TURESSON, GöTE WILHELM

(b. Malmö, Sweden, 6 April 1892; d. Uppsala, Sweden, 30 December 1970)

plant systematics, genetics.

Turesson is remembered by botanists as a pioneer in the use of experimental methods to detect genetic differences between races of plant species that adapt them to different habitats. He coined two terms, ecotype and agamospecies, that are currently used widely by ecological geneticists and evolutionary botanists.

The son of Jöns and Sophie Nilsson Turesson, both of whom were teachers, Göte acquired his strong interest in natural history from his parents, who often took him on excursions on which they collected plants and butterflies. His international outlook on genecology began in 1912 when, at the age of twenty, he went to live with his Aunt Anna in Spokane, Washington, and enrolled in the University of Washington at Seattle. He received the B.S. in 1914 and the M.S. in 1915, in plant systematics and physiology.

Turesson then returned to Sweden and became a student at the University of Lund. He passed the examination for the doctoral candidacy in 1920 and the following year became docent in botany and genetics.

Turesson’s interest in physiological ecology began while he was a student in Washington, where he published papers on plant distribution, with special emphasis on the Douglas fir and a comprehensive biological-ecological investigation of skunk cabbage (Lysichiton camstschalcense). A second interest, begun in Washington and continued at Lund, was the culture of fungi, particularly Penicillium. This led to his expert knowledge of fungal diseases of bees.

In 1916 Turesson began his investigations of prostrate races of strand plants, designed to find out whether their distinctive growth habit is purely a physiological response or is based upon genetic differences. He found that within a single species, the common orache (Atriplex patulum), the prostrate growth habit could result from either environmental influence or the action of genes, depending upon the particular race of the species. This discovery caused Turesson to perform the extensive transplantation experiments that led to his theory of the genotypical response of the species to the habitat. This theory, published in 1922, was a milestone in the progress of botanists’ understanding of the adaptation of species to their surroundings. Based not only upon Turesson’s own research but also upon his careful review of published information, it firmly established the principle that all widespread plant species include diverse populations, each of which has genetic properties that adapt it to the climatic zone and type of soil it occupies. With his research the discipline of plant genecology, or ecological genetics, was born. With respect to both his dividing a single plant into clonal divisions and planting each division, under controlled conditions, in different habitats, and his interpreting his results after a comprehensive synthesis, Turesson was without doubt a pioneer who gave a new direction to evolutionary botany.

The first of these research efforts, published in 1922, earned Turesson the Ph.D. from the University of Lund. During the following five years he expanded his program and engaged in constant, intensive research that included collecting live plants for genecological investigations from Norway, the Faroe Islands, the Siberian Altai, Britain, the Netherlands, the United States, and Canada.

In 1927, Turesson left the University of Lund for the plant breeding station at Weibullsholm, where he directed a program of improvement, using his methods, for oats, rye, and potatoes. Four years later he returned to Lund, where he hoped to be appointed to a professorship that had become vacant. For three years he and a botanist from Uppsala, Nils Heribert-Nilsson, competed for this position. Heribert-Nilsson was finally appointed, and Turesson had to settle for the much less prestigious position at the Agricultural College of Uppsala University left vacant by his rival’s departure.

This move caused a serious interruption in Turesson’s research, since he had to build anew the necessary transplant gardens and gather another cadre of co-workers. Moreover, since he was a highly competitive and contentious person, the loss of the expected professorship was a blow from which he never fully recovered. During the subsequent years Turesson turned his attention to the genetic structure of apomictic species, those that produce seed without the sexual union of egg and pollen, by virtue of several mechanisms that eliminate reduction division (meiosis) from their life cycles. He discovered that all the principal species investigated—sheep fescue (Festuca ovina), ladies’ mantle (Alchemilia alpina), and hawkweed (Hiemcium pilosella)consist of clusters of genetically different races, or “ecotypes”, as do sexual species. This research, although it was thoroughly sound, added little to previously acquired knowledge of asexually reproducing flowering plants. For all intents and purposes, Turesson’s pioneering research was compressed into the eight years between 1919 and 1927.

In 1924, Turesson married Benedicte Lehmann, his constant companion in research, who after his death did much to further recognition of him by botanists. They had one son. Per Jördan.

Turesson was dynamic, vigorous, aggressive, and contentious. He was, moreover, deeply committed to experimentation in a discipline that had previously known only description. These traits not only made possible his pioneering in experimentation and synthesis of theory, they also were responsible for his shortcomings. Since his experiments had led him to conceive of species as clusters of “ecotypes”, or distinct races, he rejected the results of other botanists who were showing during the same period that species such as Scotch pine (Pinus sylvestris) are systems of intergrading populations, of which Turessons ecotypes represent only easily recognized modes of variation. He also actively opposed their theoretical conclusions. Although he can be honored for leading the way toward the now flourishing discipline of plant ecological genetics, he can by no means be given credit for solving its major problems.

BIBLIOGRAPHY

I. Original Works. “The Genotypical Response of the Plant Species to the Habitat”, in Hereditas, 3 (1922), 211–350; “The Species and the Variety as Ecological Units”, ibid., 100–113; “The Plant Species in Relation to Habitat and Climate. Contributions to the Knowledge of Genecological Units”, ibid., 6 (1925), 147–236; “Contributions to the Genecology of Glacial Relics,” ibid., 9 (1927), 81–101; “Zur Natur und Begrenzung der Arteinheiten,” ibid., 12 (1929), 323–333; “Studien über Festuca ovina. L. II. Chromosomenzahl und Viviparie”, ibid., 13 (1930), 177–184; “The Selective Effect of Climate upon the Plant Species”. ibid., 14 (1931), 99–152; “Studien über Festuca ovina L. III. Weitere Beiträge zur Kennlnis der Chromosomenzahlen viviparer Former”, ibid., 15 (1931), 13–16; “Die Genenzentrumtheorie und das Entwicklungszentrum der Pflanzenart”, in Kungliga fisiografiska sällskapets i Lund förhandlingar, 2 , no. 6 (1932), l– and “Variation in the Apomictic Microspecies of Alchemilla vulgaris L”., in Botaniska notiser (Lund) (1943), 413–427.

II. Secondary Literature. A. Muntzing,“ Göte Wiihelm Turesson”, in Fisiografiska sällskapets drsbok (1972), 62–70: and “Turesson. Göte Wilhelm, in Käila, Nordisk familjebok (Malmö, 1955), 483.

G. Ledyard Stebbins