The Transition between Shoot Regeneration Competence and Callus Determination in Internodal Stem Explants of Populus deltoides

  • Stephen G. Ernst
  • Gary D. Coleman
Part of the NATO ASI Series book series (NSSA, volume 210)


Experiments were conducted to monitor the competence status of internodal stem expiants of 15 Populus deltoides genotypes in in vitro culture. The focus of this study was to investigate the transition from shoot regeneration competent to callus determined growth when in the presence of the inducer zeatin. Shoot regeneration competence and callus determination were measured by transferring expiant tissue from callus inducing medium (CIM: WNA medium supplemented with 0.5 mgl-1 2,4-D) to shoot inducing medium (SIM: WNA medium supplemented with 0.5 mgl-1 zeatin). Transfers from CIM to SIM were made at 1, 2, 4, 6, 8, and 10 day intervals. The number of regenerated shoots per expiant and the percent of expiants regenerating at least one shoot were determined after 60 days.

Three general expiant competence responses were observed among the 15 Populus deltoides genotypes: (1) two genotypes were initially competent, with little increase in shoot regeneration by culture on CIM before transfer to SIM; (2) seven genotypes were not initially competent for shoot regeneration, but competence was acquired by initially culturing the explants on CIM before transfer to SIM, and this resulted in marked increases in shoot regeneration; and (3) six genotypes were not initially competent, and showed only slight competence enhancement after initial culture on CIM and produced relatively few adventitious shoots. The competence state transition from high levels of shoot regeneration to callus determination was very marked for the initially competent and competence acquired genotypes. Expiants cultured on CIM for 6 days before transfer to SIM produced a relatively large number of shoots. However, expiants subjected to CIM for 8 days before transfer to SIM produced few if any shoots, and the expiants became determined for callus growth regardless of how long they remained on SIM. Genotypic responses to the different treatments will be discussed, in addition to preliminary results of analysis of protein differences associated with the competence state changes.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Brown, R.E., Jarvis, K.L. and K.J. Hyland. 1989. Protein measurement using bicinchoninic acid: elimination of interfering substances. Anal. Biochem. 180:136–139.CrossRefGoogle Scholar
  2. 2.
    Christianson, M.L. and D.A. Warnick. 1983. Competence and determination in the process of in vitro shoot organogenesis. Develop. Biol. 95:288–293.CrossRefGoogle Scholar
  3. 3.
    Christianson, M.L. and D.A. Warnick. 1985. Temporal requirements for phytohormone balance in the control of organogenesis in vitro. Develop. Biol. 112:494–497.CrossRefGoogle Scholar
  4. 4.
    Christianson, M.L. and D.A. Warnick. 1988. Organogenesis in vitro as a developmental process. Hortscience 23(3):515–519.Google Scholar
  5. 5.
    Christy, K.G. Jr., LaTart D. B. and H.W. Osterhoudt. 1989. Modifications for SDS-PAGE of proteins. Biotechniques 7(7):692–693.PubMedGoogle Scholar
  6. 6.
    Coleman, G.D., and S.G. Ernst. 1990. Shoot induction competence and callus determination in Populus deltoides. Plant Science (accepted).Google Scholar
  7. 7.
    Feldmann, K.A. and M.D. Marks. 1986. Rapid and efficient regeneration of plants from expiants of Arabidopsis thaliana. Plant Sci. 47:63–69.CrossRefGoogle Scholar
  8. 8.
    Flinn, B.S., Webb, D.T. and W. Newcomb. 1988. The role of cell clusters and promeristemoids in determination and competence for caulogenesis by Pinus strobus cotyledons in vitro. Can. J. Bot. 66:1556–1565.CrossRefGoogle Scholar
  9. 9.
    Flinn, B.S., Webb, D.T. and W. Newcomb. 1989. Morphometric analysis of reserve substances and ultrastructural changes during determination and loss of competence of Eastern white pine (Pinus strobus) cotyledons in vitro. Can. J. Bot. 67:779–789.CrossRefGoogle Scholar
  10. 10.
    Goldberg, R.B. 1988. Plants: Novel developmental processes. Science 240:1460–1467.CrossRefPubMedGoogle Scholar
  11. 11.
    Hicks, G.S. 1980. Patterns of organ development in plant tissue culture and the problem of organ determination. Bot. Rev. 46(1): 1–23.CrossRefGoogle Scholar
  12. 12.
    Laemmli, U.K. 1970. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature 227:680–685.CrossRefGoogle Scholar
  13. 13.
    McDaniel, N.C. 1984. Competence, determination, and induction in plant development. In: Pattern Formation a Primer in Developmental Biology. Macmillian, New York. pp.Google Scholar
  14. 14.
    Meins, Jr., F. and A.N. Binns. 1979. Cell determination in plant development. Bioscience 29(4):221–225.CrossRefGoogle Scholar
  15. 15.
    Schuster, A.M. and E. Davies. 1983. Ribonucleic acid and protein metabolism in pea epicotyls I. The aging process. Plant Physiol. 73:809–816.CrossRefPubMedPubMedCentralGoogle Scholar
  16. 16.
    Skoog, F. and C.O. Miller. 1967. Chemical regulation of growth and organ formation in plant tissues cultured in vitro. Symp. Soc. Exp. Biol. 11:118–140.Google Scholar
  17. 17.
    Thorpe, T.A. 1980. Organogenesis in vitro: Structural, physiological, and biochemical aspects. Int. Rev. Cytol. Suppl. 11A:71–112.Google Scholar
  18. 18.
    Valvekens, D., M. Van Montagu, and M. Van Lijsebettens. 1988. Agrobacterium tumefaciens-mediated transformation of Arabidopsis thaliana root expiants by using kanamycin selection. Proc. Natl. Acad. Sci. USA 85:5536–5540.CrossRefPubMedPubMedCentralGoogle Scholar
  19. 19.
    Walker, K.A., Wendeln, M.L. and E.G. Jaworski. 1979. Organogenesis in callus tissue of Medicago sativa. The temporal separation of induction processes from differentiation processes. Plant Sci. Lttrs. 16:23–30.CrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1991

Authors and Affiliations

  • Stephen G. Ernst
    • 1
  • Gary D. Coleman
    • 1
  1. 1.Department of Forestry, Fisheries and WildlifeUniversity of NebraskaLincolnUSA

Personalised recommendations