INVESTIGADORES
AGUIRREZABAL Luis Adolfo Nazareno
artículos
Título:
Re-watering of plants under water deficit reveals that leaf cells retain their ability to expand after the leaf has apparently reached its final size.
Autor/es:
LECHNER, L.; PEREYRA IRUJO, G.; GRANIER, C.; LUIS ADOLFO NAZARENO AGUIRREZABAL
Revista:
Annals of Botany
Editorial:
Oxford Journals
Referencias:
Año: 2008 vol. 101 p. 1007 - 1015
ISSN:
0305-7364
Resumen:
Background and Aims Leaves expand during a given period of time until they reach their final size and form, which
is called determinate growth. Duration of leaf expansion is stable when expressed in thermal-time and in the absence
of stress, and consequently it is often proposed that it is controlled by a robust programme at the plant scale. The
usual hypothesis is that growth cessation occurs when cell expansion becomes limited by an irreversible tightening
of cell wall, and that leaf size is fixed once cell expansion ceases. The objective of this paper was to test whether leaf
expansion could be restored by rewatering plants after a long soil water-deficit period.Background and Aims Leaves expand during a given period of time until they reach their final size and form, which
is called determinate growth. Duration of leaf expansion is stable when expressed in thermal-time and in the absence
of stress, and consequently it is often proposed that it is controlled by a robust programme at the plant scale. The
usual hypothesis is that growth cessation occurs when cell expansion becomes limited by an irreversible tightening
of cell wall, and that leaf size is fixed once cell expansion ceases. The objective of this paper was to test whether leaf
expansion could be restored by rewatering plants after a long soil water-deficit period.
Methods Four experiments were performed on two different species (Arabidopsis thaliana and Helianthus annuus)
in which the area of leaves that had apparently reached their final size was measured upon reversal of water stresses
of different intensities and durations.Methods Four experiments were performed on two different species (Arabidopsis thaliana and Helianthus annuus)
in which the area of leaves that had apparently reached their final size was measured upon reversal of water stresses
of different intensities and durations.
Key Results Re-growth of leaves that had apparently reached their final size occurred in both species, and its magnitude
depended only on the time elapsed from growth cessation to rewatering. Leaf area increased up to 186% inKey Results Re-growth of leaves that had apparently reached their final size occurred in both species, and its magnitude
depended only on the time elapsed from growth cessation to rewatering. Leaf area increased up to 186% in
A. thaliana and up to 88% in H. annuus after rewatering, with respect to the leaves of plants that remained under
water deficit. Re-growth was accounted for by cell expansion. Increase in leaf area represented actual growth and not
only a reversible change due to increased turgor.and up to 88% in H. annuus after rewatering, with respect to the leaves of plants that remained under
water deficit. Re-growth was accounted for by cell expansion. Increase in leaf area represented actual growth and not
only a reversible change due to increased turgor.
Conclusions After the leaf has ceased to grow, leaf cells retain their ability to expand for several days before leaf
size becomes fixed. A response window was identified in both species, during which the extent of leaf area recovery
decreased with time after the initial leaf growth cessation. These results suggest that re-growth after rewatering of
leaves having apparently attained their final size could be a generalized phenomenon, at least in dicotyledonous
plants.Conclusions After the leaf has ceased to grow, leaf cells retain their ability to expand for several days before leaf
size becomes fixed. A response window was identified in both species, during which the extent of leaf area recovery
decreased with time after the initial leaf growth cessation. These results suggest that re-growth after rewatering of
leaves having apparently attained their final size could be a generalized phenomenon, at least in dicotyledonous
plants.