The present study reports the effect of thiourea, I. A. A., ascorbic acid and coumarin both individually and jointly on the germination and growth of seedlings of Amaranthus spinosus Linn. Seeds of this plant are found to be negatively photoblastic. Thiourea at a concentration of 4 per cent has been found to induce germination in light to the extent of 48 per cent. The study suggests that I. A. A. and ascorbic acid although by themselves incapable in inducing germination of A. spinosus seeds in light, are effective in enhancing the capacity of thiourea for inducing germination. Specific interaction of I. A. A. and ascorbic acid in the seedling growth has been observed.
Im Jahre 1953 und 1971 untersuchten die Verfasser die immergrunen Laubwaldgesellschaften in der Simane Halbinsel. Diese Halbinsel liegt im hohen Nord der Tyugoku Region, wo sich die Kustenlinie von SW nach OSO biegt, und stoBt ins Japanische Meer vor, wo der Wintermonsun aus dem asiatischen Festland pradominiert und die Schneemasse ziemlich groB erreicht. Der warme Meeresstrom Tusima bespult die Nordseite dieser Halbinsel. Dieses sind Faktoren, die die Zusammensetzung von den immergrunen Laubwaldgesellschaften in der ostlichen Seite von derjenigen der westlichen genau kiassifizieren und den Monsun ohnedies besonders als eine Hauptursache wirken lassen. Die immergrunen Laubwaldgesellschaften auf der westlichen Seite sind 1. ein Litsea japonica Wald, 2. Abies firma-Cyclobalanopsis glauca Walder, wahrend in der ostlichen Seite, 3. Shiia sieboldii Walder, 4. Cyclobalanopsis stenophylla Walder, und 5. Shiia cuspidata Walder sind. Sie sind alle im Shiion sieboldii enthalten und mit den folgenden Assoziationen identifiziert. 1. zum Cyrtomio-Litseetum japonicae 2. zur Abies firma-Cyclobalanopsis glauca-Untereinheit vom Bladhio-Shiietum sieboldii 3. zum Bladhio-Shiietum sieboldii 4. zum Cyclobalanopsis stenophylla-Fazies vom Bladhio-Shiietum sieboldii 5. zum Symploco-Shiietum cuspidatae
Macropterous and brachypterous females of the brown plant-hopper, Nilaparvata lugens STAL, which had been obtained from a standard mass culture were kept either in pairs or in crowds on fresh or withered rice seedrings, and their progeny was reared at three densities, 1,3,and 5 individuals per tube, throughout the larval period. In comparison of the progeny of the macropterous female (A) and those of the brachypterous female (B), A<B in the mortality of the larvae when they were reared at the lowest density (the reverse was true at the highest density), A<B in the percentage of brachypterous females at the highest density, and A<B in the larval period at every density. A more detailed investigation suggested that the relative length of the successive larval stages of the progeny larvae was different in both maternal lines. The effects of rearing in crowd appeared on the percentage of brachypterous females of the progeny of the brachypterous females and on the larval period of the progeny of the macropterous females. In either of the maternal lines, rearing of adult females under poor food conditions resulted in raising of the mortality, lowering of the percentage of brachypterous females, and prolongation of the larval period in their progeny.
Epiphytic bryophytes on broad-leaved trees in Tokyo Metropolis was investigated to estimate the extent of atmospheric pollution. The investigation shows a geographical decline of epiphytic bryophytes both in luxuriance and in the number of species. The metropolitan area was divided into five zones according to the vegetation of the epiphytic bryophytes. The zones evidently show the extent of phytotoxic pollutants in the atmosphere. Sulfur dioxide is more toxic to bryophytes than any other pollutants which are monitored in the area investigated. The average concentration of sulfur dioxide corresponding to the decline of epiphytic bryophytes was estimated in each zone. It is over 0.05 ppm in zone I, 0.04-0.05 ppm in zone II, 0.02-0.04 ppm in zone III, 0.01-0.02 ppm in zone IV, and below 0.01 ppm in zone V. Epiphytic bryophytes are used practically as an indicator of atmospheric pollution, because they are very sensitive to it, frequently appear on trees in the urban area and are easy to identify in the field. It is certain that the investigation of epiphytic bryophytes provides us with very useful information about the atmospheric pollution, even if it is too slight for chemical methods.
This paper deals with the fauna, seasonal and annual occurrence of the snow-stoneflies (the stoneflies living on the snow), and the relation between the seasonal and annual occurrence of the snow-stoneflies and the environmental conditions, based on field observations in the district of Iiyama, Nagano Prefecture, in central Japan. 1. Twenty-three species belonging to five families of snow-stoneflies were collected. Most species emerged in early March when it thaws. 2. The examination for eight years of the annual occurrence of Allocapniella monticola KAWAI at Kijimadaira proved that there is a remarkable annual fluctuation of emerging individual numbers. 3. There is no relation between emerging individual numbers of Allocapniella monticola and the amount of annual snowfall. 4. The air temperature seems to have influence on the emergence of Allocapniella monticola. The air temperature was between-1 and 12℃ at the time of the collection, and was mostly between 0 and 6℃.
It is common that if food-linked territoriality is self-regulative, aggressive behaviour and spatial requirements should be quite rigid at higher population densities to be effective ; and this appears to be true for most fishes as well as birds, mammals, etc., but the reverse appears to hold for the Ayu-fish. It is assumed, therefore, that the territoriality of the fish might have played an effective part in self-regulation during the glacial ages and be a"relic"type of social structure in the inter-and post-glacial ages. For comfirming the hypothesis, the production rate of algae during the glacial ages was estimated, and the social structure of the fish living in Okinawa Island was examined. The territoriality was much more unstable in the island, the southern end of its distribution, than in the main islands of Japan. Interspecies territory between Ayu-fish and a herbivorous goby (Sicyopterus japonicus) was also investigated in Okinawa, and discussed from the evolutionary point of view.