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Longevity of cut flowers of many gerbera cultivars (Gerbera jamesonii) is typically short because of stem bending; hence, stem bending that occurs during the early vase life period is a major problem in gerbera. Here, we investigated the effects of sodium nitroprusside (SNP) on the delay of stem bending in the gerbera cultivars, Alliance, Rosalin, and Bintang, by examining relative fresh weight, bacterial density in the vase solution, transcriptional analysis of a lignin biosynthesis gene, antioxidant activity, and xylem blockage. All three gerbera cultivars responded to SNP by delaying stem bending, compared to the controls; however, the responses were dose- and cultivar-dependent. Among the treatments, SNP at 20 mg L-1 was the best to delay stem bending in Alliance, while dosages of 10 and 5 mg L-1 were the best for Rosalin and Bintang, respectively. However, stem bending in Alliance and Rosalin was faster than in Bintang, indicating a discrepancy influenced by genotype. According to our analysis of the role of SNP in the delay of stem bending, the results revealed that SNP treatment inhibited bacterial growth and xylem blockage, enhanced expression levels of a lignin biosynthesis gene, and maintained antioxidant activities. Therefore, it is suggested that the cause of stem bending is associated with the above-mentioned parameters and SNP is involved in the mechanism that delays stem bending in the different gerbera cultivars.

We analyzed the expression of anthocyanin biosynthesis genes and transcription factors (TFs) in the cultivars 'Bintang' and 'Alliance' that exhibit different coloration patterns. Differential expression of biosynthesis genes and TFs was associated with variable anthocyanin content at different flower developmental stages (S1-S3) in both cultivars; higher anthocyanin content was correlated with higher levels of gene expression. Exposure to different temperatures (6 and 22 °C) also resulted in different anthocyanin content levels: the lower temperature (6 °C) enhanced anthocyanin content compared to the higher temperature (22 °C). However, the increased anthocyanin content of 'Bintang' compared to 'Alliance' was the result of higher levels of expression of all detected genes, regardless of flower stage and temperature conditions. Therefore, we conclude that transcriptional control of the detected genes is associated with the mechanisms of anthocyanin biosynthesis and coloration patterns in gerberas; however, further studies of the key genes are needed.

Jonathan' apples are relatively small size which contributes to enhancing fruit consumption and gaining popularity. Thus, this study was carried out to evaluate the effects of AVG (aminoethoxyvinylglycine, ReTain®), sprayable 1-MCP (1-methylcyclopropene, Harvista TM ), and fumigation 1-MCP (SmartFresh TM ) applications on fruit quality attributes and storability in 'Jonathan' apple fruits during cold-stored. The Jonathan fruits were dipped with either ReTain (75 mg/L) or Harvista (125 mg/L) solutions for 5 min, or fumigated with SmartFresh (1 mg/L) for 18 hr before storage at 0±1℃ for 75 days. Flesh firmness and titratable acidity remained higher in all pre-treated apples than control ones during cold storage period. Flesh firmness was higher for apples treated with ReTain and SmartFresh than samples treated with Harvista, while soluble solid content and respiration rate were not affected by sample pretreatment. Internal ethylene concentration (IEC) of all pretreated apples remained below about 4.5 μL/L during the entire storage period while that of control sample greatly increased to 10.29 μL/L. Ethylene production was much higher in control fruits than in treated ones during cold storage. These results indicated that ReTain and 1-MCP treatments would be considerably effective in retention of fruit quality attributes of 'Jonathan' apple during cold-stored.

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