PRINGSHEIM, NATHANAEL

born Nov. 30, 1823, Wziesko, Silesia died Oct. 6, 1894, Berlin, Ger. botanist whose contributions to the study of algae made him one of the founders of the science of algology. Pringsheim studied at various universities, including the University of Berlin, from which he received the Ph.D. in 1848. He then taught briefly at the universities of Jena and Berlin but preferred to spend his time doing research in his private laboratory in Berlin. Pringsheim's most important work concerned reproduction in the algae. In 1855 he confirmed the occurrence of sexuality in this group of plants when he observed fertilization in the freshwater alga Vaucheria. His observations and conclusions were published in the first issue of the botanical journal Jahrbcher fr wissenschaftliche Botanik ("Annals of Scientific Botany"), which he founded in 1858 and edited until his death. In 1860 he demonstrated a similarity between the life history of freshwater algae and that of mosses. Nine years later he discovered what he considered to be the most primitive form of sexual reproduction in plants, the conjugation of zoospores in the colonial flagellated alga Pandorina. Pringsheim's observation of the formation of plant cells provided support for the belief, opposed by the German botanist Matthias Jakob Schleiden, that cells arise only by division of pre-existing cells. In 1868 Pringsheim and the botanist Julius von Sachs were the first scientists to describe the specialized bodies in the cell cytoplasm called plastids. Pringsheim also was the first to demonstrate a case of apospory, sometimes called apomixy (the production of a sexual generation from an asexual generation without the intervention of spores), in the Thallophyta (e.g., algae, fungi). By 1875 his attention had turned completely to plant physiology, and four years later he published a paper on the effects of light on chlorophyll, the green colouring matter of plants. Because Pringsheim was known as a morphologist, however, many of his views on physiology were not accepted or validated by other botanists.