• The Korean Journal of Ecology
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• v.21 no.2
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• pp.117-124
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• 1998

To clarify the effects of acid precipitates on histological damage, water status, and growth of Pinus densiflora green house experiment applyin simulated acid rain was carried out. Contact angle of water droplet on needles of P. densiflora seedlings treated with simulated acid rain of different pHs simulated acid rain was, the more rapid transpiration was. Leaf water potential after water withdrawal was also reduced rapidly in proportion to acidity of simulated acid rain. Height growth of P. densiflora seedlings treated with simulated acid rain of pH 2 decreased, while growth of seedlings treated with that of pH 3 and 4 increased comparing with that treated with normal rain of pH 5.6. pH of cultivated soil in pH 2 plot was acidified with the amount of simulated acid rain applied but that in pH 3 and 4 plots did not show any directional change. From those results, it could be interpreted that decrease of height growth in pH 2 plot was originated from multiple effects of water deficit from rapid transpiration and soil acidification. On the other hand, increased of height growth in pH 3 and 4 plots would be originated from the supply of N and S included in simulated acid rain.

• Journal of Ginseng Research
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• v.22 no.4
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• pp.294-298
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• 1998

This study was conducted to investigate the effects of growth characteristics and mineral contents of ginseng seedling grown in different locations on ginseng growth and root yield. Ginseng seedling produced in 16 farmers' field at the semi-Yangjik seedbed were planted and cultivated in a field with same cultural practices. Missing plant was increased with increased year of ginseng age, especially severe at 5-year-old ginseng. Rate of missing plant was different among the origins of the seedling, even with the same weights. Negative correlation was noted between the missing rate of 3-year-old ginseng plants and NH4-N content of the seedling, but positive correlation between the missing rate and K2O and Ca contents of the seedling. Root yield of 6-year-old ginseng was also affected by the origins of ginseng seedlings. Root yield was high in ginseng plant from 0.6∼0.9 g see dings compared to those from over 0.9 g seedlings.

• Journal of Plant Biology
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• v.29 no.2
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• pp.85-94
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• 1986

Canavanine content of the cotyledons of Canavalia lineata decreased gradually during germination and growth of seedlings but continued to increase in roots and leaves. After abscission of cotyledons, canavanine content of leaves depleted competely. The activity of canavanase could be detected in leaves and roots, but not in cotyledons. High arginase activity was observed in the cotyledons of seeds at the earlyimbibition period. During the growth of seedlings, cotyledonary canavanine appeared to be transported to the growing of seedlings where it could be utilized through nitrogen metabolic pathways. In crude cell-free extracts of leaves, maximum activities of canavanase or arginase appeared in 30mM Tris-HCl buffer (pH 9.0) or 30mM NaHCO3 buffer (pH 10.0), respectively. The activities of these two enzymes differed from each other when treated with Co2+ or Mn2+. These results support the idea that canavanase and arginase might be different enzymes.

• Journal of Bio-Environment Control
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• v.12 no.2
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• pp.101-105
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• 2003

This experiment was conducted to find out the effect of day length on the production of high quality plug seedlings in onion (Allium cepa L.). Two cultivars, ‘Changnyongdaego’ and‘Wolryun’, were grown to seedlings in 200-cell plug trays under 11.5, 12.5, 13.5 hours and natural day length. These seedlings were transplanted to the pot (16 cm In diameter) and grown under 16 hours day length. Number of leaves and neck diameter showed better growth in the longer than shorter day length treatments, but plant height old sheath length were retarded in the longer day length treatments. Growth such as no. of leaves, neck diameter, plant height and sheath length increased with the passage of day, but plant height and neck diameter decreased by treatment over 20 days with 13.5 hours day length. Bulbing and bulb size of onion after transplanting were enhanced in the seedlings cultured under longer day lengths. From the above results, treatment of long day length during seedling culture in plug tray can control the overgrowth and produce high quality plug seedlings.

• ALGAE
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• v.37 no.2
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• pp.105-121
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• 2022

Modern seaweed farming relies heavily on seedlings from natural beds or vegetative cuttings from previous harvests. However, this farming method has some disadvantages, such as physiological variation in the seed stock and decreased genetic variability, which reduces the growth rate, carrageenan yield, and gel strength of the seaweeds. A new method of seedling production that is sustainable, scalable, and produces a large number of high-quality plantlets is needed to support the seaweed farming industry. Recent use of tissue culture and micropropagation techniques in eucheumatoid seaweed production has yielded promising results in increasing seed supply and growing uniform seedlings in large numbers in a shorter time. Several seaweed species have been successfully cultured and regenerated into new plantlets in laboratories using direct regeneration, callus culture, and protoplast culture. The use of biostimulants and plant growth regulators in culture media increases the seedling quality even further. Seedlings produced by micropropagation grew faster and had better biochemical properties than conventionally cultivated seedlings. Before being transferred to a land-based grow-out system or ocean nets for farming, tissue-cultured seedlings were recommended to undergo an acclimatization process to increase their survival rate. Regular monitoring is needed to prevent disease and pest infestations and grazing by herbivorous fish and turtles during the farming process. The current review discusses recent techniques for producing eucheumatoid and other valuable seaweed farming materials, emphasizing the efficiency of micropropagation and the transition from laboratory culture to cultivation in land-based or open-sea grow-out systems to elucidate optimal conditions for sustainable seaweed production.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.2
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• pp.121-124
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• 2001

Potato (Solanum tuberosum L.) tubers of 10, 20, 30, 40, and 50 g were planted in plug trays with vermiculite-based root medium on 10 August 2000 and grown for 15 days in a glasshouse to determine the effects of mini-tuber size on plug seedling growth and field performance of plug seedlings. For a control, common potato tubers weighing 50 g were also planted. As size of seed tubers planted increased from 10 to 50 g, seedling height decreased from 24.6 to 20.0cm while shoot number per seedling increased from 2.0 to 3.5, main stem diameter from 4.3 to 6.1mm, and fresh weight of root + top from 9.3 to 19.4 g/seedling. At 90 days after transplanting plug seedlings, the total number of tubers per plant increased from 3.62 to 4.72, average tuber weight from 62.9 to 72.8g, and total tuber yield 20.5 to 23.6 t/ha with increase in seed tuber size. Plug seedlings raised from 50g tubers produced 22% more tubers per plant and had 21 % higher＞80g tuber yield than the directly planted potatoes.

• Journal of Plant Biotechnology
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• v.6 no.4
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• pp.259-264
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• 2004

The present study describes the ameliorating effect of $Ca^{++}\;on\;Cd^{++}$ toxicity on the germination, early growth of mungbean seedlings, nitrogen assimilation enzyme. s-nitrate reductase (NR), nitrite reductase (NIR), anti-oxidant enzymes (POD, CAT and SOD) and on the accumulation of hydrogen peroxide and sulphydryls. $Cd^{++}$ inhibited seed germination and root and shoot length of seedlings. While NR activity was down- regulated, the activities of NIR, POD and SOD were up- regulated with $Cd^{++}$ treatment. $Cd^{++}$ treatment also increased the accumulation of sulphydryls and peroxides, which is reflective of increased thiol rich proteins and oxidative stress. $Ca^{++}$ reversed the toxic effects of $Cd^{++}$ on germination and on early growth of seedlings as well as on the enzyme activities, which were in turn differentially inhibited with a combined treatment with calcium specific chelator EGTA. The results indicate that the external application of $Ca^{++}$ may increase the tolerance capacity of plants to environmental pollutants by both up and down regulating metabolic activities. Abbreviations: $Cd^{++}= cadmium,\;Ca^{++} = calcium$, NR= nitrate reductase, NIR=nitrite reductase, POD = peroxidse, SOD= superoxide dismutase, CAT= catalase, EGTA= ethylene glycol-bis( $\beta-aminoethyl ether$)-N,N,N,N-tetraacetic acid.

• Journal of the Korean Society of Tobacco Science
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• v.4 no.1
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• pp.43-49
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• 1982

This experiment was carried out to study the influence of temperature on the growth rate and nutrient uptake of tobacco seedlings grown on neutralized charcoal bed during temporary transplanting. The highest growth rate was obtained at tile temperature of 26-22-$l8^{\circ}C$, probably due to fast establishment of roots in the soil. Seedling growth was better in neutralized charcoal bed than in chaffy charcoal bed at each temperature. Days required for fresh weight to reach 20g/10p1ants were shortened by 9~12days as the temperature increased from 18-14-$l0^{\circ}C$ to 26-22-$l8^{\circ}C$. Compared with chaffy charcoal bed, days required for fresh weight to reach 20g/10 plants with neutralized charcoal bed were shortened by about 5 days, 4 days, and 2days at 18-14-$l0^{\circ}C$, 22-18-$l4^{\circ}C$, and 26-22-$l8^{\circ}C$, respectively. Three macronutrient (N, $P_2O_5,\;K_2O$) contents in seedlings increased with increase of temperature. At each temperature, N and $K_2O$ contents in seedlings of neutralized charcoal bed was higher than those of chaffy charcoal bed, whereas that of $P_2O_5$ was low conversely. Nitrate nitrogen from nitric acid that was used to neutralize chaffy charcoal was maintained to tile end of seedling period, providing the source of nitrate nitrogen for the better seedlings.

• Journal of Bio-Environment Control
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• v.8 no.4
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• pp.242-249
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• 1999

This study was conducted to investigate the effect of seedling age and irrigation set point on the growth and yield of white spined cucumber cv Sharp-1. Leaf area, number of lateral vines and root weight measured 70 days after planting were the greatest in 30 day-old seedling treatment. Inorganic element content measured 30 days after planting was the greatest in 30 day-old seedling treatment. Total and marketable yields were greater in 30 day-old seedlings than those of 20 or 40 day-old seedlings. The early yield was the least in 20 day-old seedlings. 40-day old seedlings lost vigor quickly. No significant differences in growth and yield observed as affected by irrigation set point.

• Journal of agriculture & life science
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• v.43 no.5
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• pp.43-46
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• 2009

The one of problems of plug seedlings production in winter season was a poor growth. This study was carried out to investigate the effects of treatments with yeast fertilizers on the growth of pepper seedlings in winter seasons. The plant height, internode length, and shoot and dry weight of pepper seedlings increased significantly by yeast fertilizers. The results showed that yeast fertilizer treatment could be more effective in soaking than foliar spray and that of dilution could be effective in $1,000{\times}$.