The vegetation and microtopography of a hilly land region were studied in the southeastern part of Gifu Prefecture, central Japan, to specify the habitat of the endemic plant Magnolia tomentosa and its community. Four types of plant community were distinguished at the second level of the TWINSPAN classification : the M. tomentosa-Alnus japonica community, the M. tomentosa-Ilex nipponica community, the Quercus serrata community and the Pinus densiflora community. The first two of these plant communities were separated from the others at the first level of the classification and were always characterized and sometimes dominated by M. tomentosa. Based on DECORANA analysis, these plant communities were presumed to have differentiated through climatic differences corresponding to differences in the vegetation zone and soil moisture of their habitats. However, they always inhabit wet sites on a particular micro-landform unit, the "channelway", which extends from the lower edge of the head of a valley.
The spatial distribution of plant communities can be used to determine their historical development. The element values (EV) calculated from the syntaxonomical table and phytogeographical element were used for the analysis : Element value=Σ(presence value P × number of species with constancy degree S), (P=0.1,0.5,1,2,3,4,5,when S=r, +, I, II, III, IV, V, respectively). The mountains Kitadake (3192m) and Shiroumadake (2933m) of the Japanese Alpine Zones were selected for comparing the geographical distribution patterns of their alpine meadow, Carici-Kobresietea bellardii. From a study of 37 phytosociological releves, both areas were classified as Kobresio-Oxytropidetum nigrescens japonicae. Syntaxonomical subunits of the community were determined as phytosociological races, which represent the geographical variation. For the association level, the EV of the northern element, including boreal and arctic elements as well as the circumpolar element, was 92.2 (80.0%) on Kitadake and 109 (89.3%) on Shiroumadake. For the race level, the EV of the northern element is 17.6 (59%) on Kitadake and 32.5 (87%) on Shiroumadake. On Kitadake, the differential species of race are derived from eastern Asia, the northern Pacific region and the Japanese lower montane regions.
To simulate the movement of water and to understand its working mechanism in the soilplant-atmosphere continuum (SPAC), studies on the distribution characteristics of resistance to water flow in the SPAC are important. The present paper discusses the spatial distribution and variability of resistance to water flow in the SPAC based on field experiments on maize and soybean at Shenyang, China, and Matsudo, Japan. Under the experimental conditions employed, the total conductive resistance to water flow from root xylem to leaf xylem (RRL) in maize and soybean plants was 85.6〜93.5% of the total resistance to water flow from soil to leaf xylem (RSL), and the total absorptive resistance for the root system (RSR) was 6.5〜14.4% of RSL. In addition, soil resistance, soil-root contact resistance, root absorptive resistance, and xylem resistance for root and stalk were 2.7〜5.0%, 0.9〜1.1%, 2.6〜8.4% and 10.1〜73.6%, and 20.0〜75.5% of RSL, respectively. Meanwhile, the rates of bulk boundary resistance (RAV) and bulk stomatal resistance (RST) for the canopy relative to the total transpiration resistance (RLA) were 51.5% and 48.5%, respectively. Aerodynamic resistance to momentum transfer, excess resistance to water vapor exchange, and leaf boundary resistance were 15.6%, 9.2%, 23.6% of RLA, respectively. Therefore, the total resistance in stomata and boundary of the leaf was about 75% of RLA. The leaf stomatal resistance shows different patterns of diurnal variation in various environmental regimes, and a significant seasonal variation in the growth period. The stomatal resistance increased along with drying of the soil, and its value for the adaxial surface was larger than that for the abaxial surface. The ratio between the two surfaces varied under different environmental conditions.
Chemical aspects of flowers pollinated by moths, especially by the Sphingidae and Noctuidae, were reviewed. Although there is a then dency among the sphingophilous flowers to posssess scents, no volatile compounds have yet been demonstrated to have the ability to attract hawkmoths. However, in noctuophilous flowers, several compounds have been identified as attractants. Methods for assaying the biological activity of volatile compounds on pollinators were reviewed. Possible improvements to the two prevailing methods, electrophysiological assay and wind-tunnel assay, were described and discussed. Evolutionary and ecological aspects of floral scents in relation to pollination and future research were discussed.