Change of germinability of seeds was studied for 24 native grasses and herbs of spring fruiting during two years of air-dry storage. No germination was found for the seeds of the following 4 species : Lamium album var. barbatum, Corydalis incisa, C. heterocarpa var. heterocarpa and Aquilegia adoxoides. From the first year results, the following six types of changes in germinability were found among the other 20 species : Conyza japonica-type, Clinopodlum confine-type, Erigeron bonariensis-type Medicago lupulina-type, Silene gallica var. quinquevulnera-type and Avena fatua-type. The Silene-type, which hardly germinate in the spring and summer in the first year, and attains the maximum germinability thereafter, was observed most frequently among the winter annuals. In the second year, the same pattern of change as of the first year was not shown for each species. The seeds with high germinability just after fruiting hardly germinated at the end of the experimental period.
Dormant one-year-old twigs were collected from the mature and young plants of a number of conifer species cultivated at Yamabe, Hokkaido, and other places during midwinter, these were artificially hardened at sub-freezing temperatures to overcome differences in site of collection and to induce maximum freezing resistance. In most of the species distributed in the sub-alpine and sub-cold zones, the leaves and the twigs resisted freezing to -70℃ or below, while most of the species distributed in the temperate zone resisted freezing to only about -30℃, and the leaves and the twigs were found to be nearly equally hardy unlike the conifers distributed in sub-alpine and sub-cold zones. Also, most of these temperate conifers were observed not to be grown in a severe cold climate in Hokkaido. Thus, in the conifers distributed in the temperate zone, winter minimal temperatures appear to be the principal factor governing their growth in severe cold climates. A marked variation in hardiness was not observed among the pines Pinus denslflora and Pinus thunbergiana from different provenances.
The distribution of variance of chlorophyll-a concentration in the Okayama estuary is applied to a minus five-third power law under the scale of less than 100 m. The spectrum of current velocity fluctuation observed simultaneously shows a trend similar to the spectrum of chlorophyll-a concentration fluctuation. The phytoplankton can be considered to be dynamically passive property within the scale under the present study. It is found that from the asumption the scale of phytoplankton patchiness agrees with chracteristic length of chlorophyll-a concentration fluctuation.
The litterfall, accumulation of soil organic matter and soil respiration were measured at different parts of a slope from the bottom to the ridge in an evergreen oak forest at Nara, central Japan, where the climax vegetation was preserved. The density of the trees and total basal area became greater toward the top of the slope, but the height and biomass of the trees were greater near the valley than on the ridge. The soil moisture content increased toward the bottom of the slope. There were no significant differences in soil temperature among the sites. The accumulation of surface litter (A_0) layer and total carbon in mineral soil increased toward the ridge, while the rates of litterfall and soil respiration decreased. It was shown that the decomposition rates of organic matter in A_0 layer and mineral soil decreased toward the top of the slope based on a simple compartment model.
About one or two hours before emergence from th cave, the bats' levels of vocalization had already risen and they flew near the roosts. Such an early awakening is probably due to endogeneous activity rhythm. A few minutes before they emerged, light sampling behavior could be seen. Accordingly, the emergence time was synchronized with the sunset time, and also correlated with the time of appearance of prey. In early spring and late autumn, the bats tended to become most active soon after sunset and secondarily active before sunrise. This activity pattern corresponded to the feeding pattern. But in summer, feeding lasted until about 2 : 00 a.m. Dispersion of the bats in early spring may reduce intraspecific competition for food. Nocturnal changes of stomach contents corresponded with quantitative and qualitative changes of insect prey collected by light trap. The staple food of the bats was Lepidoptera. The size (body length) of the prey was less than 25 mm. Though prey was very sparse in late autumn, the body fat of bats began to increase rapidly. The body weight at the onset of hibernation was heavy as their localities changed from the warm to the cool temperate zone. It was closely related to the period of hibemation.