• Korean Journal of Environmental Agriculture
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• v.32 no.1
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• pp.55-60
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• 2013

BACKGROUND: The buds of persimmon trees are susceptible to cold damage, often with the late frost, at the time of budburst. This study was conducted to determine effect of the cold damage on shoot and fruit growth the current season. METHODS AND RESULTS: 'Fuyu' trees, grown in 50-L pots, were placed for 1 h at $-2.2{\pm}0.5$, $-2.6{\pm}0.5$, or $-3.0{\pm}0.5^{\circ}C$ within a cold storage, at their budburst on April 5. Some trees under ambient temperature at $10-17^{\circ}C$ served as the control. Cold damage of the buds containing flower buds was 54% at $-2.2^{\circ}C$, and significantly increased to 95% at $-3.0^{\circ}C$. The bud damage included the complete death of all, complete death of main buds only, or the late and deformed shoot growth in the spring. Number of flower buds in early May dramatically decreased as the damage ratio increased. Since the thinning of flower buds in mid-May and fruitlets in early July was done in no or slightly damaged trees, the final number of fruits and yield did not decrease compared with the control when the damage increased by 60% and 70%, respectively. Average fruit weight and skin coloration tended to be better with increasing bud damage. Shoot growth was more vigorous in those trees whose buds were severely damaged by low temperature. CONCLUSION(S): Shoot growth and the yield may depend on the number of flower buds and percent fruit set after the cold damage.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.706-713
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• 2013

With pot-grown 4-year-old 'Fuyu' persimmon trees, this study evaluated the effect of different nitrogen (N) rates during summer on fruit characteristics, changes of leaf nutrients after harvest, reserve accumulation, and early growth the following year. A total of 0, 36 g N in June, and 72 g N in June and July was fertigated to each tree using urea solution. All the fruits were harvested on Nov. 3. Although not significant, fruits were larger for the 36 g and 72 g N than the 0 g N. Fruits for the 0 g N, having lower N concentration, were softer and had a better coloration and higher soluble solids, indicating that they matured earlier. SPAD value on Nov. 3 was 19.2 for the 0 g N and 54.9 for the 72 g N, and then the values linearly decreased in all the treatments by Nov. 14, exhibiting rapid leaf senescence. Specific leaf weight, being the lowest for the 0 g N, also gradually decreased during this period. Increasing N level significantly increased cross-sectional area of the trunk. Leaf N concentration on Nov. 3 was 0.87% for the 0 g N, whereas it was 1.18 and 1.52% for the 36 g and 72 g N, respectively. The N fertigation tended to increase leaf concentrations of soluble sugars, starch, and amino acids. Contents of N, P, K, soluble sugars, starch, and amino acids per unit leaf area gradually decreased in all the treatments during the 11 days after harvest, and the extent of the decrease was the lowest for the 0 g N. On the other hand, those of Ca, Mg, and protein did not consistently change during this period. The N fertigation resulted in higher concentrations of N in dormant shoots on Nov. 14, and although not great, it also increased soluble sugars, starch, amino acids, and protein. Clear differences were found in number of flower buds per one-year-old branch and total shoot length per tree the following year. The 72 g N trees had 5.6-fold more flower buds and 1.9-fold more shoot length, compared with those of 0 g N trees. However, it was noted that tree growth the following year was not significantly different between the 36 g and 72 g N the previous year. It was concluded that N rate during summer should be adjusted with considering the changes of fruit maturation, mobilization of leaf nutrients, and reserve accumulation.

• Horticultural Science & Technology
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• v.32 no.3
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• pp.279-288
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• 2014

To understand changes in composition and distribution of nutrients during early shoot growth of persimmon, organic compounds and inorganic elements of terminal shoots were analyzed for about 40 days from the time of foliation. Sample shoots were collected from mature 'Fuyu' trees for this three-year experiment and they were divided to stem, leaves, and the fruits including flower buds at the earliest stage. During shoot growth, concentration of soluble sugars increased in both leaves and fruits, but that of starch increased only in leaves. Those of amino acids tended to decrease in all the parts but there was no consistent change in proteins. As shoots grew, contents of all the organic compounds in a shoot increased, and they were especially higher in May leaves accounting for more than 60% of the shoot total for each nutrient. Along with shoot growth, concentrations of N and P gradually decreased in all three parts, while K decreased only in stem. However, those of Ca and Mg did not show notable changes in all the parts with wide variations depending on the year. Due to the quantitative increase in growth, contents of inorganic elements in a shoot increased in all the parts and the leaves accounted for 54-82% of the shoot total. At the cessation time of extension growth, a shoot contained 526-768 mg of soluble sugars, 245-844 mg of starch, 26-31 mg of amino acids, and 66-103 mg of proteins for three years. On the other hand, a shoot contained 203-388 mg of K, the greatest among the inorganic elements, followed by 132-159 mg of N. Changes of the nutrients in a shoot were much greater during the earlier stage of growth after foliation than during the later stage toward growth cessation, suggesting the importance of mobilizing reserve nutrients for the early growth of the shoots. The results of this study also suggested that the rate of nutrient changes, especially during the earlier stage of shoot growth, could be affected by environmental and cultural conditions.

• Horticultural Science & Technology
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• v.30 no.4
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• pp.385-391
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• 2012

The growth of terminal shoots of persimmon (Diospyros kaki) was analyzed during the first two months from the time of bud sprout to understand the dynamics of their early growth. Field-grown, mature 'Fuyu' and 'Nishimurawase' trees were used in a three-year study at two locations in Gyeongnam province. The growth of terminal shoots was most active from late April, about 10 days after foliation, to early May, followed by a gradual decline by late May. The increase in leaf area continued unabated throughout May. The weight of a flower bud increased slowly until early May and rapidly after flowering. Although its extension growth had been ceased by late May, dry weight (DW) of a terminal shoot continued to increase almost linearly throughout May due to shoot thickening and continued growth of leaves and fruits. In late May, the leaves and the stem accounted for more than 60% and less than 20% of total DW of a shoot respectively; fruit proportion increased to 7 to 17% by then. Relative growth rate (RGR) of the terminal shoot was higher than 213 $mg{\cdot}g^{-1}{\cdot}d^{-1}$ in late April, but declined to less than 63 $mg{\cdot}g^{-1}{\cdot}d^{-1}$ in late May. Like the pattern of seasonal changes in RGR, net assimilation rate (NAR) of the shoots decreased from 1.9 to 2 $mg{\cdot}cm^{-2}{\cdot}d^{-1}$ to 0.5 to 0.8 $mg{\cdot}cm^{-2}{\cdot}d^{-1}$. An early-season 'Nishimurawase' did not differ from a late-season 'Fuyu' in RGR and NAR during the first two months of growth. The early growth of the shoots was affected mainly by the reserves redistributed from permanent organs, however, environmental conditions at the time was also involved.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.728-734
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• 2010

We studied the accumulation and partitioning of dry weight (DW) and nitrogen (N) in different parts of field-grown 'Fuyu' persimmon to elucidate that the foliar applications of supplemental N in June or September compared favorably with the traditional soil application in securing leaf area and fruit production. We also estimated the proportion of N permanently removed from the tree at the end of a growing season. Urea was applied either to leaves in June and/or September or to the soil in June and September for three consecutive years, and the trees were excavated in November for analyses. Total DW ranged from 4.2-4.8, 8.7-9.2, and 17.1-21.5 kg in a 4-, 5-, and 6-year-old tree, respectively, without statistical difference among the four treatments. Of the total DW, 3.3-10.2% was in shoots, 5.7-10.5% in leaves, 8.3-31.4% in aerial woods, 13.0-27.0% in root, and 28.0-59.3% in fruits. As the trees became more productive, DW proportion of fruits significantly affected that of the root: in 6-year-old trees, root DW accounted for only 10.6-15.8% of the tree total when fruit DW accounted for 50-60%. N contents ranged from 24.6-28.3, 48.3-53.5, and 98.3-122.6 g in a 4-, 5-, and 6-year-old trees, respectively, without statistical difference among the treatments. Of the total N, 6.2-11.5% was in shoots, 16.7-24.3% in leaves, 17.6-23.5% in aerial woods, 17.2-37.5% in roots, and 16.9-34.4% in fruits. As in DW, the increase in the proportion of N in fruits decreased in the root most significantly. Application methods for supplemental N did not affect the proportion of DW and N removed from the tree through abscising leaves and harvested fruits. Percentage of DW removal was 41 in 4- and 5-year-old trees, but it was 61 in more productive 6-year-old trees; that of N was 39, 43, and 49%, respectively. No significant changes in the contents of DW and N in field-grown trees, as well as their percentages removed from the tree at the end of the season, demonstrated that foliar application of supplemental N was as good as soil applications with much less N.

• Korean Journal of Food Science and Technology
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• v.33 no.2
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• pp.200-204
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• 2001

Persimmon (Diospyros kaki. cv. Fuyu) fruits were packaged under different conditions, and then stored at $0^{\circ}C$ for 21 weeks. The tried packages were heat-sealed bag of one fruit, heat-sealed bag of five fruits, and tie-sealed bag of five fruits, which used films of three different thickness (0.03 ㎜, 0.05 ㎜ and 0.06 ㎜). Throughout the storage, package free volume, package atmosphere and quality were measured. Package free volume decreased with time with higher rate for heat-sealed bags, in which close contact between fruit and the film was eventually reached in longer storage. However, tie-sealed bags maintained the levels of stabilized free volume. The rate of free volume decrease was faster with thinner film and larger bag size for the packs sealed by the same method. Package atmosphere covered $O_2$ concentration of $1.1{\sim}17.1%$ and $CO_2$ concentration of $1.1{\sim}8.3%$, $O_2$ concentration decreased during storage, whereas $CO_2$ increased. Thinner film package created the internal atmosphere of higher $O_2$ and lower $CO_2$ concentrations. Tie-sealed bags of 5 fruits in the films of 0.05 mm and 0.06 mm thickness maintained the equilibrated package atmosphere of $1.1{\sim}3.0%\;O_2$ and $4.0{\sim}5.5%\;CO_2$, which preserved the fruits best in terms of firmness and less physiological changes of flesh browning and peel browning. At five fruit heat-sealed bag in the films of 0.06 mm thickness with $CO_2\;8.3%$, flesh browning occurred at a high rate, whereas all treatments in the film of 0.03 mm thickness with high $O_2$ and relatively low $CO_2$ contents, flesh and peel browning rates were high.

• Korean Journal of Food Science and Technology
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• v.10 no.1
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• pp.78-82
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• 1978

In a series of studies on the utilization of persimmons, the purpose of this experiment was to examine the optimum thickness of film using different number of persimmons per film bag. 'Fuyu', persimmon variety was used in this investigation. The results obtained were as follows: The optimum thickness of the film bag was 0.08mm, 0.06mm, and 0.04mm for the bags packed with 3, 10 and 50 persimnons, respectively. The changes in the ratio of firmness, loss of fresh weight, titrable acidity and percentage of sugar contents were minimal in these three optimum combinations than the others. These results could be explained by the balanced optimum gas concentration, $CO_2$ 5-10% and $O_2$ 5%, in those three optimum combination. Therefore, it was suggested that the different thickness of film bag needs a particular number of fruits packed per bag for the long term storage in persimmons.

• Horticultural Science & Technology
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• v.31 no.1
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• pp.32-37
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• 2013

Relationships among climate changes, early frost, and fruit growth were studied during the final month to harvest of late-maturing 'Fuyu' persimmon (Diospyros kaki) to assess the changes in fruit characteristics during this critical period. The heavy frost on Nov. 16 defoliated more than 70% of the leaves, but with little damage on the fruits. However, all the leaves were defoliated by the heavy frost on Nov. 20, and all the fruits were cold-damaged by $-3.3^{\circ}C$ on Nov. 21. Fruit weight increased by 8-25 g per week from Oct. 25 (142 days after full bloom) to Nov. 15, reaching to 250 g, but it decreased by 3-4 g per week after the frost. Hunter a value of fruit skin gradually increased until the last harvest on Nov. 29 with a temporary halt in early Nov. when temperature was high, whereas fruit firmness rapidly decreased after the frost on Nov. 21. Fruit soluble solids were $15.7-16.1^{\circ}Brix$ for the final month. When some branches were covered with non-woven fabrics to avoid direct contact with frost, the fruits on the branches were not visually damaged by the low temperature although 40-60% of their leaves were defoliated on Nov. 16. However, low temperature on Nov. 20 and 21 defoliated all the leaves, causing cold damage on the fruits. There was a highly significant correlation between the fruit diameter and its weight ($R^2$ = 0.73-0.91). So, the regression equations could be used to estimate weight from diameter of the fruits sampled from the branches with the non-woven fabrics. The calculated fruit weight reached to a maximum of 240 g on Nov. 15. Daily increases in fruit weight were 1.1-2.5 g from Oct. 25 to 31, 1.9-3.5 g from Oct. 31 to Nov. 7, and 1.4-1.6 g from Nov. 7 to 12. However, fruit weight decreased by 0.3-1 g per day after the cold damage on Nov. 21. The results indicate that the most appropriate harvest time could be dependent on relationship of fruit growth to climate.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1278-1284
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• 2000

The study was performed to elucidate the effects of ethylene-absorbent on the quality of 'Fuyu' persimmon fruits in the MA package. Five persimmons were packed in a MA package film (low density polyethylene, 0.055 mm film thickness), and stored at $-0.5^{\circ}C$ for 60 days. Two persimmons were repacked in a MA package with or without ethylene absorbent $(1\;M\;KMnO_4+zeolite)$ and stored at $-0.5^{\circ}C$. Ten days later, these packages was moved to $2^{\circ}C$ or $25^{\circ}C$ storage room to examine the effect of the ethylene-absorbent on the quality of the fruits. Ethylene removal by enclosed ethylene absorbent in MA packaging reduced the rate of fruit respiration at $25^{\circ}C$, so that $O_2$ and $CO_2$ concentration in packing were maintained higher and lower, respectively, compared to control. These effects were not observed, however, in $2^{\circ}C$ post-storage. Fruit firmness and sugar composition were also influenced by ethylene absorbent, showing more delayed flesh softening and higher sucrose concentration in ethylene absorbent treated fruits than control. But ethylene-absorbent treatment lowered glucose and fructose concentration. That shows that ethylene could influence on sugar composition by inhibiting sucrose inversion to glucose and fructose. The production of ethanol and acetaldehyde was reduced by ethylene removal, but the effect was not so high as other quality indices.

• Journal of agriculture & life science
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• v.45 no.5
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• pp.57-62
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• 2011

This study was conducted to determine the distribution of nitrogenous compounds to various tree parts and the extent of reserve accumulation in persimmon (Diospyros kaki) under various fruit-loads. This study also ascertained the proportion of storage nitrogen made available for the new growth the following year. On June 15, the fruit-load was adjusted to a leaf-fruit (L/F) ratio of 10, 20, and 30, and some trees were completely defruited. Between June 15 and November 11, the increase of total amino acids were greater with a high L/F ratio. The amino acids increased in the root were negligible at the 10-L/F ratio. Of the total amino acids increased during this period, the proportion distributed to the root was 64% in the 20-L/F, 18.5% in the 30-L/F, and 81% in the defruited trees, and the distribution to the fruits was 81% in 10-L/F, 12% in 20-L/F, and 35% in the 30-L/F trees. Leaf amino acids decreased in the 10-L/F trees. Total proteins increased in autumn were greater as the L/F ratio was higher. Total proteins were in the fruits the most, and the distribution to the permanent parts was decreased as the L/F ratio was decreased. At the L/F ratio of 30, 59% of the total proteins increased in the autumn was distributed to the fruits and 40% to the root. Leaf proteins decreased at 10 and 20 L/F ratios. During the new growth from April 10 to June 10 the following year, amino acids decreased in the old wood and 1-yr-old shoot, whereas proteins decreased only in the 1-year-old shoots. Amino acids and protein decreased by 540 mg and 610 mg, respectively, in the roots of the defruited trees. Total amino acid and proteins in the newly-grown parts were the most at 730 mg and 1290 mg, respectively, when defruited the previous year. They were the least at the 10-L/F ratio, being 120 mg and 400 mg, respectively.