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Growth and reproduction of Scytosiphon lomentaria (Fucophyceae) in relation to temperature in two populations from Denmark
Author(s) -
Kristiansen Aase,
Pedersen Poul Møller,
Moseholm Lars
Publication year - 1991
Publication title -
nordic journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.333
H-Index - 33
eISSN - 1756-1051
pISSN - 0107-055X
DOI - 10.1111/j.1756-1051.1991.tb01417.x
Subject(s) - sporangium , biology , thallus , botany , strain (injury) , reproduction , ecology , anatomy , spore
Two strains of Scytosiphon lomentaria from Denmark have been grown under long‐day conditions on a temperature‐gradient plate. The material from north‐west Jutland (strain No. 46) has a reduced prostrate system (a few‐celled lump) whereas the other material from the Sound (strain No. S41) has a well‐developed crust. This difference plays a significant role in growth and reproductive patterns. Strain No. 46 rapidly produces a great number of cylindrical macrothalli. Within a four‐week experimental period, formation of swarmers from plurilocular sporangia on the macrothalli takes place and results in a maximum dry weight of 32.9 mg at 18.2°C. Swarmers from the macrothalli of strain S41 always develop into knot‐filamentous or crust‐shaped thalli. The development of the macrothalli, therefore, takes a longer time than in strain 46 and the maximum dry weight is only 16.5 mg at 16°C even within an experimental period of six weeks. The reproductive pattern is more complex than in strain 46. The crusts produce unilocular sporangia at temperatures between 16°C and 23.8°C, and function, therefore, as the reproductive system during the summer as macrothalli disappear at temperatures above 18°C both in nature and in culture. Formation of plurilocular sporangia on macrothalli starts when they are from 6–9 weeks old at temperatures between 11°C and 18°C. The temperature range for growth in the two strains also differs: Strain 46 grows from 7.3–24.4°C while strain S41 grows at least from 4–5.1°C to an upper limit of 27.1°C, but lower limit has not been determined precisely in the present experiment. These results indicate that temperature ecotypes exist, even within a limited geographic area.