Document Detail

Hormonal regulation of fruitlet abscission induced by carbohydrate shortage in citrus.
MedLine Citation:
PMID:  10787058     Owner:  NLM     Status:  MEDLINE    
The hormonal signals controlling fruitlet abscission induced by sugar shortage in citrus were identified in Satsuma mandarin, Citrus unshiu (Mak.) Marc, cv. Clausellina and cv. Okitsu. Sugar supply, hormonal responses and fruitlet abscission were manipulated through full, partial or selective leaf removals at anthesis and thereafter. In developing fruitlets, defoliations reduced soluble sugars (up to 98%), but did not induce nitrogen and water deficiencies. Defoliation-induced abscission was preceded by rises (up to 20-fold) in the levels of abscisic acid (ABA) and 1-aminocyclopropane-1-carboxylic acid (ACC) in fruitlets. Applications to defoliated plants showed that ABA increased ACC levels (2-fold) and accelerated fruitlet abscission, whereas norflurazon and 2-aminoethoxyvinyl glycine reduced ACC (up to 65%) and fruitlet abscission (up to 40%). Only the full defoliation treatment reduced endogenous gibberellin A1 (4-fold), whereas exogenous gibberellins had no effect on abscission. The data indicate that fruitlet abscission induced by carbon shortage in citrus is regulated by ABA and ACC originating in the fruits, while gibberellins are apparently implicated in the maintenance of growth. In this system, ABA may act as a sensor of the intensity of the nutrient shortage that modulates the levels of ACC and ethylene, the activator of abscission. This proposal identifies ABA and ACC as components of the self-regulatory mechanism that adjusts fruit load to carbon supply, and offers a physiological basis for the photoassimilate competition-induced abscission occurring under natural conditions.
A Gómez-Cadenas; J Mehouachi; F R Tadeo; E Primo-Millo; M Talon
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Planta     Volume:  210     ISSN:  0032-0935     ISO Abbreviation:  Planta     Publication Date:  2000 Mar 
Date Detail:
Created Date:  2000-07-27     Completed Date:  2000-07-27     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  1250576     Medline TA:  Planta     Country:  GERMANY    
Other Details:
Languages:  eng     Pagination:  636-43     Citation Subset:  IM    
Departamento de Citricultura, Instituto Valenciano de Investigaciones Agrarias, Moncada, Spain.
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MeSH Terms
Abscisic Acid / metabolism*,  pharmacology
Amino Acids / metabolism*
Amino Acids, Cyclic*
Carbohydrate Metabolism*
Carbohydrates / deficiency
Chromatography, High Pressure Liquid
Citrus / metabolism*,  physiology
Enzyme-Linked Immunosorbent Assay
Glycine / analogs & derivatives,  pharmacology
Plant Growth Regulators / metabolism*
Plant Leaves / metabolism,  physiology
Pyridazines / pharmacology
Reg. No./Substance:
0/Amino Acids; 0/Amino Acids, Cyclic; 0/Carbohydrates; 0/Plant Growth Regulators; 0/Pyridazines; 21293-29-8/Abscisic Acid; 22059-21-8/1-aminocyclopropane-1-carboxylic acid; 27314-13-2/norflurazone; 49669-74-1/aminoethoxyvinylglycine; 56-40-6/Glycine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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