Seasonal changes in growth and maturation of 2 year old sporophytes of Saccharina cichorioides were surveyed on the coast of Soya, northern Hokkaido, Japan, from 2008 to 2010. Sporophytes were collected and observed every 20-90 days by SCUBA. Collected samples were measured for the blade length and width, and the sorus formation rate was calculated. On the other hand, tagged samples were observed the growth and erosion (tissue loss) rate of each individuals. Sporophytes formed a new blade in early December and the blade length and width remarkably increased between December and May. Then blade length was shortened by erosion of the tip from June, and the dry weight, dry/wet weight ratio and blade substantiality (thickness) value increased until October. Sporophytes began to form sori on the blade from the middle of September. Maximum daily growth rate was 0.7 cm day^-1 between April and May, and erosion rate was 0.5 cm day^-1 between May and July. The seasonal changes of growth and maturation of S. cichorioides can be distinguished into three phases, growth phase (end of November to May), blade thickening phase (June to October), and maturation phase (from middle of September).

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We investigated the effect on growth and photosynthesis of Meristotheca papulosa (Montagne) J. Agardh using four different light emitting diodes (LEDs) and a fluorescent light. The relative growth rates under green LEDs was obtained high values, but that under blue LEDs and red LEDs were obtained low value. Under a blue LEDs condition, the thallus color changed to red more during the culture. The gross photosynthetic rate under green LEDs was showed the highest value within all light sources, whereas that under a red LEDs condition was showed low value. Thus, it was clarified that the growth and photosynthesis of M. papulosa were promoted by using green LEDs, and were inhibited by using red LEDs. For M. papulosa, green LEDs promoting growth and blue LEDs changing the color of thalli to red will be used effectively to produce more valuable products in the future.

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The aim of this study to contribute to the establishment of a prevention method of decoloration of dried Ulva prolifera thalli in the distribution. The temporal change of the color of the thalli preserved under different conditions of drying, light and temperature was examined and clarified the common features and differences. In the experiment 1, a drying agent and/or a deoxidizing agent were enclosed with 10g of the thalli and the effects of dehumidification and deoxidization were investigated. Under a light condition at 25℃, decoloration could be prevented by enclosing a drying agent 20g. In the experiment 2, the optimal quantity of drying agent and the influence of light was investigated. When more than 10 g drying agent was enclosed with 10 g of the thalli, decoloration did not occur even if exposed under a natural sunlight through sunroof for 20 days. The results indicate that it is better to enclose more than 10g drying agent in the commercial package containing 10 g of dried Ulva prolifera thalli. Moreover, it became clear that moisture in the thalli and light are the main factors of decoloration and that dehumidification is the most effective to prevent the decoloration of the thalli in the distribution.

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Collection and usage of kelps (Konbu) by the Ainu was studied on paintings (Ainu-e) portraying the manners and culture of the Ainu were created by Japanese artists who visited Ezo in middle Edo era to early Meiji era, such as Ezokoku-fuzoku-e (A portrating of the life of the Ainu in Ezo) by Teiryo Kodama (in the late 18th century), Ezoto-no-kikan (An amazing scene of Ezo Island) by Ogimaro Hatano (1760-1808), Ezofuzoku-junigatsu-byobu Rokugatsu (Scenes of the twelve months, June) and the unclear title by Byozan Hirasawa (1822-1876), and reports on cultural assets of the Ainu by Lifelong Learning Culture Department, Hokkaido Prefectural Board of Education (1984, 1985, 1986, 1989, 1993, 1995, 1999). As a result, this study revealed for the first time that the Ainu usually harvested kelps by handling wooden long rod from a small wooden boat in summer season, and especially the Ainu in Hidaka and Kushiro districts reduced kelps dried in the sun on the beach to powder and ate it, in the end of the Meiji era to the Taisho era.

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