Hopkins Marine Station Student Paper

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(full paper is archived in the Miller Library)

Title: Morphological and physiological variation in Gigartina papillata (Rhodophyta, Gigartinales)
Student Author(s): Boggs, John M.
Faculty Advisor(s): Abbott, Isabella
%E Burnett, Robin
Pages: 23
Location: Final Papers Biology 175H
Date: June 1979
Keywords: midtide forest community
Abstract: Gigartina papillata exhibits considerable morphological and physiological variation over its range of heights in its characteristic zone in the intertidal region. Female plants are the more abundant in the lower and medium regions of the zone, whereas male/steriles predominate in the highest region. Individuals of higher regions of the zone are shorter and turflike, with relatively thicker thalli at the tips and middle protions; those of lower regions are longer and more isolated. The higher plants are better adapted to resist environmental stresses such as desiccation and salinity variation, as evidenced by slower drying rates and fewer signs of death relative to plants from medium and low regions. Male/steriles from high and low regions are shown spectrophotometrically to differ in pigment composition, with the darker-appearing low plants containing more chorophyll and biliproteins. Photosynthetic rates of lower male/steriles surpass those of plants from other regions in parallel with differences in pigment content. Results on pigment content and photosynthetic rates of female plants, especially from lower regions, are difficult to interpret, possibly because of unknown physiological effects of the numerous cystocarps.