On the involvement of adenine nucleotides in the development of brown heart in 'Conference' pears during delayed controlled atmosphere storage

It is supposed that the development of CA-induced browning disorders in 'Co nference' pears is related to the "energy charge" of the tissues which decr eased during storage period (SAQUET et al. 2000). It is known that the dela y in the establishment of the CA conditions can reduce the incidence of fle sh browning in pears (HOHN et al. 1996). This research was carried out to t est the effectiveness of a delayed CA storage treatment (21 days at 0 degre esC and ambient atmosphere before CA storage) in order to adapt fruits to C A. Thereafter, fruits were stored for up to six months in 3% CO2 + 1% O-2 a t 0 degreesC. Fruits without delay were immediately stored under CA and dev eloped 80%, 90% and 72% higher incidence of flesh browning, core browning a nd cavities, respectively, compared to delay-treated fruits. Fruits subject ed to delayed CA showed higher ethylene production and higher respiration a ctivity during the first two months of storage, and was associated with hig her concentrations of ATP in the fruit tissue. Higher ATP levels remained u ntil the fourth month of storage. A higher ATP:ADP ratio of delay-treated f ruits was also found indicating a higher energy charge of tissue during thi s period. The results suggest that 'Conference' pears can become adapted to CA during the early stages of the storage period making them more resistan t against brown heart. The possible role of ATP in maintaining membrane cel l integrity under CA conditions and thus reducing browning disorders is dis cussed.