AOBPreview published online on September 21, 2005
Annals of Botany, doi:10.1093/aob/mci269
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Department of Molecular and Cellular Biology, Axelrod Building, University of Guelph, Ontario, Canada N1G 2W1
* To whom correspondence should be addressed.
• Background and Aims Seeds of carob, Chinese senna, date and fenugreek are hard due to thickened endosperm cell walls containing mannan polymers. How the radicle is able penetrate these thickened walls to complete seed germination is not clearly understood. The objective of this study was to determine if radicle emergence is related to the production of endo- • Methods Activity of endo- • Key Results The activity of endo- • Conclusions The micropylar endosperm presents a lower physical constraint to the completion of germination than the lateral endosperm, and hence its structure is predisposed to permit radicle protrusion.
Received May 26, 2005
Revised July 12, 2005
Accepted August 8, 2005
Article
The Emergence of Embryos from Hard Seeds is Related to the Structure of the Cell Walls of the Micropylar Endosperm, and not to Endo-
-mannanase Activity
J. DEREK BEWLEY, E-mail: dbewley{at}uoguelph.ca
Abstract 
-mannanase to weaken the mannan-rich cell walls of the surrounding endosperm region, and/or if the endosperm structure itself is such that it is weaker in the region through which the radicle must penetrate.-mannanase in the endosperm and embryo was measured using a gel assay during and following germination, and the structure of the endosperm in juxtaposition to the radicle, and surrounding the cotyledons was determined using fixation, sectioning and light microscopy.-mannanase, the major enzyme responsible for galactomannan cell wall weakening increased in activity only after emergence of the radicle from the seed. Thickened cell walls were present in the lateral endosperm in the hard-seeded species studied, but there was little to no thickening in the micropylar endosperm except in date seeds. In this species, a ring of thin cells was visible in the micropylar endosperm and surrounding an operculum which was pushed open by the expanding radicle to complete germination.-mannanase, lateral endosperm, micropylar endosperm, germination, hard seeded legumes, Phoenix dactylifera.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  R. Schroder, R. G. Atkinson, and R. J. Redgwell Re-interpreting the role of endo-{beta}-mannanases as mannan endotransglycosylase/hydrolases in the plant cell wall Ann. Bot., August 1, 2009; 104(2): 197 - 204. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Iglesias-Fernandez and A. Matilla After-ripening alters the gene expression pattern of oxidases involved in the ethylene and gibberellin pathways during early imbibition of Sisymbrium officinale L. seeds J. Exp. Bot., April 1, 2009; 60(6): 1645 - 1661. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Sung, D. J. Cantliffe, R. T. Nagata, and W. M. Nascimento Structural Changes in Lettuce Seed During Germination at High Temperature Altered by Genotype, Seed Maturation Temperature, and Seed Priming J. Amer. Soc. Hort. Sci., March 1, 2008; 133(2): 300 - 311. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. C. Bethke, I. G.L. Libourel, N. Aoyama, Y.-Y. Chung, D. W. Still, and R. L. Jones The Arabidopsis Aleurone Layer Responds to Nitric Oxide, Gibberellin, and Abscisic Acid and Is Sufficient and Necessary for Seed Dormancy Plant Physiology, March 1, 2007; 143(3): 1173 - 1188. [Abstract] [Full Text] [PDF]
|
|