PLANT PHYSIOLOGY , Vol 105, Issue 4 1149-1157, Copyright © 1994 by American Society of Plant Biologists
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ENVIRONMENTAL AND STRESS PHYSIOLOGY |
Effect of Aerobic Priming on the Response of Echinochloa crus-pavonis to Anaerobic Stress (Protein Synthesis and Phosphorylation)
F. Zhang, J. J. Lin, T. C. Fox, C. V. Mujer, M. E. Rumpho and R. A. Kennedy
Departments of Horticultural Sciences (T.C.F., C.V.M., M.E.R.) and Biology (R.A.K.), Texas A&M University, College Station, Texas 77843
Echinochloa species differ in their ability to germinate and grow in the
absence of oxygen. Seeds of Echinochloa crus-pavonis (H.B.K.) Schult do not
germinate under anoxia but remain viable for extended periods (at least 30
d) when incubated in an anaerobic environment. E. crus-pavonis can be
induced to germinate and grow in an anaerobic environment if the seeds are
first subjected to a short (1-18 h) exposure to aerobic conditions (aerobic
priming). Changes in polypeptide patterns (constitutive and de novo
synthesized) and protein phosphorylation induced by aerobic priming were
investigated. In the absence of aerobic priming protein degradation was not
evident under anaerobic conditions, although synthesis of a 20-kD
polypeptide was induced. During aerobic priming, however, synthesis of 37-
and 55-kD polypeptides was induced and persisted upon return of the seeds
to anoxia. Furthermore, phosphorylation of two 18-kD polypeptides was
observed only in those seeds that were labeled with 32PO4 during the
aerobic priming period. Subsequent chasing in an anaerobic environment
resulted in a decrease in phosphorylation of these polypeptides. Likewise,
phosphorylation of the 18-kD polypeptides was not observed if the seeds
were labeled in an anaerobic atmosphere. These results suggest that the
regulated induction of the 20-, 37-, and 55- kD polypeptides may be
important for anaerobic germination and growth of E. crus-pavonis and that
the specific phosphorylation of the 18-kD polypeptides may be a factor in
regulating this induction.
