ミクロコスムの動的構造 : 生物的・無生物的要素の相互関連について

抄録

The canes of the bamboos, two months (I), three months (II), one year (III) and three years (IV) after budding, were cut at about 60cm and 10cm in length and diameter respectively. The internodes of the canes were filled with sterile tap-water, and then set in a shaddy place of a hill on the campus of the Tohoku University. 1. In about a week after setting, Diptera larvae begun to appear in almost all of the waters of such containers. Armigeres subalbatus and Eristalis were dominant in I and II, Aedes flavopictus and Eristalis in III and A. flavopictus in IV respectively. 2. The protozoan population begun to appear in these containers in a few days after setting. These populations changed successively into others with the lapse of time. The protozoan sequences in the various bodies of water of bamboo containers are summarized as shown in schema 1. 3. The habitats of Diptera larvae are characterized by a concomitant appearance of definite Protozoa, namely the Protozoa seems to play an important part as an indicator of the larval habitats; Heteromita and Chromulina became the indicator for A. flavopictus; Polytomella and Glaucoma for Eristalis; Chlamydomonas and Cercomonas for both Eristalis and Armigeres. 4. When the glass vessels containing the bamboo juices with different concentrations were placed in the field, they were characterized by a definite sequence of the protozoan succession after bacterial contamination. In this case, there exists a noticeable relation between the protozoan appearance and the starting concentration. Namely, the bamboo juices with high concentration provided the conditions suitable for the appearance of the late seral sequence, and in low concentrations the juices changed to the media of early seral ones, through the affection of bacteria on the abiotic substances. 5. However, such relationships were recognized not only in the bamboo juice but also in the media of such raw nutrient materials as the yeast extract and peptone, and in those composed of casein hydrolyzate and tryptophane. Namely, Cercomonas and Chlamydomonas appeared in the starting concentrations of 1.0 and 0.5 per cent, and both Glaucoma and Polytomella in those of 0.1 and 0.05 per cent and Heteromita and Chromulina in those less than 0.01 per cent (Tables 1,2,4). This fact clearly means that the succession of Protozoa is determined by the bacterial decomposition of the aminoacid related to the gradual changes of its concentration, as is represented by the schema 2. 6. From the above, it is conceivable that the characteristics of the water of bamboo container was determined by the combinations of the following elements : 1) the kind of bamboo, 2) Diptera larva, 3) Protozoa, 4) Bacteria, and 5) Amino acids. Therefore, the structural aspect of the present microcosm may be given by the dynamic relation existing among these elements as is shown in the schema 3.