Here's a breakdown of each:
Xylem:
* Function: Transports water and dissolved minerals upwards from the roots to the rest of the plant.
* Structure: Composed of dead cells with thickened cell walls. These cells are arranged in tubes, allowing for efficient water flow.
* Types of cells: Tracheids (long, narrow cells with pits) and vessel elements (wider, shorter cells with perforations).
Phloem:
* Function: Transports sugars produced in the leaves (photosynthesis) throughout the plant to areas where they are needed for growth and energy.
* Structure: Composed of living cells that are connected by sieve plates. These plates allow for the passage of sugars and other nutrients.
* Types of cells: Sieve-tube elements (cells with perforated walls) and companion cells (living cells that provide support to the sieve-tube elements).
Other advantages of vascular plants due to xylem and phloem:
* Greater height: Allows for taller growth, reaching sunlight and escaping competition.
* More complex structures: Allows for development of leaves, roots, and stems, leading to increased efficiency in photosynthesis, water absorption, and support.
* Adaptability to diverse environments: Enables vascular plants to thrive in a wider range of habitats, including drier and more challenging environments.
These specialized tissues are what allowed vascular plants to dominate the terrestrial environment and are a key feature distinguishing them from non-vascular plants like mosses and liverworts.
