Mitsuru Osaki | Hokkaido University (original) (raw)

Mitsuru Osaki

Mitsuru Osaki is Professor of Research Faculty of Agriculture, Hokkaido University and Professor of Graduate School of Agriculture, Hokkaido University from 2006 to 2017. Now he is Professor Emeritus, HOKKAIDO UNIVERSITY. He was trained as a plant physiologist and soil scientist, and obtained his doctorate degree in from the Faculty of Agriculture, Hokkaido University, in Japan in 1981. He worked as Associate Scientist in Maize Unit of CIMMYT in Mexico from 1982 to 1984. Until 2006, he has been working with the Graduate School of Agriculture, Hokkaido University in Japan, to implement a research and teaching on Rhizosphere Management. He also has been carried out many collaborative researches and teaching projects on tropical land management and rehabilitation of tropical forest. Also he jointed many projects such as: 1) the Japan Society for Promotion of Science (JSPS) Core University Program on "Environmental Conservation and Land Use Management of Wetland Ecosystem in Southeast Asia" between Hokkaido University, Japan, and the Research Center for Biology (LIPI), Indonesia, from April 1997 to March 2007; 2) the Science and Technology Research Partnership for Sustainable Development (SATREPS) Project on "Wildfire and Carbon Management in Peat-Forest in Indonesia" between Hokkaido University, Japan, and the National Standardization Agency (BSN), Indonesia, founded by the Japan Science and Technology Agency (JST) and Japan International Cooperation Agency (JICA) from September 2009 to March 2014; 3) the IJ-REDD project founded by JICA in 2014; and 4) the JICA-JPS-BRG Program of the Japan International Cooperation Agency (JICA, Japan), the Japan Peatland Society (JPS, Japan) and the Peatland Restoration Agency (BRG, Indonesia) from October 2017 to March 2018. The reports, proceedings and guidebooks of these projects are available from the website of the Japan Peatland Society (JPS) as follows: https://jps.sakura.ne.jp/jspsproc/jspsproc.html.
He published 228 academic papers and 72 books, presented more than 346 papers in International Symposium, Workshop, or Forum, organized 14 International Symposium or Workshop, until now. He edited and published e-book of " Tropical Peatland Ecosystem" (Springer, 2016), " Tropical Peatland Eco-management" (Springer, 2021), and " Tropical Peatland Eco-evaluation" (Springer, 2024).
Supervisors: Dr. Akira Tanaka, Faculty of Agriculture, and Hokkaido Univerrsity

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Papers by Mitsuru Osaki

Springer eBooks, 1993

... day using a dialysis membrane. At 20 d after transplanting to the -P nutrient solution,roots,... more ... day using a dialysis membrane. At 20 d after transplanting to the -P nutrient solution,roots, stems and leaves were separated and assayed for acid phosphatase by IEF and activity staining. The secreted enzyme was purified ...

Plant and Soil, Oct 1, 1993

Springer eBooks, 1997

Phosphorus deficiency induces the synthesis of acid phosphatases in roots of lupin and other plan... more Phosphorus deficiency induces the synthesis of acid phosphatases in roots of lupin and other plant species. In this study we examined the induction of secretory acid phosphatase (S-APase) at both the molecular and cellular levels. Lupin plants had increased levels of total acid phosphatase activity within two to five days after P was withered and levels approximately doubled by 15 days. Lateral roots and not main tap roots were responsible for this increase in acid phosphatase activity. Immunoblot analysis using antibodies raised against a purified S-APase showed that the synthesis of this protein was induced as early as 2 days in the P deficient treatment and that levels dramatically increased by 15 days. In contrast, no immunoreactive polypeptide was evident from crude extracts prepared from root tissues of - P treated plants. Immunocytochemical analysis revealed that the protein was located on the surface of epidermal cells of main tap roots and in the cell walls and intercellular spaces of lateral roots and lateral roots may actively secrete S-APase as soon as it is synthesized. A cDNA clone encoding the S-APase was isolated from a cDNA library constructed from lupin roots grown without P. The clone was 2,187 bp in length and had a single open reading frame of 637 amino acid residues. The deduced amino acid sequence was identical to the N-terminal region and peptide sequences of S-APase purified from lupin roots. A hydrophobic signal peptide region consisted of 31 amino acids. The primary structure was highly homologous to iron-zinc purple acid phosphatase from Phaseolus vulgaris (76%), secretory purple acid phosphatase from Arabidopsis thaliana (71%), and two Aspergillus phosphate repressible acid phosphatases (59% and 58%).

Soil Science and Plant Nutrition, Dec 1, 1995

“Standard yield variety” and “high-yielding variety” of rice, winter wheat, maize, soybean, potat... more “Standard yield variety” and “high-yielding variety” of rice, winter wheat, maize, soybean, potato, beet, and sunflower were grown, and the relationship between root growth and absorption of nitrogen was studied. To estimate the role of root in nitrogen absorption, nitrogen absorption rate (ΔN, g N m d) was parameterized into root dry weight (RW, g m) and specific absorption rate

Engei Gakkai Zasshi, 1955

Soil Science and Plant Nutrition, Mar 1, 1997

Journal of the science of soil and manure, Japan, 2009

Biomass & Bioenergy, 2017

Japan Geoscience Union, Apr 7, 2014

Soil Science and Plant Nutrition, Sep 1, 1995

Sweet potato (Ipomoea batatas L. var. Beniazuma) plants were grown in a cold region at 4 nitrogen... more Sweet potato (Ipomoea batatas L. var. Beniazuma) plants were grown in a cold region at 4 nitrogen application rates. Results are as follows.1. Total dry weight and tuberous root dry weight decreased at a high nitrogen application rate (30 g N m). The growth at 30 N was restricted from the early growth stage and the nitrogen content was higher at 30 N. As the plant architecture at 30 N did not show a large difference compared to the low nitrogen application rate, it is assumed that the carbon metabolism of sweet potato was disturbed by the high rate of nitrogen application at which level other field crops grew well, but not by mutual shading.2. Harvest index of dry weight and nitrogen for sweet potato ranged from 0.6 to 0.7, and 0.2 to 0.5, respectively. Thus, the distribution of nitrogen to tuberous roots was lower than that of carbon (dry weight). Therefore, sweet potato has an ability to attain a high potential productivity at low nitrogen application rates because a high photosynthetic rate can be maintained due to the high distribution ratio of nitrogen to leaves compared to potato or grain crops.3. Ratio of sporamine and β-amylase to total nitrogen in tuberous roots increased with growth until 105 d after transplanting, then decreased.4. Main amino acids consisted of alanine, aspartic acid, asparagine, and glutamic acid in leaves, asparagine in stems, asparagine and glutamic acid in tuberous roots.

日本土壌肥料学会講演要旨集, Mar 20, 1994

日本土壌肥料学会講演要旨集, Jul 25, 1999

Sustainability Science, Oct 23, 2013

The distribution of carbon from current photosynthates into leaf carbohydrates pool (sugars and s... more The distribution of carbon from current photosynthates into leaf carbohydrates pool (sugars and starch, which abbreviated as carbohydrates pool) and TCA/AA pool (organic acids, free amino acids and protein, which abbreviated as TCA/AA pool) provides information about carbon (C)-nitrogen (N) interactions in relation to plant nutritional status and growth stage of the rice plant (Oryza sativa L). Currently assimilated C allocation to the TCA/AA pool was high in the vegetative stage, then decreased steadily after panicle primordia formation stage. Thus, it is hypothesized that C allocation from current photosynthesis to TCA/AA or carbohydrates pool is regulated by photoperiod or growth stage. To confirm this hypothesis, short and normal day length conditions were imposed on plants in the vegetative growth stage which resulted in only 3 days difference of panicle primordia formation between the two treatments. However, under the short day condition, the C distribution from current photosynthesis into TCA/AA pool decreased significantly compared with that under the normal day condition. Thus, it is apparent that the balance of C and N metabolism in the leaf is strictly regulated by growth stage and photoperiod, which causes the change of C/N balance as the rice plant grows, and is related to the productivity of the rice plant.

Journal of Tropical Soils, Jan 25, 2013

Our previous studies showed that the extreme high yield tropical rice (Padi Panjang) produced 3-8... more Our previous studies showed that the extreme high yield tropical rice (Padi Panjang) produced 3-8 t ha-1 without fertilizers. We also found that the rice yield did not correlate with some soil properties. We thought that it may be due to ability of root in affecting soil properties in the root zone. Therefore, we studied the extent of rice root in affecting the chemical properties of soil solution surrounding the root zone. A homemade rhizobox (14x10x12 cm) was used in this experiment. The rhizobox was vertically segmented 2 cm interval using nylon cloth that could be penetrated neither root nor mycorrhiza, but, soil solution was freely passing the cloth. Three soils of different origins (Kuin, Bunipah and Guntung Papuyu) were used. The segment in the center was sown with 20 seeds of either Padi Panjang or IR64 rice varieties. After emerging, 10 seedlings were maintained for 5 weeks. At 4 weeks after sowing, some chemical properties of the soil solution were determined. These were ammonium (NH 4 +), nitrate (NO 3-), phosphorus (P) and iron (Fe 2+) concentrations and pH, electric conductivity (EC) and oxidation reduction potential (ORP). In general, the plant root changed solution chemical properties both in-and outside the soil rhizosphere. The patterns of changes were affected by the properties of soil origins. The release of exudates and change in ORP may have been responsible for the changes soil solution chemical properties.

Journal of Tropical Soils, Apr 9, 2018

Local rice varieties are commonly grown by the farmers located in acid sulfate soil area of South... more Local rice varieties are commonly grown by the farmers located in acid sulfate soil area of South Kalimantan. In South Kalimantan, more than 100 local rice varieties can be found. In 1999, a farmer found one hill (with 5 tillers) rice plant near a canal, later called Padi Panjang. The rice had panicle length of 50 cm. The panicle length of common local rice varieties are 25 cm. Since the finding, the farmer multiplied the seed for 3 years to get a reasonable amount of seeds for nearby farmers to use. In 2004, there were 25 farmers grow the Padi Panjang by themselves. Their paddocks are widely spread out in Aluh-Aluh and Gambut districts. We take this opportunity to investigate yield variation of the Padi Panjang that may be affected by soil properties variability. Ten paddocks out of the 25 paddock were selected. At harvest time (in July-August), we measured the rice yield and collected soil sample from the 10 paddocks. We found that the soil condition in the selected paddocks were marginally suitable for growing improved rice. Without fertilizer, however, the rice yield varied from 3.21 to 8.09 Mg ha-1. We also observed that the rice yield variations associated with tillers number. We did not find any correlation between rice yields with some selected soil properties, except it was observed that the tillers number was negatively correlated with soil electrical conductivity (EC). The extreme yield of Padi Panjang might be explained the involvement of N fixing bacteria and P solubilizing bacteria, large rooting system and the ability of Padi Panjang root in modifying the rhizosphere soil.