Related Experiment Video
Updated: Aug 10, 2026

The Use of Induced Somatic Sector Analysis (ISSA) for Studying Genes and Promoters Involved in Wood Formation and Secondary Stem Development
Published on: October 5, 2016
Canopy dynamics and the morphological development of Abies balsamea: effects of foliage age on specific leaf area and
D W Gilmore1, R S Seymour, W A Halteman
1Department of Forest Ecosystem Science, College of Natural Resources, Forestry and Agriculture, University of Maine, Orono, ME 04469-5755, USA.
Abstract:
Data were collected from two branches from each whorl of nine open-grown Abies balsamea (L.) Miller trees to test the hypothesis that specific leaf area (SLA, m(2) projected fresh leaf area kg(-1) oven-dry foliage) is constant among five foliage age classes (current-year, 1-year-old, 2-year-old, 3-year-old and 4-year-old-plus). Between-tree variation in SLA was greater than within-tree variation. Differences in SLA among the foliage age classes were small, but statistically significant, showing a trend of decreasing SLA with increasing foliage age. Using data from two previous biomass studies, we found that three different methods of calculating SLA of individual trees produced the same projected leaf area estimates. To test the hypothesis that foliage mass increases with foliage age as a result of secondary xylem or phloem development, we examined the secondary vascular development of foliage collected from five age classes and three crown sections in an open-grown A. balsamea. The number of rows of xylem cells was not constant among foliage age classes, but the differences were small and showed no consistent pattern of change with foliage age. Total number of rows of phloem cells increased, number of living rows of phloem cells decreased, and the number of rows of nonliving crushed phloem cells increased with foliage age.
More Related Videos
Related Concept Videos
Meristems and Plant Growth
Primary and Secondary Growth in Roots and Shoots
Morphogenesis
Light Acquisition
Adaptations that Reduce Water Loss
Softwoods and Hardwoods

