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Extramural Research

Grantee Research Project Results

Grantee Research Project Results

The Effects of Water Availability on the Morphology, Physiology, and Chemistry of the Silky Willow, Salix sericea

EPA Grant Number: U915151
Title: The Effects of Water Availability on the Morphology, Physiology, and Chemistry of the Silky Willow, Salix sericea
Investigators: Lower, Steven S.
Institution: Tufts University
EPA Project Officer: Smith, Bernice
Project Period: January 1, 1997 through January 1, 2000
Project Amount: $102,000
RFA: STAR Graduate Fellowships (1997)
Research Category: Academic Fellowships , Ecological Indicators/Assessment/Restoration , Fellowship - Ecology and Ecosystems



The objective of this research project is to investigate the effects of multiple levels of water availability on morphological, physiological, and chemical parameters in the silky willow, Salix sericea.


Salix sericea is a shrubby, wetland willow that is notable for its high production of the phenolic glycosides salicortin and 2"-cinnamoylsalicortin, which can exceed 10% percent dry weight in leaves. We created artificial water gradients in the greenhouse by elevating wooden troughs (4'' x 12" x 8") to an angle of approximately 30 degrees from the horizontal. Five cuttings per trough were planted an equal distance apart, and each trough was then watered daily from the bottom, creating an even gradient of decreasing soil water content from bottom to top. The following parameters were measured: R:S ratio, stem dry weight, leaf expansion rate, photosynthetic rate, and phenolic glycoside concentration. Generally, growth parameters were depressed when soil water content was extremely high or low, but growth was more vigorous at intermediate soil moisture. There was a marginally significant relationship (p <0.08) between soil moisture and leaf salicortin concentration. This suggests that nonlinear effects may be important in this system, and therefore deserve attention in the future.

Supplemental Keywords:

fellowship, water availability, silky willow, Salix sericea, wetland, water gradients, soil, soil water content, soil moisture.

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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