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Reorientation of Microfibrils and Microtubules at the Outer Epidermal Wall of Maize Coleoptiles During Auxin‐Mediated Growth
Author(s) -
Bergfeld R.,
Speth V.,
Schopfer P.
Publication year - 1988
Publication title -
botanica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 0932-8629
DOI - 10.1111/j.1438-8677.1988.tb00012.x
Subject(s) - coleoptile , auxin , microtubule , elongation , biophysics , cell wall , microfibril , epidermis (zoology) , microbiology and biotechnology , biology , chemistry , botany , anatomy , materials science , biochemistry , composite material , cellulose , ultimate tensile strength , gene
Abstract Auxin‐mediated elongation growth of isolated subapical coleoptile segments of maize ( Zea mays L.) is controlled by the extensibility of the outer cell wall of the outer epidermis (Kutschera et al., 1987). Here we investigate the hypothesis that auxin controls the extensibility of this wall by changing the orientation of newly deposited microfibrils through a corresponding change in the orientation of cortical microtubules. On the basis of electron micrographs it is shown that cessation of growth after removal of the endogenous source of auxin is correlated with a relative increase of longitudinally orientated microfibrils and microtubules at the inner wall surface. Conversely, reinduction of growth by exogenous auxin is correlated with a relative increase of transversely orientated microfibrils and microtubules at the inner wall surface. These changes can be detected 30–60 min after the removal and addition of auxin, respectively. The functional significance of directional changes of newly desposited wall microfibrils for the control of elongation growth is discussed.