Degree Type

Dissertation

Date of Award

1983

Degree Name

Doctor of Philosophy

Department

Forestry

Abstract

The purpose of this study was to gain a better understanding of genetic variation in growth characteristics of Alnus glutinosa (L.) Gaertn. Clones were selected from the largest and smallest individuals in one 14 and one 16 year-old plantation. The 20 selected clones plus 7 other clones of interest were propagated by softwood cuttings. Gas exchange measurements, both respiration and nitrogenase activity, of intact shoots and roots were attempted. However, due to limitations of facilities and the large number of measurements required, gas exchange measurements were foregone in favor of more detailed analysis of dry weight distribution, nitrogen fixation, and carbohydrate reserves;Rooted cuttings inoculated with Frankia were grown without combined nitrogen in pots for about 3 months. During this time, nondestructive growth data and harvest data were collected. Significant clonal variation was detected in relative growth rate of leaf area, unit leaf rate, allometric coefficient between leaf and stem growth, percent starch, dry weight, and distribution of dry weight. There was little clonal or within clone variation in percent nitrogen, indicating that nitrogen fixation coincided with growth. All measured parameters varied during the course of experiments. It was difficult, therefore, to separate pure clonal differences from developmental differences. Clonal differences in rooting and establishment probably affected subsequent growth patterns. Final dry weight was the parameter best correlated with ortet field performance. Stem diameter was better correlated than plant height with dry weight, leaf area, and total nitrogen, indicating that diameter may be a more useful measure than height. Alder tree growth was episodic and total starch contents varied widely, even from day to day. Growth and nitrogen fixation rates did not appear to be related to the carbohydrate (starch) supply.

DOI

https://doi.org/10.31274/rtd-180813-8915

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Gregory Alan Miller

Language

en

Proquest ID

AAI8407106

File Format

application/pdf

File Size

120 pages

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