IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
artículos
Título:
Quantifying the sensitivity of barley seed germination to oxygen, abscisic acid, and gibberellin using a population-based threshold model.
Autor/es:
BRADFORD K.J., BENECH-ARNOLD R.L., COME D. AND CORBINEAU F.
Revista:
JOURNAL OF EXPERIMENTAL BOTANY
Editorial:
Oxford Journals
Referencias:
Lugar: Oxford; Año: 2008 vol. 59 p. 335 - 347
ISSN:
0022-0957
Resumen:
Barley (Hordeum vulgare L.) seeds (grains) exhibit
dormancy at maturity that is largely due to the
presence of the glumellae (hulls) that reduce the
availability of oxygen (O2) to the embryo. In addition,
abscisic acid (ABA) and gibberellins (GAS) interact
with O2 to regulate barley seed dormancy. A population-
based threshold model was applied to quantify the
sensitivities of seeds and excised embryos to O2, ABA,
and GA, and to their interactive effects. The median O2Hordeum vulgare L.) seeds (grains) exhibit
dormancy at maturity that is largely due to the
presence of the glumellae (hulls) that reduce the
availability of oxygen (O2) to the embryo. In addition,
abscisic acid (ABA) and gibberellins (GAS) interact
with O2 to regulate barley seed dormancy. A population-
based threshold model was applied to quantify the
sensitivities of seeds and excised embryos to O2, ABA,
and GA, and to their interactive effects. The median O22) to the embryo. In addition,
abscisic acid (ABA) and gibberellins (GAS) interact
with O2 to regulate barley seed dormancy. A population-
based threshold model was applied to quantify the
sensitivities of seeds and excised embryos to O2, ABA,
and GA, and to their interactive effects. The median O22 to regulate barley seed dormancy. A population-
based threshold model was applied to quantify the
sensitivities of seeds and excised embryos to O2, ABA,
and GA, and to their interactive effects. The median O22, ABA,
and GA, and to their interactive effects. The median O22
requirement for germination of dormant intact barley
seeds was 400-fold greater than for excised embryos,
indicating that the tissues enclosing the embryo
markedly limit O2 penetration. However, embryo O22 penetration. However, embryo O2
thresholds decreased by another order of magnitude
following after-ripening. Thus, increases in both permeability
of the hull to O2 and embryo sensitivity to O22 and embryo sensitivity to O2
contribute to the improvement in germination capacity
during after-ripening. Both ABA and GA had relatively
small effects on the sensitivity of germination to O2,
but ABA and GA thresholds varied over several orders
of magnitude in response to O2 availability, with
sensitivity to ABA increasing and sensitivity to GA
decreasing with hypoxia. Simple additive models of
O2ABA and O2GA interactions required consideration
of these O2 effects on hormone sensitivity to
account for actual germination patterns. These quantitative
and interactive relationships among O2, ABA,
and GA sensitivities provide insight into how dormancy
and germination are regulated by a combination
of physical (O2 diffusion through the hull) and physiological
(ABA and GA sensitivities) factors.2,
but ABA and GA thresholds varied over several orders
of magnitude in response to O2 availability, with
sensitivity to ABA increasing and sensitivity to GA
decreasing with hypoxia. Simple additive models of
O2ABA and O2GA interactions required consideration
of these O2 effects on hormone sensitivity to
account for actual germination patterns. These quantitative
and interactive relationships among O2, ABA,
and GA sensitivities provide insight into how dormancy
and germination are regulated by a combination
of physical (O2 diffusion through the hull) and physiological
(ABA and GA sensitivities) factors.2 availability, with
sensitivity to ABA increasing and sensitivity to GA
decreasing with hypoxia. Simple additive models of
O2ABA and O2GA interactions required consideration
of these O2 effects on hormone sensitivity to
account for actual germination patterns. These quantitative
and interactive relationships among O2, ABA,
and GA sensitivities provide insight into how dormancy
and germination are regulated by a combination
of physical (O2 diffusion through the hull) and physiological
(ABA and GA sensitivities) factors.2ABA and O2GA interactions required consideration
of these O2 effects on hormone sensitivity to
account for actual germination patterns. These quantitative
and interactive relationships among O2, ABA,
and GA sensitivities provide insight into how dormancy
and germination are regulated by a combination
of physical (O2 diffusion through the hull) and physiological
(ABA and GA sensitivities) factors.2 effects on hormone sensitivity to
account for actual germination patterns. These quantitative
and interactive relationships among O2, ABA,
and GA sensitivities provide insight into how dormancy
and germination are regulated by a combination
of physical (O2 diffusion through the hull) and physiological
(ABA and GA sensitivities) factors.2, ABA,
and GA sensitivities provide insight into how dormancy
and germination are regulated by a combination
of physical (O2 diffusion through the hull) and physiological
(ABA and GA sensitivities) factors.2 diffusion through the hull) and physiological
(ABA and GA sensitivities) factors.
Key words: Abscisic acid, barley, germination, gibberellin,
Hordeum vulgare L., model, oxygenL., model, oxygen