Measurable Indicators of Environmental Stress in Zostera

The use of adenylates as an indicator of metabolic state in Z. marina

Photosynthetic ability


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 parameter)

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.).

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