Xylem tissue

Definition

Xylem tissue is a type of vascular tissue in plants responsible for the conduction of water and dissolved minerals from the roots to the rest of the plant. It also provides structural support, allowing plants to grow tall and withstand various environmental conditions. Composed mainly of tracheids and vessel elements, xylem plays a critical role in the overall physiology and functionality of vascular plants.

5 Must Know Facts For Your Next Test

1. Xylem is primarily composed of dead cells that form hollow tubes, allowing for efficient water transport under negative pressure.
2. In gymnosperms, xylem tissue lacks vessel elements and consists mainly of tracheids, which limits its water conduction efficiency compared to angiosperms.
3. The process of transpiration creates a negative pressure in the xylem, pulling water upward from the roots through cohesion and adhesion properties.
4. Xylem tissue also plays a role in storing water and nutrients, contributing to a plant's resilience during periods of drought.
5. Growth rings in woody plants are formed by layers of xylem tissue produced each year, indicating age and growth conditions.

Review Questions

• How does xylem tissue contribute to a plant's ability to grow tall and withstand environmental pressures?
  • Xylem tissue provides structural support through its rigid cell walls made from lignin, allowing plants to grow taller and access more sunlight. The hollow tubes formed by dead xylem cells facilitate efficient water transport from the roots to the leaves. This ability to efficiently move water not only supports the plant's growth but also helps it withstand various environmental stresses, such as wind and drought.
• Compare the structure and function of xylem tissue in gymnosperms versus angiosperms.
  • In gymnosperms, xylem tissue primarily consists of tracheids, which are elongated cells that provide both support and water conduction but are less efficient compared to angiosperm xylem. Angiosperms contain both tracheids and vessel elements, which are wider cells that significantly enhance water transport efficiency. This structural difference allows angiosperms to grow faster and thrive in a variety of environments compared to gymnosperms.
• Evaluate the significance of transpiration in relation to xylem function and overall plant health.
  • Transpiration is essential for maintaining the upward movement of water through xylem tissue, as it creates negative pressure that pulls water from roots to leaves. This process not only supports nutrient transport but also regulates temperature and facilitates gas exchange. A healthy transpiration rate is vital for overall plant health; inadequate transpiration can lead to reduced water availability, negatively impacting photosynthesis and growth.

Related terms

Phloem: Phloem is another type of vascular tissue that transports sugars and nutrients produced through photosynthesis from the leaves to other parts of the plant.

Vascular system: The vascular system is the network of xylem and phloem tissues in plants that facilitates the transport of water, nutrients, and food throughout the organism.

Tracheids: Tracheids are long, narrow cells within xylem that help transport water and provide structural support; they are found in all vascular plants.