The conjugating green alga Closteriun has been used as a material to teach various biological subjects in high school. We used Closterium as a material for teaching the relationship between asexual reproduction in unicellular organisms and cell division. Among three strains examined, a strain of C. moniliferum var. submoniliferum was better than two other strains as the teaching material, because its cells were large enough to observe under a dissecting microscope and the process of cell division could readily be observed with a conventional light microsope after the staining of cells in aceto-carmine solution. The mitotic index reached about 30% at the beginning of the dark period under the present culture conditions. Using cells at this stage, we could chase the process of cell division readily. Following the alignment of chromosomes at metaphase plate, anaphase segregation of sister chromosomes took place. The completion of septum formation separated the mother cell into two cells, and the chloroplast within each daughter cell began to divide. Each daughter nucleus migrated from the vicinity of the septum to the constricting site of the dividing chloroplast along the convex side of the cell. Accompanying the elongation of new cell walls, two cells were separated and each restored its symmetry. The alga, C. moniliferum var. submoniliferum was discussed for its application as teaching material showing the relationship between asexual reproduction in unicellular organisms and cell division in high school biology.

Plant identification exercises were conducted from April to December from 1997 to 2000 for students within the Science Education of the Elementary and Junior High School Teacher Training Course at Tokyo Gakugei University. Field activity included observation of plants and exercises using plant identification tables, and in laboratory activities, students practiced using both plant identification cards and computer programs. Plant illustration on the home page of “Tamagawa-net” was used for some classes. For homework, students worked on sketching plants, examining plant characteristics, and identifying species names. For “advanced” exercises, students examined plant characteristics of known species names and made individual identification tables for them as teaching materials. Finally, students evaluated the plant identification exercises. According to their feedback, many students realized that there are many different characteristics between plants that appear to be the same at a first glance. In general, the feedback from university students had much in common with the feedback from junior and senior high school students who had prior experience with plant identification exercises (Ohkawa 1989, 1999). About 20% of all students (nos. 236) who participated in the exercises had very little experience in observing nature. More than 90% of the students without prior experience felt that they would like to know more about nature. About 90% of all students participated felt that they would like to conduct plant identification exercises once they become teachers. These results indicate that the plant identification exercises within the Science Education of the Elementary and Junior High School Teacher Training Course are very effective to motivate students’ interests in nature, and environmental issues as well as for information education.