Premium
THE SHOOT APICAL ONTOGENY OF THE PICEA ABIES SEEDLING. III. SOME AGE‐RELATED ASPECTS OF MORPHOGENESIS
Author(s) -
Romberger J. A.,
Gregory Robert A.
Publication year - 1977
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1977.tb11901.x
Subject(s) - dome (geology) , primordium , biology , shoot , ontogeny , plant stem , apical dominance , crown (dentistry) , seedling , botany , volume (thermodynamics) , morphogenesis , anatomy , horticulture , medicine , paleontology , biochemistry , genetics , physics , dentistry , quantum mechanics , gene
We have extended our previous analyses of growth in shoot apices of Picea abies seedlings. Quantification of apical dome volume changes, more detailed analysis of the subapical caulis profile, and of the vertical distance from the base of the dome to the nth primordium, all as functions of age, revealed the dynamics of various growth variables. As seedlings age from 10 to 136 days, apical dome volume increases about 30‐fold, plastochron duration declines from 31 h to about 5 h, height of primordial internodes declines from near 10 μ m, to only 3.5 μ m, and the caulis assumes a distinct neck‐and‐shoulder profile. Relative volume growth rates for the apical dome as a whole are about twice the base‐of‐dome values and decline from 36% to 21% per day as age increases to 136 days. Relative growth rates (radial, vertical, and volume) in the caulis change in a complex manner with both plant age and internode number. We also computed the total volume of tissue generated by an apical dome per day including that part invested in increased dome volume. The investment (ϕ) ratio is greater than 20% in the 10‐day dome, but declines rapidly to become negative after 136 days. The ϕ ratio controls apical dome volume and hence augurs future growth yield.