Hormonal Control of Reaction Wood Formation

Author(s):  
Roni Aloni
Holzforschung ◽  
2016 ◽  
Vol 70 (3) ◽  
pp. 267-274 ◽  
Author(s):  
Tatsuya Shirai ◽  
Hiroyuki Yamamoto ◽  
Miyuki Matsuo ◽  
Mikuri Inatsugu ◽  
Masato Yoshida ◽  
...  

Abstract Ginkgo (Ginkgo biloba L.) forms thick, lignified secondary xylem in the cylindrical stem as in Pinales (commonly called conifers), although it has more phylogenetic affinity to Cycadales than to conifers. Ginkgo forms compression wood-like (CW-like) reaction wood (RW) in its inclined stem as it is the case in conifers. However, the distribution of growth stress is not yet investigated in the RW of ginkgo, and thus this tissue resulting from negative gravitropism is still waiting for closer consideration. The present study intended to fill this gap. It has been demonstrated that, indeed, ginkgo forms RW tissue on the lower side of the inclined stem, where the compressive growth stress (CGS) was generated. In the RW, the micorofibril angle in the S2 layer, the air-dried density, and the lignin content increased, whereas the cellulose content decreased. These data are quite similar to those of conifer CWs. The multiple linear regression analysis revealed that the CGS is significantly correlated by the changes in the aforementioned parameters. It can be safely concluded that the negative gravitropism of ginkgo is very similar to that of conifers.


1964 ◽  
Vol 12 (1) ◽  
pp. 24 ◽  
Author(s):  
AB Wardrop ◽  
GW Davies

The cell wall organization of tracheids of natural and chemically induced compression wood of Pinus radiata and Actinostrobus pyramidalis has been shown to be the same, and is similar to that established in previous studies of natural compression wood. In the secondary wall only two layers were present. In the second of these there was a well-developed system of helical cavities, separating ribs of cellulose. The ribs of cellulose were parallel to the direction of microfibril orientation; were complex in form; and the cellulose lamellae lay parallel with the wall surface. A well-developed wart structure was present. During the differentiation of compression wood tracheids, the intercellular spaces were formed during the phase of surface enlargement of the differentiating tracheids. At an early stage the intercellular spaces appeared to contain cytoplasmic ground substance. During the development of the layer S1 the cytoplasmic organization was similar to that of normal tracheids, the cells containing a large vacuole with a well-developed tonoplast and plasmalemma. During the development of the layer S2 the cytoplasm contained numerous small vesicles with no large vacuoles, and in many instances the plasmalemma was absent. At the conclusion of the differentiation of the cell the plasmalemma was again present and penetrated the helical cavities of the wall. Compression wood induced by 3-indoleacetic acid (IAA) alone, gibberellic acid (GA) alone, or IAA and GA in combination was identical with that formed under natural conditions. The localized lateral application of IAA to vertical stems caused conspicuous bending of the stem as well as compression wood formation.


2007 ◽  
Vol 49 (2) ◽  
pp. 131-143 ◽  
Author(s):  
Sheng Du ◽  
Fukuju Yamamoto
Keyword(s):  

2017 ◽  
Vol 63 (3) ◽  
pp. 307-312
Author(s):  
Haruna Aiso ◽  
Futoshi Ishiguri ◽  
Tatsuya Toyoizumi ◽  
Yuya Takashima ◽  
Mineaki Aizawa ◽  
...  

Holzforschung ◽  
2016 ◽  
Vol 70 (9) ◽  
pp. 801-810 ◽  
Author(s):  
Noritsugu Terashima ◽  
Chisato Ko ◽  
Yasuyuki Matsushita ◽  
Ulla Westermark

Abstract A large amount of monolignol glucosides (MLGs: p-glucocoumaryl alcohol, coniferin, syringin) are found in lignifying soft xylem near cambium and they disappear with the progress of lignification. Recently, it became a matter of debate whether those MLGs are real intermediates in lignin biosynthesis or only a storage form of monolignols outside of the main biosynthetic pathway. The latter is partly based on a misinterpretation of 14C-tracer experiments and partly on the simple generalization of the results of gene manipulation experiments concerning the flexible and complex lignification. In the present paper, it could be confirmed by the most reliable 13C-tracer method that MLGs are real intermediates in the pathway from l-phenylalanine to macromolecular lignin-polysaccharides complexes in the cell walls. This pathway via MLGs is essential for transport and programmed delivery of specific monolignols in a stable form from intracellular space to specific lignifying sites within the cell wall. The pool size of MLGs is large in most gymnosperm trees and some angiosperm species that emerged in an early stage of phylogeny, while the pool size is small in most angiosperms. This difference in pool size is reasonably understandable from the viewpoint of plant evolution, in the course of which the role of MLGs changed to meet variation in type of major cells, reaction wood formation, and postmortem lignification.


Plants ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 90
Author(s):  
Tobias ◽  
Spokevicius ◽  
McFarlane ◽  
Bossinger

Recent advances in our understanding of the molecular control of secondary cell wall (SCW) formation have shed light on molecular mechanisms that underpin domestication traits related to wood formation. One such trait is the cellulose microfibril angle (MFA), an important wood quality determinant that varies along tree developmental phases and in response to gravitational stimulus. The cytoskeleton, mainly composed of microtubules and actin filaments, collectively contribute to plant growth and development by participating in several cellular processes, including cellulose deposition. Studies in Arabidopsis have significantly aided our understanding of the roles of microtubules in xylem cell development during which correct SCW deposition and patterning are essential to provide structural support and allow for water transport. In contrast, studies relating to SCW formation in xylary elements performed in woody trees remain elusive. In combination, the data reviewed here suggest that the cytoskeleton plays important roles in determining the exact sites of cellulose deposition, overall SCW patterning and more specifically, the alignment and orientation of cellulose microfibrils. By relating the reviewed evidence to the process of wood formation, we present a model of microtubule participation in determining MFA in woody trees forming reaction wood (RW).


1986 ◽  
Vol 62 (5) ◽  
pp. 433-439 ◽  
Author(s):  
A. N. Burdett ◽  
P. A. F. Martin ◽  
H. Coates ◽  
R. Eremko

Young trees sometimes lean, or topple by pivoting about a point below the ground. Geotropic curvature in the lower part of the stem restores the leading shoot to the vertical. The resultant stem bowing reduces potential lumber recovery, and is associated with reaction wood formation. Toppling has occurred in lodgepole pine (Pinus conforta Dougl.) plantations throughout British Columbia. Generally the number of trees affected has been small; although in the southern interior of the province the majority of trees in some plantations have toppled. In areas where toppling in planted trees has occurred, naturally established lodgepole pine is relatively stable. Since planted trees are usually of the native provenance, this suggests that toppling in plantations is primarily the result of nursery and planting effects on root morphology. More normal root morphogenesis, and hence greater stability can be achieved by planting young seedlings that retain the capacity to initiate primary lateral roots. Pruning the lateral roots of older stock provides another approach. A chemical method for pruning lateral roots of container-grown lodgepole pine seedlings has been developed and adopted commercially in British Columbia and elsewhere.


Sign in / Sign up

Export Citation Format

Share Document