Which of These Stores and Transports Water in Vascular Plants

Vascular plants, also known as tracheophytes, have a highly evolved system for transporting water from their roots to their leaves for photosynthesis. There are two types of vascular tissue in these plants, xylem and phloem. Xylem is primarily responsible for storing and transporting water, whereas phloem is responsible for transporting sugars and other organic compounds.

Xylem

Xylem tissue consists of a network of dead cells that form hollow tubes through which water is transported. These tubes are made up of two types of cells, tracheids and vessel elements. Tracheids are found in almost all types of vascular plants and have thin, overlapping walls that allow water to move through them. Vessel elements, on the other hand, are only found in angiosperms and some gymnosperms. They have wider openings than tracheids, which allows for faster water transport, but they are also more prone to damage.

Xylem tissue is also responsible for providing structural support to the plant. The walls of these cells are reinforced with lignin, which gives them the strength they need to resist the force of gravity and keep the plant upright. In addition, the movement of water through the xylem creates a suction force that helps to pull water up from the roots to the leaves.

Phloem

Phloem tissue is made up of living cells that are responsible for transporting sugars and other organic compounds throughout the plant. These cells are known as sieve-tube members and are connected end-to-end to form long tubes. In addition to sieve-tube members, phloem tissue also contains companion cells, which provide metabolic support to the sieve-tube members.

The movement of sugars and other organic compounds through the phloem is driven by pressure gradients. Sugars are actively transported into the sieve-tube members from photosynthetic cells in the leaves, which creates a high concentration of sugars in the phloem. This high concentration then creates a pressure gradient that drives the movement of sugars to other parts of the plant, such as the roots or developing flowers.

Conclusion

In conclusion, while both xylem and phloem are important for the overall health and survival of vascular plants, it is the xylem tissue that is primarily responsible for storing and transporting water. Without the xylem, these plants would not be able to absorb the water and nutrients they need to survive. However, the phloem is also an important tissue that enables these plants to transport sugars and other organic compounds to the parts of the plant where they are needed most.