Plant Cell Reports

, Volume 9, Issue 8, pp 463–465 | Cite as

Establishing axenic cultures from mature pecan embryo explants on media with low water availability

  • Ahmed A. Obeidy
  • M. A. L. Smith


Endophytic fungi associated with mature pecan (Carya illinoensis (Wangenh.) C. Koch) nuts prevented successful, contaminant-free in vitro culture of embryo expiants, even after rigorous surface disinfestation of the nuts and careful aseptic shelling. Disinfestation with sodium hypochlorite after shell removal was also unsuccessful, because even dilute concentrations which were ineffective against the fungal contaminants prevented subsequent growth from the embryo. Explanting media with low water availability which would not sustain growth of fungal contaminants, but supported growth from mature pecan embryos, were developed as an alternative disinfestation method. The explanting media were supplemented with 0.9–1.5% agar, and other media components were selectively omitted to test their influence on water availability and fungal growth. Disinfestation of up to 65% of the cultures was accomplished, depending on the medium formulation, compared to 100% loss to contamination on control medium (0.5% agar). A complete medium (containing sucrose, salts, vitamins, 18 μM BAP, and 5 μM IBA) with 1.5% agar provided control of contamination, and encouraged subsequent regeneration from the embryo expiants, which remained free of contaminant growth through subsequent subcultures.

Key words

pecan disinfestation embryo culture internal contamination water activity 





indole-3-butyric acid


Murashige and Skoog medium

Tween 20

polyoxyethylene sorbitan mono-oleate




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  1. Beuchat LR (1975) Appl. Microbiol. 29:852–854.Google Scholar
  2. Borazjani A, Graves CH, Hedin PA (1983) Pecan Quart. 17:9–13.Google Scholar
  3. Chipley JR, Heaton EK (1971) Appl. Microbiol. 22:252–253.Google Scholar
  4. Duncan DB (1955) Multiple range and multiple F tests. Biometrics 11:1–42.Google Scholar
  5. Griffin DH (1981) In: Fungal Physiology. John Wiley & Sons, Inc, New York.Google Scholar
  6. Hanlin RT (1971) Proc. Ga. Pecan Grow. Assn. 2:20–26.PubMedGoogle Scholar
  7. Hanlin RT, Blanchard RO (1974) Bul. Ga. Acad. Sci. 32:68–75.Google Scholar
  8. Hao DYY, Heaton EK, Beuchat LR (1989) J. Food Sci. 54:472–474.Google Scholar
  9. Knox CAP, Smith RH (1980) In Vitro 16:651–654.Google Scholar
  10. Langhans VE, Hedin PA, Graves CH Jr. (1977) Abstr., Proc. Am. Phytopathological Soc. 1976, 3, 339.Google Scholar
  11. Merkle SA, Wetzstein HY, Sommer HE (1987) Hort Sci. 22:128–130.Google Scholar
  12. Murashige T, Skoog F (1962) Physiol. Plant. 15:473–497.Google Scholar
  13. Owens LD, Wozniak CA (1990) Abstr., VIIth International Congress on Plant Tissue and Cell Culture. 1990, 30.Google Scholar
  14. Papendick RI, Campbell GS (1981) In: Water Potential Relations in Soil Microbiology. Soil Science Society of America, SSSA special publication number 9.Google Scholar
  15. Schroeder HW, Cole RJ (1977) J. Agric. Food Chem. 25:204–206.Google Scholar
  16. Scott, WJ (1957) In Advances in Food Research 7:83–127.Google Scholar
  17. Staba EJ (1962) J. Pharm. Sci. 51:249–254.Google Scholar
  18. Wells JM (1980) J. Food Safety 4:213–220.Google Scholar
  19. Wetzstein HY, Ault JR, Merkle SA (1989) Plant Sci. 64:193–201.Google Scholar
  20. Wood BW (1982) HortSci. 17:890–891.Google Scholar
  21. Yates IE, Wood BW (1989) J. Amer. Soc. Hort. Sci. 114:1025–1029.Google Scholar
  22. Yates IE, Reilly CC (1990) HortSci. 25:573–576.Google Scholar

Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • Ahmed A. Obeidy
    • 1
  • M. A. L. Smith
    • 1
  1. 1.Department of HorticultureUniversity of IllinoisUrbanaUSA

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