Metabolism of etiolated and green asparagus before and after harvest

Pre- and post-harvest respiratory activity and ethylene production of etiolated and green asparagus (Asparagus officinalis L.) were measured at 15 degreesC in whole spears. The growing asparagus spears had an extremely high CO2 production (5.0-8.0 mmol kg(-1) h(-1)) but a quite low ethylene production (46-85 nmol kg(-1) h(-1)). Higher respiratory activity (by a factor of 1.58) as well as higher ethylene production (by a factor of 1.84) was found in green spears compared with etiolated ones. Apparently, as a result of wounding stress from harvesting, the respiration and ethylene production increased immediately after harvest in both green and etiolated spears. The effect of wounding induced by cutting of spears was greater in the green than in the etiolated spears. Subsequently, respiration rate declined before reaching an equilibrium level of around 3.4 and 2.3 mmol CO2 kg(-1) h(-1) in the green and the etiolated spears, respectively, while ethylene production, after a decline until 6 h after harvest, almost doubled by the 24th h and later decreased to a level of about 21 nmol kg(-1) h(-1) in both green and etiolated spears.