IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
artículos
Título:
Hypoxia interferes with ABA metabolism and increases ABA sensitivity in embryos of dormant barley grains
Autor/es:
BENECH-ARNOLD, R.L., GUALANO, N.A., LEYMARIE, J., COME D. AND CORBINEAU F.
Revista:
JOURNAL OF EXPERIMENTAL BOTANY
Referencias:
Año: 2006 vol. 57 p. 1423 - 1430
ISSN:
0022-0957
Resumen:
Two mechanisms have been suggested as being responsible
for dormancy in barley grain: (i) ABA in the
embryo, and (ii) limitation of oxygen supply to the
embryo by oxygen fixation as a result of the oxidation
of phenolic compounds in the glumellae. The aim of
the present work was to investigate whether hypoxia
imposed by the glumellae interferes with ABA metabolism
in the embryo, thus resulting in dormancy. In
dormant and non-dormant grains incubated at 20 8C
and in non-dormant grains incubated at 30 8C (i.e.
when dormancy is not expressed), ABA content in the
embryo decreased dramatically during the first 5 h of
incubation before germination was detected. By contrast,
germination of dormant grains was less than
2% within 48 h at 30 8C and embryo ABA content increased
during the first hours of incubation and then
remained 24 times higher than in embryos from grains
in which dormancy was not expressed. Removal of
the glumellae allowed germination of dormant grains
at 30 8C and the embryos did not display the initial
increase in ABA content. Incubation of de-hulled grains
under 5% oxygen to mimic the effect of glumellae, restored
the initial increase ABA in content and completely
inhibited germination. Incubation of embryos
isolated from dormant grains, in the presence of a wide
range of ABA concentrations and under various oxygen
tensions, revealed that hypoxia increased embryo
sensitivity to ABA by 2-fold. This effect was more
pronounced at 30 8C than at 20 8C. Furthermore, when
embryos from dormant grains were incubated at 30 8C
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
embryos from dormant grains were incubated at 30 8C
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
increase in ABA content. Incubation of de-hulled grains
under 5% oxygen to mimic the effect of glumellae, restored
the initial increase ABA in content and completely
inhibited germination. Incubation of embryos
isolated from dormant grains, in the presence of a wide
range of ABA concentrations and under various oxygen
tensions, revealed that hypoxia increased embryo
sensitivity to ABA by 2-fold. This effect was more
pronounced at 30 8C than at 20 8C. Furthermore, when
embryos from dormant grains were incubated at 30 8C
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
embryos from dormant grains were incubated at 30 8C
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
during the first hours of incubation and then
remained 24 times higher than in embryos from grains
in which dormancy was not expressed. Removal of
the glumellae allowed germination of dormant grains
at 30 8C and the embryos did not display the initial
increase in ABA content. Incubation of de-hulled grains
under 5% oxygen to mimic the effect of glumellae, restored
the initial increase ABA in content and completely
inhibited germination. Incubation of embryos
isolated from dormant grains, in the presence of a wide
range of ABA concentrations and under various oxygen
tensions, revealed that hypoxia increased embryo
sensitivity to ABA by 2-fold. This effect was more
pronounced at 30 8C than at 20 8C. Furthermore, when
embryos from dormant grains were incubated at 30 8C
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
embryos from dormant grains were incubated at 30 8C
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
increase in ABA content. Incubation of de-hulled grains
under 5% oxygen to mimic the effect of glumellae, restored
the initial increase ABA in content and completely
inhibited germination. Incubation of embryos
isolated from dormant grains, in the presence of a wide
range of ABA concentrations and under various oxygen
tensions, revealed that hypoxia increased embryo
sensitivity to ABA by 2-fold. This effect was more
pronounced at 30 8C than at 20 8C. Furthermore, when
embryos from dormant grains were incubated at 30 8C
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
embryos from dormant grains were incubated at 30 8C
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
when dormancy is not expressed), ABA content in the
embryo decreased dramatically during the first 5 h of
incubation before germination was detected. By contrast,
germination of dormant grains was less than
2% within 48 h at 30 8C and embryo ABA content increased
during the first hours of incubation and then
remained 24 times higher than in embryos from grains
in which dormancy was not expressed. Removal of
the glumellae allowed germination of dormant grains
at 30 8C and the embryos did not display the initial
increase in ABA content. Incubation of de-hulled grains
under 5% oxygen to mimic the effect of glumellae, restored
the initial increase ABA in content and completely
inhibited germination. Incubation of embryos
isolated from dormant grains, in the presence of a wide
range of ABA concentrations and under various oxygen
tensions, revealed that hypoxia increased embryo
sensitivity to ABA by 2-fold. This effect was more
pronounced at 30 8C than at 20 8C. Furthermore, when
embryos from dormant grains were incubated at 30 8C
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
embryos from dormant grains were incubated at 30 8C
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
increase in ABA content. Incubation of de-hulled grains
under 5% oxygen to mimic the effect of glumellae, restored
the initial increase ABA in content and completely
inhibited germination. Incubation of embryos
isolated from dormant grains, in the presence of a wide
range of ABA concentrations and under various oxygen
tensions, revealed that hypoxia increased embryo
sensitivity to ABA by 2-fold. This effect was more
pronounced at 30 8C than at 20 8C. Furthermore, when
embryos from dormant grains were incubated at 30 8C
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
embryos from dormant grains were incubated at 30 8C
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
during the first hours of incubation and then
remained 24 times higher than in embryos from grains
in which dormancy was not expressed. Removal of
the glumellae allowed germination of dormant grains
at 30 8C and the embryos did not display the initial
increase in ABA content. Incubation of de-hulled grains
under 5% oxygen to mimic the effect of glumellae, restored
the initial increase ABA in content and completely
inhibited germination. Incubation of embryos
isolated from dormant grains, in the presence of a wide
range of ABA concentrations and under various oxygen
tensions, revealed that hypoxia increased embryo
sensitivity to ABA by 2-fold. This effect was more
pronounced at 30 8C than at 20 8C. Furthermore, when
embryos from dormant grains were incubated at 30 8C
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
embryos from dormant grains were incubated at 30 8C
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
increase in ABA content. Incubation of de-hulled grains
under 5% oxygen to mimic the effect of glumellae, restored
the initial increase ABA in content and completely
inhibited germination. Incubation of embryos
isolated from dormant grains, in the presence of a wide
range of ABA concentrations and under various oxygen
tensions, revealed that hypoxia increased embryo
sensitivity to ABA by 2-fold. This effect was more
pronounced at 30 8C than at 20 8C. Furthermore, when
embryos from dormant grains were incubated at 30 8C
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
embryos from dormant grains were incubated at 30 8C
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
and in non-dormant grains incubated at 30 8C (i.e.
when dormancy is not expressed), ABA content in the
embryo decreased dramatically during the first 5 h of
incubation before germination was detected. By contrast,
germination of dormant grains was less than
2% within 48 h at 30 8C and embryo ABA content increased
during the first hours of incubation and then
remained 24 times higher than in embryos from grains
in which dormancy was not expressed. Removal of
the glumellae allowed germination of dormant grains
at 30 8C and the embryos did not display the initial
increase in ABA content. Incubation of de-hulled grains
under 5% oxygen to mimic the effect of glumellae, restored
the initial increase ABA in content and completely
inhibited germination. Incubation of embryos
isolated from dormant grains, in the presence of a wide
range of ABA concentrations and under various oxygen
tensions, revealed that hypoxia increased embryo
sensitivity to ABA by 2-fold. This effect was more
pronounced at 30 8C than at 20 8C. Furthermore, when
embryos from dormant grains were incubated at 30 8C
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
embryos from dormant grains were incubated at 30 8C
in the presence of 10 lM ABA, their endogenous ABA
content remained constant after 48 h of incubation
under air, while it increased dramatically in embryos
incubated under hypoxia, indicating that the apparent
increase in embryo ABA responsiveness induced by
hypoxia was, in part, mediated by an inability of the
embryo to inactivate ABA. Taken together these results
suggest that hypoxia, either imposed artificially or by
the glumellae, increases embryo sensitivity to ABA
and interferes with ABA metabolism.
con