Examination of endogenous and exogenously influenced physiological patterns of post-transplant Quercus rubra seedlings
Abstract
Northern red oak (Quercus rubra L.) comprises a large portion of the seedlings planted in the Central Hardwood Forest region and constitutes a significant component of existing forest ecosystems. Members of the genus Quercus exhibit a recurrently flushing, episodic growth pattern different from and more complex than co-occurring non- Quercus species. This episodic growth pattern results in complex physiological patterns, which have been shown to vary with seedling ontogeny. For this reason, the Quercus morphological index (QMI) was developed, providing a means of identifying ontological growth stages using simple morphological measurements; it has subsequently proven useful for the description of endogenous patterns of physiological development within firstyear, pre-transplant northern red oak seedlings and for the distinction of exogenous influences from effects of these endogenous patterns. This dissertation describes a series of experiments designed to examine the validity of long-standing, yet largely untested, assumptions of the QMI and to assess post-transplant carbon allocation and physiological patterns in northern red oak seedlings as they occur endogenously and in response to exogenous factors, such as fertilization at time of transplant and environmental stresses commonly experienced by transplanted seedlings. Post-transplant physiological patterns relative to seedling ontogeny were found to resemble those of first-year, pre-transplant seedlings and to remain highly consistent across genotypes, thus supporting post-transplant use of the QMI. Post-transplant interactions between endogenous physiological patterns and flooding were demonstrated, as well as positive physiological effects of controlled release fertilizer (CRF) application at the time of transplant. Controlled release fertilizer was not found to interact with moisture availability in the present study, and post-transplant moisture stress was observed to influence seedling physiology independently of nutrient-availability effects. Patterns of observed post-transplant physiology of northern red oak seedlings resulted primarily from endogenous phenomena associated with episodic ontological development, although such patterns were demonstrably alterable by exogenous influences.
Degree
Ph.D.
Advisors
Jacobs, Purdue University.
Subject Area
Plant biology|Forestry
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