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This research was designed to test the combined efficacy of hot water dipping (HWD) and leaf extracts of Cistus creticus L. subsp. creticus on the storage quality of fresh Valencia oranges. Experiments were laid down according to a completely randomised design with 10 different treatments. Five replications, with five fruits in each replication, were used in the current study, and research was designed to continue for 150 days. Quality characteristics were observed with 30-days interval. The applications of this study were (1) Control [dipping in water at 25°C for 5 min]; (2) HWD at 50°C for 5 min; (3) HWD + Additives (A) [Arabic gum (0.2%), potassium sorbate (0.05%), citric acid (0.05%) and vitamin C (0.05%)] at 50°C for 5 min; (4) Additives alone at 25°C for 5 min; (5) 1.0% C. creticus leaf + HWD + A; (6) 1.0% C. creticus leaf + A; (7) 0.5% C. creticus leaf + HWD + A; (8) 0.5% C. creticus leaf + A; (9) 0.5% C. creticus leaf + HWD and (10) 0.5% C. creticus leaf. According to the results obtained, both the HWD and C. creticus, alone or in combination, were effective in preserving orange weight during storage, preventing pathogenic decay, maintaining visual quality and fruit firmness, delaying the reduction in titratable acidity, increasing ascorbic acid content and reducing respiration rate of the orange fruits. Results also suggested that the combined effect of HWD with C. creticus leaf extracts provided the highest efficacy.

Although cuticle is known to play an important role in the biotic and abiotic stress resistance of citrus fruit, there has been rare research on preharvest exogenous treatments to regulate cuticle metabolites and improve the postharvest storability of citrus fruit. In this study, the effect of spraying 10% glycerol 90 days before harvest on cutin, wax, fruit storability, and primary metabolites of citrus fruit was analyzed. The results demonstrated that exogenous glycerol could promote the biosynthesis of cutin at the early stage and delay the degradation of wax at the later stage of treatment, which could be attributed to the induction of genes associated with cuticle metabolism. Among them, the expression of CsLACS1 , CsLACS2 , CsCYP86A8 , and CsMYB106 showed the highest correlation with cutin metabolism. Exogenous glycerol could further reduce postharvest water loss, decay, respiration rate, and accumulation off-flavor compounds such as acetaldehyde and ethanol, thereby improving fruit storability. Moreover, exogenous glycerol showed no effect on fruit quality before harvest, and the low levels of stress-response metabolites (such as γ-aminobutyric acid) suggested that glycerol-treated fruit were in a less stressful state compared to control fruit. In conclusion, preharvest glycerol treatment may be a safe and effective method to improve citrus fruit storability by regulating cuticle metabolism. • Preharvest glycerol spray promotes cutin accumulation and delays wax degradation. • The expression of cuticle related genes induced by exogenous glycerol. • Preharvest glycerol treatment reduces fruit weight loss and decay. • Preharvest glycerol spray improves the postharvest storability of citrus fruit. [ABSTRACT FROM AUTHOR]

Nonclimacteric varieties of guava (Psidium guajava L.), such as 'Jen-Ju Bar' ('JJB'), have been cultivated in tropical areas due to their crispy texture and long storability. However, the molecular mechanism resulting in different ripening behaviors among guava varieties is still obscure. To elucidate the underlying mechanism, four cDNA clones of two ACC synthases (ACS) and two ACC oxidases (ACO), the key enzymes of ethylene biosynthesis, were isolated based on the conserved nucleotide sequences. Their enzymatic activities were confirmed by heterologous expression in Escherichia coli. The expression levels of PgACS1 , PgACO1 , and PgACO2 increased dramatically with the advance of ripening in the climacteric cultivar 'Li-Tzy Bar' ('LTB'), whereas the transcripts of these genes, especially PgACS1 and PgACO2 , were barely detected in 'JJB' throughout the phase. In addition, PgACS1 and PgACO2 transcription were induced by ethylene and repressed by 1-methylcyclopropene, an ethylene action inhibitor, which exhibited the features of system-2 ethylene production genes. These results suggested that PgACS1 and PgACO2 are two important coordinators for controlling autocatalytic ethylene biosynthesis in guava fruit. The major defect of system-2 ethylene production in 'JJB' is caused by the silencing of PgACS1 during ripening. Consequently, 'JJB' behaves nonclimacterically and has a long storability. • The first detailed report describes the molecular mechanism of nonclimacteric guava. • Two ACC synthases and two ACC oxidases of guava are cloned and characterized. • PgACS1 is the main determinant between climacteric and nonclimacteric guava. • The long storability of nonclimacteric 'JJB' is ascribed to low ethylene emission. [ABSTRACT FROM AUTHOR]

Para determinar o rendimento de bulbos curados de seis genótipos de cebola cultivados em solo de várzea, e a conservabilidade pós-colheita destes, em ambiente natural, foram conduzidos dois experimentos na Universidade Federal de Santa Maria, em 1995 e 1996. Todos os genótipos apresentaram rendimento comercial acima de 20t/ha. Os genótipos ‘Crioula’ apresentaram os melhores rendimentos quanti-qualitativos. Houve diferença significativa para rendimento comercial e não comercial, peso médio de bulbos e rendimento de bulbos classes 2 e 3. Até 100 dias de armazenamento, os bulbos de todos os genótipos sofreram perda de peso de cerca de 15%. Não houve interação significativa entre genótipos e número de dias de armazenamento. Houve correlação entre perdas de peso e número de bulbos e duração do período de armazenamento. Houve correlação negativa entre o número e o peso dos bulbos e as percentagens de perda de peso e de número de bulbos.To determine yield of six onion genotypes grown in lowland, and postharvest room storability of cured bulbs, two experiments were performed at the Federal University of Santa Maria in 1995 and 1996. Yields of marketable bulbs were over 20t/ha for all genotypes under study. Yields of ‘Crioula’ genotypes were the highest, quantitatively and qualitatively. Marketable bulb yields, culls, average bulb weight and yields of bulb grades 2 and 3 were significantly different. Up to 100 days under storage, bulb weight loss was approximately 15% for all genotypes. No significant interaction between genotypes and storage period was found. Losses in bulb weight and bulb number correlated with storage period. Bulb number and bulb weight correlated negatively with percentages of bulb weight loss and bulb number loss.