• Horticultural Science & Technology
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• v.32 no.1
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• pp.18-25
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• 2014

This study was conducted to investigated effects of water relation of mulching and trickle irrigation on the external and internal fruit quality in Satsuma mandarin grafted on trifoliate orange rootstock in a orchard assigned to randomly three groups; whole period of Tyvex mulching (TM), Tyvex mulching with trickle irrigation once a week from October 22 to harvesting season (WM) and non-mulching treatment (NM). The average soil moisture content in the TM was lower than the WM during the time of trickle irrigation from Oct. 21 to Nov. 28. The leaf water potential was at the level of ${\Psi}max$ of -1.5 to -2.5 MPa during whole period of Tyvex mulching treatment but gradually increased at the point of supplement of water. The water and osmotic potential in juice vesicle was decreased by drought but increased again in response to the supply of water in WM. The total soluble solids (TSS) in fruit juice was increased by drought stress, but diminished in response to supply of water after drought. The content of titratible acidity was increased by drought stress but gradually decreased due to supplement of water after drought, reached it at the level of 1%. It was suggested that the accumulation of the total soluble solids compensates the degree of active osmoregulation and the decrease in content of acidity accounts for the fast respiration and water uptake resulted of the water after drought.

• Horticultural Science & Technology
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• v.28 no.4
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• pp.561-566
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• 2010

The effects of calcium concentrations of coating bag treatment to reduce berry cracking were investigated through the changes of pericarp structure and berry cracking rate in 'Kyoho' grape. The soluble solids and anthocyanin contents in harvested grapes were highest at $18.1^{\circ}Brix$ and $2.56{\mu}g{\cdot}cm^{-2}$ in non bagging group compared with those of calcium coating bag treatments. The firmness of pericarp was lowest in non bagging group ($1.18kg{\cdot}5mm^{-1}{\O}$) compared with bagging treatments (1.23, 1.24, 1.27, $1.35kg{\cdot}5mm^{-1}{\O}$) which increased effectively in proportion to calcium concentration. As a result of histological observation of the fruit skin, the bagging with higher calcium concentration developed thicker epidermal and sub-epidermal layer of cell wall than that of non bagging. Moreover, the strengthened berry skin of calcium treatments effectively decreased berry cracking rate under critical turgor pressure. However, the 9% calcium coating bag treatment which was the most effective for cracking reduction seriously decreased marketability of harvested grape with white color staining on berry skin caused by eluted calcium from the coated paper bag. Based on our results, we recommend that 6% calcium coating bag be available for berry cracking reduction and higher quality production.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.942-947
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• 2010

In the present study, pollen tube growth and fruit set in Asian pear ($Pyrus$ $pyrifolia$) were examined upon the mechanical damage on the stigma and style following the artificial pollination. When the upper middle part of style was cut off at 48 h after the artificial pollination, pollen tube grew to the middle of the style and the subsequent pollen tube elongation and fruit set normally occurred. When the style was cut off before the pollen tube reached the middle of the style, however, no pollen tube elongation and fruit set occurred. With the pollen tube elongation through the style, callose plugs at the basal part of the pollen tube were formed to the direction of the elongation at regular intervals. When the upper part of pollen tube attached pollen grain was cut off, however, callose plugs were formed defectively in the pollen tube, and the pollen tube opened and lost their turgor pressure. These facts might be the reason for the ceased or delayed pollen tube elongation and ultimately the failure of the fertilization.

• Korean Journal of Agricultural Science
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• v.36 no.1
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• pp.27-40
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• 2009

Six strains of Phycomyces blakesleeanus (DEL, A56, C9, C47, C111, and G5) were cultured in continuous light condition for 6 days. The increase in fresh and dry weight after the culture period was similar in all strains. However, the increase in fresh weight was sustained throughout the culture period in all strains, whereas the increase in dry weight was prominent only during the first 3 days of culture. The development and phototropism of macrophores was observed after 3 days of culture, These results suggest that the development and phototropism is ascribed to the increase in turgor pressure in sporangiophores where water entered. A56 and G5 showed a higher sensitivity to light than C9 and C47, whereas C111 showed no photosensitivity. Antagonistic relations were observed between photosensitivity and development of microphores, suggesting that the development and phototropism of macrophores is regulated by a common recognition factor (photoreceptor).

• Horticultural Science & Technology
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• v.28 no.3
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• pp.381-386
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• 2010

The berry growth and pericarp characteristics were characterized to confirm the effects of bagging periods on berry cracking during berry development in 'Kyoho' grape. The berry weight was the highest at 13.4 g in late period of bagging treated at 7 to 9 weeks after full bloom (WAFB) as compared with the lowest of 12.3 g in total period bagging. The berry cracking rate under critical turgor pressure in the non-bagging control was 53.3%, while those of bagging treatments were decreased in the order of 42.7%, 37.3%, 33.3%, and 18.7% in bagged during 3 to 9, 3 to 5, 5 to 7, and 7 to 9 WAFB, respectively. In the results of observation on histological characteristics of pericarp, berry lenticels of whole bagging treatments had smaller and normal shape compared with non-bagging control treatment. Especially on the pericarp of late period bagged during 7 to 9 WAFB, suberization around stomata and micro-cracking were not observed and structural strength of pericarp was increased with thicker sub-epidermal layer and cell wall. Therefore, the results indicate that bagging treatment for two weeks just before the veraison when the day length and daylight is relatively longer and stronger can effectively reduce berry cracking by strengthening structure of pericarp in 'Kyoho' grape.