Plant ecologist studying
leaf senescence, nitrogen
use & carbon gain with
emphasis on global change issues.


Graduate School of Science and Engineering
/College of Science

Bldg. A303
Ibaraki University
Mito 310-8512

Institute for Global Change Adaptation Science
Ibaraki University
Mito 310-8512

Email Shimpei

Last update:
Aug 15, 2018

Copyright Shimpei
Oikawa © 2010
Researth interests The researches in our lab are driven by the following questions:
1. Why leaves of plant senesce and drop?: what are the evolutional significance and the ecophysiological mechanism controlling leaf phenology? (funded by JSPS and the Sasakawa Foundation)
2. How much nitrogen is resorbed during leaf senescence? How different are legume and non-legume species in this respect? Does the former use nitrogen more luxury? (funded by the NISSAY (Nippon Life Insurance) Foundation) and JSPS; and
3. How global changes influence these issues? What is their feedback to climate?
4. Which plant traits were improved and lost during crop cultivation? (funded by the Innovation Fund Project of Ibaraki University)
5. Is Japanese dodder generalist or specialist? (funded by the Fujiwara Natural History Foundation)


Ayaka Togashi, Shimpei Oikawa (2021) Leaf productivity and persistence have been improved during soybean (Glycine max) domestication and evolution. Journal of Plant Research 134: 223-233

Yui Takase, Shimpei Oikawa, Tadao Enomoto, Genki Katata, Nobuo Sakagami (2020) People's attitude towards strategies to control kudzu (Pueraria lobata (Willd.) Ohwi) during road slope revegetation. Papers on Environmental Information Science 34: 174-179 (in Japanese)

Shimpei Oikawa, Yusuke Matsui, Michio Oguro, Masanori Okanishi, Ryou Tanabe, Tomoki Tanaka, Ayaka Togashi, Tomoyuki Itagaki (2020) Species-specific nitrogen resorption proficiency in legumes and nonlegumes. Journal of Plant Research 133: 639-648

Tomoki Tanaka, Chiharu Kurokawa, Shimpei Oikawa (2018) Leaf shedding increases the photosynthetic rate of the canopy in N2-fixing and non-N2-fixing woody species. Tree Physiology 38: 1903-1911

Shimpei Oikawa, Hitomi Ehara, Mika Koyama, Tadaki Hirose, Kouki Hikosaka, Charles P. Chen, Hirofumi Nakamura, Hidemitsu Sakai, Takeshi Tokida, Yasuhiro Usui, Toshihiro Hasegawa (2017) Nitrogen resorption in senescing leaf blades of rice exposed to Free-Air CO2 Enrichment (FACE) under different N fertilization levels. Plant and Soil 418: 231-240

Shimpei Oikawa, Koya Suno, Noriyuki Osada (2017) Inconsistent intraspecific pattern in leaf life span along nitrogen-supply gradient. American Journal of Botany 104: 342-346

Shimpei Oikawa, Elizabeth A. Ainsworth (2016) Changes in leaf area, nitrogen content and canopy photosynthesis in soybean exposed to an ozone concentration gradient. Environmental Pollution 215: 347-355

Kouki Hikosaka, Niels P.R. Anten, Almaz Borjigidai, Chiho Kamiyama, Hidemitsu Sakai, Toshihiro Hasegawa, Shimpei Oikawa, Atsuhiro Iio, Makoto Watanabe, Takayoshi Koike, Kazuya Nishina, Akihiko Ito (2016) A meta-analysis of leaf nitrogen distribution within plant canopies. Annals of Botany 118: 239-247

Takahiro Ogawa, Shimpei Oikawa, Tadaki Hirose (2016) Nitrogen-utilization efficiency in rice: an analysis at leaf, shoot, and whole-plant level. Plant and Soil 404: 321-344

Kouki Hikosaka, Takehiro Sasaki, Chiho Kamiyama, Masatoshi Katabuchi, Shimpei Oikawa, Masaya Shimazaki, Hiroshi Kimura and Tohru Nakashizuka (2015) Trait-based approaches for understanding species niche, coexistence, and functional diversity in subalpine moorlands. In: Gaku Kudo (ed), Structure and Function of Mountain Ecosystems in Japan. Springer

Takahiro Ogawa, Shimpei Oikawa, Tadaki Hirose (2015) Leaf dynamics in growth and reproduction of Xanthium canadense as influenced by stand density. Annals of Botany116: 807-819

Noriyuki Osada, Shimpei Oikawa, Kaoru Kitajima (2014) Implications of lifespan variation within a leaf cohort for evaluation of the optimal timing of leaf shedding. Functional Ecology 29: 308-34

Chiho Kamiyama, Shimpei Oikawa, Kouki Hikosaka (2014) Seasonal change in light partitioning among coexisting species of different functional groups along elevation gradient in subalpine moorlands. New Phytologist 20: 913-923

Kouki Hikosaka, Takehiro Sasaki, Chiho Kamiyama, Masatoshi Katabuchi, Shimpei Oikawa, Masaya Shimazaki, Hiroshi Kimura and Tohru Nakashizuka (2014) Understanding of species niche, coexistence and extinction based on functional traits: approaches from community and physiological ecology for subalpine moorland plant communities. Chikyukankyo 19: 33-46 (In Japanese)

Shimpei Oikawa, Masumi Okada, Kouki Hikosaka (2013) Effects of elevated CO2 on leaf area dynamics in nodulating and non-nodulating soybean stands. Plant and Soil 373: 627-639

Noriyuki Osada, Shimpei Oikawa, Onno Muller, Rie Miyata (2013) Future perspectives of the study of leaf lifespan. Japanese Journal of Ecology 63: 81-83 (In Japanese)

Shimpei Oikawa, Noriyuki Osada (2013) Leaf shedding and whole-plant carbon gain. Japanese Journal of Ecology 63: 59-67 (In Japanese)

Noriyuki Osada, Shimpei Oikawa, Rie Miyata, Chiho Kamiyama, Soichiro Nagano, Satomi Shiodera, Azusa Tabata, Kiyomi Ono (2013) Patterns of within-species variation in leaf lifespan in relation to environmental factors: General trends and differences across species of different functional types. Japanese Journal of Ecology 63: 19-36 (In Japanese)

Shimpei Oikawa, Noriyuki Osada, Yoshiyuki Miyazawa, Rie Miyata, Onno Muller (2013) A brief history of leaf lifespan research. Japanese Journal of Ecology 63: 11-17 (In Japanese)

Zhu Chunwu, Weigo Chen, Hidemitsu Sakai, Shimpei Oikawa, Rebecca C Laza, Yasuhiro Usui, Toshihiro Hasegawa (2013) Effects of elevated [CO2] on stem and root lodging among rice cultivars. Chinese Science Bulletin 58: 1787-1794

Tadaki Hirose, Shimpei Oikawa (2012) Mean residence time: leaf number, area, dry mass, and nitrogen in canopy photosynthesis. Oecologia 169: 927-937

Toshihiko Kinugasa, Takashi Sato, Shimpei Oikawa, Tadaki Hirose (2011) Demand and supply of N in seed production of soybean (Glycine max) at different N fertilization levels after flowering. Journal of Plant Research 125: 275-281

Kouki Hikosaka, Shimpei Oikawa, Toshihiko Kinugasa, Yusuke Onoda, Tadaki Hirose (2011) Effects of elevated CO2 concentration on seed production in C3 annual plants. Journal of Experimental Botany 62: 1523-1530

Chiho Kamiyama, Shimpei Oikawa, Takuya Kubo, Kouki Hikosaka (2010) Light interception in species with different functional groups coexisting in moorland plant communities. Oecologia 164: 591-599

Shimpei Oikawa, Kay-May Miyagi, Kouki Hikosaka, Masumi Okada, Toshinori Matsunami, Makie Kokubun, Toshihiko Kinugasa, Tadaki Hirose (2010) Interactions between elevated CO2 and N2-fixation determine soybean yield - a test using a non-nodulated mutant. Plant and Soil 330: 163-172

Shimpei Oikawa (2008) Structure of herbaceous plant stands and canopy photosynthesis models. In: Low Temperature Science Vol. 67 (Eds. Institute of Low Temperature Science, Hokkaido University and The Japanese Association for Photosynthesis Research), pp.103-112 (In Japanese) (Erratum)

Yosuke Matsumoto, Shimpei Oikawa, Yuko Yasumura, Tadaki Hirose, Kouki Hikosaka (2008) Reproductive yield of individuals competing in a dense stand of an annual, Xanthium canadense. Oecologia 157: 185-195

Shimpei Oikawa, Kouki Hikosaka, Tadaki Hirose (2008) Does leaf shedding increase the whole-plant carbon gain despite some nitrogen being lost with shedding? New Phytologist 178: 617-624

Shimpei Oikawa, Kouki Hikosaka, Tadaki Hirose (2006) Leaf lifespan and lifetime carbon gain of individual leaves in a stand of an annual herb, Xanthium canadense. New Phytologist 172: 104-116

(This article appeared in Virtual Special Issue on 'Plant ecological strategy axes in leaf and wood traits' of New Phytologist in June 2008 again.)

Shimpei Oikawa, Kouki Hikosaka, Tadaki Hirose (2005) Dynamics of leaf area and nitrogen in a canopy of an annual herb, Xanthium canadense. Oecologia 143: 517-526

Shimpei Oikawa, Kouki Hikosaka, Tadaki Hirose, Masae Shiyomi, Shigeo Takahashi, Yoshimichi Hori (2004) Cost-benefit relationships in fronds emerging at different times in a deciduous fern, Pteridium aquilinum. Canadian Journal of Botany 82: 521-527