02557naa a2200229 a 450000100080000000500110000800800410001902200140006010000220007424501760009626000090027252018460028165000130212765000220214065000130216265000120217565000160218765000210220370000190222470000210224377300630226420207472023-05-18       2015    bl uuuu     u00u1 u    #d  a0925-52141 aPEREIRA, M. E. C.  aDelayed and prolonged ethylene treatment alleviates firmness asynchrony enhanced by 1-methylcyclopropene exposure in Guatemalan-West Indian avocado.h[electronic resource]  c2015  aStudies were conducted to determine the efficacy of a delayed and prolonged ethylene treatment in alleviating firmness asynchrony enhanced by 1-methylcyclopropene (1-MCP) exposure in avocado. ?Booth 7? and ?Booth 8? avocados, mid-season cultivars in Florida, were harvested and immersed in water (control) or aqueous 1-MCP at 16.7 mmol L 1 a.i. (900 mg L 1) for 1 min at 20 C; all fruit were held at 20 C/89 2% relative humidity until ripe, based on whole fruit firmness, respiration and ethylene evolution. The effect of delayed and prolonged ethylene treatment was investigated by exposing 1-MCP-treated fruit to ethylene (100 mL L 1) for 2 or 4 d at 20 C upon reaching two progressive ripening stages (120 N or 80 N of whole fruit firmness, respectively). Ripe fruit (10?15 N) from all treatments were assessed for peel color, pulp firmness and polygalacturonase (PG) activity. 1-MCP significantly delayed ripening of ?Booth 7? and ?Booth 8? avocado. Firmness asynchrony was confirmed in control fruit of both cultivars, with a difference of more than 20% in pulp firmness between apical and distal end segments regardless of ripeness stage.1-MCP-treated fruit showed pronounced firmness asynchrony, with pulp firmness for apical end 10-fold higher than for distal end. PG activity was not directly related to firmness asynchrony, since even when strong asynchrony was observed for 1-MCP-treated fruit, PG activity did not differ from control. A 2-d delayed exposure of fruit at either 120 N or 80 N whole fruit firmness to ethylene was not consistently sufficient to promote ripening recovery (in terms of whole fruit firmness). However, a prolonged, 4-d ethylene treatment of fruit at either progressive ripening stages from both ?Booth 7? and ?Booth 8? effectively overcame the pronounced firmness asynchrony caused by 1-MCP treatment.  aAvocados  aPolygalacturonase  aRipening  aAbacate  aMaturação  aPersea Americana1 aSARGENT, S. A.1 aHUBER, DONALD J.  tPostharvest Biology and Technologygv.108, p. 54-60, 2015.