The seminal root primordia in barley and the participation of their non-meristematic cells in root construction |
| |
Authors: | Mária Luxová |
| |
Institution: | (1) Institute of Experimental Biology and Ecology, Centre of Biological and Ecological Sciences, Slovak Academy of Sciences, Dúbravská 14, 814 34 Bratislava, Czechoslovakia |
| |
Abstract: | In addition to the primary seminal primordium, the so-called secondary seminal root primordia are also initiated in a barley
embryo. The primary root primordium is developmentally most advanced. It is formed by root meristem covered with the root
cap, and by a histologically determined region with completed cell division. On germination, the restoration of growth processes
begins in this non-meristematic region of root primordium by cell elongation, with the exception of the zone adjacent to the
scutellar node, the cells of which do not elongate but continue differentiating. In the root primordia initiated later, the
zone with completed cell division is relatively shorter, in the youngest primordia the non-meristematic cells may be lacking.
The root meristem is reactivated after the primary root primordium has broken through the sheath-like coleorrhiza and emerges
from the caryopsis as the primary root. The character of root meristem indicates a reduced water content at the embryonic
development of root primordium. With progressing growth the root apex becomes thinner, the meristematic region becomes longer,
and the differences in the extent of cell division between individual cell types increase. — The primary root base is formed
of cells pre-existing in the seminal root primordium. Upon desiccation of caryopsis in maturation, and subsequent quiescent
period, their development was temporarily broken, proceeding with the onset of germination. The length of this postembryonically
non-dividing basal zone is different in individual cell types. The column of central metaxylem characteristic of the smallest
number of cell cycles, has, under the given conditions, a mean length of about 22 mm, whereas the pericycle, as the tissue
with most prolonged cell division, has a mean length of about 6 mm. In the seminal root primordia initiated later the non-dividing
areas are relatively shorter. The basal region of seminal roots thus differs in its ontogenesis from the increase which is
formed “de novo” by the action of root meristem upon seed germination. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|