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Toyoki Kozai

Toyoki Kozai

D-Index & Metrics

Discipline name D-Index World Ranking Current World Ranking National Ranking Current National Ranking Publications Citations
Plant Science and Agronomy 62 1103 1012 32 32 391 13113

Toyoki Kozai publications per year

The chart shows the history of publications by Toyoki Kozai between 1968 and 2025, highlighting the no. of papers published in each year and offering an overview of the publication velocity of this scholar. Toyoki Kozai published across 58 years, from 1968 to 2025, averaging 7.2 papers a year. Output peaked at 34 publications in 2000. 1 of the 419 publications appeared in the last two years.

No. of publications
10 20 30
Bar chart. Horizontal axis: year, 1968 to 2025. Vertical axis: number of publications, 0 to 34. Peak 34 publications in 2000. 1968: 2 publications 1969: 0 publications 1970: 1 publication 1971: 0 publications 1972: 2 publications 1973: 1 publication 1974: 3 publications 1975: 1 publication 1976: 1 publication 1977: 1 publication 1978: 1 publication 1979: 0 publications 1980: 4 publications 1981: 0 publications 1982: 5 publications 1983: 2 publications 1984: 1 publication 1985: 7 publications 1986: 7 publications 1987: 2 publications 1988: 9 publications 1989: 7 publications 1990: 4 publications 1991: 9 publications 1992: 13 publications 1993: 7 publications 1994: 6 publications 1995: 31 publications 1996: 15 publications 1997: 16 publications 1998: 9 publications 1999: 12 publications 2000: 34 publications 2001: 29 publications 2002: 15 publications 2003: 13 publications 2004: 5 publications 2005: 25 publications 2006: 23 publications 2007: 10 publications 2008: 4 publications 2009: 0 publications 2010: 3 publications 2011: 3 publications 2012: 5 publications 2013: 5 publications 2014: 1 publication 2015: 5 publications 2016: 20 publications 2017: 2 publications 2018: 12 publications 2019: 4 publications 2020: 6 publications 2021: 2 publications 2022: 8 publications 2023: 5 publications 2024: 0 publications 2025: 1 publication
1968 2025

419 publications in total across all disciplines

View publications per year as a table
Toyoki Kozai: publications per year, 1968 to 2025
Year Publications
1968 2
1969 0
1970 1
1971 0
1972 2
1973 1
1974 3
1975 1
1976 1
1977 1
1978 1
1979 0
1980 4
1981 0
1982 5
1983 2
1984 1
1985 7
1986 7
1987 2
1988 9
1989 7
1990 4
1991 9
1992 13
1993 7
1994 6
1995 31
1996 15
1997 16
1998 9
1999 12
2000 34
2001 29
2002 15
2003 13
2004 5
2005 25
2006 23
2007 10
2008 4
2009 0
2010 3
2011 3
2012 5
2013 5
2014 1
2015 5
2016 20
2017 2
2018 12
2019 4
2020 6
2021 2
2022 8
2023 5
2024 0
2025 1
Total 419
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Toyoki Kozai publication distribution in Plant Science and Agronomy in 2026

The chart shows the distribution of publications by all Research.com ranked scientists in the field of Plant Science and Agronomy in 2026. The highlighted bar marks where Toyoki Kozai sits on this spectrum.

No. of scientists
50 100 150 200 250
Bar chart with 88 bars. Horizontal axis: publications, 36–40 to 467+. Vertical axis: number of scientists, 0 to 255. Most scientists, 255, have 111–115 publications. The last bar groups every scientist with 467 publications or more. The highlighted bar, 391–395 publications, is where this scientist sits. 36–40 publications: 2 scientists 41–45 publications: 7 scientists 46–50 publications: 40 scientists 51–55 publications: 58 scientists 56–60 publications: 60 scientists 61–65 publications: 107 scientists 66–70 publications: 130 scientists 71–75 publications: 153 scientists 76–80 publications: 191 scientists 81–85 publications: 199 scientists 86–90 publications: 206 scientists 91–95 publications: 218 scientists 96–100 publications: 226 scientists 101–105 publications: 227 scientists 106–110 publications: 247 scientists 111–115 publications: 255 scientists 116–120 publications: 253 scientists 121–125 publications: 233 scientists 126–130 publications: 219 scientists 131–135 publications: 201 scientists 136–140 publications: 194 scientists 141–145 publications: 176 scientists 146–150 publications: 157 scientists 151–155 publications: 147 scientists 156–160 publications: 151 scientists 161–165 publications: 159 scientists 166–170 publications: 137 scientists 171–175 publications: 128 scientists 176–180 publications: 126 scientists 181–185 publications: 98 scientists 186–190 publications: 114 scientists 191–195 publications: 100 scientists 196–200 publications: 90 scientists 201–205 publications: 71 scientists 206–210 publications: 98 scientists 211–215 publications: 70 scientists 216–220 publications: 86 scientists 221–225 publications: 61 scientists 226–230 publications: 58 scientists 231–235 publications: 53 scientists 236–240 publications: 64 scientists 241–245 publications: 39 scientists 246–250 publications: 46 scientists 251–255 publications: 51 scientists 256–260 publications: 36 scientists 261–265 publications: 44 scientists 266–270 publications: 35 scientists 271–275 publications: 30 scientists 276–280 publications: 33 scientists 281–285 publications: 35 scientists 286–290 publications: 36 scientists 291–295 publications: 26 scientists 296–300 publications: 26 scientists 301–305 publications: 31 scientists 306–310 publications: 30 scientists 311–315 publications: 21 scientists 316–320 publications: 29 scientists 321–325 publications: 14 scientists 326–330 publications: 15 scientists 331–335 publications: 15 scientists 336–340 publications: 17 scientists 341–345 publications: 15 scientists 346–350 publications: 12 scientists 351–355 publications: 17 scientists 356–360 publications: 18 scientists 361–365 publications: 12 scientists 366–370 publications: 11 scientists 371–375 publications: 6 scientists 376–380 publications: 6 scientists 381–385 publications: 11 scientists 386–390 publications: 9 scientists 391–395 publications: 10 scientists 396–400 publications: 8 scientists 401–405 publications: 4 scientists 406–410 publications: 9 scientists 411–415 publications: 11 scientists 416–420 publications: 4 scientists 421–425 publications: 7 scientists 426–430 publications: 4 scientists 431–435 publications: 3 scientists 436–440 publications: 5 scientists 441–445 publications: 8 scientists 446–450 publications: 6 scientists 451–455 publications: 7 scientists 456–460 publications: 5 scientists 461–465 publications: 6 scientists 466 publications: 2 scientists 467+ publications: 99 scientists
36–40 publications 467+

This scientist: 391 publications — 97th percentile

97% of scientists in this discipline score the same or lower.

The last bar groups every scientist with 467 publications or more.

View publications distribution as a table
Number of Plant Science and Agronomy scientists by publication count, Research.com 2026 ranking edition. Based on 6,494 ranked scientists.
Publications Scientists This scientist
36–40 2
41–45 7
46–50 40
51–55 58
56–60 60
61–65 107
66–70 130
71–75 153
76–80 191
81–85 199
86–90 206
91–95 218
96–100 226
101–105 227
106–110 247
111–115 255
116–120 253
121–125 233
126–130 219
131–135 201
136–140 194
141–145 176
146–150 157
151–155 147
156–160 151
161–165 159
166–170 137
171–175 128
176–180 126
181–185 98
186–190 114
191–195 100
196–200 90
201–205 71
206–210 98
211–215 70
216–220 86
221–225 61
226–230 58
231–235 53
236–240 64
241–245 39
246–250 46
251–255 51
256–260 36
261–265 44
266–270 35
271–275 30
276–280 33
281–285 35
286–290 36
291–295 26
296–300 26
301–305 31
306–310 30
311–315 21
316–320 29
321–325 14
326–330 15
331–335 15
336–340 17
341–345 15
346–350 12
351–355 17
356–360 18
361–365 12
366–370 11
371–375 6
376–380 6
381–385 11
386–390 9
391–395 10 391
396–400 8
401–405 4
406–410 9
411–415 11
416–420 4
421–425 7
426–430 4
431–435 3
436–440 5
441–445 8
446–450 6
451–455 7
456–460 5
461–465 6
466 2
467+ 99
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Toyoki Kozai D-index placement in Plant Science and Agronomy in 2026

The chart shows the D-index (discipline H-index) distribution of Plant Science and Agronomy scientists ranked by Research.com in 2026. The highlighted bar marks where Toyoki Kozai sits on this spectrum.

No. of scientists
50 100 150 200 250
Bar chart with 80 bars. Horizontal axis: D-Index, 30 to 109+. Vertical axis: number of scientists, 0 to 288. Most scientists, 288, have 34 D-Index. The last bar groups every scientist with 109 D-Index or more. The highlighted bar, 62 D-Index, is where this scientist sits. 30 D-Index: 200 scientists 31 D-Index: 236 scientists 32 D-Index: 253 scientists 33 D-Index: 283 scientists 34 D-Index: 288 scientists 35 D-Index: 240 scientists 36 D-Index: 246 scientists 37 D-Index: 243 scientists 38 D-Index: 247 scientists 39 D-Index: 229 scientists 40 D-Index: 232 scientists 41 D-Index: 230 scientists 42 D-Index: 228 scientists 43 D-Index: 219 scientists 44 D-Index: 193 scientists 45 D-Index: 164 scientists 46 D-Index: 158 scientists 47 D-Index: 143 scientists 48 D-Index: 131 scientists 49 D-Index: 127 scientists 50 D-Index: 122 scientists 51 D-Index: 122 scientists 52 D-Index: 110 scientists 53 D-Index: 102 scientists 54 D-Index: 98 scientists 55 D-Index: 79 scientists 56 D-Index: 85 scientists 57 D-Index: 88 scientists 58 D-Index: 91 scientists 59 D-Index: 62 scientists 60 D-Index: 61 scientists 61 D-Index: 59 scientists 62 D-Index: 54 scientists 63 D-Index: 61 scientists 64 D-Index: 59 scientists 65 D-Index: 58 scientists 66 D-Index: 41 scientists 67 D-Index: 49 scientists 68 D-Index: 39 scientists 69 D-Index: 32 scientists 70 D-Index: 40 scientists 71 D-Index: 47 scientists 72 D-Index: 38 scientists 73 D-Index: 28 scientists 74 D-Index: 29 scientists 75 D-Index: 28 scientists 76 D-Index: 22 scientists 77 D-Index: 21 scientists 78 D-Index: 25 scientists 79 D-Index: 26 scientists 80 D-Index: 19 scientists 81 D-Index: 16 scientists 82 D-Index: 12 scientists 83 D-Index: 16 scientists 84 D-Index: 14 scientists 85 D-Index: 11 scientists 86 D-Index: 17 scientists 87 D-Index: 13 scientists 88 D-Index: 10 scientists 89 D-Index: 12 scientists 90 D-Index: 18 scientists 91 D-Index: 16 scientists 92 D-Index: 16 scientists 93 D-Index: 17 scientists 94 D-Index: 12 scientists 95 D-Index: 8 scientists 96 D-Index: 9 scientists 97 D-Index: 9 scientists 98 D-Index: 11 scientists 99 D-Index: 12 scientists 100 D-Index: 5 scientists 101 D-Index: 8 scientists 102 D-Index: 4 scientists 103 D-Index: 11 scientists 104 D-Index: 5 scientists 105 D-Index: 9 scientists 106 D-Index: 7 scientists 107 D-Index: 4 scientists 108 D-Index: 8 scientists 109+ D-Index: 99 scientists
30 D-Index 109+

This scientist: 62 D-Index — 84th percentile

84% of scientists in this discipline score the same or lower.

The last bar groups every scientist with 109 D-Index or more.

View D-Index distribution as a table
Number of Plant Science and Agronomy scientists by D-index, Research.com 2026 ranking edition. Based on 6,494 ranked scientists.
D-Index Scientists This scientist
30 200
31 236
32 253
33 283
34 288
35 240
36 246
37 243
38 247
39 229
40 232
41 230
42 228
43 219
44 193
45 164
46 158
47 143
48 131
49 127
50 122
51 122
52 110
53 102
54 98
55 79
56 85
57 88
58 91
59 62
60 61
61 59
62 54 62
63 61
64 59
65 58
66 41
67 49
68 39
69 32
70 40
71 47
72 38
73 28
74 29
75 28
76 22
77 21
78 25
79 26
80 19
81 16
82 12
83 16
84 14
85 11
86 17
87 13
88 10
89 12
90 18
91 16
92 16
93 17
94 12
95 8
96 9
97 9
98 11
99 12
100 5
101 8
102 4
103 11
104 5
105 9
106 7
107 4
108 8
109+ 99
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Overview

What is he best known for?

The fields of study he is best known for:

  • Botany
  • Ecology
  • Horticulture

Botany, Micropropagation, Horticulture, Photosynthesis and Shoot are his primary areas of study. His Botany research integrates issues from Sugar and Sucrose. As part of his studies on Micropropagation, Toyoki Kozai often connects relevant subjects like Somatic embryogenesis.

Toyoki Kozai interconnects Hypericin, Sugar free, Optoelectronics, Multiplication and Hypericum perforatum in the investigation of issues within Horticulture. His Photosynthesis research incorporates themes from Ventilation, Carbon dioxide and Cutting. His research investigates the connection with Shoot and areas like Transpiration which intersect with concerns in Root system, Leafy, Vermiculite and System dynamics.

His most cited work include:

  • Automation and environmental control in plant tissue culture (294 citations)
  • Micropropagation under photoautotrophic conditions (184 citations)
  • Melatonin in Glycyrrhiza uralensis: response of plant roots to spectral quality of light and UV-B radiation. (176 citations)

What are the main themes of his work throughout his whole career to date?

Toyoki Kozai mostly deals with Botany, Horticulture, Micropropagation, Photosynthesis and Greenhouse. His study on Shoot is often connected to Explant culture as part of broader study in Botany. His study in the field of Dry weight, photoperiodism and Cutting also crosses realms of Plantlet.

Micropropagation is a subfield of Tissue culture that Toyoki Kozai explores. The study incorporates disciplines such as Chlorophyll, Carbon dioxide and Plant physiology in addition to Photosynthesis. His work in Greenhouse addresses subjects such as Environmental engineering, which are connected to disciplines such as Coefficient of performance.

He most often published in these fields:

  • Botany (38.51%)
  • Horticulture (34.20%)
  • Micropropagation (22.70%)

What were the highlights of his more recent work (between 2009-2021)?

  • Artificial light (12.64%)
  • Plant factory (5.75%)
  • Greenhouse (16.09%)

In recent papers he was focusing on the following fields of study:

Artificial light, Plant factory, Greenhouse, Photosynthesis and Agricultural engineering are his primary areas of study. His studies deal with areas such as Resource, Light-emitting diode, Horticulture and LED lamp as well as Plant factory. As a member of one scientific family, Toyoki Kozai mostly works in the field of Horticulture, focusing on Shading and, on occasion, Plant density, Leafy vegetables, Senescence and Fresh weight.

His Photosynthesis study improves the overall literature in Botany. The Botany study combines topics in areas such as Airflow and Animal science. The various areas that he examines in his Agricultural engineering study include Plant production, Vertical farming, Root mass and Hydroponic culture.

Between 2009 and 2021, his most popular works were:

  • Resource use efficiency of closed plant production system with artificial light: Concept, estimation and application to plant factory (122 citations)
  • Development and application of photoautotrophic micropropagation plant system (95 citations)
  • Plant Factory: An Indoor Vertical Farming System for Efficient Quality Food Production (66 citations)

In his most recent research, the most cited papers focused on:

  • Botany
  • Ecology
  • Mechanical engineering

His primary areas of investigation include Photosynthesis, Greenhouse, Botany, Plant factory and Artificial light. He conducts interdisciplinary study in the fields of Photosynthesis and Micropropagation through his works. His Greenhouse research is multidisciplinary, incorporating perspectives in Heat transfer, Outside air temperature and Electric potential energy.

His Botany research is multidisciplinary, relying on both Airflow and Horticulture. His work on Leafy vegetables, Plant density and Sowing is typically connected to Ascorbic acid as part of general Horticulture study, connecting several disciplines of science. His research in Plant factory tackles topics such as Electricity which are related to areas like Agricultural engineering and Mechanical engineering.

Best Publications

  • Plant Factory: An Indoor Vertical Farming System for Efficient Quality Food Production

    Toyoki Kozai

  • Resource use efficiency of closed plant production system with artificial light: Concept, estimation and application to plant factory

    Toyoki Kozai

  • Automation and environmental control in plant tissue culture

    Jenny Aitken-Christie;Toyoki Kozai;Mary Ann Lila Smith

  • Micropropagation under photoautotrophic conditions

    T. Kozai

  • Temperature stress can alter the photosynthetic efficiency and secondary metabolite concentrations in St. John's wort.

    S.M.A. Zobayed;F. Afreen;T. Kozai

  • Melatonin in Glycyrrhiza uralensis: response of plant roots to spectral quality of light and UV-B radiation.

    F. Afreen;S. M. A. Zobayed;T. Kozai

  • Fundamental Studies on Environments in Plant Tissue Culture Vessels

    Kazuhiro Fujiwara;Toyoki Kozai;Ichiro Watanabe

  • Phytochemical and physiological changes in the leaves of St. John's wort plants under a water stress condition

    S.M.A. Zobayed;F. Afreen;T. Kozai

  • Development and application of photoautotrophic micropropagation plant system

    Yulan Xiao;Genhua Niu;Toyoki Kozai

  • Multiplication of potato plantlets in vitro with sugar free medium under high photosynthetic photon flux.

    T. Kozai;Y. Koyama;I. Watanabe

  • Effects of CO2 Enrichment and Sucrose Concentration Under High Photon Fluxes on Plantlet Growth of Carnation (Dianthus caryophyllus L.) in Tissue Culture During the Preparation Stage

    Toyoki Kozai;Yoshie Iwanami

  • DEVELOPMENT OF A PHOTOAUTOTROPHIC TISSUE CULTURE SYSTEM FOR SHOOTS AND/OR PLANTLETS AT ROOTING AND ACCLIMATIZATION STAGES

    K. Fujiwara;T. Kozai;I. Watanabe

  • LED lighting for urban agriculture

    Toyoki Kozai;Kazuhiro Fujiwara;Erik S. Runkle

  • Environmental control for the large-scale production of plants through in vitro techniques

    Toyoki Kozai;Chieri Kubota;Byoung Ryoung Jeong

  • Plant-environment interactions: Accumulation of hypericin in dark glands of Hypericum perforatum.

    S. M. A. Zobayed;F. Afreen;E. Goto;T. Kozai

  • Effects of CO 2 enrichment and supporting material in vitro on photoautotrophic growth of Eucalyptus plantlets in vitro and ex vitro

    C. Kirdmanee;Y. Kitaya;T. Kozai

  • Automation in plant tissue culture — general introduction and overview —

    Jenny Aitken-Christie;Toyoki Kozai;Shinsaku Takayama

  • Transplant Production Systems

    K. Kurata;T. Kozai

  • Fundamental studies on environments in plant tissue culture vessels, 2: Effects of stoppers and vessels on gas exchange rates between inside and outside of vessels closed with stoppers.

    T Kozai;K Fujiwara;I Watanabe

  • Physical microenvironment and its effects

    Kazuhiro Fujiwara;Toyoki Kozai

  • Photosynthetic Photon Flux, Photoperiod, and CO2 Concentration Affect Growth and Morphology of Lettuce Plug Transplants

    Yoshiaki Kitaya;Genhua Niu;Toyoki Kozai;Maki Ohashi

Frequent Co-Authors

Chieri Kubota
Chieri Kubota The Ohio State University
Genhua Niu
Genhua Niu Texas A&M University
Wataru Yamori
Wataru Yamori University of Tokyo
Kee-Yoeup Paek
Kee-Yoeup Paek Chungbuk National University
Tess Astatkie
Tess Astatkie Dalhousie University
Erik S. Runkle
Erik S. Runkle Michigan State University
Eun-Joo Hahn
Eun-Joo Hahn Chungbuk National University

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