Difference Between Protoxylem and Metaxylem

Main Difference

The main difference between protoxylem and metaxylem is that the protoxylem is the part of the xylem structure that designed earlier, whereas the metaxylem is the part of the xylem structure designed after.

Protoxylem vs. Metaxylem

Protoxylem is the part of xylem that designed earlier, whereas the metaxylem is the part of xylem that designed later. Protoxylem contains cell wall thickenings in the form of helices or rings, whereas the metaxylem contains cell wall thickenings in the form of continuous sheets or ladder-like transverse bars. Protoxylem contains small and narrow vessels, whereas the metaxylem contains large and thick vessels. Protoxylem formed by the cell differentiation of procambium, whereas the metaxylem formed by the cell differentiation of fascicular cambium. Protoxylem gets ripe before the ripening of other plant organs, whereas the metaxylem gets ripe after the completion of the growth of the other plant organs. Protoxylem is present near to the center of the stem, whereas the metaxylem is present near to the periphery of the stem. Protoxylem is present near to the periphery of the root in vascular plants, whereas the metaxylem is present near to the center of the root. Protoxylem also contains a larger amount of parenchyma, whereas metaxylem contains a smaller amount of parenchyma. Protoxylem has tracheids which have a narrow lumen, whereas the metaxylem has tracheids which have a wide lumen. In protoxylem, tylose formation is absent, whereas in metaxylem tylose formation is present. In protoxylem, the efficiency of conduction is less efficient, whereas, in metaxylem, the efficiency of water is better. In protoxylem, the xylem fibers are absent, whereas, in metaxylem, xylem fibers are present.

Comparison Chart

ProtoxylemMetaxylem
The part of xylem that formed earlier and characterized by the presence of cell wall thickening primitive cells and narrow xylem vessels.The part of xylem that formed later and characterized by the presence of an advanced form of primitive cells broad vessels.
Differentiation
Procambium differentiates into protoxylemFascicular cambium differentiates into metaxylem
Maturation
Gets mature before the maturation of other plant organsGets mature after the maturation of plant organ
Occurrence in Stem
Present near to the center of the stemPresent near to the periphery of the stem
Occurrence in Roots
Present near to the periphery of the rootPresent near to the center of the root
Tylose Formation
It is absent in protoxylemIt is absent in metaxylem
Xylem Fibers
It is absent in protoxylemIt is present in metaxylem
Water Conduction
Less efficient in itMore efficient in it
Lysigenous Cavity
Protoxylem is involved in the formation of a lysigenous cavity in monocot stemIt is not responsible for the formation of a lysigenous cavity in monocot stem

What is Protoxylem?

Protoxylem is the part of xylem that formed earlier. It is formed from the differentiation of procambium. Protoxylem gets ripe early to the growth of other plant organs. Protoxylem contains a larger number of parenchyma cells and less amount of tracheids. Protoxylem also has the tracheids that have the narrow lumen. Protoxylem contains tracheids that have the primitive form of cell wall thickening. Protoxylem is the part of the xylem structure in which xylem is not present. The efficiency of water conduction is less efficient in protoxylem. In protoxylem, xylem fibers are absent. Protoxylem can also endanger to stress and strain. Protoxylem in the xylem is also answerable for the production of a cavity of lysigenous in the monocot plant stem. Protoxylem is present near to the periphery of the root in vascular plants. Protoxylem that is made from procambium tissues consists of spiral cell wall thickening. These are formed during the different stages of development. Proxylem also gives strength to the main plant stem. Proxylem also gives some functions to the xylem. It is also formed on the inner side of the bundles of xylem. It is the complex tissue contains both dead and living tissues. It consists of three types of cells that are tracheids, vessels, and parenchyma. The important function is the transport of minerals throughout the plant portions.

What is Metaxylem?

Metaxylem is the part of xylem that formed later. It is formed by the differentiation of fascicular cambium. Metaxylem gets ripe after the development of other plant portions. Metaxylem contains a smaller number of parenchyma cells and a large number of tracheids. Metaxylem also has tracheids that have a broad and wide lumen. Metaxylem contains tracheids that have an advanced form of cell wall thickening. Metaxylem is the part of the xylem in which the formation of tylose formation is present. The efficiency of water conduction is much better at it. Metaxylem is the part of xylem that has fibers of xylem. Metaxylem cannot endanger to stress and strain. Metaxylem is not responsible for the formation of lysigenous cavity monocot plant stem. Metaxylem is present near the center of the root in vascular plants. These are formed during the different stages of development. It also gives the strength to the main plant stem. It also has some important functions of the xylem. It is also made on the inner side of bundles of bundles of xylem. It is the complex tissue contains both dead and living tissues. It consists of three different types of cells that are tracheids, vessels, and parenchyma. The main function is the transport of water and minerals.

Key Differences

  1. Protoxylem is the part of xylem that is formed earlier, whereas the part of xylem that is formed later.
  2. Protoxylem has no xylem fibers, whereas the metaxylem has xylem fibers.
  3. Protoxylem is less efficient in conduction of water conversely metaxylem is more efficient in conduction of water.
  4. Protoxylem gets mature before the maturation pf other plant organs conversely metaxylem gets mature after the maturation of other plant organs.
  5. Protoxylem has a large number of parenchyma cells, whereas the metaxylem has a small number of parenchyma cells.
  6. Protoxylem has narrow tracheids lumen, whereas the metaxylem has broad and wide lumen.
  7. Protoxylem differentiates from the procambium, whereas the metaxylem differentiates from the fascicular cambium.

Conclusion

The above discussion concludes that protoxylem and metaxylem both are the parts of xylem. Protoxylem is the part of xylem that is formed earlier and has tracheids of the narrow lumen, whereas the metaxylem is the part of xylem that is formed later and has tracheid of the wide lumen.

Janet White

Janet White is a writer and blogger for Difference Wiki since 2015. She has a master's degree in science and medical journalism from Boston University. Apart from work, she enjoys exercising, reading, and spending time with her friends and family. Connect with her on Twitter @Janet__White

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