• Horticultural Science & Technology
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• v.30 no.6
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• pp.673-679
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• 2012

This study was conducted to examine the effect of artificial light source and photoperiod on the growth of leaf lettuce (Lactuca sativa L.) 'Seonhong Jeokchukmyeon' in a closed-type plant production system. Seedlings were grown under 3 light sources, fluorescent lamp (FL, Philips Co. Ltd., the Netherlands), WL #1 (Hepas Co. Ltd., Korea), and WL #2 (FC Poibe Co., Ltd., Korea), each with 3 photoperiods, 12/12, 18/6, and 24/0 (Light/Dark). An irradiance spectrum analysis showed that FL has various peaks in the 400-700 nm range, while WL #1 and WL #2 have only one monochromatic peak at 450 and 550 nm, respectively. The greatest plant height, fresh and dry weights were obtained in the 24/0 (Light/Dark) photoperiod. The 24/0 (Light/Dark) photoperiod treatment promoted vegetative growth of the leaf area. Length of the longest root, number of leaves, fresh weight, and total anthocyanin contents were greater in FL than in either WL #1 or #2. The greatest chlorophyll fluorescence (Fv/Fm) was found in the 12/12 (Light/Dark) photoperiod with FL treatment. The energy use efficiency of the LED increased by about 35-46% as compared to FL. Results suggest a possibility of LED being used as a substitute light source for fluorescent lamp for lettuce cultivation in a plant factory system.

• Korean Journal of Environmental Agriculture
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• v.32 no.2
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• pp.123-127
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• 2013

BACKGROUND: The incandescent bulb and compact fluorescent lamp are widely using as a light sources for daylength extension of chrysanthemum. But, these light sources consume a lot of electricity and have short longevity. A light-emitting diode (LED) is a semi conductor light source. LEDs have many advantages over incandescent light sources including lower energy consumption, longer lifetime. In this study, we investigated the intensity of red light to control flowering of chrysanthemum (Dendranthema grandiflorum cv. "Shinma") by using LEDs. METHODS AND RESULTS: The red (660 nm) and far-red (730 nm) light were irradiated subsequently to investigate photo-reversible flowering responses of chrysanthemum. The flowering of chrysanthemum was inhibited by night interruption with red light but subsequently irradiated far-red light induced the flowering of chrysanthemum. This photoreversibility, reversion of the inductive effect of a brief red light pulse by a subsequent far-red light pulse, is a property of photo responses regulated by the plant photoreceptor phytochrome B. Four different intensity of red light of 0.7, 1.4, 2.1, and $2.8{\mu}mol/m^2/s$ (PAR) were irradiated at growth room in order to determine the threshold for floral inhibition of chrysanthemum. Over $1.4{\mu}mol/m^2/s$ of the red lights irradiated chrysanthemums were not flowered. The plant length, fresh weight, number of leaves, and leaf area of chrysanthemum irradiated with red light were increased by 17%, 36%, 11%, and 48%, respectively, compared to those of compact fluorescent lamp. CONCLUSION(S): The red light and subsequential far-red light showed that the photoreversibility on flowering of chrysanthemum. The red light ($1.4{\mu}mol/m^2/s$ of red LEDs) and white light (50 Lux of compact fluorescent lamp) have the same effect on inhibition of flowering in chrysanthemum. Additionally, the red light increased the plant height and dry weight of chrysanthemum.

• Journal of Bio-Environment Control
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• v.15 no.3
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• pp.239-243
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• 2006

This research compared growth and flowering of potted $Viola{\times}wittrockiana$ 'Majestic GT Scarlet Shadow' in various mixtures of recycled perlite and cellular glass foam (CGF). The crop was cultured in a mat subirrigation system. Numbers of leaves, opened flowers, flower buds, and branches, fresh and dry weights of shoot, leaf area, and total chlorophyll concentration were the greatest in plants grown in the medium of used perlite + granular rockwool+ peatmoss (25:50:25, v/v/v). Plant height and length of the longest root were the highest and longest, respectively, in plants grown in the medium of CGF+peatmoss (25:75, v/v). The medium of CGF+peatmoss (25:75, v/v) was better than the medium of used perlite+peatmoss (25:75, v/v) in plant growth. The medium of CGF + granular rockwool (25:75, v/v) was poorer than the medium of recycled perlite + granular rockwool (25:75, v/v).

• Journal of Bio-Environment Control
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• v.16 no.3
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• pp.228-232
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• 2007

We have also clarified the effects of the different substrates; (perlite, peatmoss and granular rock-wool) on the plant growth and the mineral contents of Campanula takesimana until 70 days after transplanting. Overall plant growth in terms of plant height, stem diameter, number of leaves, root length, fresh and dry weight of shoot and root were increased in the order of that mixed perlite and peat moss (50 : 50, v/v)>peat moss (100%)>perlite (100%)>granular rock wool (100%). Mineral contents in plants were much more in the order of potassium $(15.38-43.91cmol^+/kg)$, calcium $(5.48-7.78cmol^+/kg)$, magnesium $(4.38-6.55cmol^+/kg)$ and sodium $(1.25-1.69cmol^+/kg)$. The higher mineral contents of plants were also most made in the mixed substrates of perlite and peat moss (50 : 50, v/v).

• Journal of Bio-Environment Control
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• v.16 no.3
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• pp.199-204
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• 2007

This experiment was conducted to investigate the effect of nutrient solution strength on the growth of miniature multiflora P. amabilis and P. Taisuco Red Jewel at two growth stages during four months cultivation in an ebb and flow system. Early stage plants gained the biggest leaf length and width when nutrient solution strength was EC 0.5 or $1.0dS{\cdot}m^{-1}$ in P. amabilis, and EC $1.5dS{\cdot}m^{-1}$ in P. Taisuco Red Jewel. Root length and weight were the greatest when nutrient solution strength was EC $0.5dS{\cdot}m^{-1}$ in both cultivars and this trend was also found in middle stage plants. Fresh and dry weights of leaves increased as nutrient solution strength was elevated and were the greatest when nutrient solution strength was EC $1.5dS{\cdot}m^{-1}$ in P. amabilis. On the contrary elevation of nutrient solution strength decreased fresh weight of roots, being the greatest when nutrient solution strength was EC $0.5dS{\cdot}m^{-1}$. This trend was also found in P. Taisuco Red Jewel and P. amabilis at middle growth stage. The T/R ratio and chlorophyll content increased with nutrient solution strength and were the greatest regardless of cultivar and growth stage when nutrient strength was EC $1.5dS{\cdot}m^{-1}$.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.779-786
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• 2012

Many farmers have been seeking alternatives to chemical fertilizer for successful organic fruit production. This experiment was carried out to investigate the replaceability of chemical fertilizer by cover crop and slurry composting biofiltration (SCB) liquid manure (LM) application in pear orchard. Three treatments were contained in this experiment; cover crop only and cover crop + LM treatment, and control (chemical fertilizer application). Dry weight and mineral contents of gramineous cover crops were significantly increased in LM-combined treatments than that of leguminous species. Bulk density of soil was decreased in rye + LM and hairy vetch + LM treatments, compared with each cover crop treatment. Soil pH was lowest in fertilizer treatment and soil nitrate content became similar between treatments after rainy season. Available soil phosphate was lower in cover crop and cover crop + LM treatmemts than control, but exchangeable Mg was higher. The mineral content and net assimilation rate of leaves showed no difference between the treatments. As a result, it is suggested that the application of SCB liquid manure in pear orchard managed by cover crops is desirable to maintain the productivity by improving soil physical properties and potential nutrient recovery.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.3
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• pp.327-331
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• 2007

This study was carried out to analyze major chemical components of dried Pimpinella brachycarpa leaves. Proximate compositions of the dried Pimpinella brachycarpa were 8.96% moisture content, 28.73% crude protein, 2.66% lipids, 19.14% ash, and 40.50% carbohydrates. Major components of the free sugars and disaccharides were glucose and maltose. A total of 15 kinds of amino acids were isolated from Pimpinella brachycarpa. Essential amino acids accounted for 49.13% of the total amino acids and non-essential amino acids accounted for 50.87%. A major fatty acid was linolenic acid. A ratio of polyunsaturated fatty acids to saturated fatty acids (P/S ratio) was 2.18. Oxalic acid was a major organic acid. The contents of the vitamins A and E were 9.23 mg% and 0.26 mg%, respectively. Among the minerals in the dried Pimpinella brachycarpa, the content of calcium was the highest (765.13 mg%) and those of magnesium and sodium were also comparatively high (303.00 mg%, 96.21 mg%).

• The Korean Journal of Ecology
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• v.17 no.1
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• pp.23-35
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• 1994

To investigate phytotoxic substances in Artemisia argyi, the donor plant, and their biological activities, seed germination and seedling growth of receptor plants such as Arundinella hirta, Echinochloa crus-galli, Rumex crispus and Lactuca sativa were examined at different concentrations of aqueous extracts of the donor plant. Germination of four receptor species was inhibited by the extracts, while seedling growth was decreased to a lesser degree than in the germintion test. Germination, seedling growth and dry weight growth of Achyranthes japonica grown in pot were proportionally inhibited by the extracts. Volatile substances emitted from A, argi plant caused slight inhibition in the germination and seedling growth of the receptor species. Essential oil of the plant extracted by Karlsruker's apparatus inhibited growth of microorganisms and callus growth of Pinellia ternata and Oryza sativa. The GC /MS method was employed for analysis and identification of allelochemicals from A. argyi leaves. Sixty-one chemical substances such as a-pinene, camphene, 1. 8-cineol, etc. were identified from essential oil of A. argyi. The results of this experiment on seed germination, seedling growth, microorganism culture and tissue culture indicated that naturally occurring chemical substances from A. argyi would be responsible for the growth inhibition of plants studied.

• Journal of Bio-Environment Control
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• v.23 no.1
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• pp.43-49
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• 2014

This study was designed to determine the effect of red LEDs during healing and acclimatization process on the survival rate and quality of grafted tomato seedlings. Red LEDs and no light (darkness) were used for treating three rootstock cultivars, which are 'B-Blocking', 'Kanbarune', 'High-power' in healing room. Results showed that survival rates of grafted seedlings in red LEDs were higher than those in no light treatment. Significant variation on survival rates of rootstock cultivars was observed in no light treatment but there was not significant variation in red LEDs treatment. Light treatment also reduced the percentage of infected plants, except for the 'Kanbarune' cultivar. Seedling quality in red LEDs was better than that in no light treatment by improving growth parameters such as plant height, leaf length, leaf width, leaf area, fresh and dry weight of shoot and root. Light treatments and rootstock cultivars did not affect number of leaves, leaf chlorophyll value and T/R ratio of seedlings, but seedlings in red LEDs were significantly more compact than those in no light treatment. Moreover, the root morphology of seedlings such as total root surface area, total root length, and number of toot tips in red LEDs was also greater than that in no light treatment.

• Journal of Bio-Environment Control
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• v.16 no.1
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• pp.40-46
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• 2007

This study was conducted to clarify the effects of the different substrates in terms of perlite (100%), peat moss (100%), granular rock wool (100%) and mixing perlite (50%) with peat moss (50%) on the growth responses and mineral contents of hydroponically grown Plantago asiatic in aggregate culture. Overall early plant growth such as plant height, stem diameter, number of leaves, root length, fresh and dry weight of shoot and root were increased in the order of that miked perlite and peat moss (50%:50%, v/v)>peat moss (100%)>granular rock wool (100%)>perlite (100%). Ca and Mg contents in plants became highest in the plants grown in the peat moss, however, Mg and Na in the granular rock wool. $P_2O_5$ content in plants were most increased in proportion to the plant growth increment in the peat moss (100%) and the mixing substrates of perlite and peat moss (50:50, v/v).