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  • Author or Editor: Irma Voipio x
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Seedlings of aster [Callistephus chinensis (L.) Nees], dusty miller [Senecio bicolor (Willd.) Tod.], and petunia (Petunia Juss.) were subjected to brushing with burlap in two experiments. The spring experiment tested the daily duration of brushing (60, 120, or 180 minutes per day) and the autumn experiment tested the stimulus of brushing (brushing for 2 hours with single-layer, double-layer, or triple-layer burlap). Brushing was done with slow-moving apparatus. The increase in daily brushing duration led to a greater reduction of growth, although differences between the species were noted. Aster showed a growth reduction after 20 days of treatment, whereas dusty miller and petunia took longer to respond. Aster and petunia responded significantly even to the shortest daily brushing duration, whereas dusty miller needed 2 hours per day to achieve any significant growth reduction. Increasing the brushing stimulus resulted in injuries to aster leaves in autumn. Brushing with double-layer burlap caused maximum growth reductions in all the species. Brushing most clearly reduced the growth of dusty miller and petunia in autumn, but aster showed similar growth reductions in spring and autumn.

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Ethylene is produced by tomato fruit (Lycopersicon esculentum) at a rate that is dependent on fruit size, maturity stage, and adherence of calyxes. Production rate of ethylene declined with increased maturity stages. Small fruit produced higher ethylene compared to medium or large sizes. Ethylene production is positively correlated with rate of respiration, but not with visible pitting. Fruit stored with calyx produced less ethylene than those that were stored without calyxes.

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Hot water treatment at 38, 42, 46, 50, and 54 °C for 30 60 and 90 minutes were applied to mature green tomatoes before storing at 2°C for 2, 4 and 6 weeks. Control fruit were treated at 20°C water. After storage all fruit were held at 20°C for 7 days. Control fruit showed lower weight loss, lycopene content, pH, and TSS but higher decay, chlorophyll content, TA, and more Firmness than hot-water-treated fruit. Weight loss, lycopene content, pH, and TSS were progressively increased with increased water temperature from 38 to 54°C, while chlorophyll content, TA and fruit firmness were declined. Among hot-water-treated fruit, least decay were detected in fruit treated at 46°C water 6 weeks stored fruit showed higher weight loss, more decay, lower chlorophyll and lycopene content, TSS, TA, less firmer and higher pH than those fruit stored for 2 or 4 weeks. Increased immersion time from 30 to 90 minutes resulted higher weight loss, lower decay, chlorophyll content, TA, and less firm, but higher lycopene content, TSS, and pH.

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Mature green tomatoes (cv. Vibelco) were stored at 2°C for 2, 3, and 4 weeks. Intermittent warming treatments for 12, 24, and 36 hours at 24°C were applied at the end of every week. Control Fruit were held continuously at 2°C. All fruit were subjected to poststorage ripening at 24°C for 7 days. Fruit decay, chlorophyll and lycopene content, fruit firmness, pH, TSS and TA were detected after storage or 7 days after transfer to 24°C. Results were compared between control and intermittently warmed fruit when stored at 2°C for 2, 3, and 4 weeks. Compared to fruit kept continuously at 2°C, intermittent warming at 24°C for 12, 24, and 36 hours reduced decay, increased chlorophyll disappearance, lycopene synthesis, and fruit firmness, enhanced pH and TSS, and declined TA. Fruit intermittently warmed for 36 hours/week showed the least decay, higher chlorophyll disappearance, and lycopene synthesis; retention of fruit firmness, pH, and TSS; and lower TA than fruit intermittently warmed for 12 and 24 hours/week. Decay percentage, lycopene content, pH, and TSS were increased from 2 to 4 weeks, but chlorophyll content, fruit firmness, and TA were declined.

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