• Journal of Life Science
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• v.8 no.3
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• pp.272-278
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• 1998

To investigate the effects of different UV-B levels on plant growth, cucumber plants were subjected to three levels of biologically effective ultraviolet-B(UV--$B^{BE}$ radiation [daily dose : 0.03(No UV-B), 6.40(Low UV-B) and 11.30 (High UV-B) kJ $m^{-2}$, UV--$B^{BE}$] in the growth chambers for 3 weeks during the early growth period. High and low levels of UV-B irradiation drastically decreased both dry weight and leaf area, but increased specific leaf weight of cucumber. Plants subjected to UV-B resulted in 30% and 20% reduction of photosynthesis rate by high and low UV-B, respectively. However, respiration rate was not affected by the UV-B. With increasing UV-B intensity, total chlorophyll contents were decreased linearly, while the contents of flavonoid were increased linearly. These results suggest that the present levels of UV-B may affect the growth of cucumber plant compared with a UV-B-free condition. It is likely that the growth of cucumber will be affected by enhanced UV-B due to ozone depletion in the near future.

• Journal of Environmental Science International
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• v.15 no.12
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• pp.1093-1101
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• 2006

In the present study we studied the growth, photosynthetic traits and protective mechanisms against oxidative stress in the primary loaves of cucumber (Cucumis sativus L.) seedlings with or without UV-B treatment. Cucumber seedings were irradiated with UV-B for 10 days in environment-controlled growth chambers. The primary leaves irradiated with UV-B showed reduction in leaf length and decreased biomass production. The reduced biomass production seemed to be due to a negative effect of UV-B radiation on the photosynthetic process. Changes in chemical properties of leaf, such as chi a/b ratio affected photosynthesis. UV-B significantly affected chl b content compared with chi a in the light harvesting complex resulting reduced photosynthetic activity Fv/Fm decreased with an UV-B stress, suggesting that the photosynthetic apparatus, and particularly, PS II was damaged under UV-B stress. Malondialdehyde(MDA) concentration which represents the state of membrane lipid peroxidation Increased significantly under UV-B stress confirming an oxidative stress. UV-B exposure with SA solution(0.1-1.0 mM) can partially ameliorated some of the detrimental effects of UV-B stress. Leaf injuries including loss of chlorophyll and decreased ratio of Fv/Fm were reduced with combined application of UV-B and SA. ABA and JA showed similar mode of action in physiological effects on photosynthetic activities though the levels were lower than those from SA treated plants. Chloroplast ultrastructure was also affected by UV-B exposure. The thickness of leaf tissue components decreased and the number of grana and thylakoids was reduced in chloroplast applied UV-B or SA alone. At combined stress granal and stromal thylakoids were less affected. The leaves under combined stress acquired a significant tolerance to oxidative stress. From these results, it can be suggested that SA may have involved a protective role against UV-B induced oxidative damage.

• Journal of Environmental Science International
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• v.16 no.12
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• pp.1345-1353
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• 2007

The effect of salicylic acid(SA) on antioxidant system and protective mechanisms against UV-B induced oxidative stress was investigated in cucumber(Cucumis sativus L.) leaves. UV-B radiation and SA were applied separately or in combination to first leaves of cucumber seedlings, and dry matter accumulation, lipid peroxidation and activities of antioxidant enzymes were measured in both dose and time-dependant manner. UV-B exposure showed reduced levels of fresh weight and dry matter production, whereas SA treatment significantly increased them. SA noticeably recovered the UV-B induced inhibition of biomass production. UV-B stress also affected lipid peroxidation and antioxidant enzyme defense system. Malondialdehyde(MDA), a product of lipid peroxidation, was greatly increased under UV-B stress, showing a significant enhancement of a secondary metabolites, which may have antioxidative properties in cucumber leaves exposed to UV-B radiation. Combined application of UV-B and SA caused a moderate increase in lipid peroxidation. These results suggest that SA may mediate protection against oxidative stress. UV-B exposure significantly increased SOD, APX, and GR activity compared with untreated control plants. Those plants treated with 1.0 mM SA showed a similar pattern of changes in activities of antioxidant enzymes. SA-mediated induction of antioxidant enzyme activity may involve a protective accumulation of $H_2O_2$ against UV-B stress. Moreover, their activities were stimulated with a greater increase by UV-B+SA treatment. The UV-B+SA plants always presented higher values than UV-B and SA plants, considering the adverse effects of UV-B on the antioxidant cell system. ABA and JA, second messengers in signaling in response to stresses, showed similar mode of action in UV-B stress, supporting that they may be important in acquired stress tolerance. Based on these results, it can be suggested that SA may participates in the induction of protective mechanisms involved in tolerance to UV-B induced oxidative stress.

• Horticultural Science & Technology
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• v.31 no.4
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• pp.393-399
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• 2013

The effect of solution temperature and nitrogen form on cucumber (Cucumis sativus L.) growth, photosynthesis and nitrogen metabolism was investigated in hydroponic culture. Cucumber plants were grown for 35 days in a greenhouse at three constant solution temperatures ($15^{\circ}C$, $20^{\circ}C$, and $25^{\circ}C$) within a natural aerial temperature ($15-30^{\circ}C$). Four nitrate:ammonium ($NO{_3}^-:NH{_4}^+$) ratios (10:0, 8:2, 5:5, and 2:8 $mmol{\cdot}L^{-1}$) at constant nitrogen (N) concentration of $10mmol{\cdot}L^{-1}$ were applied within each solution temperature treatment. Results showed an increasing solution temperature enhanced plant growth (height, dry weight, and leaf area) in most N treatments. Dry weight accumulation was greatest at the 10:0 $NO{_3}^-:NH{_4}^+$ ratio in the $15^{\circ}C$ solution, the 5:5 ratio in the $20^{\circ}C$ solution and the 8:2 ratio in the $25^{\circ}C$ solution. Photosynthetic rate (Pn) response to solution temperature and $NO{_3}^-:NH{_4}^+$ ratio was similar to that of plant growth. Probably, the photosynthate shortage played a role in the reduced biomass formation. Increasing solution temperature enhanced the nitrate reductase (NR) activity, and further reduced shoots nitrate content. Our results indicate that the optimal ratio of nitrate to ammonium that promotes growth in hydroponic cucumber varies with solution temperature.

• Korean Journal of Plant Tissue Culture
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• v.25 no.6
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• pp.501-505
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• 1998

Conditions for high frequency plant regeneration from cryopreserved embryogenic cell suspension cultures derived from hypocotyl explants of cucumber (Cucumis sativus L.) are described. Cells cryoprotected with a mixture of 2 M DMSO and 0.4 M sucrose exhibited a regeneration frequency of 85%. However, cells cryoprotected with different concentrations of glycerol showed no regeneration after cryopreservation. Pretreatment of cells in a high osmotic medium was not necessary to the process. Upon transfer to MS medium supplemented with 1 mg/L 2,4-dichlorophenoxyacetic acid, regenerated calli gave rise to numerous somatic embryos, then underwent development into plantlets.

• The Korean Journal of Ecology
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• v.19 no.2
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• pp.151-163
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• 1996

To investigate the early symptoms of light-chilling, alterations of chlorophyll fluorescence transients were monitored in cucumber (Cucumis sativus L. cv. Ilmichungjang) leaves. During 24 h chilling, decreases in (Fv)m/Fm, qE and qQ, and an increase in Fo were observed. The chilling effects were not recovered at room temperature, and a significant increase in Fo was observed during the recovery period. After 6 h chilling, ‘dip’(D) level of the transients became obscure, and the negative slope after ‘peak’(P) disappeared. The first derivative (dFv/dt) of the fast fluorescence rise curve was used to obtain more accurate information about the changes in the transients. The maximal rate of the fluorescence increase in the D-p rise curve (Fr) has been the most frequently used chilling stress indicator. However, a correct value of Fr could not be measured when the D level became obscure. This problem was overcome by introducing a new indicator, HFr (dFv/dt at Fv = 1/2 (Fv)m), and HFr gave very similar values to Fr. To monitor the changes in curvature around D level, another new parameter, ${\Delta}S$(D-Fr), was also introduced. These three parameters decreased very sensitively during light-chilling. In addition, increases in these parameters were observed during the first 2 h chilling, but this increase in Fr was also observed in pea leaf discs dark-chilled for 15 min, suggesting that this very early change is a common response to chilling in both pea and cucumber leaves. Quenching coefficients were also very sensitive to chilling, especially qE. Discussion on the usage of these parameters as chilling stress indicators is given in the text.

• Korean Journal of Plant Tissue Culture
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• v.26 no.4
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• pp.289-291
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• 1999

Hypocotyl explants from 7 days old seedlings of one $F_1$ hybrid cultivar and two pure lines of cucumber formed embryogenic calli at frequencies of up to 8% when cultured on Murashige and Skoog medium (MS) supplemented with 1 mg/L 2,4-D for 3 weeks. Embryogenic calli gave rise to somatic embryos. When slices of somatic embryos were cultured on the same medium for 4 weeks, they formed embryogenic calli. Embryogenic cell suspension cultures were established with embryogenic calli in MS liquid medium with 1 mg/L 2,4-D. Embryogenic potential of cell suspension cultures was maintained by subculturing every seven days. When the level of 2,4-D in the medium was lowered to 0.2 mg/L by diluting with liquid MS basal medium, embryogenic cell suspension cultures underwent development into numerous somatic embryos. When plated onto MS basal medium, over 95% of somatic embryos developed into plantlets. Plantlets were transplanted to potting soil and grown to maturity.

• Journal of Plant Biotechnology
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• v.44 no.3
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• pp.229-234
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• 2017

Photoperiod is one of the factors affecting productivity of cucumber plant by inducing ethylene hormone production and so triggering flower sex differentiation into female flower. However, only few studies have been perfomed in order to reveal the effect of photoperiod in molecular level in relation to the flower differentiation. Therefore, in this study, Mercy cultivar of cucumber (andromonoecious) was treated with photoperiod of 8, 12, 16 hours of light, while control received no treatment of additional light. Photoperiod of 8 hours was achieved by blocking the sunlight with shade net and 16 hours by giving longer light exposure using white LEDs. Cucumber's flowers were quantified and the apical and lateral shoots were extracted to evaluate the gene profile related to the photoperiod, ethylene production, and female flower differentiation, which were CsACS2, CsETR1, CsCaN, and CsPIF4 using PCR method. Photoperiod of 8 hours affected the production of female flower with average number of 6.7 flowers in main stem and 8.0 flowers in lateral stem, compared to photoperiod of 12 and 16 hours which produced 3.7 and 2.0 flowers in main stem with 7.0 and 11.3 in lateral stem, respectively. In silico studies in this experiment resulted in proposed model of signal transduction that showed the connection between ethylene production and flower differentiation. PCR analysis confirmed the expression of CsACS2, CsETR1, and CsCaN, that was positively correlated with numbers of female flowers in cucumber, but the expression of CsPIF4 that represent photoperiod haven't been confirmed correlated with the ethylene production and flower differentiation.

• Journal of Biosystems Engineering
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• v.37 no.6
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• pp.404-410
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• 2012

Purpose: The objective of this research was to select high quality cucumber (cucumis sativus) seed by classifying into viable or non-viable one using Raman spectroscopy. Method: Both transmission and back-scattering Raman spectra of viable and non-viable seeds in the range from $150cm^{-1}$ to $1890cm^{-1}$ were collected with a laser illumination. Results: The Raman spectra of cucumber seed showed Raman peaks with features of polyunsaturated fatty acids. The partial least squares-discriminant analysis (PLS-DA) to predict viable seeds was developed with measured transmission and backscattering spectra with Raman spectroscopy and germination test results. Various types of spectra pretreatment were investigated to develop the classification models. The results of developed PLS-DA models using the transmission spectra with mean normalization or range normalization, and back-scattering spectra with mean normalization treatment or baseline correction showed 100% discrimination accuracy. Conclusions: These results showed that Raman spectroscopy technologies can be used to select the high quality cucumber seeds.

• Journal of Bio-Environment Control
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• v.8 no.4
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• pp.265-274
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• 1999

This experiment was carried out to investigate the effect of container size and substrate volume on the growth and fruit yield of hydroponically grown cucumber(Cucumis sativus L.) plants. Seeds were sown in plug tray filled with coir dust on Feb. 13, 1998. Seedlings with 5 to 6 true leaves were transplanted in $2{\ell},\;4{\ell},\;6{\ell},\;8{\ell}\;and\;10{\ell}$ plastic pots filled with perlite. Cucumber fruits were harvested with 1 to 2 days interval, and fresh weight, number of normal and malformed fruit were recorded. Plant height, stem diameter, number of leaves and leaf area were highly depended on the container size. Total fresh weight and the number of fruit were increased with increasing container size. NAR(net assimilation rate) and CGR(crop growth rate) increased also with increasing the container size. Optimum container size for hydroponically grown cucumber plant using perlite was recommended as $8{\ell}$ per plant.