ARS | Publication request: CHLOROPHYLL FLUORESCENCE IMAGING TO DETECT POSTHARVEST QUARANTINE-INDUCED CITRUS RIND INJURY

Submitted to: American Society for Horticultural Science Abstracts 2000
Publication Type: Proceedings
Publication Acceptance Date: January 1, 2003
Publication Date: January 1, 2003
Citation: Obenland, D.M., Neipp, P.W. 2003. Chlorophyll fluorescence imaging to detect postharvest quarantine-induced citrus rind injury. HortScience 38:855

Technical Abstract: Chlorophyll fluorecence (Fchl) changes is very sensitive to stress, and has been proposed as a means of predicting stress-induced tissue injury. Development of citrus rind injury following postharvest quarantine treatments is often not uniform and difficult to assess using standard hand-held fluorometers due to limited coverage of the surface area of the fruit. In this study, an imaging fluorometer was used to quantify Fchl over large surface areas of the fruit to determine the relationship between rind injury induced by high temperature treatment and changes in rind Fchl. Limes were immersed in 55C water for 0, 1, 3, and 5 min and both sides of the fruit imaged for Fchl following 24 h and 1 wk of storage at 5C. Following 1 min of hot water treatment and 24 h of storage maximum fluorescence yield (Fm) dropped by 36% while after 3 and 5 min Fm declined by 55%. In contrast, initial fluorescence (F0) increased by 26% after 1min of treatment and by 60% following 3 and 5 min. Fluorescence images taken after a week of storage indicated that some recovery of Fm occurred while F0 continued to increase. The ratio of F0/(Fm-F0) increased most dramatically between 1 and 3 min and was associated with the occurrence of rind injury in the treated lines.