Untitled

Abstract

Passe-Crassane pears require a 3-month chilling treatment at 0 degrees C to be able to produce ethylene and ripen autonomously after subsequent rewarming. The chilling treatment strongly stimulated ACC oxidase activity, and to a lesser extent ACC synthase activity. At the same time, the levels of mRNAs hybridizing to ACC synthase and ACC oxidase probes increased dramatically. Fruit stored at 18 degrees C immediately after harvest did not exhibit any of these changes, while fruit that had been previously chilled exhibited a burst of ethylene production associated with high activity of ACC oxidase and ACC synthase upon rewarming. ACC oxidase mRNA strongly accumulated in rewarmed fruits, while ACC synthase mRNA level decreased. The chilling-induced accumulation of ACC synthase and ACC oxidase transcripts was strongly reduced when ethylene action was blocked during chilling with 1-methylcyclopropene (1-MCP). Upon rewarming ACC synthase and ACC oxidase transcripts rapidly disappeared in 1-MCP-treated fruits. A five-week treatment of non-chilled fruits with the ethylene analog propylene led to increased expression of ACC oxidase and to ripening. However, ethylene synthesis, ACC synthase activity and ACC synthase mRNAs remained at very low level. Our data indicate that ACC synthase gene expression is regulated by ethylene only during, or after chilling treatment, while ACC oxidase gene expression can be induced separately by either chilling or ethylene.

Low-temperature-modulated fruit ripening is independent of ethylene in 'Sanuki Gold' kiwifruit

“…In winter pears, a chilling treatment is necessary for uniform acceleration of fruit ripening (Lelievre et al , 1997). In ‘Passe-Crassane’ pears, chilling treatments induced fruit ripening after subsequent re-warming through the increased activities and accumulation of ACC oxidase and ACC synthase transcripts, which result in the production of ethylene (Looney, 1972; Lelievre et al , 1997).…”

“…In ‘Passe-Crassane’ pears, chilling treatments induced fruit ripening after subsequent re-warming through the increased activities and accumulation of ACC oxidase and ACC synthase transcripts, which result in the production of ethylene (Looney, 1972; Lelievre et al , 1997). It was also demonstrated in ‘La France’ pears that storage of fruit at 1 °C for 3 weeks induced ethylene biosynthesis and PG mRNA accumulation after removal from cold storage, leading to fruit softening (Hiwasa et al , 2003).…”

Aplicação de 1-metilciclopropeno e absorção de etileno em maçã da cultivar 'Royal Gala' colhida tardiamente

“…(MA et al, 2006), transmitindo um sinal fisiológico para a síntese de enzimas que atuarão nos processos bioquímicos característicos do amadurecimento, como degradação da parede celular e quebra da clorofila (TAIZ & ZEIGER, 2004). A aplicação pós-colheita de 1-meticiclopropeno (1-MCP), inibidor da ação do etileno, pode manter a qualidade de frutos, como maçãs (BRACKMANN et al, 2004;CORRENT et al, 2004;, peras (LELIÈVRE et al, 1997), bananas (SISLER & SEREK, 1997) e abacates (KLUGE et al, 2002). O composto volátil 1-MCP, por possuir uma composição química semelhante ao etileno, liga-se irreversivelmente aos receptores de etileno de forma competitiva, no entanto não transmite o sinal característico desse fitohormônio e, deste modo, bloqueia sua ação na célula do fruto, retardando o amadurecimento (SISLER & SEREK, 1997;BLANKENSHIP & DOLE, 2003;WATKINS, 2006).…”

Ethylene action blockade and cold storage affect ripening of ‘Golden’ papaya fruit

“…Thus, relating ripening changes only to respiratory activity seems to present an oversimplified view of this process. In addition, the increase in respiratory activity depends on many factors, such as the variety of fruit being used and the environmental conditions and ripening stage (Lelièvre et al 1997b). This makes it difficult to classify fruits according to respiratory activity.…”