• Horticultural Science & Technology
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• v.33 no.6
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• pp.860-868
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• 2015

The effect of Si supplied during plant cultivation on tolerance to high temperature stress in Euphorbia pulcherrima Willd. 'Ichiban' was investigated. Rooted cuttings were transplanted into 10-cm pots and a complete nutrient solution, containing 0 or $50mg{\cdot}L^{-1}$ Si as either $K_2SiO_3$, $Na_2SiO_3$, or $CaSiO_3$, was supplied through subirrigation or weekly foliar applications. After two months of cultivation, plants were placed in an environment-controlled chamber and subjected to $35{\pm}1^{\circ}C$ (high temperature) conditions for 18 days. Enhanced specific activities of enzymatic antioxidants (APX) and suppressed specific activities of non-enzymatic antioxidants (ELP) were observed in the high temperature-stressed plants with Si application. The Fv/Fm (maximum quantum yield of photosystem II), photosynthetic rate, and Si contents in the shoot increased in the treatments of $K_2SiO_3$ and $Na_2SiO_3$ supplied through subirrigation. The Si-treated plants had more tolerance of high temperature stress than the control plants. Of the Si sources and application methods tested, $K_2SiO_3$ and $Na_2SiO_3$ supplied through subirrigation were found to be the most effective in enhancing tolerance to high temperature stress.

• Horticultural Science & Technology
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• v.35 no.3
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• pp.314-322
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• 2017

The aim of this study was to determine suitable oxygen transmission rate (OTR) films for modified atmosphere (MA) storage of asparagus spears (Asparagus officinalis L.), and to examine the related changes in asparagus spear quality. Asparagus spears were packed with 10,000, 20,000, 40,000, 70,000, and $100,000cc/m^2{\cdot}day{\cdot}atm$ OTR film treatments for MA storage, and perforated film (conventional storage) was used as the control. The fresh weight loss rate was less than 1% in all OTR film treatments but not in the control. In all OTR film treatments, ethylene content rapidly increased on the first day of storage, and gradually decreased thereafter to $2.0{\mu}L{\cdot}L^{-1}$ by the final storage day. In the 10,000 cc and 20,000 cc OTR film treatments, carbon dioxide content was maintained within the permissible range for asparagus spears under recommended controlled atmosphere (CA) and MA conditions (5-12%). The oxygen content was maintained between 12% and 20% in all OTR film treatments. Hue angles and total chlorophyll content were highest in the 10,000 cc OTR film treatment in both tips and stems. Visual quality was maintained at a saleable level only in the 10,000 cc OTR film treatment until the final storage day (25 days). Based on sensory evaluation, the least off-odor was detected in the 10,000 cc OTR film treatment, and the most in the control treatment. While the soluble solids content decreased with all film treatments, it was maintained at the highest level in the 10,000 cc OTR film treatment. Vitamin C content decreased with all film treatments during storage, but was maintained at higher levels in the 10,000, 20,000, and 40,000 cc OTR film treatments. The firmness of tips and stems increased with storage duration in all film treatments, stems were firmer under the perforated film, 10,000, and 20,000 cc OTR film treatments. Given these results, the 10,000 cc OTR film treatment is considered the most appropriate for MA asparagus spear storage since visual quality and soluble solids content were maintained, and fresh weight loss, vitamin C content, off-odor, and yellowing were suppressed during storage.

• Korean Journal of Environmental Agriculture
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• v.20 no.1
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• pp.44-49
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• 2001

To study whether the secondary toxic substances such as ethylene and reactive oxygen species(ROS) are induced by air pollutants in foliage plants, $SO_2$ was fumigated to Pachira aquatica, Spathiphyllum patinii, and Hedera helix. $SO_2$ was controlled to $1\;{\mu}L/L$ and then fiumigated to plants for 2 days(8 hrs/day). It resulted in visible injury in P. aquatica and H. helix while no symptom appeared in S. patinii. Photosynthetic rate and water use efficiency were most remarkably reduced in P. aquatica compared to other two species whereas least in S. patinii. Two days after $SO_2$ fumigation, ethylene evolution was quantified to 23.56, 10.43 and 4.79 nL/g/h in P. aquatica, H. helix and S patinii, respectively. On the other hand, antioxidative enzymes were clearly activated by $SO_2$ treatment in all tested plant species implying ROS production. In conclusion, we could suggest that ethylene and ROS have been intimately related to the defense mechanism against $SO_2$ and their induction degree increased with plant susceptibility to $SO_2$. Furthermore, it was found that S. patinii was tolerant and P. aquatica sensitive to $SO_2$ on the basis of antioxidative enzyme activity and ethylene evolution.

• Journal of Bio-Environment Control
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• v.15 no.2
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• pp.162-166
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• 2006

The objectives of this study were to determine the effect of cultivation time on the incidence of brown fruit stem (BFS) in glasshouse sweet pepper (cv. Special) and to investigate environmental causes of this disorder. The plants transplanted on 31 August (T1) showed more incidence of BFS than those on 24 November (T2) (6.1% vs.2.9%; P<0.01). The BFS symptom began to appear after completion of fruit enlargement, more often around fruit coloring period. Comparing the environmental factors between T1 and T2, with their data collected for 3 weeks around fruit coloring period, the factor that was most likely responsible for BFS incidence was found to be the night-time humidity deficit (HD) ($1.9g{\cdot}m^{-3}\;vs\;2.9g{\cdot}m^{-3}HD$). These results were reconfirmed as T1 was compared to the plants (T3) that were transplanted at a similar time of the following year to T1, but designed to reduce BSF by increasing air HD via heating at night. That is,T3 had much higher night-time HD than T1 ($5.9g{\cdot}m^{-3}\;vs\;1.9g{\cdot}m^{-3}HD$), and showed no incidence of BFS. These results indicated that, to prevent BFS incidence in the winter-harvesting sweet pepper plants, air humidity at night should be controlled low, especially for the fruit coloring period after fruit enlargement period is completed.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.381-390
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• 2018

This study was conducted to examine the growth characteristics of seedlings of several major fruit vegetables and compare them between plants grown with the conventional plug seedling system (Plug) and those grown with the cylindrical paper pot system (CPP). There were no significant differences in shoot growth characteristics, such as plant height, leaf area, dry weight, and fresh weight, between tomato, cucumber, and watermelon plants grown with the CPP and Plug systems. The total root lengths of tomato and cucumber plants grown with Plug were longer than those grown with CPP at the beginning of seedling growth, and the total root lengths of watermelon grown with Plug were longer than those grown with CPP throughout the whole seedling period. The length of root that separated five steps according to the diameter of the root of tomato did not differ between CPP and Plug, but those of cucumber and watermelon were 20-251% longer with Plug than with CPP for all kinds of roots. The fresh weight of Plug-grown tomato roots was about 30% heavier than that of CPP-grown tomato during the seedling period, but the difference decreased as growth progressed. Finally, there was no difference between plants before and after transplanting. The fresh weights of the Plug-grown plants were about 20-30% heavier than those of CPP-grown ones in terms of the whole seedling. After transplanting to the Wagner pot, the shoot growth of Plug-grown watermelon plants in terms of dry weight was low until 7 days had passed. However, this tendency was reversed from 8 days after transplantation onward. In conclusion, there were no significance differences in the growth of shoots between plants grown with the CPP and Plug systems. However, root development was better with Plug than with CPP.

• Current Research on Agriculture and Life Sciences
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• v.14
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• pp.67-75
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• 1996

Capsicum annuum 'Nokkwang' plug seedlings were treated with 9 different day and night temperatures to investigate on growth and differentiation in controlled environment conditions. The plant height was the most affected by day temperature and DIF and stem length was the similler results as plant height. However, Leaf unfolding rate and leaf length and width increased as average daily temperature increased. and especially fresh weight was worst at ADT was $15^{\circ}C$ and increased as ADT increased. In contrast with fresh weight, chlorophyll content calculated highest when ADT was $15^{\circ}C$, and decreased as NT increased respectively. The stem lengths were not significantly different among treatments with exception of DT/NT=15/$15^{\circ}C$ which significantly decreased. The ultimate +DIF condition, DT/NT=30/$15^{\circ}C$, caused high T/R ratio due to abundant top growth. It is concluded that DT is $22.5^{\circ}C$, and NT is ranged from $15^{\circ}C$ to $22.5^{\circ}C$ to be produced short, healthy plug seedlings in Capsicum annuum 'Nokkwang'.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.265-278
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• 2011

Effects of the open level of the side window were studied to control the temperature and relative humidity in the fog cooling greenhouse. The greenhouse was cooled by air atomizing spray nozzles of the air and water two-fluid process. The control process includes the measuring of environmental variables, setting and coding of the water balance equations and heat balance in greenhouse, calculating of the roof window open and spray water, and operating of the motor and pump. The target temperature and relative humidity were set at $28^{\circ}C$, 75%, respectively. The three modes of the side window open level were 0%, 50% and 100%. The average dry bulb temperatures of the inside air were 28.2, 27.2 and $26.3^{\circ}C$, respectively and their standard deviation was ranged from $0.4^{\circ}C$to $0.8^{\circ}C$. Also the relative humidity of the 0% mode was the best controlled one with the average of 76.3% and the standard deviation of 2.1%.

• Horticultural Science & Technology
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• v.34 no.6
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• pp.871-877
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• 2016

Recycling nutrient solutions in closed hydroponic production systems is usually accompanied by an imbalance of nutrient solutions when concentration is controlled according to electrical conductivity (EC) levels. This study investigated whether it was possible to automatically control the concentrations of five essential elements nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) using only N, K and Ca ion sensors. N, P, K, Ca, and Mg uptake was measured in the nutrient solution, and relationships between absorbed ions were analyzed through twice-repeated experiments in lettuce. Results confirmed that the pattern of $PO_4$ ion uptake was similar that of N, and the pattern of Mg ion uptake was similar that of Ca. $PO_4$ ion uptake was most highly correlated with N, and Mg was most highly correlated with Ca. Regression coefficients of N and $PO_4$ were significantly different at 1.04 and 0.55, respectively, but were similar between Ca and Mg at 0.35 and 0.40, respectively. Additional experiments were conducted to measure nutrient uptake in pak choi and rose plants, both to confirm the results from the first experiment in lettuce, and to assess possible application to other crops. Coefficients of determination both for N and $PO_4$, and Ca and Mg were considerably high ($R^2=0.86$) in cultured pak choi, and similar results were observed in cultured rose ($R^2=0.87$ and 0.73, respectively). Regression coefficients for cultured pak choi were 0.56 and 0.24, respectively, and for rose were 0.51 and 0.16, respectively. Although the results obtained for N and $PO_4$ were not consistent between the lettuce experiments, N and $PO_4$ have similar regression coefficients for all crops. No common coefficient was found between Ca and Mg.

• Journal of Plant Biotechnology
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• v.46 no.4
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• pp.274-281
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• 2019

Pistacia chinensis Bunge has not only been used as a medicinal plant to treat various illnesses but its young shoots and leaves have also been used as vegetables. In addition, P. chinensis is used as a rootstock for Pistacia vera (pistachio). Here, the transcriptome of P. chinensis was sequenced to enrich genetic resources and identify secondary metabolite biosynthetic pathways using Illumina RNA-seq methods. De novo assembly resulted in 18,524 unigenes with an average length of 873 bp from 19 million RNA-seq reads. A Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation tool assigned KO (KEGG orthology) numbers to 6,553 (36.2%) unigenes, among which 4,061 unigenes were mapped into 391 different metabolic pathways. For terpenoid backbone and carotenoid biosynthesis pathways, 44 and 22 unigenes encode enzymes corresponding to 30 and 16 entries, respectively. Twenty-two unigenes encode proteins for 16 entries of the carotenoid biosynthesis pathway. As for the phenylpropanoid and flavonoid biosynthesis pathways, 63 and 24 unigenes were homologous to 17 and 14 entry proteins, respectively. Mining of simple sequence repeat identified 2,599 simple sequence repeats from P. chinensis unigenes. The results of the present study provide a valuable resource for in-depth studies on comparative and functional genomics to unravel the underlying mechanisms of the medicinal properties of Pistacia L.

• Journal of Plant Biotechnology
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• v.4 no.4
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• pp.163-170
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• 2002

Radiation induced and somaclonal variations were investigated in the regenerates from gamma irradiated and controlled embryogenic callus (EC) of sweetpotato cvs., Yulmi and White Star by morphological, RAPD and AFLP analysis. Most (approx. 90%) of the EC produced somatic embryos developed into plantlets after being transferred to the auxin-free medium. The frequency of morphological variants derived from the irradiated callus ranged from 3 to 7.8% compared to 0.1-1.1% of that derived from the non-irradiated. Morphological variants were selected from the regenerates and analyzed by RAPD and AFLP procedures. RAPD polymorphisms of Yulmi and White Star regenerates from irradiated calli were 8.8% and 6.1%, respectively. However, the polymerphisms among regenerates from the non-irradiation treatment in these two cultivars were non-detectable and 3%, respectively. AFLP polymorphisms of Yulmi and White Star regenerates from irradiated calli were 29.9% and 28.6%, respectively. while the frequencies for those form non-irradiated calli were 8.5% and 5.6%, respectively. Both the control plants and variants from the nonirradiated were clustered together, while variants from irradiated were separated from the group by Nearest-Neighbor-Interchange Branch Swapping Abbreviation: EC (Embryogenic callus), AFLP (Amplified Fragment Length Polymorphism), RAPD (Random amplified polymorphic DNA)