• Journal of Korean Society of Forest Science
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• v.102 no.4
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• pp.537-542
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• 2013

Field performance of somatic plants (somatic embryo derived-plants) of yellow-poplar (Liriodendron tulipifera) produced from somatic embryogenesis was compared with that of seedlings at age 5. In comparison of photosynthetic rate (seedling, $10.67{\mu}mol$ $CO_2m^{-2}s^{-1}$; somatic plant, $9.04{\mu}mol$ $CO_2m^{-2}s^{-1}$), stomatal conductance rate (seedling, 0.2 $H_2Om^{-2}s^{-1}$; somatic plant, 0.166 $H_2Om^{-2}s^{-1}$) and respiration rate (seedling, 1.71 mmol $H_2Om^{-2}s^{-1}$; somatic plant, 1.513 mmol $H_2Om^{-2}s^{-1}$), no significant differences were found between plants. The seedlings were a little higher in comparison of stomatal density (seedling, $23.33/mm^2$; somatic plant, $22.43/mm^2$), length (seedling, $25.83{\mu}m$; somatic plant, $23.46{\mu}m$) and width (seedling, $15.87{\mu}m$; somatic plant, $15.3{\mu}m$). In comparison of DNA content of the leaves using flow cytometry, no differences in ploidy level were found between the seedlings and somatic plants.

• Korean Journal of Organic Agriculture
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• v.19 no.spc
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• pp.135-138
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• 2011

In traditional organic rice culture practices, control of weeds is a big problem. This study was conducted to increase the rice production. Results showed that Plant height, SPAD, root length and weight were higher in pot raised seedling than broadcasting method except number of panicles. High plant density caused reduction in plant height, number of culm and chlorophyll content of the rice. No lodging was observed in both methods. Thickness of third internode and culm length was more in pot raised seedlings at both sites. When organic material was used rice yield increased by 3.81%. Higher rice production (10%) was recorded in the fields planted with pot raised seedlings. From the above study it could be conclude that the pot raised seedlings perform better than the seedlings raised by broadcasting methods.

• Korean Journal of Agricultural Science
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• v.11 no.1
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• pp.68-76
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• 1984

The study was conducted to investigate an optimum growing condition for various sizes of seedlings of rice for mechanical transplantation under different sowing rates, different levels of fertilizers, different sowing dates and g rowing days. The plant height, leaf number and dry weight of seedlings increased as the sowing rate decreased and amount of fertilizer applied were increased. Also those seedling characters increased as the rice planted late and the total growing periods increased. The factors affected seedling chracters were ordered as following-sowing times>growing days>sowing rate>fertilizer levels. 200 gr. of seeds per box and 4 gr. of fertilizers were optimum for young seedling growth, when sown early. For medium size of seed ling growth, 50 grams and 100 to 125 grams of rice seemed to be adequate for 25 days old and 35 days old seedling, respectively. However, the 45 days old seedling grew too mach and were not suitable for mechanical transplantation. When planted late, similar results were obtained with more differences among treatments. In other words, the suitable plant density was obtained when 100 gr. of seeds were planted per box. Middle class of seedlings were obtained when 100 to 150 gr. of rice were planted per box and grown for 25 days. The seedlings from the box with 100 to 150 gr. of rice per box were over grown and ratio of suitable seedling was also low if they were grown over 35 days.

• Plant Resources
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• v.8 no.3
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• pp.258-262
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• 2005

In autumn, to determine the optimal planting date and plant density of rapeseed in southern areas of Korea, Yudal variety for autumn sowing, the highest yielding variety was grown under three different planting dates and five different plant densities. Yield components such as plant height, ear length, number of seedling stand per $m^2$, number of branches and pod length were highest at the plots with Sep. 30 of planting date and 30/20 cm drilling of plant density. Yield of seed, oil and 1,000 grains weight were highest at the Sep.30 of planting date and 30/20 cm drilling of plant density. Judging from the results reported above, at optimum planting date and plant density of rapeseed seemed to be Sep.30 of planting date and 30/20cm plant density in autumn sowing.

• Korean Journal of Environmental Agriculture
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• v.22 no.1
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• pp.60-64
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• 2003

This study was conducted to examine the effects of plug tray cell size and growth media on good seedling production of Gerbera hybrida Hort. Seedlings were grown for 60 days in 50, 72, 128, 162 cell trays contanning perlite, cocopeat and perlite+cocopeat(1:1, v/v). Perlite showed higher bulk density than cocopeat and perlite+cocopeat. Total porosity was greater in perlite, cocopeat and perlite+cocopeat in order. Cocopeat showed the highest water holding capacity. Number of leaves were greatest in 128 cell tray containing cocopeat. Leaf area was greatest in 50 cell tray containing cocopeat. Seedling growth was also better in plug tray of bigger cell size. Seedling growth of fresh and dry weight of shoot and root was much better in the growth media of perlite+cocopeat.

• Korean Journal of Medicinal Crop Science
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• v.15 no.2
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• pp.138-141
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• 2007

Good quality seedlings produced in the seedbed of Yangjik, traditional seedling cultivation, is one of the most important factors in determining the yield and quality of $4{\sim}6-year-old$ ginseng. This study was carried out to substitute Yacto, traditional organic fertilizer, for economical compost in the cultivation of seedling by fertilizing relatively little amount of compost into seedbed soil. Bulk density and solid phase were decreased in physical properties of seedbed soil, while air phase and porosity were increased by more addition of compost. When the amount of applied compost in seedbed soil was above $8{\ell}$ per Kan, the contents of nutrient were exceeded the range of optimal standard for ginseng cultivation. Chlorophyll content and stem length were increased by more addition of compost, while the length and the width of leaves showed the highest value at the application level of $8{\ell}$ per Kan. Heat injury was also increased distinctly above the application level of $8{\ell}$ per Kan. The number of first grade seedlings and usable seedlings, and fresh root weight per plant showed the peak at application level of $8{\ell}$ per Kan, respectively. Fertilizing the compost of $8{\ell}$ per Kan into seedbed soil was the optimal amount for producing the good quality seedlings.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.4
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• pp.61-67
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• 2007

Paper sludges collected from three different paper mills were physico-chemically analyzed in order to use them as raw materials for making bed soils and seedling pots. The sludge from a fine paper mill contained lots of inorganic pigment particles used for coating, as those from a newsprint mill and a tissue mill had not. It was clearly through XRD analysis confirmed that all sludges included calcium carbonate. The paper sludge from the tissue mill contained the greatest amount of particles, which would contribute to water absorption and nutrient storage. The sludge from the fine paper mill had the highest density due to many inorganic elements. While the ash content and the total nitrogen content were the highest in the sludge from the fine paper mill, the C/N ratio was the lowest in the fine paper mill sludge. All sludges seemed to have insufficient contents of potassium. The sludges from the newsprint mill and the tissue mill showed more silicon contents than that from the fine paper mill. It was concluded that the sludge from the fine paper mill would be able to be the most efficient raw materials for making bed soils and seedling pots and the other two sludges would be more efficient for intensive culture for crops such as rice and grain with additional supplement of nitrogen and other nutrients.

• Korean Journal of Medicinal Crop Science
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• v.26 no.1
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• pp.64-71
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• 2018

Background: The cultivation of ginseng (Panax ginseng C. A. Meyer) in greenhouses could reduce the use of pesticides and result in higher yield; however, construction costs are problematic. The adaptation of direct-sowing culture in greenhouses could reduce the cost of ginseng production. Methods and Results: To improve seedling establishment in direct-sowing culture, effects of sowing density (SD), number of seeds sown per hole (SN), and thinning (TH) treatment on the root yield were investigated after 3 years of seeding. The emergence rate was significantly influenced by SD, but not by SN or TH. Damping-off and rusty roots increased with an increase in SN with diminishing effects of SN on seedling establishment. Root weight and diameter were affected by SD, SN, and TH, however, there were no statistical significances. The total number of roots harvested per unit area increased with increasing SD and SN, and the weight of roots was affected by SD, but not by SN or TH. Conclusions: Multi-seed sowing per hole and/or thinning might not be an efficient method for the direct-sowing culture of ginseng. The SD for direct seeding culture in greenhouses should be approximately $33-42seeds/m^2$ for an optimum yield of 3-year-old ginseng.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.52-57
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• 2006

This research was carried out to determine the effect of controlling nitrogen application on tiller development, yield, and quality of rice under scanty or excess seedling stands in direct-seeded rice on flooded soil surface. Seedling stand was set to 3 levels: scanty $(60/m^2)$, optimum $(120/m^2)$, and excess $(200/m^2)$. In the scanty plot, additional 4 kg/10a nitrogen was applied at the 3rd leaf stage to promote tiller development. On the other hand, applying 3.3 kg/10a nitrogen at 5th leaf stage in the excess plot was omitted to suppress tillering. Maximum numbers of tillers per plant were 15.2 and 8.6 in scanty and excess plots, respectively, as compared with 9.8 in optimum plot. Productive tiller rate decreased with the increase in number of seedling stands. Regardless of seedling density, the first tiller developed on the 3rd node of rice stem from the bottom. The primary tillers developed at 3, 4, 5, 6, 7 nodes in scanty plot, 3, 4, 5 nodes in optimum plot, and 3, 4 nodes in excess plot. The secondary tillers developed only in some portion of plants in scanty and optimum plots. The order of tiller emergence was negatively correlated to stem length, panicle length, non-productive tiller number, grain number per panicle, and fertility in scanty plot, and to perfect grain ratio in excess plot. In the optimum plot, however, the order of tiller emergence was not correlated to any of the mentioned characteristics. The perfect grain ratio of scanty plot was the highest because green-kerneled rice was a very small portion in the primary tillers as compared with those of optimum and excess plots. Yield indexes of scanty and excess plots were 99%, and 97%, respectively, of the yield (494 kg/10a) in optimum plot. In conclusion, when seedling stands are not at optimum level, rice yield and quality similar to optimum planting density level can be obtained by means of controlling nitrogen application.

• Journal of Korean Society of Forest Science
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• v.112 no.3
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• pp.280-289
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• 2023

Diverse native tree species are distributed in Korean forests; however, information on their regeneration strategies is limited. This study analyzed seed rain from 2011 to 2013, seedling emergence, seedling survival, lifespan distribution, and the relationship between seedling mortality and herbaceous vegetation for 3 years, from 2012 to 2014, to understand the natural regeneration and early survival characteristics of Fraxinus rhynchophylla Hance in natural broad-leaved forests. Seed rain and emerged seedling density significantly differed among the years (p < .05). An increase in seed rain was followed by an increase in seedling emergence in the following year. Seed rain in 2013 and seedling emergence in 2014 showed a significant correlation (p < .05), confirming the trait of F. rhynchophylla seeds that germinate in the following year after seed production. Seedlings emerged in late spring and early summer. Of the seedlings, 78% emerged in the early summer of 2014. Most seedlings died immediately after emergence. Of the seedlings that emerged in August 2012, 56% died within 2 months, and 38% of those that emerged in July 2014 died within 1 month. Shade and competition against ground vegetation chiefly affected the seedling survival of F. rhynchophylla. Fraxinus rhynchophylla showed mast seeding, with a large number of seed production in a particular year. A surge of seedling emergence followed in the early summer of the next year. However, most seedlings died in the same year of emergence. Fraxinus rhynchophylla has a high seedling mortality, but mast seeding and the resulting high seedling emergence produce a few survived seedlings, enabling the continuation of the F. rhynchophylla population. Efforts and research on the natural regeneration of native tree species are required to effectively manage natural forests in Korea.