Soil CO2 efflux at timberline on Mt. Fuji

Soil CO2 effluxes were investigated at timberline on Mt. Fuji. Three study plots along a sequence of vegetation zones (dwarf, tall Japanese larch, and Veitch\u27s silver fir proceeding downward) in the vicinity of timberline were selected for the measurement of soil CO2 efflux. The results showed differences in the temperature dependence of the soil CO2 efflux among the three study plots. The highest value (Q10 = 4.4) was derived at the upper plot where the vegetation and soil formation were underdeveloped. Environmental data also showed differences among the three plots in soil temperature and soil water content. The upper study plot was exposed to higher soil temperature and lower soil moisture than the other two plots because of poor vegetation cover and underdeveloped soil formation. The total soil CO2 efflux during the snow free period from June to October was estimated for the upper, middle, and lower plots as 3.3, 3.0, and 3.7 Mg C ha-1 5 months-1. The results suggest that the amount of soil CO2 efflux does not always correspond to vegetation and soil development

Relationships between soil moisture content and root morphology of three herbs on alpine scoria desert of Mt. Fuji.

Artemisia pedunculosa, Polygonum cuspidatum and P. weyrichii are codominant species on the Hoei second crater of Mt. Fuji. The aim of this study is to describe root systems and the relationship between soil moisture and root morphology of these species. Most of the root distribution of A. pedunculosa was restricted within 20cm depth and was widely spread in the surface soil. More than 1m vertical and shorter horizontal root extension was found for the latter two species. The fine root mass per leaf area (FRMLA) of A. pedunculosa was more than 7 times and 3 times greater than these of P. weyrichii and P. cuspidatum, respectively. From the above results, A. pedunculosa depends on a large area of surface soil water, while the two Polygonum species depend on deep-layer soil water. The vertical root extension of the two Polygonum species is assumed to support their establishment on slope sites where surface soil movement is frequent and moisture content is low

Freezing tolerance in alpine plants as assessed by the FDA-staining method

We established a method employing fluorescein diacetate (FDA)-staining with a laser scan microscope for evaluation of the freezing tolerance of leaf mesophyll cells, and applied it to assessments of freezing tolerance in leaves of nine alpine plants, Arcterica nana, Cassiope lycopodioides, Diapensia lapponica, Empetrum nigrum, Loiseleuria procumbens, Phyllodoce nipponica, Rhododendron aureum, Schizocodon soldanelloides, and Vaccinium vitis-idaea, which naturally occur on Mt. Iwo (36°00′N, 138°22′W, 2760 m a.s.l.) in 2001. The results obtained with the FDA-staining method were strongly correlated with those of the electrolyte-leakage test, suggesting that this method is highly reliable. Leaf mesophyll cells in all these plants collected in early September survived after freezing at -5°C, but did not survive below -30°C. The survival ratio at subzero temperatures, ranging from -5 to -16°C, varied among the species. On the other hand, all the mesophyll cells of the plants collected in the middle of November survived freezing at -30°C. However, the survival ratio decreased after freezing at -80°C in Phyllodoce nipponica and Empetrum nigrum. Using the FDA-staining method, we were able to confirm the increase of the freezing tolerance of alpine plants from September to November. Advantages of the new method are discussed

Successional changes in mycorrhizal type in the pioneer plant communities of a subalpine volcanic desert on Mt. Fuji, Japan

Isolated island-like plant communities dominated by the perennial herb Polygonum cuspidatum are typical pioneer vegetation in the subalpine volcanic deserts of Japan. To study the relationship between mycorrhizal associations and plant community development, we conducted a survey of the mycorrhizal status of plants in subalpine island communities in a volcanic desert on Mt. Fuji. Roots of 45 native species, belonging to 23 families, were collected from island communities at 3 different successional stages: (I) pioneer communities dominated by P. cuspidatum, (II) mixed communities of herbs and grass, and (III) mixed communities of herbs and shrubs. Arbuscular mycorrhiza (AM) was the predominant mycorrhizal type in the early stages of community successions (I and II). P. cuspidatum, which had previously been reported as a non-mycorrhizal species, formed AM at the study site. In the later stage (III), 5 mycorrhizal types, AM, ecto-, ericoid, arbutoid and orchid mycorrhizal, were observed. Seven woody species had two types of mycorrhizas (AM and ectomycorrhiza). High spore densities of AM fungi were observed in the soil of the island communities, whereas few spores were observed in bare ground without vegetation cover. The average colonization levels of the AM fungi were within a wide range of 0.1 to 72%, independent of successional progress. These data show that marked increases in mycorrhizal types occur during the succession of island communities, although AM is the predominant mycorrhizal type throughout the successional process

Mycorrhizal status of alpine plant communities on Mt. Maedake Cirque in the Japan South Alps

To clarify the mycorrhizal status of alpine plants, we sampled roots of 33 species from 15 families growing on Mt. Maedake Cirque in the Japan South Alps. Ericoid mycorrhiza, ectomycorrhiza and arbuscular mycorrhiza (AM) were observed in the study site. Colonization classified as ericoid mycorrhizal was observed with Phyllodoce aleutica, Tripetaleia bracteata, Vaccinium uliginosum, Rhododendron aureum, Arcterica nana and Shortia soldanelloides f. alpina, and ectomycorrhizal colonization with Pinus pumila and Polygonum viviparum. AM plants were found in species belonging to the following families: Compositae, Geraniaceae, Ranunculaceae, Rosaceae, Gramineae, Liliaceae, Violaceae, Crassulaceae, Gentianaceae and Campanulaceae. AM was the predominant mycorrhizal type in the study site and average colonization levels of AM fungi were within a wide range of 1.2 to 76.1%. In conclusion, mycorrhizal associations were observed in most (91%) of the plant species examined under the severe climate conditions of the study site

Response of germination and seedling growth to soil particle size of three herbaceous perennials on alpine zone of Mt. Fuji

Polygonum cuspidatum, P. weyrichii and Artemisia pedunculosa are herbaceous perennials in the alpine zone on Mt. Fuji. The effect of soil particle size on seed germination and seedling growth of these species was investigated. In the experiment three different particle size soils (large particle size LPS, medium particle size MPS, and small particle size SPS) were used. The other experiment was designed under three different watering intervals (every day, every two days, and every four days). Soil particle size had a great impact on seed germination and seedling growth. The highest percentage of seeds germinated in SPS and lowest in LPS soil, irrespective of the species. In the case of A. pedunculosa there was no significant difference of seed germination between SPS and MPS soils. However, the other two species had significantly reduced percentages of seed germination with increasing soil particle size. The maximum root length of seedlings was significantly longer in LPS and MPS compared to the SPS soil group, for all species. The number of root tips was increased with decreasing soil particle size, irrespective of the species. Further, larger aboveground biomass was found in seedlings of SPS than those of LPS and MPS. A. pedunculosa showed a slightly different pattern of seed germination and seedling growth compared to the two Polygonum species. Seed germination of A. pedunculosa was comparatively independent of soil particle size, and it may have conservative water use strategy. On the other hand, seed germination of Polygonum species was highly affected by the soil particle size, and those species may adapt to the water deficit condition by taking up water from deeper soil

A new application of the SFDA-staining method to assessment of the freezing tolerance in leaves of alpine plants

For the first time, this study used 5- (6-) sulfofluorescein diacetate (SFDA), a fluorescent product in plant cells converted by esterase activity to fluorescein-5- (and 6-) sulfonic acid (FSA), to assess the freezing tolerance of leaf cells. We were able to readily distinguish living and dead cells, and detect differences in freezing tolerance among five alpine plants using the SFDA-staining method. We also compared this method with two conventional methods, the electrolyte leakage test and fluorescein diacetate (FDA) staining method. The electrolyte leakage test often over- or underestimated freezing injury. With the uninjured control samples, the FDA-staining method failed to stain all leaf cells, while the SFDA-staining method stained almost 100%. From these results, we concluded that SFDA-staining is a more convenient, accurate and reproducible method for analyses of freezing tolerance

高山帯における山岳地形と高山植物の分布―富士山・白馬岳・八ヶ岳・アポイ岳

Alpine plants are distributed on high mountain area in Japanese archipelago. Mainly, they are growing on al-pine vegetation zone. On Japanese North and South Alps, alpine zone exists higher than 2,500 m above sea level. Mt. Fuji（3,776 m）is the highest mountain, so that it has a higher zone situated above the alpine zone. On the other hand, there is a narrow alpine zone on southern part of Mt. Yatsugatake. Distribution patterns of alpine plants are discussed on each mountain in comparison with Mt. Apoi in Hokkaido, northern Japan

Microbial biomass in relation to primary succession on arctic deglaciated moraines

Microbial biomass in arctic soil was examined in relation to a primary succession on arctic deglaciated moraines in Ny-Alesund, Svalbard (79°N, 12°E). Soil samples at four study sites representing different successional stages were collected at every 1cm depth from the soil surface to 3cm depth in early August 1995. Microbial biomass was measured with a substrate-induced respiration procedure. The microbial biomass was highest at the soil surface (0-1cm depth) in all successional stages, and decreased to a negligible amount at 3cm depth. Mean microbial biomass in 0-2cm layer increased from 0.06mgCg^ soil d. w. in the youngest site to 1.03mgC g^ soil d. w. in the oldest site, which is comparable to ecosystems in warmer regions. Throughout all successional stages, there was positive high correlation between soil carbon or nitrogen content and microbial biomass

Soil respiration in a high arctic glacier foreland in Ny-Alesund, Svalbard

Soil respiration rates were measured in a successional glacier foreland in Ny-_lesund, Svalbard, and the amount of CO2 efflux during the plant-growing season was estimated using a simple regression model. Three study sites (Site 1, Site 2 and Site 3) were set up along with the primary succession in the deglaciated area of East Br_gger glacier in Ny-_lesund, Svalbard, Norway (79‹N 12‹E). Another study site, Site RB, was set up on a riverbed in the Bay River between Site 2 and Site 3. Soil respiration (SR), air temperature at 10 cm height (AT), soil surface temperature (SST) and soil temperature at 1 cm depth (ST) were measured at the four study sites with an open-airflow system using an infra-red gas analyzer from July to August, 1995. The mean soil respiration rate varied among the four sites: 6.2, 44, 63 and 3.7 mg CO2 m-2 h-1 at Site 1, Site 2, Site 3 and Site RB, respectively. These differences in the soil respiration rate among the four sites corresponded with the soil organic amount, microbial biomass, and root biomass. The soil respiration rate showed the best correlation with AT at Site 1, Site 2 and Site RB, and with ST at Site 3. The cumulative amount of CO2 efflux calculated using correlation equations obtained from the above relationships between SR and AT or ST was 5.8, 46, 69 and 3.3 g CO2 m-2 at Site 1, Site 2, Site 3 and Site RB, respectively, for two months (from July to August, 1995). These values were extremely low compared to those of warmer ecosystems, such as low-arctic tundra, temperate mixed forests, and tropical moist forests