Caudle, Keri , Maricle, Brian .
Responses of respiration and photosynthesis to spilled oil in coastal wetland grasses.
The presence of petroleum hydrocarbon can affect plants in several ways, including toxicity to cells, disruption of plant nutrient uptake, and reduced exchange of oxygen between the plant and environment. The objective for this project was to study the effects of spilled oil on photosynthesis and respiration in several important members of the Gulf Coast plant community. Native smooth cordgrass (Spartina alterniflora), introduced reed canarygrass (Phalaris arundinacea), and introduced common reed (Phragmites australis) were exposed to 6 L m-2 oil for six weeks in greenhouse experiments. Photosynthesis and anaerobic respiration were measured following exposure to oil in sediments. Maximum photosynthesis rates were 50% higher in C4 S.alterniflora compared to C3 P. arundinacea and P. australis. However, photosynthesis was not influenced by oil in any of the three species. Root alcohol dehydrogenase (ADH) activities indicated oxygen deficiency in roots of P. arundinacea, but not in S. alterniflora or P. australis. Root ADH activities increased ten-fold in flooded P. arundinacea. By contrast, root ADH activities remained low and unchanged in flooded S. alterniflora and P. australis. Tolerance to spilled oil in soil relates to tolerance of anaerobic conditions in submerged tissues. The highly flooding-tolerant S. alterniflora and P. australis were better able to tolerate limited gas exchange in roots compared to the relatively flooding-sensitive P. arundinacea, which became oxygen stressed by the oil treatment. Therefore, oil spills could lead to opportunities for invasion by highly flood-tolerant nonnative species in coastal marshes. Understanding physiological responses to environmental stress, such as an oil spill, could lead to ecological awareness and preservation of wetland habitats.
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1 - Fort Hays State University, Department Of Biological Sciences, 600 Park St., Hays, KS, 67601-4099, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Forsyth Room/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 1:35 PM