Leaf Abscission lnduced by Ethylene in Water-Stressed lntact Seedlings of Cleopatra Manda& Requires Previous Abscisic Acid Accumulation in Roots
The involvement of abscisic acid (ABA) in the process of leaf abscission induced by 1 -aminocyclopropane-1 -carboxylic acid (ACC) transported from roots to shoots in Cleopatra mandarin (Citrus reshni Hort. ex Tan.) seedlings grown under water stress was studied using norflurazon (NF). Water stre...
| Autores principales: | , , , |
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| Formato: | article |
| Lenguaje: | Inglés |
| Publicado: |
ASBP
2020
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| Materias: | |
| Acceso en línea: | http://hdl.handle.net/20.500.11939/6433 http://www.plantphysiol.org/content/112/1/401/tab-article-info |
| Sumario: | The involvement of abscisic acid (ABA) in the process of leaf
abscission induced by 1 -aminocyclopropane-1 -carboxylic acid
(ACC) transported from roots to shoots in Cleopatra mandarin
(Citrus reshni Hort. ex Tan.) seedlings grown under water stress was
studied using norflurazon (NF). Water stress induced both ABA
(24-fold) and ACC (16-fold) accumulation in roots and arrested
xylem flow. Leaf bulk ABA also increased (&fold), although leaf
abscission did not occur. Shortly after rehydration, root ABA and
ACC returned to their prestress levels, whereas sharp and transitory
increases of ACC (1 7-fold) and ethylene (1 O-fold) in leaves and high
percentages of abscission (up to 47%) were observed. NF suppressed
the ABA and ACC accumulation induced by water stress in
roots and the sharp increases of ACC and ethylene observed after
rewatering in leaves. NF also reduced leaf abscission (7-1070).
These results indicate that water stress induces root ABA accumulation
and that this is required for the process of leaf abscission to
occur. It was also shown that exogenous ABA increases ACC levels
in roots but not in leaves. Collectively, the data suggest that ABA,
the primary sensitive signal to water stress, modulates the levels of
ethylene, which is the hormonal activator of leaf abscission. This
assumption implies that root ACC levels are correlated with root
ABA amounts in a dependent way, which eventually links water
status to an adequate, protective response such as leaf abscission |
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