Phlorotannin concentrations

In brown algae, phlorotannins are localized in specialized bodies called physodes (Ragan 1976). Shifting the experimental approach, from chemical assays of total phlorotannin concentration to microscopic methods that describe physode transport and establish the timeframes at which phlorotannins accumulate in response to abiotic or biotic stimuli, has provided new insight into the understanding of phlorotannin production and function. It is known that physodes are derived from the endoplasmic reticulum (ER) and Golgi of the cell (Schoenwaelder and Clayton 2000). It appears that physodes are transferred across the cytosol and incorporated into the cell wall, where the phlorotannins are assumed to have a structural role and thus be involved in primary metabolism (Schoenwaelder and Clayton 2000 Arnold and Targett 2003). 

A second global-scale pattern in phlorotannin concentrations exists between brown algae in the northeast temperate Pacific and Australasia. Concentrations of phlorotannins in Australasian... 

FIGURE 8.1 Histograms of phlorotannin concentrations in northeastern Pacific and Australasian kelps and rockweeds. Data are means of values for each species taken from the literature.19-24-25-2931 33 35 37 39 41 42 78 141 150 151... 

Differences in the phlorotannin concentrations of northeastern Pacific and Australasian brown algae provide an example of how such an approach may help explain current geographic patterns of chemical defense concentrations. Concentrations of phlorotannins in temperate Pacific rockweeds and kelps appear to be higher in algae from Australasia than from the northeastern Pacific26 33 40 62... 

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