• Journal of Environmental Science International
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• v.28 no.12
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• pp.1061-1069
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• 2019

Common reed (Phragmites australis) is widespread in reclaimed land and wetland habitats. Every year, the common reed produces extensive colonies by means of underground rhizomes and ground-surface stolons. From an agricultural point of view, the common reed's large biomass is a good material for supplying organic matter. However, it has not yet been studied in terms of seedling production, transplanting conditions, and decomposition characteristics in reclaimed land. Seeds were harvested from the native common reed in Saemangeum, South Korea, the previous year and stored on an open field. The seeds were sowed in the greenhouse at the beginning of April. Common reed decomposition was studied from June to September, with the use of coarse mesh (5 mm) stem litterbags, on three samping dates and with five replicate packs per sample. These packs were dug in five soil condition (low-salinity topsoil, subsoil, high-salinity topsoil, subsoil, paddy topsoil) to 0.2 m and 0.4 m depth. The highest germination rate of common reed seeds was observed in non-salt solution, but the exhibited germination rate was 70% at 9.38 dS m^-1. The plant height of young reed decreased steadily with increasing salinity, but leaf number did not decrease by 9.38 dS m^-1. The survival rate of the two-year-old reed was 83.3%, which was 35% higher than that of the one-year reed. The transplant success rate was 0% in the no vinyl mulching in the soil, but the first year and second year seedlings survived rates were 63% and 83.3%, respectively, in vinyl mulching. Common reed decomposition rates were faster low salinity than high salinity. All nutrient contents were found to fluctuate significantly with time by soil conditions. We also need to study the growth rate of reed transplanting seedlings by soil moisture contents and the comparison of degradation in common reed tissues.

• Journal of The Korean Society of Grassland and Forage Science
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• v.7 no.1
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• pp.25-30
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• 1987

There are differences in opinion as to whether nitrogen fertilizer should be used when establishing alfalfa (Medicago sativa L.). Various reports show that under a hot environment, rhizobia (Rhizobium meliloti) are not as effective in fixing atmospheric nitrogen as they are under moderate temperatures. It is also believed that the addition of nitrogen fertilizer inhibits nodulation of alfalfa seedlings. A replicated experiment was conducted under controlled environmental conditions at the University of Nevada-Reno, Reno, Nevada, USA, to determine the effects of nitrogen application on seedling growth and nodulation of alfalfa grown in a hot environment. Sterile sand was used as the growing media to which a complete nutrient solution minus nitrogen was applied volumetrically to each pot daily. In addition, half of the pots received NH4-$NO_3$, at the rate of 11.2 kg per ha at seeding and at two and four weeks after planting giving a total nitrogen application rate of 33.6 kg per ha during the seven-week experimental period. Rhizobia inoculant (R-12) consisted of a mixture of strains 171-15a, 1682c and 80 PI 265 of (Rhizobium meliloti). Inoculant was applied to the seeds prior to planting and to the sand media at two and four weeks after seeding. Twenty seeds were planted in pots 14.0 cm in diameter and 11.5 cm deep. Plants were thinned to ten plants per pot after emergence and were grown in a controlled environment chamber with a 16-hour light period. Soil temperature at 6 cm depth ranged from 17.4^{\circ}C.$ to 31.1^{\circ}C.$ and had a daily mean of 26.5^{\circ}C.$. Plants were harvested at weekly intervals for seven weeks. Root, shoot and total length, dry weight, volume and number of nodules per plant were determined. Root, shoot, and total length were greater in seedlings grown in soil where nigrogen was applied than that grown in soil to which no nitrogen was applied. The average size of the seedlings as determined by volume and weight was more than two times greater where plants were fertilized with nitrogen. Nodule number per seedling was also greater when nitrogen was applied compared to those which received no nitrogen. The differences were greater as the plants became older. The rhizobia did not fix enough nitrogen for adequate growth of seedlings. This is probably due to high temperature growing conditions that caused the rhizobia to become relatively ineffective as compared to cooler growing conditions. Data suggests it would be desirable to apply nitrogen at seeding when alfalfa is established under hot conditions that occur in mid- or late summer.

• Horticultural Science & Technology
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• v.34 no.3
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• pp.414-423
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• 2016

Growers in plug seedling production think that root media in which rockwool is a component has given rise to several environmental problems. Therefore, the demand for new materials as a substitute for rockwool has been increased. This study examined the possibility of cultivation of tomato plug seedlings using a newly developed growing medium with phenolic foam. Plug seeds of tomato cultivar 'Madison' were sown in four pellet-type growing media: Grodan rockwool (GRW), UR rockwool (URW), phenolic foam LC (LC) or phenolic foam LC-lite (LC-lite). Then, the seedlings were transplanted to the four cube-type growing media 19 days after sowing. Seeds were germinated in a growth chamber ($25{\pm}2^{\circ}C$, 80% relative humidity, and dark) for 4 days and then the seedlings were grown with a nutrient solution supplied by an overhead irrigation system in a greenhouse. Plant height, number of leaves, leaf area, and fresh or dry weight of tomato seedlings were the greatest for the seedlings transplanted to URW cube media after being grown on LC-lite pellets. Root grade was the greatest for the seedlings transplanted on LC or LC-lite cube media after being grown on LC pellets. Chemical properties of all media tested for tomato growth were maintained within a stable range, while physical properties of URW showed high values in container capacity, air space, and total porosity. These results demonstrated that the phenolic foam media were effective for seedling growth and can substitute for rockwool as a root medium.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.2
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• pp.183-187
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• 1983

The investigate the varietal differences is physiological characteristics related to nutrient uptake and response to nitrogen and phosphorus, a pot experiment was conducted in a temperature control chamber. Three varieties with different cold resistances were grown under normal ($23^{\circ}-25^{\circ}C$) and cold ($15^{\circ}C$) conditions with three nitrogen and phosphorus application levels. The cold temperature was treated for twelve days after thirty days from seeding. The results were summarized as follows: 1. Dry weight and nutrient contents were reduced in cold temperature treatment compared with control and the reduced ratio by low temperature were in order of dry weight 29.4% $P_2O_5$ 21.3%, N 15.3%, $K_2O$ 10.1%, $SiO_2$ 8.7%. 2. The reduced ratio of phosphorus contents of each varieties to normal condition were 13.5% in resistant, 19.5% in medium, 31.1% in susceptible variety, respectively. 3. The phosphorus and silicate contents of plants showed a good relationship with varietal differences in cold resistance but nitrogen and potassium didn't showed, therefore, phosphorus and silicate contents might be used as the index for physiological characteristics related with cold resistance. 4. Phosphorus content slightly increased with nitrogen application but silicate content decreased. Upon phosphorus application, nitrogen and silicate contents were increased.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.4
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• pp.283-291
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• 2000

The beneficial effects of mycorrhizal fungi on plant growth has largely been attributed to higher uptake of P and other mineral nutrients. However, the effects of mycorrhizal colonization on uptake of mineral nutrients are conflicting in various past investigations. This study was carried out to investigate the effect of P application rate on mycorrhizal colonization and nutrient uptake of Poncirus trifoliata (trifoliate orange) seedlings grown in non-cultivated volcanic ash soil of Cheju island. Five levels of P (40, 573, 1,106, 1,373. $1,640mg\;P\;kg^{-1}$) were applied with double superphosphate. Seedlings inoculated with mycorrhizal fungi were grown for 5 month in a greenhouse. As the level of P application increased, mycorrhizal colonization in the seedlings decreased, and the colonization was significantly reduced when available P was higher than $150mg\;P\;kg^{-1}$ levels. There was a significant correlation between mycorrhizal colonization and P uptake by trifoliate orange seedlings at lower P applications. The effectiveness of mycorrhiaze on P uptake was more significant at lower P applications. Uptake of N, K, Ca, Mg an Zn by trifoliate orange seedlings also increased as mycorrhizal colonization increased, but mycorrhizae could not enhance the uptake of Cu by trifoliate orange seedlings in volcanic ash soil of Cheju island.

• Korean Journal of Environmental Agriculture
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• v.39 no.1
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• pp.50-57
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• 2020

BACKGROUND: Biochar is used in various environmental fields, such as water quality and soil restoration, and affects soil fertility and nutrient cycling. Also, when crops are grown on biochar-applied soil, their characteristics may be affected. Biochar is used especially with commercial vegetable seedlings. METHODS AND RESULTS: The objective of this study was to determine the effects of biochar content in seeding mixes on early growth of lettuce (Lactuca sativa L.), Chinese cabbage (Brassica rapa L.), and red pepper (Capsicum annuum L.). Treatments consisted of a control (0: 10, ratio of biochar to seeding mixes (w/w)), 1: 9 (biochar 10%), 3: 7 (biochar 30%), 5: 5 (biochar 50%), and 7: 3 (biochar 70%). The biochar was made from risk husk and had a C/N ratio of 104. As the mixing ratio of biochar increased, pH increased whereas EC and nitrogen content decreased. The highest phosphorus content was with the treatment of 30% biochar, while there were significant increases in the weight of lettuce seedlings and concentrations of T-N, P₂O₅, K₂O, MgO, and Na with the treatments of 30% and 50% biochar. Although the weight of Chinese cabbage seedlings increased with the treatment of 10% biochar, the increase was not statistically significant. Also, there was an increase in the weight of red pepper seedlings with the treatment of 30% biochar, but the increase was not statistically significant. With increases in the biochar mixing ratio, the K₂O concentration of red pepper seedlings increased, but the concentrations of P₂O₅, CaO, MgO, and Na decreased. It was believed that this was because of absorption inhibition by calcium-phosphate formation in the seeding mixes owing to increased pH. CONCLUSION: In conclusion, adding biochar to seeding mixes is considered to be an important mean for growing healthy vegetable seedlings. More field experiments are needed to verify the effect of biochar on vegetable crop growth over the entire growing season.

• Journal of Plant Biotechnology
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• v.6 no.1
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• pp.55-61
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• 2004

Callus induction and somatic embryogenesis are fundamental to cotton tissue culture biotechnology. An efficient protocol for callus induction, somatic embryogenesis and their maturation have been developed to regenerate plantlets from cotton (Gossypium hirsutum L.) variety coker 312. Embryogenic callus was initiated from hypo-cotyl region that was used as an explant at seedling stage when it was about 7-8 days old. Callus induction was achieved through culturing hypocotyls (5-7mm) on $MS_{1a} medium supplemented with 2,4-D (0.1 mg/L) and KT (0.5 mg/L) for six weeks. A friable, colorless, bulky and well proliferating callus becomes greenish with the addition of NAA (2.0 mg/L), ZT (0.1 mg/L) and removal of 2,4-D (M $S_{1b}$) cultured for two weeks then again transferred to $MS_{1a}. 2,4-dichlorophenoxyacetic acid (2,4-D) promoted the proliferation of embryogenic callus, but had a negative effect on the differentiation and germination of somatic embryos. ZT (0.1mg/L) and activated charcoal (2g/L), both hormones play an important role in differentiation and germination of somatic embryos in hypocotyls derived embryogenic callus but in case of cotton, such a capability have been observed on MS medium with 1.92 g/L $KNO_3$, but it is considered to attain somewhat more improvement. High embryogenesis frequency was achieved through nutrient deficient stress treatment. The frequency of globular embryogenesis (two-three folds) was achieved when well proliferating callus was (from $MS_{1a}$ media) cultured on MS (1/5 strength) medium for four weeks. Here the development of anthocyanins is the best indicator for somatic embryogenesis. However, when embryoid callus was cultured on MS (full strength) medium, the globular embryos were developed into normal plantlets immediately. In this procedure 27.49% cotyledenary embryos were developed. Of that 70% cotyledenary embryos were developed not only into normal plantlets but rooted simultaneously, when cultured on MS (with 0.05 mgg/L giberrelic acid) medium. So complete plants could be regenerated through somatic embryogenesis from hypocotyl explants within 6 months.s.

• Journal of Microbiology and Biotechnology
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• v.28 no.9
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• pp.1527-1535
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• 2018

Bacterial strain BAS23 was isolated from rice field soil and identified as Bacillus amyloliquefaciens. Based on dual culture method results, the bacterium BAS23 exhibited potent in vitro inhibitory activity on mycelial growth against a broad range of dirty panicle fungal pathogens of rice (Curvularia lunata, Fusarium semitectum and Helminthosporium oryzae). Cell-free culture of BAS23 displayed a significant effect on germ tube elongation and mycelial growth. The highest dry weight reduction (%) values of C. lunata, H. oryzae and F. semitectum were 92.7%, 75.7%, and 68.9%, respectively. Analysis of electrospray ionization-mass spectrometry (ESI-MS) and $^1H$ nuclear magnetic resonance (NMR) spectroscopy revealed that the lipopeptides were iturin A with a C14 side chain (C14 iturinic acid), and a C15 side chain (C15 iturinic acid), which were produced by BAS23 when it was cultured in nutrient broth (NB) for 72 h at $30^{\circ}C$. BAS23, the efficient antagonistic bacterium, also possessed in vitro multiple traits for plant growth promotion and improved rice seedling growth. The results indicated that BAS23 represents a useful option either for biocontrol or as a plant growth-promoting agent.

• Ocean and Polar Research
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• v.36 no.2
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• pp.199-208
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• 2014

Copepods are a major food source for marine fish larvae in nature. Many studies on copepods culture have been conducted to develop a new live food for the seedling production of marine fish larvae. But fish farmers still depend on rotifer and Artemia nauplii. This study was carried out to find suitable copepods as live food for the larvae in hatchery. Eight species of copepods (1 calanoid, 2 cyclpoid, 5 harpacticoid) that were fed Isochrysis galbana were examined in terms of the size of nauplii, fecundity, amino acids, and fatty acids contents. These species were divided into small (nauplii length 46-86 ${\mu}m$) and large (nauplii length 120-188 ${\mu}m$) size group. Nitokra spinipes in the small group and Tigriopus japonicus in the large group showed the highest fecundity with 151.1 and 139.6 nauplii production per gravid female, respectively. With regard to nutrients, essential amino acids were the highest with 21.2% in cyclopoid Paracyclopina nana in the small group and n-3 HUFA were the highest in calanoid Pseudodiaptomus inopinus (8.5 ${\mu}g/mg$) in the large group and P. nana (8.8 ${\mu}g/mg$). In terms of the size, fecundity, and nutritional value of copepods examined in this study, N. spinipes and P. nana seem to be suitable copepod species to develop as a new live food for small mouth fish larvae.

• Horticultural Science & Technology
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• v.35 no.1
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• pp.46-58
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• 2017

This study was conducted to investigate the optimal conditions for spore germination, prothallus propagation, sporophyte formation and seedling growth in Microlepia strigosa (Thunb.) C. Presl. Spore germination and prothallus development were promoted by low concentrations of Knop medium nutrient solution. The optimal medium for prothallus propagation and antheridium formation was 2X MS medium with 3% sucrose. The activated charcoal content of the medium did not affect prothallus proliferation. Among the various combinations of culture soil (bedding soil, peat moss, perlite and decomposed granite), a mixture of bedding soil, peat moss and decomposed granite at a ratio of 1 : 1 : 1 (v : v : v) had a positive effect on sporophyte formation. The most efficient conditions for promoting the growth of whole plants (sporophyte seedlings) were 50 - cell plug trays filled with a mixture of bedding soil and decomposed granite at a 2 : 1 (v : v) ratio.