Tylosis (botany)

Formation of outgrowths in plant xylem

Tylosis is a botanical term referring to the formation of outgrowths in the xylem vessels of plants. These structures are formed when parenchyma cells adjacent to the xylem vessels protrude into the vessel lumen, effectively blocking it. Tyloses are significant in the process of wood formation and are often associated with the natural aging of trees or in response to injury or infection.

Formation

Tyloses form when the parenchyma cells surrounding a xylem vessel extend through the pits in the vessel walls. This process is typically triggered by the plant's response to stress, such as drought, mechanical damage, or pathogen attack. The formation of tyloses can help prevent the spread of pathogens by blocking the xylem vessels, thus limiting the movement of water and nutrients.

Function

The primary function of tyloses is to protect the plant by isolating damaged or infected areas. By blocking the xylem vessels, tyloses can prevent the spread of fungal or bacterial infections. Additionally, they play a role in the natural aging process of trees, contributing to the heartwood formation by sealing off non-functional vessels.

Occurrence

Tyloses are commonly found in hardwood species such as oak (Quercus), walnut (Juglans), and maple (Acer). They are less common in softwoods. The presence of tyloses can affect the quality and properties of wood, influencing its use in various applications such as furniture making and construction.

Impact on Wood Properties

The presence of tyloses can enhance the durability and resistance of wood to decay, making it more suitable for outdoor use. However, they can also make wood more difficult to work with, as the blocked vessels can affect the wood's permeability and drying characteristics.

Gallery

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  Cross-section of Carpinus betulus showing tyloses.
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  Tyloses in Quercus petraea.

Related pages

• Xylem
• Heartwood
• Parenchyma

References

• Esau, K. (1965). Plant Anatomy. John Wiley & Sons.
• Beck, C.B. (2010). An Introduction to Plant Structure and Development. Cambridge University Press.

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  Tylosis in Carpinus betulus
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  Tylosis in Quercus petraea