Measurable Indicators of Environmental Stress in Zostera
The use of adenylates as an indicator of metabolic state
in Z. marina
The use of adenylates as an indicator of metabolic
state in Z. marina
The adenylate energy charge (AEC) regulates metabolic processes in
plants by controlling rates of enzymic reactions, and has been widely applied as an index
of sub-lethal stress. Delistraty and Hershner (1984) studied adenine nucleotide levels
(adenylates) and the adenylate energy charge in Z. marina to evaluate whether they
could be used as an indicator of the metabolic state of the plant in response to
environmental stress. It was found that adenylate and AEC responses to environmental
variation appeared to provide useful measures of the metabolic state of Z. marina
under certain conditions, but it was concluded that they posed difficulties when
attempting to evaluate the effects of a single variable.
Photosynthetic ability (Fv/Fm fluorescence kinetics
Changes in the photosynthetic ability of Zostera are a good
indicator of environmental stress. With the appropriate equipment, sublethal effects can
be measured easily and quickly in the field, using the Fv/Fm fluorescence kinetics
parameter, which measures the efficiency of the light harvesting aspect of photosynthesis.
Recently, this has successfully been used to investigate the effects of the triazine
antifouling herbicide Irgarol, on Zostera species. The technique may have
applications for investigating the effects of other herbicides, TBT, heavy metals, as well
as light stress and nutrient effects (P. Donkin, pers. comm.).