The key difference between xylem and phloem is that xylem is the tissue that conducts water and minerals throughout the plant body while phloem is the tissue that conducts sugar (foods) around the plant body.
Tracheophytes are the vascular plants that contain a vascular system. The vascular system is a network of plant cells that comprised of specialized tissues and associated cells. They run longitudinally inside the plant body as separate vascular bundles or tubes. Basically, the vascular system takes care of the transportation of things around the plant body. For this purpose, there are two kinds of conducting elements or tissues namely xylem and phloem in plants. Xylem and phloem differ from each other structurally as well as functionally. Therefore, we can discuss the difference between xylem and phloem based on these two.
CONTENTS
1. Overview and Key Difference
2. What is Xylem
3. What is Phloem
4. Similarities Between Xylem and Phloem
5. Side by Side Comparison – Xylem vs Phloem in Tabular Form
6. Summary
What is Xylem?
Xylem is a tubular plant tissue that transports water and dissolved minerals from roots to other parts of the plant body. Xylem runs next to phloem in the vascular bundle, and it also runs longitudinally from roots to stems and leaves. Structurally, xylem is an assemblage of several different cell types. Moreover, after an in-depth analysis, we can see that xylem consists of the following cells; vessels, tracheids and xylem fibres and parenchyma.
Figure 01: Xylem
Tracheids are the long thin cells that have tapering ends and connected to each other in order to form a tube-like structure. On the other hand, vessel elements are the shorter and wider cells that have perforated plates in each side of the cells. Apart from vessels and tracheids, xylem parenchyma and fibres structurally support the xylem tissue. In the time of maturity, they exist as tissues that are non-living.
What is Phloem?
Phloem is the tubular plant tissue that conducts foods from photosynthetic parts of the plant to the other parts of the plant body. It facilitates bidirectional movements of foods. Structurally, it comprises three main types of cells namely sieve tube cells, companion cells and phloem parenchyma.
Figure 02: Phloem
Unlike the xylem, phloem does not have lignified cell walls, instead, all cells have soft cell walls. Furthermore, the cells are living. In the vascular bundle, phloem occurs at the outside of the vascular bundle.
What are the Similarities Between Xylem and Phloem?
- Phloem and xylem are closely associated and are usually found right next to one another.
- Also, they together make a vascular bundle.
- And, both are tubular structures.
- Furthermore, they are complex tissues.
What is the Difference Between Xylem and Phloem?
Xylem conducts water and minerals from roots to the different parts of the plant. On the other hand, phloem transports foods from leaves to other plant parts in order to survive. Hence, this is the key difference between xylem and phloem. Also, one other difference between xylem and phloem is that the xylem becomes non-living in maturity while phloem remains alive even in maturity.
Moreover, a structural difference between xylem and phloem is the nature of their wall. That is; the xylem tissues are hard-walled while phloem tissues are soft-walled in nature. In addition to that, the movement of water and minerals along the xylem is unidirectional while the movement of foods along the phloem is bidirectional. The below infographic on difference between xylem and phloem shows more differences between both.
Summary – Xylem vs Phloem
Xylem is a part of the vascular tissue that is hard-walled. On the other hand, phloem is the second part of the vascular tissue that is soft-walled. Furthermore, xylem transports water and minerals while phloem transports food and nutrients. We can consider this as the key difference between xylem and phloem. Additionally, xylem movements are unidirectional while phloem movements are bidirectional. However, both xylem and phloem are complex tissues comprising of several cell types.
Reference:
1.“Xylem.” Wikipedia, Wikimedia Foundation, 5 Nov. 2018. Available here
2.Libretexts. “25.4B: Vascular Tissue: Xylem and Phloem.” Biology LibreTexts, Libretexts, 16 July 2018. Available here
Image Courtesy:
1.”Xylem cells”By Kelvinsong – Own work, (CC BY-SA 3.0) via Commons Wikimedia
2.”Phloem cells”By Kelvinsong – Own work, (CC BY-SA 3.0) via Commons Wikimedia