressure.

Phloem:

Phloem is a living tissue made of sieve tubes and companion cells that transports food and organic solutes bidirectionally between leaves, storage organs, and growing parts through active transport.

 

Translocation is the movement of organic solutes through phloem, occurring downward (leaves to roots/storage) and upward (storage to growing parts).

It requires ATP, where sucrose loading creates osmotic pressure that drives movement based on the plant’s needs.

 

Translocation of solutes