• Korean Journal of Soil Science and Fertilizer
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• v.45 no.1
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• pp.79-82
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• 2012

Blossom-end rot is probably the most recognizable Ca deficiency that affects fruit production including pepper. We investigated the induction of blossom-end rot during the period of rapid vegetative growth and fruit setting, and the effect of Ca fertilization on the suppression of blossom-end rot in pepper plants grown in a plastic-film house. During the first fruit setting period, more than 60% of pepper fruits larger than 8 cm showed the symptoms of blossom-end rot. Under the condition of transpiration occurring at a much faster rate, growing leaves of pepper plants could be the greater sinks for Ca than developing fruits. The incidence of blossom-end rot was significantly decreased after two weeks of Ca fertigation. Calcium application during the rapid vegetative growth and fruit setting period could be suggested as a preventive step to overcome the local Ca deficiency inducing blossom-end rot of pepper fruits.

• International Journal of Industrial Entomology and Biomaterials
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• v.30 no.2
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• pp.58-63
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• 2015

An experimental rearing of tropical tasar silkworm, Antheraea mylitta Drury was conducted to study silkworm-food plant-interaction and thereby to search for an alternate silkworm food plant. The silkworm-food-plant-interaction was studied with six different food plant species viz. Terminalia tomentosa, Terminalia arjuna, Terminalia belerica, Terminalia chebula of Combretaceae family and Lagerstroemia speciosa, Lagerstroemia parviflora of Lythraceae family. The rearing performance of silkworm on Lagerstroemia speciosa in terms of cocoons per DFL and silk ratio was found comparable with Terminalia tomentosa and Termonalia arjuna, the primary tasar silkworm food plant species. These three plant species also possessed better results in terms of physiological (leaf moisture content and net photosynthesis rate) and biochemical (Chlorophyll, protein, carbohydrate and crude fibre contents) characteristics to support silkworm rearing than Terminalia belerica, Terminalia chebula and Lagerstroemia parviflora. The correlation study between silkworm rearing performance and food plant's constituents indicates commercial perspective of Lagerstroemia speciosa as an alternate food plant for tasar silkworm rearing.

• Mycobiology
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• v.32 no.2
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• pp.79-87
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• 2004

An experiment was carried out to investigate the effects of pre-inoculation with the mycorrhizal fungus Glomus clarum and foliar application of kinetin on the growth of mungbean plant irrigated wht different dilution of seawater. Arbuscular-mycorrhizal(AM) infection significantly increased dry weight, height, chlorophyll, sugar and protein content, nitrogen and phosphorus-use efficiencies, leaf conductivity, transpiration rate, nitrogenase, acid and alkaline phosphates activities of all salinized mungbean plants in comparison with control and non-mycorrhizal plants irrespective of the presence or absence of kinetin. Mycorrrhizal plants showed higher concentrations of N, P, K, Ca and Mg and lower Na/N, Na/P, Na/K, Na/Ca and Na/Mg ratios than non-mycorrhizal plants when irrigated with certain dilution of seawater. Mungbean plants showed 597% and 770% dependency on AM fungus G. clarum in absence and presence of kinetin, respectively, for biomass production under a level of 30% of seawater. The average value of tolerance index for mycorrhizal plants accounted 267% and 364% in absence and presence kinetin respectively. This study provides evidence for the benefits of kinetin which are actually known for mycorrhizal than non-mycorrhzal plants. AM fungus and kinetin protected the host plants against the detrimental effects of salt. However, mycorrhizal infection was much more effective than kinetin applications. Thus management applications of this arbuscular mycorrhizal endophyte(G. clarum) with kinetin could be of importance in using seawater in certain dilution for irrigation in agriculture.

• 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.

• Horticultural Science & Technology
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• v.17 no.3
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• pp.325-328
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• 1999

This experiment was conducted to investigate the effect of the automatic control of night temperature and day length on the flower bud initiation growth responses and yield of strawberries. Flower bud initiation was observed only 14 days after treatment in plants forced with automatic system but not in plants forced with traditional methods, and flower bud development was further progressed by an automatic system. In genernal, the crown diameter of runner plants derived from strawberries grown with the automatic system was smaller than those from the plants grown under hand-operated system and this tendency was clear in plants placed at middle and low position during forcing. The rate of transpiration was higher in plants treated with hand operated method but the content of chlorophyll was lower than those treated with the automatic system. Results indicated that automatic system has an advantage in stimulation of flower bud initiation and improving the quility of runner plants.

• Korean Journal of Environmental Agriculture
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• v.19 no.2
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• pp.166-170
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• 2000

This study was conducted in to elucidate the changes of growth characteristics and photosynthesis in three soybean (Glycine max L. cv. Danwonkong, Hwangkeumkong and Kwangankong) 30 day old seedlings to 100mM NaCl concentration containing 1/2 Hoagland's nutrient solution in sand culture. The main stem height and number of main stem node were decreased. thus, leaf area and dry matter were decreased with 100mM NaCl. Growth reduction was less little in Hwangkeumkong than other cultivars. The stem growth rate was affected less than other parts as root or leaf, by NaCl treatment. The specific leaf area (SLA), shoot : root ratio and leaf : root ratio decreased with NaCl solution except for those of Hwangkeumkong. There is no general tendency in leaf thickness by leaf position of three cultivars. The chlorophyll content (SPAD) of the primary and 2nd leaf slightly decreased under NaCl solution but rapidly increased in non-NaCl solution at 15 days after treatments. The photosynthesis, stomatal conductance and transpiration of 2nd leaf positions reduced by NaCl and there were a sigificant correlation between photosynthesis and stomatal conductance or transpiration.

• Applied Biological Chemistry
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• v.43 no.2
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• pp.116-123
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• 2000

A numerical model of three-dimensional soil water distribution for drip irrigation management under cropped conditions was developed using Richards equation in Cartesian coordinates. The model accounts for both seasonal and diurnal changes in evaporation and transpiration, and the growth of plant root and the shape of root zone. Solutions were numerically approximated using the Crank-Nicolson implicit finite difference technique on the block-centered grid system and the Gauss-Seidel elimination in tandem. The model was tested under several conditions to allow the flow rates and configurations of drip emitters vary. In general, simulation results agreed well with experimental results and were as follows. The velocity of soil-water flow decreased drastically with distance from the drip source, and the rate of expansion of the wetted zone decreased rapidly during irrigation. The wetting front of wetted zone from a surface drip emitter traveled farther in vertical direction than in horizontal direction. Under this experimental weather condition, water use efficiency of a drip-irrigated apple field was greatest for 4-drip-emitter system buried at 25 cm, resulting from 10% increase in transpiration but 20% reduction in soil evaporation compared to those for surface 1-drip emitter system. Soil moisture retention curve obtained using disk tension infiltrometer showed significant difference from the curve obtained with pressure plate extractor.

• Journal of Bio-Environment Control
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• v.8 no.2
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• pp.108-114
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• 1999

This study was conducted to investigate the optimum environment for leaf lettuce (Lactuca sativa L. var. crispa) in a plant factory to increase mass-production efficiency of quality leaf lettuce. Transpiration rate and $CO_2$ assimilation rate were increased with increasing the photosynthetic photon flux density (PPFD). The highest fresh weight and dry weight were observed at the PPFD of 200 and 300 U moi $m^{-2}$ $s^{-l}$, respectively. The optimum aerial environment for the growth and quality of leaf lettuce in the plant factory was determined to be over 200 $\mu$mol $m^{-2}$ $s^{-1}$ for PPFB. Although the interaction between light intensity and nutrient level was not significant, the lettuce growth was the best under electrical conductivity (EC) of 1.8 mS $cm^{-1}$ / at high light intensity (250 $\mu$mol $m^{-2}$ $s^{-1}$ ) and EC of 2.4 mS cm-1 at low light level (150 $\mu$mol $m^{-2}$ $s^{-1}$ ) respectively.y.

• Journal of Ecology and Environment
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• v.39 no.1
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• pp.81-90
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• 2016

This study was to investigate the effect of salt stress on physiological characteristics such as plant growth, photosynthesis, solutes related to osmoregulation of Beta vulgaris. A significant increase of dry weight was observed in 50 mM and 100 mM NaCl. The contents of Chl a, b and carotenoid were lower in NaCl treatments than the control. On 14 day after NaCl treatment, photosynthetic rate (P_N), the transpiration rate (E) and stomatal conductance of CO₂ (g_s) were reduced by NaCl treatment. On 28 day after NaCl treatment, the significant reduction in g_s and E was shown in NaCl 200 mM. However, P_N and water use efficiency (WUE) in all NaCl treatments showed higher value than that of control. Total ion contents (TIC) and osmolality were higher than the control. On 14 day after treatment, the contents of proline (Pro) increased significantly in 200 mM and 300 mM NaCl concentration compared with control, whereas on 28 day in all treatments it was lower than that of the control. The contents of glycine betaine (GB) increased with the increase of NaCl concentration. The contents of Na⁺, Cl^-, GB, osmolality and TIC increased with the increase of NaCl concentrations. These results suggested that under severe NaCl stress conditions, NaCl treatment did not induce photochemical inhibition on fluorescence in the leaves of B. vulgaris, but the reduction of chlorophyll contents was related in a decrease in leaf production. Furthermore, increased GB as well as Na⁺ and Cl^- contents resulted in a increase of osmolality, which can help to overcome NaCl stress.

• Journal of Ecology and Environment
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• v.35 no.3
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• pp.203-212
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• 2012

The physiological effects of elevated $CO_2$ concentration and temperature were examined for Quercus gilva and Q. glauca grown under control (ambient $CO_2$ and temperature) and treatment (elevated $CO_2$ and temperature) conditions for 39 months. The objective of the study was to measure the long-term responses, in physiological parameters, of two oaks species exposed to elevated $CO_2$ and temperature. The photosynthetic rate of Q. gilva was found to be decreased, but that of Q. glauca was not significantly affected, after long-term exposure to elevated $CO_2$ and temperature. Stomatal conductance of Q. glauca was reduced by 21.7%, but that of Q. gilva was not significantly affected, by long-term exposure to $CO_2$ and temperature. However, the transpiration rate of the two oak species decreased. Water use efficiency of Q. gilva was not significantly affected by elevated $CO_2$ and temperature, while that of Q. glauca was increased by 56.6%. The leaves of Q. gilva grown under treatment conditions had an increased C:N ratio due to their reduced nitrogen content, while those of Q. glauca were not significantly affected by long-term exposure to elevated $CO_2$ and temperature. These results suggest that the long-term responses to elevated $CO_2$ and temperature between Q. gilva and Q. glauca are different, and that Q. gilva, the endangered species, is more sensitive to elevated $CO_2$ and temperature than Q. glauca.