• Journal of Bio-Environment Control
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• v.10 no.1
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• pp.55-60
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• 2001

To investigate the effect of red light (R) and far-red light(FR) on controlling the growth of tomato transplants, height, length of 1st internode, and stem diameter of plant were measured every 12 days during 24 days of light treatment. At the end of experiment, fresh and dry weights of roots and shoots were measured. Generally, it was shown that the height of plant was suppressed by the treatment of FR. However, the effect of light-treatment time (10 or 20 min) on plant height was not significant. Stem diameter of the plant treated with R was greater than that of the plant treated with FR or the control. Dry weight ratio of shoot to root of the plant treated with R was smaller that of the plant treated with FR. R was more effective than the control, which was more effective than FR, in making the transplant compact.

• Korean Journal of Organic Agriculture
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• v.23 no.2
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• pp.267-280
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• 2015

The study was conducted to evaluate effects of time and degree of defoliation on growth of 'Wonhwang' pear (Pyrus pyrifolia Nakai) trees managing with low pesticides as well as regrowth of cuttings in vitro. Treatments included degree of defoliation (20% and 60%) with time of defoliation (Early-Aug, End-Aug, and Early-Sep); Early-Aug (20%), Early-Aug (60%), End-Aug (20%), End-Aug (60%), Early-Sep (20%), Early-Sep (60%), and No defoliation. No defoliation and Early-Sep (20%) defoliation increased growth of water sprouts and new shoots, which were improved by delayed defoliation or 20% of defoliation. Total-C, total-N, B, and free sugar contents increased in No defoliation-shoots but decreased in End-Aug (60%)-shoots. Delayed defoliation increased total-C, total-N, and free sugar in shoots, with high contents of C, K, Ca, Mg, and B observed for 20% of defoliation-trees. Fruit yield and weight or fruit length increased in No defoliation, End-Aug (20%) defoliation, and Early-Sep (20%) defoliation, but reduced in End-Aug (60%). Fruit soluble solids content reduced in defoliation in August. Time of defoliation did not affect the fruit yield and fruit quality, while degree of defoliation influenced yield and fruit weight and length. Defoliation at End-Aug (60%) mostly increased the leakage rates of the stem cuttings at $-18^{\circ}C$ and $-21^{\circ}C$ in vitro and reduced the germination rates at $-24^{\circ}C$ and $-27^{\circ}C$. Under comparison of time and degree of defoliation, the Early-Sep defoliation increased germination rates of the stem cuttings at $-27^{\circ}C$ in vitro, and 60% of defoliation decreased the germination rates compared to the 20% of defoliation.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2002.11a
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• pp.29-30
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• 2002

The goal of this research was to develop the effectiveness of in vitro culture method for A. formosanus and study the environment in vitro conditions affecting on growth. The first series of experiments were examined to investigate the response of three different basal media, MS (Murashige and Skoog, 1962), Knudson (KC; Knudson, 1946) and modified hyponex on growth and multiplication during in vitro culture. Multiple shoot proliferation was induced in shoot tip explants on Hyponex (H3) media supplemented with BA (1 mg1$\^$-1/) or TDZ (1-2 mg1$\^$-1/). Addition of activated charcoal (1%) to the TDZ containing medium promoted rapid shoot tip proliferation (11.1 shoots per explant) but the same medium had an opposite effect resulting in poor proliferation in the nodal explants. However, the regenerated shoots had slow growth rate and failed to elongate. This problem was overcome by transferring the shoot clumps to a hormone free H3 media supplemented with 2% sucrose and 0.5% activated charcoal. Using bioreactor culture for scaling up was also shown the best way for multiple shoot induction and growth of this plant. The second series of experiments was studied to investigate the effect of physical environment factors on growth of in vitro plantlets. The Anoectochilus formosanus plantlets were cultured under different air exchange rate (0.1, 0.9, 1.2h$\^$-1/), without sucrose or supplement 20g.1$\^$-1/ (photoautotrophic or photomixotrophic, respectively), and different photosynthesis photon flux (40, 80, 120 ,${\mu}$mol.m$^2$.s$\^$-1/- PPF). Under non-enrichment CO$_2$ treatment, slow growth was observed in photoautotrophical condition as compared with photomixotrophical condition on shoot height, fresh weigh and dry weight parameters; High air exchange (1.2.h-l) was found to be inadequate for plant growth in photomixotrophical condition. On the contrary, under CO$_2$, enrichment treatment, the plant growth parameters were sharply (visibly) improved on photoautotrophic treatments, especially on the treatment with air exchange rate of 0.9.h-1. The growth of plant in photoautotrophic condition was not inferior compared with photomixotrophic, and the best growth of plantlet was observed in treatment with low air exchange rate (0.9.h-1). Raising the PPF level from 80 to 120${\mu}$mol.m$\^$-2/.s$\^$-1/ decreased the plant height, particularly at 120${\mu}$mol.m$\^$-2/.s$\^$-1/ in photoautotrophic condition, fresh weight and dry weight declined noticeably. At the PPF of 120${\mu}$mol.m$\^$-2/,s$\^$-1/, chlorophyll contents lowed compared to those grown under low PPF but time courses of net photosynthesis rate was decreased noticeably. Light quality mainly affected morphological variables, changes of light quality also positively affected biomass production via changes in leaf area, stem elongation, chlorophyll content. Plant biomass was reduced when A. formosanus were grown under red LEDs in the absence of blue wavelengths compare to plants grown under supplemental blue light or under fluorescent light. Stem elongation was observed under red and blue light in the present experiment. Smaller leaf area has found under blue light than with other lighting treatments. Chlorophyll degradation was more pronounced in red and blue light compared with white light or red plus blue light which consequent affected the photosynthetic capacity of the plant. The third series of experiment were studied to investigate the effect of physical environment factors on growth of ex vitro plants including photosynthesis photon flux (PPF), light quality, growing substrates, electrical conductivity (EC) and humidity conditions. In the present experiments, response of plant on PPF and light quality was similar in vitro plants under photosynthesis photon flux 40${\mu}$mol.m,$\^$-2/.s$\^$-1/ and white light or blue plus red lights were the best growth. Substrates testing results were indicated cocopeat or peat moss were good substrates for A. formosanus growth under the greenhouse conditions. In case of A. formosanus plants, EC is generally maintained in the range 0.7 to 1.5 dS.m-1 was shown best results in growth of this plant. Keeping high humidity over 70% under low radiation enhanced growth rate and mass production.

• Applied Biological Chemistry
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• v.36 no.6
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• pp.495-501
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• 1993

This experiment was carried out to find out the dormancy physiology, method of softening culture and evaluation of nutritional value of wild garlic, Ulrung-native Allium victorialis var. platyphyllum. In March, a new bulbs, the shoot and bulbs began to develop until the bulbs showed their complete dormant states in late August. The bulbs renewed to another one in every years. When shoots germinated about $1{\sim}2\;cm$ from mother bulbs, the soft tissues in the mother bublbs was degenerated and finally remained as only fiberous tissues unlike the other bulbaceous plants. There was a high inhibiting activities like ABA in the bulbs. This is believed that this inhibiting substance like ABA in the bulbs is related to the dormancy of wild garlic. Although the immatured bulbs, harvested at May and June, was treated with chilling for 90 days, it didn't germinate their shooting, but the matured bulbs, harvested at July and August, could germinate their shooting over 1 cm in 75 and 60 days chilling treatment, respectively. The shoot elongation was promoted by the longer chilling periods, the later harvesting day and the dark condition. The crude fiber content of leaf and stem increased at more expanded leaf and higher light intensity condition. Since the shoots, grown from germinating to leaf expanding time, had a good quality for food stuff and had less crude fibers, we supposed this period is to be most appropriate for harvesting time.

• Journal of Ecology and Environment
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• v.42 no.4
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• pp.174-182
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• 2018

Background: In this study, we observed their growth and physiological responses using a variety of duty ratio under the mixed light using red, blue, and white lights. The red+blue mixed light was treated with 95%, 90%, 85%, 80%, and 75% duty ratios and red+blue+white mixed light with 85% and 70% duty ratios. We examined the width and length of leaves, total number of leaves, and number of shoots to examine their growth responses. The physiological responses were studied by measuring their photosynthetic rate, transpiration rate, stomatal conductance, water use efficiency, chlorophyll content, and fluorescence ($F_o$, $F_m$, and $F_v/F_m$). Results: We found that lower duty ratio caused the length and width of the leaves to grow longer under red+blue mixed light but that it did not cause any difference in the red+blue+white mixed light condition. In addition, there was no difference in the number of leaves and shoots among all treatments. In the red+blue mixed light condition, the photosynthetic rate was no difference, but both transpiration rate and stomatal conductance were the highest at 95% duty ratio than in other ratios. Water use efficiency pattern was similar to that of photosynthetic rate; water use efficiency was no difference. Chlorophyll content was the highest at 95% duty ratios, and it was the least at 90%, 85%, and 75% duty ratio. $F_o$ and $F_m$ values were relatively high at 85% and 80% duty ratio and low at 90% duty ratio while $F_v/F_m$ showed no difference. Conclusions: Under the red+blue+white mixed light, all physiological items showed no difference between 70 and 85% treatments. But, photosynthetic rate, water use efficiency, chlorophyll content, and $F_v/F_m$ were relatively greater in the red+blue+white mixed light than in the red+blue mixed light. Therefore, red+blue+white mixed light treated with 70% duty ratio could lessen the environmental stress and save more power when cultivating Silene capitata in a plant factory.

• Journal of Korean Society of Forest Science
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• v.110 no.4
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• pp.601-609
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• 2021

The fructification characteristics, fruit quality, and yield of the 'Hwangsil' jujube tree were analyzed at various stages of growth age (3-8 years old) to obtain basic data for developing high-quality jujube production technology. The average height, crown area, stem diameter near the root, stem clear length, the number of the main branches, and the distance between any two main branches were 230.8 cm (224.4~247.2 cm), 3.0 m² (2.1~3.8m²), 4.8 cm (2.4~6.2 cm), 69.1 cm (46.6~78.0 cm), 12.9 (8.6~19.6), and 8.1 cm (7.4~9.0 cm), respectively. Tree age was positively correlated with the crown area, stem diameter near the root, but stem clear length negatively correlated with the number of main branches. The average number of fruits per mother bearing shoot and tree was 20.0 (14.3~26.3) and 302.8 (257.3~373.5), respectively. There was no correlation between tree age and fructification characteristics, such as the number of fruit-bearing mother shoots per the main branch, the number of fruit-bearing shoots per fruit-bearing mother shoot, and the number of fruits per fruit-bearing shoot. Since the shape of the jujube tree is constantly managed based onthe growing area and type of greenhouse where the tree grown. The average fruit weight, fruit hardness, and soluble solid content were 24.2 g (22.4~26.8 g), 28.4 N (27.3~30.0 N), and 19.0% (17.1~19.8%), respectively, with no correlation between the tree age and fruit quality. The average yield was 7.4 kg per tree (5.7~9.1 kg), with significantly high quantities were produced in six and seven years old trees.

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.319-327
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• 2023

To harvest marketable cucumbers, high quality seedlings must be used. Producing seedlings in the greenhouse during the low radiation period decreases marketability due to insufficient light for growth. Supplemental lighting with artificial light of different quality can be used to improve low light conditions and produce high quality seedlings. Therefore, this study was conducted to select the appropriate supplemental light sources on the growth and seedling quality of grafted cucumber seedlings during the low radiation period. Three cultivars of cucumber were used as scions for grafting; 'NakWonSeongcheongjang', 'Sinsedae', and 'Goodmorning baekdadagi'. Figleaf gourd (Cucurbita ficifolia) 'Heukjong' was used as the rootstock. The seeds were sown on January 26, 2023, and grafted on February 9, 2023. After graft-taking, cucumbers in plug trays were treated with RB light-emitting diodes (LED, red and blue LED, red:blue = 8:2), W LED (white LED, R:G:B = 5:3:2), and HPS (high-pressure sodium lamp), respectively. Non-treatment was used as the control. Supplemental lighting was applied 2 hours before sunrise and 2 hours after sunset for 19 days. The stem diameter and fresh and dry weights of roots did not differ significantly by supplemental light sources. The plant height and hypocotyl length were decreased in W LED. However, the leaf length, leaf width, leaf area, and fresh and dry weights of shoots were the highest in the RB LED. Seedling qualities such as crop growth rate, net assimilation rate, and compactness were also increased in RB LED and W LED. After transplanting, most of the growth was not significant, but early yield of cucumber was higher in LED than non-treatment. In conclusion, using RB LED, W LED for supplemental light source during low radiation period in grafted cucumber seedlings improved growth, seedling quality, and early yield of cucumber.

• Korean Journal of Environmental Agriculture
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• v.37 no.2
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• pp.87-96
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• 2018

BACKGROUND: The vigorous shoot growth in upper part of apple tree canopy leads to poor fruit quality and flower bud formation in lower part of canopy. So, this study was conducted to develop the proper control method about the shoot growth in upper part of apple tree canopy. METHODS AND RESULTS: Trunks of 'Fuji'/M9 apple trees were cut (back pruned) to 2.5 m in tree height on 11 February (dormant) or 12 April (full bloom). Naphthalene acetic acid (NAA) was applied at 2.0% to cut surface when trunk was pruned. Prohexadione-calcium (Pro-Ca) was sprayed at 250 mg/L above 2.0 m in tree height at 23 April (petal fall). The NAA or Pro-Ca application after trunk was pruned at dormant (TR-2 and TR-3) significantly reduced shoot growth in upper part of canopy compared with the control (tree was only pruned at dormant, TR-1), but the percent of shoots showing the secondary growth of TR-3 was higher over 2 times than that of TR-2. The reduction of shoot growth in upper part of canopy by TR-2 and TR-3 increased the fruit red color from the lower part in the treating year and blooming of the lower part in the following year. CONCLUSION: Applying 2.0% NAA to cut surface of pruned apple trunk at dormant was the most effective way for stabilization of the tree vigor in upper part of the canopy in a high density apple orchard.

• The Plant Pathology Journal
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• v.24 no.2
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• pp.118-124
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• 2008

Skin sooty dapple disease, a fungal disease that lowers Asian pear fruit quality, has emerged recently in Korea but has not yet been thoroughly characterized. This disease affects the surface of fruit, leaves, and young shoots of the Asian pear, typically appearing as a dark or pale black dapple on the fruit surface. The disease initiates on the fruit with small circular lesions that become bigger, eventually spreading to form large circular or indefinite lesions. Sparse dark or flourishing white-greyish aerial mycelia and appearance of a dark or pale black dapple on the fruit surface are typical signs of this disease. The disease was severe during cold storage of the Niitaka and Chuhwangbae varieties, but more limited on the Gamcheonbae and Hwangkeumbae varieties. To identify causal pathogens, 123 fungal isolates were obtained from lesions. The fungi that caused typical skin sooty dapple disease symptoms in our bioassay were identified. Based on their morphological characteristics, 74% of the isolates were Cladosporium sp. and 5-7 % of the isolates were Leptosphaerulina sp., Tripospermum sp., or Tilletiopsis sp. None of the isolates caused severe soft rot by injection to a wound plug, but some of the Cladosporium sp. isolates caused mild maceration. Therefore this microbiol complex cannot account for the soft rot also observed in stored fruits. The high frequency of isolation of Cladosporium sp. from disease tissues and bioassay on pear fruit surface suggest that Cladosporium sp. could be a major pathogen in the microbial complex associated with skin sooty dapple disease of the Asian pear in Korea.

• Horticultural Science & Technology
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• v.31 no.2
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• pp.165-172
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• 2013

This study was conducted to investigate the effect of bulblet size on growth and bulb enlargement of Lilium Oriental hybrids, such as 'Sorbonne', 'Siberia', and 'Casa Blanca', grown in areas of high altitude (780 m), in 2009. The bulblets were oriented from tissue culture and planted to produce virus-free bulblets. All the three cultivars showed high vitality, with more than 93% producing shoots, even from small bulblets with a bulb circumference (BC) of less than 6 cm. Bulblets with BC 9-10 cm showed an increased height and number of leaves rapidly to induce the phase conversation from vegetative growth to reproductive growth. The bulblets of BC 9-10 cm in 'Sorbonne', 'Siberia', and 'Casa Blanca' had 2.0, 2.9, and 2.8 flower bud sets per plant, respectively. However, the flowers from those bulblets were not adequate as standard bulbs to produce cut-flowers for the domestic market. The larger bulblets showed more prosperous characteristics in growth and development of Lilium Oriental hybrids. Small bulblets had a high occurrence of viruses and leaf blight symptoms during cultivation, indicating the aggravated disease symptoms in the previously infected bulbs. 'Sorbonne' cultivars showed a high rate of enlargement of bulbs, and small bulblets under BC 6 cm produced more than 23% of the standard bulbs of BC 14-16 cm, which could produce cut-flowers for export. However, 'Casa Blanca' bulblets with BC 6-9 cm produced low bulbs of BC 14-16 cm at 21% level. 'Casa Blanca' cultivars had more bulb roots, longer root lengths, and higher weights than 'Sorbonne' and 'Siberia' cultivars. 'Casa Blanca' cultivars with BC over 9-10 cm grew rapidly and produced a high quantity of bulbs. In these results, 'Sorbonne' bulblets of BC 9-10, 'Siberia' bulblets of BC 10-12 cm, and 'Casa Blanca' bulblets of BC 10-12 cm produced 89%, 86%, and 93% of the standard bulbs of BC 14-16 cm, respectively. It is recommended that bulblets larger than the above sizes be used to produce cut-flowers for the export market. Experiment results suggest that production of bulbs larger than BC 18 cm requires bulblets that are larger than BC 12-14 cm of the three cultivars for the highest quality cut-flowers.