Summary
An isolate of Saprolegnia australis grew readily and produced abundant sex organs on a chemically defined medium. The optimal temperature for growth was higher (25°) than the optimal temperature for sexual reproduction (20°). Addition of the purines, adenine and hypoxanthine to the medium stimulated production of oogonia while addition of kinetin and 6-benzylaminopurine inhibited this process. When kinetin and adenine were added together, the two purines interacted in affecting oogonial production, and adenine overcame the inhibitory action of kinetin. It is suggested that purines may play some specific role in the synthesis of one or more of the hormones which probably initiate sexual reproduction in S. australis and that kinetin and 6-benzylaminopurine may inhibit hormone synthesis. Two other growth regulators of higher plants, indol-3-ylacetic acid and gibberellic acid, did not affect development of the fungus. No evidence was found to suggest that S. australis was producing any substance with cytokinin activity.
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References
Barksdale, A. W.: Effect of nutritional deficiency on growth and sexual reproduction of Achlya ambisexualis. Amer. J. Bot. 49, 633–638 (1962).
Chee, K. H., and F. J. Newhook: Variability in sexual reproduction of Phytophthora cinnamomi Rands. N. Z. J. agric. Res. 8, 947–950 (1965).
Elliott, R.F.: Morphological variation in New Zealand Saprolegniaceae. I. Achlya caroliniana Coker and A. flagellata Coker. N. Z. J. Bot., in press (a).
Elliott, R. F. II. Saprolegnia terrestris Cookson and S. australis sp. nov. N. Z. J. Bot., in press (b).
Gruen, H. E.: Auxins and fungi. Ann. Rev. Plant Physiol. 10, 405–440 (1959).
Hawker, L. E.: The physiology of reproduction in fungi. Cambridge: Univ. Press 1957.
Lee, B. O.: Effects of kinetin on the fertility of some strains of Neurospora crassa. Nature (Lond.) 192, 288 (1961).
Letham, D. S.: Regulators of cell division in plant tissue I. Inhibitors and stimulants of cell division in developing fruits; their properties and activity in relation to the cell division period. N. Z. J. Bot. 1, 336–350 (1963).
—: II. A cytokinin in plant extracts: isolation and interaction with other growth regulators. Phytochemistry 5, 269–286 (1966).
Raper, J. R.: Sexual hormones in Achlya VII. The hormonal mechanism in homothallic species. Bot. Gaz. 112, 1–24 (1950).
Robbins, W. J., and F. Kavanagh: Guanine and factor Z, growth substances for Phycomyces. Proc. nat. Acad. Sci. (Wash.) 28, 4–8 (1942a).
——: Hypoxanthine, a growth factor of Phycomyces. Proc. nat. Acad. Sci. (Wash.) 28, 65–69 (1942b).
Sommer, N. F.: Production by Taphrina deformans of substances stimulating cell elongation and division. Physiol. Plantarum (Copenh.) 14, 460–469 (1961).
Stowe, B. B., and T. Yamaki: The history and physiological action of the gibberellins. Ann. Rev. Plant Physiol. 8, 181–216 (1957).
Street, H. E., M. P. McGonagle, and S. M. McGregor: Observations on the “staling” of White's medium by excised tomato roots. II. Iron availability. Physiol. Plantarum (Copenh.) 5, 248–276 (1952).
Torrey, J. G.: Auxin and purine interactions in lateral root initiation in isolated pea root segments. Physiol. Plantarum (Copenh.) 15, 177–185 (1962).
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Elliott, R.F. Effects of kinetin and related compounds on growth and sexual reproduction of Saprolegnia australis . Planta 77, 164–175 (1967). https://doi.org/10.1007/BF00387453
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DOI: https://doi.org/10.1007/BF00387453