首页 | 本学科首页   官方微博 | 高级检索  
     


Structure and distribution of lignin in primary and secondary cell walls of maize coleoptiles analyzed by chemical and immunological probes
Authors:G. Müse  T. Schindler  R. Bergfeld  K. Ruel  G. Jacquet  C. Lapierre  V. Speth  P. Schopfer
Affiliation:(1) Institut für Biologie II der Universität, Schänzlestrasse. 1, D-79104 Freiburg, Germany;(2) Centre de Recherches sur les Macromolécules Végétales (CERMAV-CNRS), F-38041 Grenoble, France;(3) Laboratoire de Chimie Biologique, INRA-CBAI, Institut National Agronomique, Centre de Grignon, F-78850 Thiverval-Grignon, France
Abstract:Lignin is an integral constituent of the primary cell walls of the dark-grown maize (Zea mays L.) coleoptile, a juvenile organ that is still in the developmental state of rapid cell extension. Coleoptile lignin was characterized by (i) conversion to lignothiolglycolate derivative, (ii) isolation of polymeric fragments after alkaline hydrolysis, (iii) reactivity to antibodies against dehydrogenative polymers prepared from monolignols, and (iv) identification of thioacidolysis products typical of lignins. Substantial amounts of lignin could be solubilized from the coleoptile cell walls by mild alkali treatments. Thioacidolysis analyses of cell walls from coleoptiles and various mesocotyl tissues demonstrated the presence of guaiacyl-, syringyl- and (traces of)p-hydroxyphenyl units besidesp-coumaric and ferulic acids. There are tissue-specific differences in amount and composition of lignins from different parts of the maize seedling. Electron-microscopic immunogold labeling of epitopes recognized by a specific anti-guaiacyl/syringyl antibody demonstrated the presence of lignin in all cell walls of the 4-d-old coleoptile. The primary walls of parenchyma and epidermis were more weakly labeled than the secondary wall thickenings of tracheary elements. No label was found in middle lamellae and cell corners. Lignin epitopes appeared first in the tracheary elements on day 2 and in the parenchyma on day 3 after sowing. Incubation of coleoptile segments in H2O2 increased the amount of extractable lignin and the abundance of lignin epitopes in the parenchyma cell walls. Lignin deposition was temporally and spatially correlated with the appearance of epitopes for prolinerich proteins, but not for hydroxyproline-rich proteins, in the cell walls. The lignin content of coleoptiles was increased by irradiating the seedlings with white or farred light, correlated with the inhibition of elongation growth, while growth promotion by auxin had no effect. It is concluded that wall stiffness, and thus extension growth, of the coleoptile can be controlled by lignification of the primary cell walls. Primary-wall lignin may represent part of an extended polysaccharide-polyphenol network that limits the extensibility of the cell walls.Abbreviations G, S, H guaiacyl, syringyl andp-hydroxyphenyl constituents of lignin - HRGP hydroxyproline-rich glycoprotein - LTGA lignothioglycolic acid - PRP proline-rich proteinDedicated to Professor Benno Parthier on occasion of his 65th birthdayDeceased 7 November 1996
Keywords:Coleoptile (lignin formation)  Hydrogen peroxide (lignin formation)  Hydroxyproline-rich glycoprotein (maize coleoptile)  Lignin (maize coleoptile)  Phytochrome (lignin formation)  Zea (lignin formation)
本文献已被 SpringerLink 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号