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Elongation of wood fibers combines features of diffuse and tip growth
Author(s) -
Majda Mateusz,
Kozlova Liudmila,
Banasiak Alicja,
DerbaMaceluch Marta,
Iashchishyn Igor A.,
MorozovaRoche Ludmilla A.,
Smith Richard S.,
Gorshkova Tatyana,
Mellerowicz Ewa J.
Publication year - 2021
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.17468
Subject(s) - xylem , turgor pressure , elongation , xyloglucan , tip growth , biophysics , cell wall , fiber , cellulose , microfibril , chemistry , botany , biology , materials science , composite material , ultimate tensile strength , biochemistry , pollen , pollination , pollen tube
Summary Xylem fibers are highly elongated cells that are key constituents of wood, play major physiological roles in plants, comprise an important terrestrial carbon reservoir, and thus have enormous ecological and economic importance. As they develop, from fusiform initials, their bodies remain the same length while their tips elongate and intrude into intercellular spaces. To elucidate mechanisms of tip elongation, we studied the cell wall along the length of isolated, elongating aspen xylem fibers and used computer simulations to predict the forces driving the intercellular space formation required for their growth. We found pectin matrix epitopes (JIM5, LM7) concentrated at the tips where cellulose microfibrils have transverse orientation, and xyloglucan epitopes (CCRC‐M89, CCRC‐M58) in fiber bodies where microfibrils are disordered. These features are accompanied by changes in cell wall thickness, indicating that while the cell wall elongates strictly at the tips, it is deposited all over fibers. Computer modeling revealed that the intercellular space formation needed for intrusive growth may only require targeted release of cell adhesion, which allows turgor pressure in neighboring fiber cells to ‘round’ the cells creating spaces. These characteristics show that xylem fibers’ elongation involves a distinct mechanism that combines features of both diffuse and tip growth.