Algae Anatomy, Biochemistry, and Biotechnology

18 Algae: Anatomy, Biochemistry, and Biotechnology
FIGURE 1.25 Trichome of Arthrospira sp.
(Bar: 20 mm.)
FIGURE 1.26 Cells of Prochloron sp.
(Bar: 10 mm.)
nanoplankton and obligate symbionts within marine didemnid ascidians and holothurians, and are
mainly limited to living in tropical and subtropical marine environments, with optimal growth
temperature at about 248C. Prochlorophytes possess chlorophylls a and b similar to euglenoids
and land plants, but lack phycobilins, and this is the most significance difference between these and cyanobacteria;
other pigments are b-carotene and several xanthophylls (zeaxanthin is the principal
one). Their thylakoids, which lie free in the cytoplasm, are arranged in stacks. Prochlorophytes
FIGURE 1.27 Heterocyst (arrow) of Anabaena azollae. (Bar: 10 mm.)