Date of Award

1995

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

First Advisor

Jim Lee Chambers

Abstract

Flooding is a common natural stress occurring in wetland/bottomland forests. Submergence, total immersion, is a special case of flooding, which has received limited attention in the literature. This study provides information on the impacts of three submergence treatments on three bottomland tree species. The results indicated that submergence would inhibit shoot and root growth for the three tested species during the submergence period. However, the survival of these species under submergence conditions were different. Taxodium distichum (L.) Rich survived even after 30 days of water coverage and survival continued to be high during the recovery period. Quercus nuttallii Palmer was a moderately submergence tolerant species with most seedlings able to survive 20 days of submergence treatment. Quercus michauxii Nutt. was the least submergence tolerant species with high mortality occurring after submergence for only 20 days. During the recovery stage, the rapid resumption in root growth, and shoot growth of baldcypress was indicative of its tolerance to submergence impacts. However, the two oak species responded with inhibited growth of both shoots and roots. Physiological responses measured after de-submergence such as photosynthetic rates did not yield significant or consistent differences related to apparent submergence tolerance of these species. Two stress tolerance indices were developed to provide a quantitative means of describing the submergence tolerance for the three tested species. These indices appear to provide information consistent with cluster analysis. They also provide a quantitative ranking of stress tolerance, potentially useful in models of species change related to stress levels in the environment.

Pages

105

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