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Cytokinin

February 16, 2024

Not to be confused with Cytokine, a class of small proteins important in cell signaling.

Cytokinins (CK) are a class of plant hormones that promote cell division, or cytokinesis, in plant roots and shoots. They are involved primarily in cell growth and differentiation, but also affect apical dominance, axillary bud growth, and leaf senescence.

The cytokinin zeatin is named after the genus of corn, Zea.

There are two types of cytokinins: adenine-type cytokinins represented by kinetin, zeatin, and 6-benzylaminopurine, and phenylurea-type cytokinins like diphenylurea and thidiazuron (TDZ).[1] Most adenine-type cytokinins are synthesized in roots.[2] Cambium and other actively dividing tissues also synthesize cytokinins.[3] No phenylurea cytokinins have been found in plants.[4] Cytokinins participate in local and long-distance signalling, with the same transport mechanism as purines and nucleosides.[5] Typically, cytokinins are transported in the xylem.[2]

Cytokinins act in concert with auxin, another plant growth hormone. The two are complementary,[6][7] having generally opposite effects.[2]

History edit

The idea of specific substances required for cell division to occur in plants actually dates back to the German physiologist J. Wiesner, who, in 1892, proposed that initiation of cell division is evoked by endogenous factors, indeed a proper balance among endogenous factors. Somewhat later, the Austrian plant physiologist, G. Haberlandt, reported in 1913 that an unknown substance diffuses from the phloem tissue which can induce cell division in the parenchymatic tissue of potato tubers.[8] In 1941, Johannes Van Overbeek found that the milky endosperm of immature coconut also had this factor, which stimulated cell division and differentiation in very young Datura embryos.[9][10]

Jablonski and Skoog (1954) extended the work of Haberlandt and reported that a substance present in the vascular tissue was responsible for causing cell division in the pith cells.[11][12] Miller and his co-workers (1954) isolated and purified the cell division substance in crystallised form from autoclaved herring fish sperm DNA.[11] This active compound was named as Kinetin because of its ability to promote cell division and was the first cytokinin to be named. Kinetin was later identified to be 6-furfuryl-amino purine. Later on, the generic name kinin was suggested to include kinetin and other substances having similar properties.[8]

The first naturally occurring cytokinin was isolated and crystallised simultaneously by Miller and D.S. Lethum (1963–65) from the milky endosperm of corn (Zea mays) and named Zeatin. Lethem (1963) proposed the term Cytokinins for such substances.[13]

Function edit

Cytokinins are involved in many plant processes, including cell division and shoot and root morphogenesis. They are known to regulate axillary bud growth and apical dominance. According to the "direct inhibition hypothesis", these effects result from the ratio of cytokinin to auxin.[citation needed] This theory states that auxin from apical buds travels down shoots to inhibit axillary bud growth. This promotes shoot growth, and restricts lateral branching. Cytokinin moves from the roots into the shoots, eventually signaling lateral bud growth. Simple experiments support this theory. When the apical bud is removed, the axillary buds are uninhibited, lateral growth increases, and plants become bushier. Applying auxin to the cut stem again inhibits lateral dominance.[2] Moreover, it has been shown that cytokinin alone has no effect on parenchyma cells. When cultured with auxin but no cytokinin, they grow large but do not divide. When cytokinin and auxin are both added together, the cells expand and differentiate. When cytokinin and auxin are present in equal levels, the parenchyma cells form an undifferentiated callus. A higher ratio of cytokinin induces growth of shoot buds, while a higher ratio of auxin induces root formation.[2]

Cytokinins have been shown to slow aging of plant organs by preventing protein breakdown, activating protein synthesis, and assembling nutrients from nearby tissues.[2] A study that regulated leaf senescence in tobacco leaves found that wild-type leaves yellowed while transgenic leaves remained mostly green. It was hypothesized that cytokinin may affect enzymes that regulate protein synthesis and degradation.[14]

Cytokinins have recently been found to play a role in plant pathogenesis. For example, cytokinins have been described to induce resistance against Pseudomonas syringae in Arabidopsis thaliana[15] and Nicotiana tabacum.[16] Also in context of biological control of plant diseases cytokinins seem to have potential functions. Production of cytokinins by Pseudomonas fluorescens G20-18 has been identified as a key determinant to efficiently control the infection of A. thaliana with P. syringae..[17]

While cytokinin action in vascular plants is described as pleiotropic, this class of plant hormones specifically induces the transition from apical growth to growth via a three-faced apical cell in moss protonema. This bud induction can be pinpointed to differentiation of a specific single cell, and thus is a very specific effect of cytokinin.[18]

Mode of action edit

Cytokinin signaling in plants is mediated by a two-component phosphorelay. This pathway is initiated by cytokinin binding to a histidine kinase receptor in the endoplasmic reticulum membrane. This results in the autophosphorylation of the receptor, with the phosphate then being transferred to a phosphotransfer protein. The phosphotransfer proteins can then phosphorylate the type-B response regulators (RR) which are a family of transcriptions factors. The phosphorylated, and thus activated, type-B RRs regulate the transcription of numerous genes, including the type-A RRs. The type-A RRs negatively regulate the pathway.[19]

Biosynthesis edit

Adenosine phosphate-isopentenyltransferase (IPT) catalyses the first reaction in the biosynthesis of isoprene cytokinins. It may use ATP, ADP, or AMP as substrates and may use dimethylallyl pyrophosphate (DMAPP) or hydroxymethylbutenyl pyrophosphate (HMBPP) as prenyl donors.[20] This reaction is the rate-limiting step in cytokinin biosynthesis. DMADP and HMBDP used in cytokinin biosynthesis are produced by the methylerythritol phosphate pathway (MEP).[20]

Cytokinins can also be produced by recycled tRNAs in plants and bacteria.[20][21] tRNAs with anticodons that start with a uridine and carrying an already-prenylated adenosine adjacent to the anticodon release on degradation the adenosine as a cytokinin.[20] The prenylation of these adenines is carried out by tRNA-isopentenyltransferase.[21]

Auxin is known to regulate the biosynthesis of cytokinin.[22]

Uses edit

Because cytokinins promote plant cell division and growth, they have been studied since the 1970s as potential agrochemicals, however they have yet to be widely adopted, probably due to the complex nature of their effects.[23] One study found that applying cytokinin to cotton seedlings led to a 5–10% increase in yield under drought conditions.[24] Some cytokinins are utilized in tissue culture of plants and can also be used to promote the germination of seeds.

References edit

  1. ^ Aina O, Quesenberry K, Gallo M (2012). "Thidiazuron-Induced Tissue Culture Regeneration from Quartered-Seed Explants of Arachis paraguariensis". Crop Science. 52 (3): 555. doi:10.2135/cropsci2011.07.0367. S2CID 82510749.
  2. ^ a b c d e f Campbell NA, Reece JB, Urry LA, Cain ML, Wasserman SA, Minorsky PV, Jackson RB (2008). Biology (8th ed.). San Francisco: Pearson, Benjamin Cummings. pp. 827–30. ISBN 978-0-555-03883-3.
  3. ^ Chen CM, Ertl JR, Leisner SM, Chang CC (July 1985). "Localization of cytokinin biosynthetic sites in pea plants and carrot roots". Plant Physiology. 78 (3): 510–513. doi:10.1104/pp.78.3.510. PMC 1064767. PMID 16664274.
  4. ^ Mok DW, Mok MC (June 2001). "Cytokinin Metabolism and Action". Annual Review of Plant Physiology and Plant Molecular Biology. 52 (1): 89–118. doi:10.1146/annurev.arplant.52.1.89. PMID 11337393.
  5. ^ Sakakibara H (2006). "Cytokinins: activity, biosynthesis, and translocation". Annual Review of Plant Biology. 57 (1): 431–449. doi:10.1146/annurev.arplant.57.032905.105231. PMID 16669769. S2CID 25584314.
  6. ^ Schaller GE, Bishopp A, Kieber JJ (January 2015). "The yin-yang of hormones: cytokinin and auxin interactions in plant development". The Plant Cell. 27 (1): 44–63. doi:10.1105/tpc.114.133595. PMC 4330578. PMID 25604447.
  7. ^ Großkinsky DK, Petrášek J (February 2019). "Auxins and cytokinins - the dynamic duo of growth-regulating phytohormones heading for new shores". The New Phytologist. 221 (3): 1187–1190. doi:10.1111/nph.15556. PMID 30644580.
  8. ^ a b Moore TC (1979), Moore TC (ed.), "Cytokinins", Biochemistry and Physiology of Plant Hormones, New York, NY: Springer US, pp. 147–180, doi:10.1007/978-1-4684-0079-3_4, ISBN 978-1-4684-0079-3, retrieved 2022-06-17
  9. ^ VAN Overbeek J, Conklin ME, Blakeslee AF (October 1941). "Factors in Coconut Milk Essential for Growth and Development of Very Young Datura Embryos". Science. 94 (2441): 350–351. Bibcode:1941Sci....94..350V. doi:10.1126/science.94.2441.350. PMID 17729950.
  10. ^ Collins S (1964-08-14). "Plant Physiology: The Lore of Living Plants . By Johannes van Overbeek and Harry K. Wong. National Science Teachers Association, Washington, D.C., 1964. 160 pp. 50g". Science. 145 (3633): 698–699. doi:10.1126/science.145.3633.698.c. ISSN 0036-8075. S2CID 239878163.
  11. ^ a b Amasino R (July 2005). "1955: kinetin arrives: the 50th anniversary of a new plant hormone". Plant Physiology. 138 (3): 1177–1184. doi:10.1104/pp.104.900160. PMC 1176392. PMID 16009993.
  12. ^ Eckardt NA (2003-11-01). "A New Classic of Cytokinin Research: Cytokinin-Deficient Arabidopsis Plants Provide New Insights into Cytokinin Biology". The Plant Cell. 15 (11): 2489–2492. doi:10.1105/tpc.151110. ISSN 1040-4651. PMC 540265.
  13. ^ Chen CM (1998-02-01), "The Discovery of Cytokinins", Discoveries in Plant Biology, vol. 1, WORLD SCIENTIFIC, pp. 1–15, doi:10.1142/9789812817563_0001, ISBN 978-981-02-1313-8
  14. ^ Thomas H (January 1978). "Enzymes of nitrogen mobilization in detached leaves of Lolium temulentum during senescence". Plant Physiology. 142 (2): 161–169. doi:10.1104/pp.116.1.329. PMC 35173. PMID 24408097.
  15. ^ Choi J, Huh SU, Kojima M, Sakakibara H, Paek KH, Hwang I (August 2010). "The cytokinin-activated transcription factor ARR2 promotes plant immunity via TGA3/NPR1-dependent salicylic acid signaling in Arabidopsis". Developmental Cell. 19 (2): 284–295. doi:10.1016/j.devcel.2010.07.011. PMID 20708590.
  16. ^ Grosskinsky DK, Naseem M, Abdelmohsen UR, Plickert N, Engelke T, Griebel T, et al. (October 2011). "Cytokinins mediate resistance against Pseudomonas syringae in tobacco through increased antimicrobial phytoalexin synthesis independent of salicylic acid signaling". Plant Physiology. 157 (2): 815–830. doi:10.1104/pp.111.182931. PMC 3192561. PMID 21813654.
  17. ^ Großkinsky DK, Tafner R, Moreno MV, Stenglein SA, García de Salamone IE, Nelson LM, et al. (March 2016). "Cytokinin production by Pseudomonas fluorescens G20-18 determines biocontrol activity against Pseudomonas syringae in Arabidopsis". Scientific Reports. 6: 23310. Bibcode:2016NatSR...623310G. doi:10.1038/srep23310. PMC 4794740. PMID 26984671.
  18. ^ Decker EL, Frank W, Sarnighausen E, Reski R (May 2006). "Moss systems biology en route: phytohormones in Physcomitrella development". Plant Biology. 8 (3): 397–405. Bibcode:2006PlBio...8..397D. CiteSeerX 10.1.1.319.9790. doi:10.1055/s-2006-923952. PMID 16807833.
  19. ^ Hutchison CE, Kieber JJ (2002-01-01). "Cytokinin signaling in Arabidopsis". The Plant Cell. 14 (Suppl): S47–S59. doi:10.1105/tpc.010444. PMC 151247. PMID 12045269.
  20. ^ a b c d Hwang I, Sakakibara H (2006). "Cytokinin biosynthesis and perception". Physiologia Plantarum. 126 (4): 528–538. doi:10.1111/j.1399-3054.2006.00665.x.
  21. ^ a b Miyawaki K, Matsumoto-Kitano M, Kakimoto T (January 2004). "Expression of cytokinin biosynthetic isopentenyltransferase genes in Arabidopsis: tissue specificity and regulation by auxin, cytokinin, and nitrate". The Plant Journal. 37 (1): 128–138. doi:10.1046/j.1365-313x.2003.01945.x. PMID 14675438.
  22. ^ Nordström A, Tarkowski P, Tarkowska D, Norbaek R, Astot C, Dolezal K, Sandberg G (May 2004). "Auxin regulation of cytokinin biosynthesis in Arabidopsis thaliana: a factor of potential importance for auxin-cytokinin-regulated development". Proceedings of the National Academy of Sciences of the United States of America. 101 (21): 8039–8044. Bibcode:2004PNAS..101.8039N. doi:10.1073/pnas.0402504101. PMC 419553. PMID 15146070.
  23. ^ Koprna R, De Diego N, Dundálková L, Spíchal L (February 2016). "Use of cytokinins as agrochemicals". Bioorganic & Medicinal Chemistry. Recent Developments in Agrochemistry. 24 (3): 484–492. doi:10.1016/j.bmc.2015.12.022. PMID 26719210.
  24. ^ Yao S (March 2010). "Plant Hormone Increases Cotton Yields in Drought Conditions". News & Events. Agricultural Research Service (ARS), U.S. Department of Agriculture.

External links edit

  • Agrares Fertilizer with cytokinins
  • Lincoln T, Zeiger E (2010). "Ch. 21: Cytokinins: Regulators of Cell Division". Plant Physiology (5th ed.). Sinauer. ISBN 978-0-87893-866-7.
  • Plant Physiology:Cytokinin
  • Regulation of Leaf Senescence by Cytokinin, Sugar, and Light

February 16, 2024
cytokinin, confused, with, cytokine, class, small, proteins, important, cell, signaling, class, plant, hormones, that, promote, cell, division, cytokinesis, plant, roots, shoots, they, involved, primarily, cell, growth, differentiation, also, affect, apical, d. Not to be confused with Cytokine a class of small proteins important in cell signaling Cytokinins CK are a class of plant hormones that promote cell division or cytokinesis in plant roots and shoots They are involved primarily in cell growth and differentiation but also affect apical dominance axillary bud growth and leaf senescence The cytokinin zeatin is named after the genus of corn Zea There are two types of cytokinins adenine type cytokinins represented by kinetin zeatin and 6 benzylaminopurine and phenylurea type cytokinins like diphenylurea and thidiazuron TDZ 1 Most adenine type cytokinins are synthesized in roots 2 Cambium and other actively dividing tissues also synthesize cytokinins 3 No phenylurea cytokinins have been found in plants 4 Cytokinins participate in local and long distance signalling with the same transport mechanism as purines and nucleosides 5 Typically cytokinins are transported in the xylem 2 Cytokinins act in concert with auxin another plant growth hormone The two are complementary 6 7 having generally opposite effects 2 Contents 1 History 2 Function 3 Mode of action 4 Biosynthesis 5 Uses 6 References 7 External linksHistory editThe idea of specific substances required for cell division to occur in plants actually dates back to the German physiologist J Wiesner who in 1892 proposed that initiation of cell division is evoked by endogenous factors indeed a proper balance among endogenous factors Somewhat later the Austrian plant physiologist G Haberlandt reported in 1913 that an unknown substance diffuses from the phloem tissue which can induce cell division in the parenchymatic tissue of potato tubers 8 In 1941 Johannes Van Overbeek found that the milky endosperm of immature coconut also had this factor which stimulated cell division and differentiation in very young Datura embryos 9 10 Jablonski and Skoog 1954 extended the work of Haberlandt and reported that a substance present in the vascular tissue was responsible for causing cell division in the pith cells 11 12 Miller and his co workers 1954 isolated and purified the cell division substance in crystallised form from autoclaved herring fish sperm DNA 11 This active compound was named as Kinetin because of its ability to promote cell division and was the first cytokinin to be named Kinetin was later identified to be 6 furfuryl amino purine Later on the generic name kinin was suggested to include kinetin and other substances having similar properties 8 The first naturally occurring cytokinin was isolated and crystallised simultaneously by Miller and D S Lethum 1963 65 from the milky endosperm of corn Zea mays and named Zeatin Lethem 1963 proposed the term Cytokinins for such substances 13 Function editCytokinins are involved in many plant processes including cell division and shoot and root morphogenesis They are known to regulate axillary bud growth and apical dominance According to the direct inhibition hypothesis these effects result from the ratio of cytokinin to auxin citation needed This theory states that auxin from apical buds travels down shoots to inhibit axillary bud growth This promotes shoot growth and restricts lateral branching Cytokinin moves from the roots into the shoots eventually signaling lateral bud growth Simple experiments support this theory When the apical bud is removed the axillary buds are uninhibited lateral growth increases and plants become bushier Applying auxin to the cut stem again inhibits lateral dominance 2 Moreover it has been shown that cytokinin alone has no effect on parenchyma cells When cultured with auxin but no cytokinin they grow large but do not divide When cytokinin and auxin are both added together the cells expand and differentiate When cytokinin and auxin are present in equal levels the parenchyma cells form an undifferentiated callus A higher ratio of cytokinin induces growth of shoot buds while a higher ratio of auxin induces root formation 2 Cytokinins have been shown to slow aging of plant organs by preventing protein breakdown activating protein synthesis and assembling nutrients from nearby tissues 2 A study that regulated leaf senescence in tobacco leaves found that wild type leaves yellowed while transgenic leaves remained mostly green It was hypothesized that cytokinin may affect enzymes that regulate protein synthesis and degradation 14 Cytokinins have recently been found to play a role in plant pathogenesis For example cytokinins have been described to induce resistance against Pseudomonas syringae in Arabidopsis thaliana 15 and Nicotiana tabacum 16 Also in context of biological control of plant diseases cytokinins seem to have potential functions Production of cytokinins by Pseudomonas fluorescens G20 18 has been identified as a key determinant to efficiently control the infection of A thaliana with P syringae 17 While cytokinin action in vascular plants is described as pleiotropic this class of plant hormones specifically induces the transition from apical growth to growth via a three faced apical cell in moss protonema This bud induction can be pinpointed to differentiation of a specific single cell and thus is a very specific effect of cytokinin 18 Mode of action editCytokinin signaling in plants is mediated by a two component phosphorelay This pathway is initiated by cytokinin binding to a histidine kinase receptor in the endoplasmic reticulum membrane This results in the autophosphorylation of the receptor with the phosphate then being transferred to a phosphotransfer protein The phosphotransfer proteins can then phosphorylate the type B response regulators RR which are a family of transcriptions factors The phosphorylated and thus activated type B RRs regulate the transcription of numerous genes including the type A RRs The type A RRs negatively regulate the pathway 19 Biosynthesis editAdenosine phosphate isopentenyltransferase IPT catalyses the first reaction in the biosynthesis of isoprene cytokinins It may use ATP ADP or AMP as substrates and may use dimethylallyl pyrophosphate DMAPP or hydroxymethylbutenyl pyrophosphate HMBPP as prenyl donors 20 This reaction is the rate limiting step in cytokinin biosynthesis DMADP and HMBDP used in cytokinin biosynthesis are produced by the methylerythritol phosphate pathway MEP 20 Cytokinins can also be produced by recycled tRNAs in plants and bacteria 20 21 tRNAs with anticodons that start with a uridine and carrying an already prenylated adenosine adjacent to the anticodon release on degradation the adenosine as a cytokinin 20 The prenylation of these adenines is carried out by tRNA isopentenyltransferase 21 Auxin is known to regulate the biosynthesis of cytokinin 22 Uses editBecause cytokinins promote plant cell division and growth they have been studied since the 1970s as potential agrochemicals however they have yet to be widely adopted probably due to the complex nature of their effects 23 One study found that applying cytokinin to cotton seedlings led to a 5 10 increase in yield under drought conditions 24 Some cytokinins are utilized in tissue culture of plants and can also be used to promote the germination of seeds References edit Aina O Quesenberry K Gallo M 2012 Thidiazuron Induced Tissue Culture Regeneration from Quartered Seed Explants of Arachis paraguariensis Crop Science 52 3 555 doi 10 2135 cropsci2011 07 0367 S2CID 82510749 a b c d e f Campbell NA Reece JB Urry LA Cain ML Wasserman SA Minorsky PV Jackson RB 2008 Biology 8th ed San Francisco Pearson Benjamin Cummings pp 827 30 ISBN 978 0 555 03883 3 Chen CM Ertl JR Leisner SM Chang CC July 1985 Localization of cytokinin biosynthetic sites in pea plants and carrot roots Plant Physiology 78 3 510 513 doi 10 1104 pp 78 3 510 PMC 1064767 PMID 16664274 Mok DW Mok MC June 2001 Cytokinin Metabolism and Action Annual Review of Plant Physiology and Plant Molecular Biology 52 1 89 118 doi 10 1146 annurev arplant 52 1 89 PMID 11337393 Sakakibara H 2006 Cytokinins activity biosynthesis and translocation Annual Review of Plant Biology 57 1 431 449 doi 10 1146 annurev arplant 57 032905 105231 PMID 16669769 S2CID 25584314 Schaller GE Bishopp A Kieber JJ January 2015 The yin yang of hormones cytokinin and auxin interactions in plant development The Plant Cell 27 1 44 63 doi 10 1105 tpc 114 133595 PMC 4330578 PMID 25604447 Grosskinsky DK Petrasek J February 2019 Auxins and cytokinins the dynamic duo of growth regulating phytohormones heading for new shores The New Phytologist 221 3 1187 1190 doi 10 1111 nph 15556 PMID 30644580 a b Moore TC 1979 Moore TC ed Cytokinins Biochemistry and Physiology of Plant Hormones New York NY Springer US pp 147 180 doi 10 1007 978 1 4684 0079 3 4 ISBN 978 1 4684 0079 3 retrieved 2022 06 17 VAN Overbeek J Conklin ME Blakeslee AF October 1941 Factors in Coconut Milk Essential for Growth and Development of Very Young Datura Embryos Science 94 2441 350 351 Bibcode 1941Sci 94 350V doi 10 1126 science 94 2441 350 PMID 17729950 Collins S 1964 08 14 Plant Physiology The Lore of Living Plants By Johannes van Overbeek and Harry K Wong National Science Teachers Association Washington D C 1964 160 pp 50g Science 145 3633 698 699 doi 10 1126 science 145 3633 698 c ISSN 0036 8075 S2CID 239878163 a b Amasino R July 2005 1955 kinetin arrives the 50th anniversary of a new plant hormone Plant Physiology 138 3 1177 1184 doi 10 1104 pp 104 900160 PMC 1176392 PMID 16009993 Eckardt NA 2003 11 01 A New Classic of Cytokinin Research Cytokinin Deficient Arabidopsis Plants Provide New Insights into Cytokinin Biology The Plant Cell 15 11 2489 2492 doi 10 1105 tpc 151110 ISSN 1040 4651 PMC 540265 Chen CM 1998 02 01 The Discovery of Cytokinins Discoveries in Plant Biology vol 1 WORLD SCIENTIFIC pp 1 15 doi 10 1142 9789812817563 0001 ISBN 978 981 02 1313 8 Thomas H January 1978 Enzymes of nitrogen mobilization in detached leaves of Lolium temulentum during senescence Plant Physiology 142 2 161 169 doi 10 1104 pp 116 1 329 PMC 35173 PMID 24408097 Choi J Huh SU Kojima M Sakakibara H Paek KH Hwang I August 2010 The cytokinin activated transcription factor ARR2 promotes plant immunity via TGA3 NPR1 dependent salicylic acid signaling in Arabidopsis Developmental Cell 19 2 284 295 doi 10 1016 j devcel 2010 07 011 PMID 20708590 Grosskinsky DK Naseem M Abdelmohsen UR Plickert N Engelke T Griebel T et al October 2011 Cytokinins mediate resistance against Pseudomonas syringae in tobacco through increased antimicrobial phytoalexin synthesis independent of salicylic acid signaling Plant Physiology 157 2 815 830 doi 10 1104 pp 111 182931 PMC 3192561 PMID 21813654 Grosskinsky DK Tafner R Moreno MV Stenglein SA Garcia de Salamone IE Nelson LM et al March 2016 Cytokinin production by Pseudomonas fluorescens G20 18 determines biocontrol activity against Pseudomonas syringae in Arabidopsis Scientific Reports 6 23310 Bibcode 2016NatSR 623310G doi 10 1038 srep23310 PMC 4794740 PMID 26984671 Decker EL Frank W Sarnighausen E Reski R May 2006 Moss systems biology en route phytohormones in Physcomitrella development Plant Biology 8 3 397 405 Bibcode 2006PlBio 8 397D CiteSeerX 10 1 1 319 9790 doi 10 1055 s 2006 923952 PMID 16807833 Hutchison CE Kieber JJ 2002 01 01 Cytokinin signaling in Arabidopsis The Plant Cell 14 Suppl S47 S59 doi 10 1105 tpc 010444 PMC 151247 PMID 12045269 a b c d Hwang I Sakakibara H 2006 Cytokinin biosynthesis and perception Physiologia Plantarum 126 4 528 538 doi 10 1111 j 1399 3054 2006 00665 x a b Miyawaki K Matsumoto Kitano M Kakimoto T January 2004 Expression of cytokinin biosynthetic isopentenyltransferase genes in Arabidopsis tissue specificity and regulation by auxin cytokinin and nitrate The Plant Journal 37 1 128 138 doi 10 1046 j 1365 313x 2003 01945 x PMID 14675438 Nordstrom A Tarkowski P Tarkowska D Norbaek R Astot C Dolezal K Sandberg G May 2004 Auxin regulation of cytokinin biosynthesis in Arabidopsis thaliana a factor of potential importance for auxin cytokinin regulated development Proceedings of the National Academy of Sciences of the United States of America 101 21 8039 8044 Bibcode 2004PNAS 101 8039N doi 10 1073 pnas 0402504101 PMC 419553 PMID 15146070 Koprna R De Diego N Dundalkova L Spichal L February 2016 Use of cytokinins as agrochemicals Bioorganic amp Medicinal Chemistry Recent Developments in Agrochemistry 24 3 484 492 doi 10 1016 j bmc 2015 12 022 PMID 26719210 Yao S March 2010 Plant Hormone Increases Cotton Yields in Drought Conditions News amp Events Agricultural Research Service ARS U S Department of Agriculture External links editAgrares Fertilizer with cytokinins Lincoln T Zeiger E 2010 Ch 21 Cytokinins Regulators of Cell Division Plant Physiology 5th ed Sinauer ISBN 978 0 87893 866 7 Plant Physiology Cytokinin Regulation of Leaf Senescence by Cytokinin Sugar and Light Retrieved from https en wikipedia org w index php title Cytokinin amp oldid 1207079019, wikipedia, wiki, book, books, library,

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