Temperature Responses of Porphyra tenera Kjellman and P. yezoensis Ueda (Bangiales, Rhodophyta) from Korea

Abstract

Temperature responses of the conchosporophytes and gametophytes of Porphyra tenera and P. yezoensis were investigated in culture. The growth of conchosporophytes and the formation of conchosporangial branches were high at in both species. The conchospore release was high at and in P. tenera and at in P. yezoensis. Conchosporophytes were tolerant at for 4 weeks in both species and tolerant up to in P. tenera and in P. yezoensis for 2 weeks. The relative growth rates (RGRs) of the gametophytes decreased as they grew. The temperature for the highest RGR of gametophytes was changed from at the 1st stage (2-4 week) to and in P. tenera and in P. yezoensis at the 3rd stage (8-10 week). The reproductive structures developed early as temperature increased. Monospores were released not only from the early stage of gametophytes at the condition above or but also from mature plants at the same time of spermatium release at lower temperature. It is apparent that P. tenera and P. yezoensis are well adapted to the temperature variation in nature for the alternation of generations and the growth and reproduction of each generation.