• Journal of Bio-Environment Control
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• v.15 no.4
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• pp.340-345
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• 2006

A potato (Solanum tuberosum L. cv. Superior) cultivar was grown in aeroponic cultivation system to investigate the effect of root zone cooling in summer. Based on their nutrient uptake, growth responses, and tuberization, the possibilities for potato seed production were determined. Although shoot growth and early tuberization increased in the conventional non-cooling root zone system (root zone temperature of $25\pm2^{\circ}C$), stolen growth, photosynthesis, transpiration rate and number of tubers produced were higher in the cooling root zone system ($20\pm2^{\circ}C$) than in the non-cooling system. Increasing root zone temperature above $25^{\circ}C$ stimulated absorption of K more than T-N, P, Ca, Fe and Mn. On the other hand, root zone temperatures in the range of $20^{\circ}C$ to $25^{\circ}C$ did not affect Mg contents. The lower uptake and supply to leaves of T-N, Fe and Mn at the high root zone temperature promoted early tuberization and advanced haulm senescence. The results stress the importance of keeping root zone temperature to as low as below 20, particularly in summer under temperate Bone.

• Journal of Bio-Environment Control
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• v.17 no.1
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• pp.14-19
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• 2008

The experiment was investigated the effects of lower root zone temperature on shoot and root growth of 'Akihime' strawberries in aeroponics in cold season. Root growth was decreased with decrease of root zone temperature, especially in lateral roots. Elongation of main roots was highest in $18^{\circ}C$ of root zone temperature. Number of lateral roots and length of lateral roots were lowest in $8^{\circ}C$ of root zone temperature. Lower root zone temperature resulted significantly in decrease of fresh weight of root and shoot and leaf area of strawberry. But there were no significant statistical differences in shoot fresh weight and leaf area in $8^{\circ}C$ and $13^{\circ}C$ of root zone temperature. Leaf length, leaf width and number of leaves of strawberry were decreased in lower root zone temperature. The results of this experiment will be utilized in the winter season cultivation for strawberry in hydroponics.

• Journal of Bio-Environment Control
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• v.9 no.4
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• pp.207-211
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• 2000

This study was conducted to investigate the effect of soil zone temperature on the growth responses of two grapevine varieties. Campbell Early was cultivated under unprotected environment and Black Olympia was cultivated in the greenhouse. As responses, growth, photosynthetic rate and contents of mineral elements as affected by four different soil zone temperatures (10, 15, 20, and $25^{\circ}C$)were examined. Weights of leaves, stems and roots were higher at 20 and $25^{\circ}C$ than at 10 or 15$^{\circ}C$ root zone temperature in both varieties. Chlorophyll concentration and photosynthetic rate were the greatest at 2$0^{\circ}C$ root zone temperature. Contents of phosphate, potassium, and calcium increased with increasing root zone temperature.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.4
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• pp.273-278
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• 1998

Carbohydrate metabolism and partitioning are dependent on relationships between sources and sinks which can be affected by rates of photosynthesis and respiration. Fructan, the major form of stored carbohydrate in tall fescue (festuca arundineacea Schreb.), changes in concentration during growth and in response to the environment. Objectives of this study were i) to examine the content and the composition of carbohydrates in five tissues (mature leaf blade, immature leaf blade, leaf elongation zone, terminal meristem, and root tips) of two tall fescue genotypes, one with high yield per tiller (HYT) and one with low yield per tiller (LYT), and ii) to compare the reserved and utilized carbohydrates among above five different tissues, particularly between the leaf elongation zone and root tips. The established vegetative tillers of the HYT and LYT genotypes were grown in a controlled-environment growth chamber. Water-soluble carbohydrate (WSC) in the leaf elongation zone was about 22% of dry weight in the HYT and about 19% in the LYT genotype. The root tip also had high WSC, about 12% of dry weight in the HYT and 6% in the LYT genotype. Hexoses and sucrose were the major components of total WSC in all tissues except the leaf elongation zone. The growing tissues (sinks), i.e., the leaf elongation zone and root tip, had a high proportion of low degree of polymerization fructan, i.e., 3 to 8 hexose units.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.3
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• pp.353-359
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• 2012

The identification of effective root zone would clarify dynamics of plant available water and soil water balance. Using the relationship between soil properties and electrical resistivity (ER) the purpose of this research is to identify soil zone affected by a plant root activity using electrical resistivity tomography (ERT) technique. Four plastic containers were prepared for two different soil textures (clay and sandy loam) and one container for each texture was selected for planting four corn seedlings (Zea mays L.) and the others were prepared for the blank. For ERT monitoring, we prepared 0.8 m plastic sticks with 17 electrodes installed with 5 cm space. The Ministing (AGI Inc., Texas) instrument for electrical resistivity measurement and semi-auto converter of electrode arrangement were set up for dipole-dipole array. During 2 months of the corns growing, ERT monitoring was made 3 to 4 days after the irrigation practice. Despite of the same amount water supplied into soils, two textures showed very different apparent resistivity values due to different clay content. The apparent electrical resistivity is consistently lower in clay loam comparing to sandy loam soil implying that plant root does not significantly alter the overall trend of resistivity. When plant root system, however, is active both soils with plants showed 2-7 times higher electrical resistivity and higher coefficient variation than soils without plant, implying the effect of root system on the resistivity, in which may caused by. This result suggests plant root activities regulating the soil water dynamics mainly control the variation of electrical resistivity over soil textural difference. Therefore the identification of water uptake zone would highly be correlated to plant root activities, thus ERT will be feasible approach to identify spatial characteristics of a plant root activity.

• Journal of Bio-Environment Control
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• v.7 no.2
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• pp.139-143
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• 1998

This experiment was conducted to investigate the effect of soil heating on control of root-knot nematode(Meloidogyne incognita Chitwood) by root zone warming system. Root zone was warmed by hot water flowing through pipe set at 35cm depth from the ridge The lowest soil temperatures at 20cm depth were set at 3$0^{\circ}C$, 4$0^{\circ}C$, $50^{\circ}C$ and non-warming. under soil submerging condition and non-submerging condition. Soil heating was done for 5 days(120 hours) from Aug. 1 to Aug. 5. The root-knot nematode juvenile densities of 4$0^{\circ}C$ under submerging condition. and $50^{\circ}C$ under non-submerging condition were 0 which was expected lower than the economic injury level. The contents of OM P$_2$ $O_{5}$, Ca Mg and EC in soil were decreased by root zone warming The EC was considerably lowered under submerging condition.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.286-291
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• 2022

The effect of root-zone local cooling on seedling growth of tomato was investigated. Lower pipe cooling was used for local cooling of the root zone, and the root zone temperature was set at 20 and 25℃. There was no difference in plant height, root length, and leaf number according to local cooling temperature. Leaf area, fresh weight, dry weight, and chlorophyll content of the shoot and root was higher in the 25℃ than those of 20℃ at 28 DAS. These results showed that cooling for seedling growth of tomato 25℃ is sufficient considering energy efficiency. This study will be helpful in the development of local cooling technology that can reduce the energy required for cooling during the production of tomato seedlings in the high temperature season.

• Journal of Bio-Environment Control
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• v.11 no.2
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• pp.81-87
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• 2002

This study was conducted to investigate the cooling efficiency and growth of tomatoes by root zone cooling device using a pad-box and cultivated system. The structure of the root zone cooling system using a pad-box was four piece of pads bonded an the side and a fan set at the bottom. Cool wind was generated by the outside air which was punched at intervals of 10 cm along three rows. Cold wind flowed to the root zone in the culture medium. The root zone cooling efficiency of cold wind generation by using a pad-box flowing through a wet-pad was determined. Major characteristic of this cuttural system consist of bed filled with a perlite medium and a ventilation pipe using PVC. The cold wind generation by a pad box (CWP) was compared to that of cold wind generation by a radiator (CWR), cold water circulation using a XL-pipe (CWX) and the control (non-cooling). When the temperature of water supplied was 16.2-18.4$^{\circ}C$, temperatures in the medium were 20.5~23.2$^{\circ}C$ for CWP 22.7~24.2$^{\circ}C$ for CWR, 22.8~24.27$^{\circ}C$ for CWX and 23.1~-29.6$^{\circ}C$ for the control. The results show that the cold wind temperature using the pad-box was lower by 1~2$^{\circ}C$ than that of cold water circulation in the XL-pipe and lower by 5~6$^{\circ}C$ than that of the control. Growth such as leaf length, leaf width, fresh weight and dry weight, was greater in three root zone cooling methods than in the control. Root activity was higher in the rat zone cooling methods than in the control. However, there was no significant difference among root zone cooling methods.

• Journal of Bio-Environment Control
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• v.8 no.2
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• pp.115-124
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• 1999

This study was conducted to determine the optimum root zone environment condition and proper nutrient management system for lettuce in hydroponics. For the root zone environment condition, several level of pH and electrical conductivity (EC) were treated respectively. Though all the level of pH 4 to pH 8, except pH 3, performed better growth without any visible physiological disorder, the optimum pH of the nutrient solution for lettuce production was pH 5.5 to 6.0. The optimum ionic strength of the solution was EC 1.2 to 1.6 mS $cm^{-1}$ / because higher nutrient level caused tip burn symptom by calcium deficiency. Considering the above results, it is concluded that lettuce can be efficiently mass-produced through the optimum root zone environment.

• Journal of Bio-Environment Control
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• v.10 no.1
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• pp.30-35
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• 2001

This experiment was undertaken to investigate the effect of root zone temperature during the night on absorption of mineral nutrients, growth, and fruit yield of the truss-limited hydroponic tomatoes in winter. The root zone temperature was either controlled to 10, 15, 20, $25^{\circ}C$, or left uncontrolled at ambient temperatures. Temperature of the covered beds rose as root zone temperature was raised, but it in all treatments was less than 3$^{\circ}C$ higher than that in the control. Raising root zone temperature, except $25^{\circ}C$, showed positive effect on plant height, leaf length, stem diameter, and plant fresh and dry weight, but not on T/R ratio which was the greatest in the control. Root activity in all treatments except $25^{\circ}C$ increased as compared to the control. Mean fruit weight, fruit count per plant, and fruit yield were the greatest in 2$0^{\circ}C$ treatment. Root zone temperature did not significantly affect the contents of total nitrate and magnesium in leaves, stems and roots. Concentrations of phosphate and calcium increased in leaves and stems, but decreased in roots as root zone temperature increased. Overall, 2$0^{\circ}C$ treatment gave the greatest growth and energy efficiency.