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Kyong Ju Choi, Gap Chae Chung, and Sung Ju Ahn

Cucumber (Cucumis sativus L.) seedlings were grafted onto cucumber-(CG) or figleaf gourd (FG, Cucurbita ficifolia Bouche) seedlings in order to determine the effect of solution temperature 12, 22, and 32C) on the mineral composition of xylem sap and plasma membrane K+–Mg++–ATPase activities of the roots. Low solution temperature (12C) lowered the concentration \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{NO}_{3}^{-}\) \end{document} and \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{H}_{2}\mathrm{PO}_{4}^{-}\) \end{document} in xylem sap of CG plants, but not of FG plants. Concentrations of K+, Ca++, and Mg++ in xylem sap were less affected than anions by solution temperature. The plasma membrane of FG plants grown in 12C solution temperature showed the highest K+–Mg++–ATPase activity at all ATP concentrations up to 3 mM and at low reaction temperature up to 12C, indicating resistance of figleaf gourd to low root temperature.

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Seung-Ku Yang, Kyong-Ju Choi, Soon-Ju Chung, and Wol-Soo Kim*

In order to cultivate tomato of the first fruit cluster harvest a lot of nursery plants were required as much as 75,000 to 100,000 plants per hectare in green house in Korea. Therefore, it needs too many expenses to buy tomato seeds. This study was carried out to confirm the possibility of alternative use of the tomato cuttings instead of tomato seedlings of two varieties. The cutting materials of each node were taken from the suitable transplanting tomato seedling nursery plants in commercial green house. Four to five nodes of seedling nursery plants were cut into plug tray with 50 to 128 cells, 23 to 80 mL/cell in cell capacity. At 5 days after cutting rooting was initiated and the rooted plants could be transplanted as cutting nursery plants. The cutting nursery plants of Rockusanmaru and Momotarou-yoku varieties were planted to the perlite media in hydroponics bench in green house with 111,110 plants/ha (90 cm × 10 cm) in planting density at 8 May 2002. The matured fruits were harvested from 9 July through 26 July 2002. The number of harvested fruits was 2.9 to 3.3 for the two varieties. The fruit weight was 138 to 153 g for `Rockusanmaru', and 127 to 146 g for `Momotarou-yoku'. The cutting nursery plants of `Rockusanmaru' showed higher fruit yields as much as 51.5 tons/ha than that of seedlings as 40.3 tons/ha. There was a similar result in `Momotarou-yoku'. The duration from cutting to harvest of first fruit cluster was required 89 to 105 days, as well as 63 to 79 days from field planting to harvest. In conclusion the cultivation with tomato cutting nursery plants was considered as better effects in shorter periods in nursery raising and higher yields in comparison to conventional cultivation with seedlings.

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Yang-Key Na, Byeong-Sam Kim, Kyong-Ju Choi, Young Kim, and Wol-Soo Kim*

Recently, the acreages Japanese apricot have been increased for being known of the medical functions. However, the increase of tree height, overgrowing trees and light deficiency at the bottom of canopy induced the poor fruit quality and higher labor charges. This study was conducted to assess the effects of training time, angle and length of water sprout on tree growth, the shoot-curbing, and the occurrence of new shoot for 2 years. Water sprouts were trained on 5, and 25 June, and 15 July with three varying angles of 30°, 45° and 60°, and cut at three lengths (50, 80, 110_) after harvest. Compared to control, the treatment on June 25 showed the highest values of 76%, 82% of internode and shoot length respectiely. In the treatment of training angle, shoot length was 71% in both 30° and 45° but heavily limited to 36% in 60° with comparing to control. The occurrence of shoots showed 18.1, 24.6, and 36.3 in treatment of 50, 80 and 110 cm, respectively, and in 80 cm, the number of shoot with diameter more than 0.5 mm, which is suitable for bearing mother branch, was higher. The best result was obtained in method of branch training with 45° and heading-back 80 cm at height on 15 June for the renewal of lateral branch.

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Yang-Key Na, Kwang-Chul Na, Byeong-Sam Kim, Kyong-Ju Choi, Gil-Ho Shin, and Wol-Soo Kim*

The objective of this study was to determine the effect of Rhodopseudomonas p., which isolated from domestic soil on the density of microorganism in soil, leaf and SSC in pear (Pyrus pyrifolia) fruit. The solution of Rhodopseudomonas p. was sprayed over canopy and fertigated around trunk in 12-year-old `Niitaka' pear with Y-training system. The spray and fertigation were performed 11 times at 15-day intervals from 22 Apr. to 22 Sept. with 200 times diluted solution (v/v). The width and length of treated leaf was increased by 1.4 mm and 0.9 mm compared to them of control. There was no difference in chlorophyll a content between treatments. The treatment increased SSC relatively to control by 0.7% and fruit firmness by 0.29 higher but there was no difference fruit weight. Hinter `L' value was higher by 3.5 and Hunter `a' lower by 0.2 compared to control so fruit color was more clean than control. In fertigation treatment, the density of microorganism and fluorescent bacteria in soil showed increasing tendency compared to control but the opposite in bacteria. These results suggested that the spray and fertigation of Rhodopseudomonas p. solution improve SSC and color of pear fruit.