• Korean Journal of Environmental Agriculture
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• v.25 no.2
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• pp.164-169
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• 2006

This study was conducted for 10 days from 17 July to 26 July in 2005 to measure the amount of xylem sap flow under short-term variation of soil moisture regimes at -20 kPa, -50 kPa and -80 kPa in eight-year-old 'Fuji'/M.9 apple trees with different fruit loads. Fruit load was adjusted as three different treatments with standard (100%), 1/2 times (50%) and 2 times (200%) on the basis of optimum fruiting number per tree as the standard fruit load of Fuji cultivar. Trees with standard fruit load during the experimental period showed higher xylem sap flow at -50 kPa of soil moisture regimes than those of trees with 1/2 times and 2 times fruit load. Trees with 1/2 times and 2 times fruit load had similar patterns of the diurnal changes of xylem sap flow, vapor pressure deficit (VPD), and maximum evapotranspiration (ETm). However, trees with 2 times fruit load at -50 kPa and -80 kPa of soil moisture regimes produced lower amount of xylem sap flow than ETm. Trees with standard fruit load produced $1.06{\sim}3.93$ L/tree more amount of xylem sap flow than ETm at all soil moisture regimes. But xylem sap flow of tees with 2 times fruit load had 21% lower at -50 kPa and $31{\sim}36%$ lower at -20 kPa and -80 kPa of soil moisture regimes, respectively than that of trees with standard fruit load. Shoot growth and leaf area were significantly the highest in trees with standard fruit load while those of trees with 2 times fruit load recorded significantly lowest. Leaf water potential of trees with standard fruit load was lower than that of trees with 1/2 times and 2 times fruit load. It indicated that tees with standard fruit load had higher water use for transpiration than other treatments and tees with 2 times fruit load received more stress for the transpiration process under low soil moisture regimes. Consequently, 'Fuji'/M.9 apple trees, the fruit load and soil moisture should be maintained optimum to increase xylem sap flow and transpiration during higher growth period.

• Horticultural Science & Technology
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• v.18 no.3
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• pp.387-390
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• 2000

The experiment was conducted to investigate the effects of vine management and yield on fruit quality and bud burst of 'Campbell Early' grapevines in Hwaseong and Suwon area. The extreme value of minimum temperature of Hwaseong area, frequently causing cold damage, was lower than that of Suwon area in winter. Narrow spacing, overbearing, and poor vine management were observed in Hwaseong area, where the harvest time was delayed by 7 days compared with that of Suwon area. Total carbohydrate content of bearing mother branches was lower with 1.2~1.7%, and the percentage of bud burst was extremely lower at $-15^{\circ}C$. In Suwon area, there were no differences in cluster and berry size, but soluble solids content was lower and skin coloration was poorer when yield was high. Total carbohydrate content was lower when yield was high. The percentage of bud burst was lower at cold treatments below $-20^{\circ}C$. The results suggest that appropriate yield based on fruit quality is 2.3~2.6 MT/10a.

• Horticultural Science & Technology
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• v.16 no.4
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• pp.514-516
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• 1998

This study was conducted to observe the effects of urea foliar spray to replace soil fertilization on defoliation ratio, shoot growth and fruit setting in satsuma mandarin (Citrus unshiu Marc.). Twice foliar sprays of 1% urea after harvest increased N and chlorophyll contents in leaves, and decreased defoliation during the winter season. The growth of the ovary and spring shoot was stimulated by the twice 0.8% urea foliar spray around the time of bud emergence. In addition, the treatments increased the number of flowers and fruit setting, but didn't influence fruit quality.

• Korean Journal of Environmental Agriculture
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• v.31 no.4
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• pp.313-317
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• 2012

BACKGROUND: Citrus is usually propagated by grafting onto a rootstock. In Korea, As trifoliate orange (Poncirus trifoliata) has dwarf and strong cold hardness, it is widely used as the rootstock of satsuma mandarin. Because 'Shiranuhi' ((Citrus unshiu ${\times}$ C. sinensis) ${\times}$ C. reticulata), a kind of citrus, also, generally is grafted onto a trifoliate orange, most of farmer has been recognized that 'Shiranuhi' root is naturally trifoliate orange. Meanwhile, reduction of flowering in 'Shiranuhi' orchard has been issued among the farmers and researchers over past few years and they guessed it was occurred by severe prune, oversupply of fertilization, overfruiting and temperature of growth period. However, a few researchers strongly assumed that it would be caused by scion rooting of 'Shiranuhi'. So, this study was carried out to identify the existence of scion rooting in 'Shiranuhi' tree in Korea. METHODS AND RESULTS: To identify the existence of scion rooting in 'Shiranuhi' tree, we randomly selected six 'Shiranuhi'orchards and we surveyed three to four trees, which flowering was not enough, from six 'Shiranuhi' orchards respectively. We took the root samples of 'Shiranuhi' mandarin, and then separated the two group which were non-scion rooting (Trifoliate orange), and scion rooting ('Shiranuhi' mandarin). To identity the scion rooting, we used primer set of three types which were a F2/R15, F4/R15 and F5/R15 primer set. As a result, when we conducted the DNA analysis, fourteen tree in less bloomed twenty tree was proved as tree with the scion rooting of 'Shiranuhi' mandarin. CONCLUSION(S): Scion roots of 'Shiranuhi'mandarin were usually observed in a deeply planted tree, and xylem of 'Shiranuhi' root indicated more white color than a case of trifoliata orange. 'Shiranuhi' tree by scion rooting was more vigorous but less flowering than trees grafted onto trifoliata orange. When we used F2/R15, F4/R15 and F5/R15 primer set for discriminance of 'Shiranuhi'mandarin root and trifoliate root, we identified the existence of scion rooting in 'Shiranuhi', From our results, it is suggested that the influence of scion root should be reviewed in 'Shiranuhi'orchards.

• 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.

• Journal of Bio-Environment Control
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• v.11 no.3
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• pp.127-132
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• 2002

Enhanced supply of $Ca^{2＋}$ as well as NO$_3$$^{[-10]}$ is known to restrict the uptake of the Na$^{＋}$ and Cl$^{[-10]}$ ion and ameliorate growth under saline conditions. This test was conducted to investigate the ameliorating effects of Ca(NO$_3$)$_2$ or CaCl$_2$ on the growth and yield of NaCl-stressed tomato plants grown in plastic pot filled with soil. All treatments except for the control were supplied with 80 mM NaCl fur two weeks after transporting. The saline solutions with nutrient were supplemented with either 0, 10 or 20 mM Ca(NO$_3$)$_2$ and either 0, 10 or 20 mM CaCl$_2$ during harvesting time from two weeks after transporting. Ca(NO$_3$)$_2$ or CaCl$_2$ application enhanced the growth such as plant height, fresh weight, dry weight, fruit number, and fruit weight, and yield of NaCl-stressed tomato, and also their effects increased greater as concentration of supplemented Ca(NO$_3$)$_2$ or CaCl$_2$increased. Yield increased in 20 mM Ca(NO$_3$)$_2$ compared with the others except fur the control. Photosynthetic rate in Ca treatments was lower than that of the control, but higher than that of NaCl treatment. Leaf chlorophyll content was higher in Ca treatments compared with the others, especially in younger leaf, while that was not affected by concentration of supplemented Ca. Ca(NO$_3$)$_2$ or CaCl$_2$ supply increased the $K^{＋}$ and $C^{2＋}$ concentration of tomato plants, whereas the Na$^{＋}$ transport to the leaves was inhibited. There was a strong increase in the $K^{＋}$/Na$^{＋}$ ratio in plants treated Ca(NO$_3$)$_2$, or CaCl$_2$. Cl$^{[-10]}$ content of plants was decreased by supplemental Ca(NO$_3$)$_2$ but Cl$^{[-10]}$ was increased in plants with CaCl$_2$compared with Ca(NO$_3$)$_2$. N concentration in plants of tomato increased with enhanced Ca(NO$_3$)$_2$ or CaCl$_2$supply, In conclusion, our study confirms the potential of Ca(NO$_3$)$_2$ or CaCl$_2$to alleviate NaCl-induced growth reductions in tomato.

• Economic and Environmental Geology
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• v.39 no.1 s.176
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• pp.27-38
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• 2006

To understand the geologic and hydrogeochemical controls on the occurrence of high fluoride concentrations in bedrock groundwaters of South Korea, we examined a total of 367 hydrochemistry data obtained from deep groundwater wells (avg. depth=600 m) that were drilled fur exploitation of hot springs. The fluoride concentrations were generally very high (avg. 5.65mg/L) and exceeded the Drinking Water Standard (1.5 mg/L) in $72\%$ of the samples. A significant geologic control of fluoride concentrations was observed: the highest concentrations occur in the areas of granitoids and granitic gneiss, while the lowest concentrations in the areas of volcanic and sedimentary rocks. In relation to the hydrochemical facies, alkaline $Na-HCO_3$ type waters had remarkably higher F concentrations than circum-neutral to slightly alkaline $Ca-HCO_3$ type waters. The prolonged water-rock interaction occurring during the deep circulation of groundwater in the areas of granitoids and granitic gneiss is considered most important for the generation of high F concentrations. Under such condition, fluoride-rich groundwaters are likely formed through hydrogeochemical processes consisting of the removal of Ca from groundwater via calcite precipitation and/or cation exchange and the successive dissolution of plagioclase and F-bearing hydroxyl minerals (esp. biotite). Thus, groundwaters with high pH and very high Na/Ca ratio within granitoids and granitic gneiss are likely most vulnerable to the water supply problem related to enriched fluorine.