Short-Term Effects of γ-Irradiation on 1-Aminocyclopropane-1-Carboxylic Acid Metabolism in Early Climacteric Cherry Tomatoes

Abstract

ABSTRACT'y-Irradiation of early climacteric (breaker) cherry tomatoes (Lycopersicon pimpinellifollium L.) caused a sharp burst in ethylene production during the first hour. The extent of ethylene production was dose dependent and was maximum at about 3 kilograys. The content of 1-aminocyclopropane-1-carboxylic acid (ACC), followed the same evolution as ethylene production, while malonyl ACC increased steadily with time in irradiated fruits. The burst in ethylene production was accompanied by a sharp stimulation of ACC synthase activity which began 15 minutes after irradiation. The stimulation was completely prevented by cycloheximide, but not by actinomycin D or cordycepin. In contrast with irradiation, mechanical wounding continuously stimulated ethylene production over several hours. '-Irradiation and cordycepin applied to wounded tissues both caused the cessation of this continuous increase, but the initial burst was still persisting. These data suggest that a-irradiation, like wounding, stimulates the translation of preexisting mRNAs. It also reduces, at least temporarily, the subsequent transcription-dependent stimulation of ethylene production. '-Irradiation greatly inhibited the activity of ethylene-forming enzyme at doses higher than 1 kilogray. Such sensitivity is in accordance with a highly integrated membranebound enzyme.

Gamma radiation control quality and lignification of bamboo shoots ( Phyllostachys praecox f . prevernalis. ) stored at low temperature

“…Effect of radiation on reducing ethylene production through lowering activities of ACS and ACO has also been reported in apricot by ionizing radiation (Egea et al, 2007). The suppression of ACS and ACO activities by gamma radiation in fruits and vegetables were suggested being associated with its well-known action on DNA (Larrigaudière et al, 1990).…”

Effet du stress salin sur la variation de certains metabolites chez Lycopersicon esculentum et Lycopersicon sheesmanii

“…Hoffman et Yang (1980) ont égale-ment trouvé des valeurs très faibles et attribuent celles-ci à l'inaptitude de ces tissus à convertir SAM en ACC. Par ailleurs, Larrigaudière et al (1990) rapportent que la stimulation de la production d'éthylène par le stress est probablement le résultat de l'activation de ARNm préexistante du fait que cette synthèse peut être évitée par le cycloheximide (inhibiteur de la traduction) mais non pas par la cordycepine (inhibiteur de la transcription). La non stimulation de la production d'éthylène dans les fruits prématurés suggère que ces fruits de tomate ne contiennent pas ARNm préformé et codant pour l'ACC synthase à ce stade de développement.…”

The influence of electron-beam ionization on ethylene metabolism and quality parameters in apricot (Prunus armeniaca L., cv Búlida)

“…Specifically, in banana treated at doses over 0.4 kGy (Strydom & Whitehead, 1990) and in Gala apple treated at 0.44 and 1.23 kGy (Fan, Argenta, & Mattheis, 2001), an inhibition of ethylene synthesis was observed. On the contrary, in another climacteric fruit, Cherry tomato, there was an intense increase of ethylene production in the breaker stage of ripeness after 15 min of treatment (Larrigaudie´re, Latche´, Pech, & Triantaphylides, 1990) and a lesser increase for tomatoes in the mature-green state (Larrigaudie´re, Latche´, Pech, & Triantaphylides, 1991).…”