This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Shih, L.-M. Articles by Galston, A. W. Search for Related Content PubMed PubMed Citation Articles by Shih, L.-M. Articles by Galston, A. W. Agricola Articles by Shih, L.-M. Articles by Galston, A. W.

Articles

Effects of Exogenous 1,3-Diaminopropane and Spermidine on Senescence of Oat Leaves ¹

I. Inhibition of Protease Activity, Ethylene Production, and Chlorophyll Loss as Related to Polyamine Content

Department of Biology, Yale University, New Haven, Connecticut 06511

Excision and dark incubation of oat (Avena sativa L., var. Victory) leaves cause a sharp increase in protease activity, which precedes Chl loss. Both these senescence processes are inhibited by exogenously applied 1,3-diaminopropane (Dap), which occurs naturally in leaf segments. The inhibition of protease activity is much greater in vivo than in vitro, suggesting inhibition of protease synthesis as well as protease action by Dap. Chl breakdown in leaves of radish and broccoli, which also senesce rapidly in the dark, is only slightly inhibited by DaP. These differences between cereal and dicotyledonous plants are correlated with the natural occurrence of Dap in cereals. In the light, Dap promotes, rather than retards, the loss of Chl in oat leaves. This resembles previously described effects of other polyamines. Addition of Mg²⁺ to the medium does not antagonize this effect. In the dark, the accumulated Dap also inhibits ethylene production and decreases titer of other polyamines. Addition of Ca²⁺ to the incubation medium containing Dap competitively reduces the effects of Dap. Thus, Dap, like other polyamines, seems to require an initial attachment to a membrane site shared with Ca²⁺ before exerting its antisenescence action.

³ Present address: Institute of Plant Physiology, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland.

¹ Supported by grant DAR 7813294 from the National Science Foundation and I-44-79 from the Binational Agricultural Research and Development (BARD) agency to A. W. G.

This article has been cited by other articles:

				N. N. Tun, C. Santa-Catarina, T. Begum, V. Silveira, W. Handro, E. I. S. Floh, and G. F. E. Scherer Polyamines Induce Rapid Biosynthesis of Nitric Oxide (NO) in Arabidopsis thaliana Seedlings Plant Cell Physiol., March 1, 2006; 47(3): 346 - 354. [Abstract] [Full Text] [PDF]