The main components of the transport system in highly organized plants are the xylem and phloem. Xylem transports water and minerals from the roots to the rest of the plant, while phloem transports sugars produced during photosynthesis from the leaves to other parts of the plant.
Here’s a more detailed breakdown:
1. Xylem:
Function:
Primarily responsible for transporting water and dissolved minerals from the soil to the rest of the plant.
Components:
Xylem consists of specialized cells like tracheids and vessels, which are elongated, tubular cells that create a continuous pathway for water movement.
Mechanism:
Water is pulled upwards through the xylem due to the process of transpiration (water loss through leaves), creating a negative pressure that draws water from the roots.
2. Phloem:
Function:
Transports sugars and other organic compounds produced during photosynthesis from the leaves to other parts of the plant, such as roots, stems, and storage organs.
Components:
Phloem consists of sieve tubes and companion cells. Sieve tubes are elongated, interconnected cells with pores that allow for the flow of sugars. Companion cells support and regulate the function of the sieve tubes.
Mechanism:
The movement of sugars through the phloem is a process called translocation, which is driven by pressure gradients and requires active transport of sugars into the phloem.