Effect of ethylene and 1-MCP treatments on strawberry fruit ripening.
BACKGROUND
Strawberry is a soft fruit, considered as non-climacteric, being auxins the main hormones that regulate the ripening process. The role of ethylene in strawberry ripening is currently unclear and several studies have considered a revision of the possible role of this hormone.


RESULTS
Strawberry fruit were harvested at the white stage and treated with ethephon, an ethylene-releasing reagent, or 1-methylcyclopropene (1-MCP), a competitive inhibitor of ethylene action. The effects of the treatments on fruit quality parameters and on the activity of enzymes related to anthocyanin synthesis and cell wall degradation were evaluated. Some aspects of ripening were accelerated (anthocyanin accumulation, total sugar content and increment of phenylalanine ammonia-lyase (PAL; EC 4.3.1.24) and beta-galactosidase (EC 3.2.1.23) activities), while others were repressed (chlorophyll levels and increment of endo-1,4-beta-glucanase (EC 3.2.1.4) and beta-xylosidase (EC 3.2.1.37) activities) or unchanged (reducing sugar content, pH, titratable acidity and alpha-L-arabinofuranosidase (EC 3.2.1.55) activity) by ethylene. 1-MCP treatment caused the opposite effect. However, its effects were more pronounced, particularly in anthocyanin accumulation, phenolics, PAL and polygalacturonase (EC 3.2.1.15 and EC 3.2.1.67) activities.


CONCLUSIONS
These observations probably indicate that strawberry produces low levels of ethylene that are sufficient to regulate some ripening aspects.
Villarreal
Natalia M
NM
Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIB-INTECH; CONICET-UNSAM), B7130IWA Chascomús, Argentina.
Bustamante
Claudia A
CA
Civello
Pedro M
PM
Martínez
Gustavo A
GA
D003521:Cyclopropanes / Q000494:pharmacology*; D005030:Ethylenes / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism*; D031985:Fragaria / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D005638:Fruit / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D009943:Organophosphorus Compounds / Q000494:pharmacology*; D010937:Plant Growth Regulators / Q000096:biosynthesis / Q000378:metabolism*
D003521:Cyclopropanes; D005030:Ethylenes; D009943:Organophosphorus Compounds; D010937:Plant Growth Regulators; C036216:ethylene; C412563:1-methylcyclopropene; C005073:ethephon