Premium
A QUANTITATIVE STUDY OF CELLULAR EVENTS IN THE SHOOT APICAL MERISTEM OF BRASSICA CAMPESTRIS (CRUCIFERAE) DURING TRANSITION FROM VEGETATIVE TO REPRODUCTIVE CONDITION
Author(s) -
Orr Alan R.
Publication year - 1981
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.1537-2197.1981.tb06351.x
Subject(s) - biology , meristem , botany , inflorescence , apex (geometry) , shoot , mitotic index , population , mitosis , anatomy , microbiology and biotechnology , demography , sociology
Vegetative plants were induced to flower by 16‐hr‐long days. Apical buds were collected at intervals during several developmental phases up to 63 hr. A stereologic analysis and mitotic index study was conducted on median longitudinal sections of shoot apical meristems. A rise in the mitotic index occurred between 12 and 24 hr within central, peripheral and pithrib meristem zones. Preceding the floral stage a second increase in the mitotic index was observed in peripheral and central zones, but not in the pith‐rib meristem zone. A significant rise in apical volume, cell number, height, and width began in the transitional stage and continued to the floral stage. Significant correlation coefficients were observed between these apical parameters. Relative volume and cell population of each zone remained constant from the vegetative to the reproductive stage. Volume fraction occupied by the nucleus and nucleolus remained constant within each zone during the same time period. In each zone the volume of the nucleus was significantly correlated to volume of the nucleolus. It appears a pre‐inflorescence apex, while larger, is structurally similar to a vegetative apex.