Takayoshi Koike
Hokkaido University, Department of Forest Science, Faculty Member
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Serpentine soils are characterized by the presence of heavy metals (Ni and Cr) and excess Mg; these elements often suppress plant growth. Picea glehnii is nevertheless distributed widely on serpentine soils in northern Japan. Growth... more
Serpentine soils are characterized by the presence of heavy metals (Ni and Cr) and excess Mg; these elements often suppress plant growth. Picea glehnii is nevertheless distributed widely on serpentine soils in northern Japan. Growth characteristics were compared among P. glehnii, Picea jezoensis (distributed in the same region) and Picea abies (planted for timber production), and concentrations of elements in various tissues over time and the amount of ectomycorrhizal infection in short roots were evaluated. Seedlings of three spruce species were planted in two types of experimental plots, comprising serpentine soil and brown forest (non-serpentine) soil, and these seedlings were grown for 3 years. Growth, ectomycorrhizal infection of short roots, and elemental composition of tissues were examined. The total dry mass of P. glehnii planted on serpentine soil was almost the same as on brown forest soil, and a large number of needles survived to reach later age classes. By contrast, gr...
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The effect of ectomycorrhizal Pisolithus tinctorius (Pt) infection was studied on the growth and photosynthetic characteristics of Pinus densiflora seedlings grown at ambient (360 µmol mol−1, AC) and elevated (720 µmol mol−1, EC) CO2... more
The effect of ectomycorrhizal Pisolithus tinctorius (Pt) infection was studied on the growth and photosynthetic characteristics of Pinus densiflora seedlings grown at ambient (360 µmol mol−1, AC) and elevated (720 µmol mol−1, EC) CO2 concentrations. After 18 weeks, Pt inoculation had led to significantly increased dry mass and stem diameter of P. densiflora at both CO2 concentrations, relative to non-inoculated seedlings. Moreover, EC significantly increased the ectomycorrhizal development. The phosphate content in needles inoculated with Pt was about three times higher than without inoculation at both CO2 concentrations. The PAR saturated net photosynthetic rates (P sat) of P. densiflora inoculated with Pt were clearly higher than for control seedlings at both CO2 concentrations, and the maximum net photosynthetic rate (P N) at saturated CO2 concentration (P max) was higher than in controls. Moreover, the carboxylation efficiency (CE) and RuBP regeneration rate of the P N/C i curve...
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Abstract The temperature coefficient, Q10 (fractional change in rate with a 10°C increase in temperature) describes the temperature sensitivity of soils, roots, and stems, as well as their possible performance in global warming processes.... more
Abstract The temperature coefficient, Q10 (fractional change in rate with a 10°C increase in temperature) describes the temperature sensitivity of soils, roots, and stems, as well as their possible performance in global warming processes. It is also a necessary parameter for the ...
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Research Interests: Climate Change, China, Carbon Cycle, Multidisciplinary, Forest Conservation, and 15 moreForests, Soils, Sol, Soil organic matter, Soil Carbon, Climatic Change, Soil Temperature, Chine, Carbon dynamics, Carbon Budget, Linear Regression, Clearcutting, Temperature Sensitive Polymer, Soil microbial biomass, and Root biomass
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We evaluated the effects of elevated carbon dioxide concentration ([CO2]) and two nutrient regimes on stem growth rate, annual ring structure and temporal variations in photosynthetic characteristics of seedlings of Japanese larch (Larix... more
We evaluated the effects of elevated carbon dioxide concentration ([CO2]) and two nutrient regimes on stem growth rate, annual ring structure and temporal variations in photosynthetic characteristics of seedlings of Japanese larch (Larix kaempferi (Lamb.) Carr.). Seedlings were grown in phytotron chambers in an ambient (360 ppm) or an elevated (720 ppm) [CO2] in two nutrient regimes for one growing season. Elevated [CO2] reduced stem height and increased stem basal diameter compared with ambient [CO2]. The effect of elevated [CO2] on growth tended to be greater at high-nutrient supply than at low-nutrient supply. Elevated [CO2] had no significant effect on ring width or the number of tracheids per radial file. There was no obvious difference in cell wall thickness or the relative area of the cell wall between seedlings grown in ambient or elevated [CO2]. Although growth in elevated [CO2] resulted in a slight increase in cell diameter, the increase had a relatively minor effect on the relative area of the cell wall. Net assimilation rate increased in response to elevated [CO2]; however, the increase in whole-crown photosynthetic rate (Total Agrowth) in seedlings in the elevated [CO2] treatment was minimal because of the smaller specific needle area and acclimation of the photosynthetic characteristics of the needles to the growth [CO2]. In conclusion, we observed no obvious enhancement in the capacity for carbon fixation in Japanese larch seedlings grown in the presence of elevated [CO2] that might be attributable to changes in stem growth. However, elevated [CO2] caused changes in the temporal pattern of stem growth and in some anatomical features of the tracheids.
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... The response of woody plants to distur-bance: Patterns of establishment and growth. p.197-217. In Pickett, STA and PSWhite.(cds.) The ecology of natural disturbance andpatch dynamics. Aca-demic Press. San Diego. ... Trees 4: 227-233.... more
... The response of woody plants to distur-bance: Patterns of establishment and growth. p.197-217. In Pickett, STA and PSWhite.(cds.) The ecology of natural disturbance andpatch dynamics. Aca-demic Press. San Diego. ... Trees 4: 227-233. Ellsworth, DS and PB Reich. 1992. ...
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... Some crops raised at high CO2 changed aspects of their growth rhythm, such as the timing of winter bud-setting or shoot development (Kimball, 1983). ... 5), in a similar manner to that in European white birch (Pettersson and McDonald,... more
... Some crops raised at high CO2 changed aspects of their growth rhythm, such as the timing of winter bud-setting or shoot development (Kimball, 1983). ... 5), in a similar manner to that in European white birch (Pettersson and McDonald, 1994). ...
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ABSTRACT To provide a more detailed description of the forest light environment useful in interpreting the growth response of herbs and tree seedlings in the forest understory, we present light measurements taken under different sky... more
ABSTRACT To provide a more detailed description of the forest light environment useful in interpreting the growth response of herbs and tree seedlings in the forest understory, we present light measurements taken under different sky conditions, seasons and spatial locations both vertically and along transects. Cloudy skies reduced the heterogeneity in both PPFD (photosynthetically-active photon flux density) and R.FR (red to far red ratio, 656-664 pm/ 726-734 nm) in shade and forest gaps. Under cloudy conditions, R:FR was relatively stable across different PPFD. The mean light intensity in some forest sites was higher under cloudy skies than under clear skies because of increased penetration of diffuse light. In areas where overcast conditions are frequent, growth of understory plants may show strong correspondence with the cloudy PPFD and R:FR conditions. Percent canopy opening was stable during the summer but daily sunfleck duration varied considerably because of the shifting solar track. Because of the presence of ground vegetation, light gradient above the forest floor is greatest from 0 to 1 m in the shade. Light environment may become dimmer with increasing heights beyond 1 m as shading from low tree branches imposes a greater influence. Across a forest transect, percent canopy opening showed marginal to five-fold increases from 0 to 1 m indicating higher PPFD on cloudy days. On clear days, plants at 1 m could experience more sunflecks of higher intensity and longer individual duration. Carbon balance of forest understory plants may vary significantly with vertical location and weather conditions.
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Though birch and alder are the common pioneer tree species which dominate in northeast Asia, little is known about the effects of the predicted increase in atmospheric CO2 concentrations ([CO2]) upon their photosynthesis in field... more
Though birch and alder are the common pioneer tree species which dominate in northeast Asia, little is known about the effects of the predicted increase in atmospheric CO2 concentrations ([CO2]) upon their photosynthesis in field conditions. To investigate this, we grew 2-year-old saplings of three Betulaceae species (Betula platyphylla var. japonica Hara, Betula maximowicziana Regel, and Alnus hirsuta Turcz) for
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Research Interests: Photosynthesis, Plant Biology, Japan, Plant, Light, and 7 moreBetula, Ozone, Seedling, Seasons, Plant Leaves, Chloroplasts, and Plant Transpiration
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The ectomycorrhizal fungi (ECM fungi) are both abundant and widespread in boreal forests. Host plant provides the assimilated carbon to the infecting ECM fungi. Many studies indicate that at most 10-30% of the assimilated carbon by the... more
The ectomycorrhizal fungi (ECM fungi) are both abundant and widespread in boreal forests. Host plant provides the assimilated carbon to the infecting ECM fungi. Many studies indicate that at most 10-30% of the assimilated carbon by the host plant photosynthesis may be used by the fungal partner for the production and sustenance of its external biomass (Smith and Read 1997). On the other hand, ECM fungi exude extracellular enzymes that are able to break down complex organic substances and consequently transmit the inorganic nutrients to their hosts. Such ECM activity results in greater plant growth under severe environmental conditions of the boreal forests (Read 1991; Chalot and Brun 1998). Tree seedlings infected with ECM can significantly improve their growth when compared with nonmycorrhizal seedlings.