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Search Results: 1 - 10 of 22423 matches for " Enhanced UV-B Radiation "
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The Distribution and Morphology Alterations of Microfilaments and Microtubules in Mesophyll Cells and Root-Tip Cells of Wheat Seedlings under Enhanced Ultraviolet-B Radiation  [PDF]
Limei Gao, Yongfeng Li, Aihua Guo, Jingru Zhai, Rong Han
American Journal of Plant Sciences (AJPS) , 2014, DOI: 10.4236/ajps.2014.522358
The distribution and morphology alterations of microfilaments and microtubules in the mesophyll cells and root-tip cells of wheat seedlings, which had been radiated by enhanced ultraviolet-B (10.08 KJ·m-2·d-1), were examined through the confocal laser scanning microscope (Model FV1000, Olympus, Japan). Microtubule was labeled with an indirect immunofluorescence staining method, and microfilament was labeled with fluorescein isothiocyanate-phalloidin (FITC-Ph) as probes. The results indicated that microtubules in mesophyll cells, compared with the controls, would be depolymerized significantly, and dispersed randomly showing some spots or short rods in the cytoplasm, under the enhanced UV-B radiation condition. The microtubule bundles tended to be diffused, and the fluorescence intensity of that significantly decreased. The distribution pattern of microfilaments, which usually arranged parallelly in control cells, was broken up by enhanced UV-B radiation. We further investigated the distribution and morphology of microtubules in root-tip cells during every stage of cell division, and found that these aberrant phenomena of microtubules were often associated with abnormal cell division. Our findings suggested that the distribution, morphology and structure of cytoskeleton in mesophyll cells and root-tip cells of wheat seedlings would be affected by enhanced UV-B radiation, which might be related to abnormal cell division caused by enhanced UV-B radiation as an extracellular signal.
Different Doses of the Enhanced UV-B Radiation Effects on Wheat Somatic Cell Division  [PDF]
Feifeng Liu, Huize Chen, Rong Han
CellBio (CellBio) , 2015, DOI: 10.4236/cellbio.2015.42004
Abstract: Being sessile, plants are continuously exposed to DNA-damaging agents presenting in the environment such as ultraviolet (UV). Sunlight acts as an energy source for photosynthetic plants; hence, avoidance of UV radiations (namely, UV-A, 315 - 400 nm; UV-B, 280 - 315 nm; and UV-C, <280 nm) is unpreventable. DNA in particular strongly absorbs UV-B; therefore, it is the most important target for UV-B induced damages. This paper mainly used different doses of the enhanced UV-B radiation (B1 group: 4.05 kJ•m-2•d-1, B2 group: 10.08 kJ•m-2•d-1, B3 group: 7.05 kJ•m-2•d-1, B4 group: 23.02 kJ•m-2•d-1) treatment wheat, then, explored on the growth of wheat root and wheat root tip cell of chromosome aberration effect. In wheat, root-tip cells were observed with confocal laser scanning microscopy (CLSM), the results showed that low doses of B1 group (4.05 kJ•m-2•d-1) promoted the growth of wheat root and cell mitosis frequency. But high dose of B2 group (10.08 kJ•m-2•d-1), B3 group (17.05 kJ•m-2•d-1), B4 group (23.02 kJ•m-2•d-1) inhibited the growth of wheat root tip, and made crooked growth of wheat root, and inhibited the wheat root tip cell mitotic frequency and processed that induce root tip cells of wheat produce all kinds of aberration of chromosome in the interphase containing “multiple nucleoli nuclei”, “incomplete nuclei”, “long round nuclei”, “bean sprouts nucleus”. In mitosis M period contains “dissociative chromosome”, “chromosome bridge”, “adhesion chromosome”, “multi-bundle divide”, “nuclear anomalies”. After, high doses of enhanced UV-B radiation treatment, most of the cell cycle anomaly concentrated in mitosis interphase. In mitosis M period, with UV-B radiation dose enhanced chromosome aberration rate was on the rise and the aberration types also increasing.
Effect of enhanced UV-B radiation on polyamine contents and the activity of related enzymines in rice (Oryza sativa L.)

GUO Yu-Chun,LIN wen-Xiong,WU Xing-Chun,LIANG Kang-Jing,LIANG Yi-Yuan,

中国生态农业学报 , 2003,
Abstract: Experimental results show that when the plants are exposed to enhanced UV-B radiation for 7 ~ 14 days,the activities of agrininc decarboxylase (ADC),ornithine decarboxyiase (ODC) and s-adenosylmethionine decarboxylase (SAMDC) in leaves are increased by 165.74%,104.60% and 89.60% in "Shan You63" (Sy63),59.91%,41.30% and 23.68% in "Nancheum" (NC) and 115.93%,14.45% arid-33.01% in IR65600-85,respectively.However,the three enzymic activities turn to decrease with the treatment time increasing (21~28d) and the decreased extents of ODC and SAMDC are much higher than that of ADC,.The activities of ADC and ODC are increased by 89.72% and 3.71% in Sy63 and 73.95 % and 27.38 % in NC exposed to UV-B radiation for 21 ~ 28 days.The activity of ADC is also increased by 94.41% but ODC activity is decreased by 13.57% in the leaves of IR65600-85 compared with the controls.As far as SAMDC is concerned,the enzymic activities in Sy63,NC and IR65600-85 are reduced by 40.06%,19.20% and 38.21% respectively when they are exposed to enhanced UV-B radiation for 21~28 days.The reverse is true in the case of poly-amine oxidase (PAO),indicating its lower activity in earlier treatment courses (7~14d),but much higher activity in late courses (21~28d) compared with the controls.These in turn result in the increased contents of polyamine (PA),especially putrescine (Put) and the results of the experiment have shown their differences in diverse rice genotypes.
Impacts of enhanced UV-B radiation on N2O emissions from soil-soybean systems

生态学报 , 2009,
Abstract: 通过大田试验和室外盆栽试验,采用人工增加紫外辐射的方法模拟UV-B辐射增强,用静态箱-气相色谱法测定N_2O排放通量,研究地表UV-B辐射增强对土壤-大豆系统N_2O排放的影响.结果表明:在相同的气象条件和田间管理措施下,UV-B辐射增强没有改变土壤-大豆系统N_2O排放通量的季节性变化规律.但从植株结荚到成熟,UV-B辐射增强降低了土壤-大豆系统N_2O排放通量,进而降低了N_2O的累积排放量.收割实验发现,在分枝开花期,UV-B辐射增强对土壤N_2O排放影响明显,降低了土壤N_2O排放通量;从结荚至鼓粒期,UV-B辐射增强主要通过降低植株地上部分N_2O排放通量来降低土壤-大豆系统的N_2O排放.UV-B辐射增强显著降低了植株的生物量,并影响到植株的氮代谢和土壤NH_4~+-N与微生物氮.UV-B辐射增强可能会导致农田生态系统N_2O排放量降低.
Effects of Enhanced UV-B Radiation on Biomass and Contents of Camptothecin and 10-hydroxy-camptothecin in Camptotheca acuminata

WANG Hai-Xia,LIU Wen-Zhe,

植物科学学报 , 2011,
Abstract: The effects of enhanced UV-B radiation on biomass and contents of camptothecin and 10-hydroxy-camptothecin in Camptotheca acuminata were investigated in a pots experiment.The results showed that:(1) Comparing to the control group,the fresh weight of C.acuminata seedlings and of the various organs did not change significantly in the first 20 days after treatment.After 40 days,however,the biomass of the whole plant and the various organs was higher than in the untreated plants.Finally,the biomasses per plant ...
Influence of Enhanced UV-B Radiation on Chlorophyll Fluorescence Characteristics of Soybean

LI Han-mao,HU Zheng-hu,YANG Yan-ping,CHEN Shu-tao,LI Cen-zi,SUO Fu-xi,SHEN Shuang-he,

环境科学 , 2009,
Abstract: 利用脉冲振幅调制叶绿素荧光仪测定大豆不同生育期叶片的荧光参数和快速光曲线,以研究UV-B辐射增强对大豆叶绿素荧光特性的影响.结果表明, UV-B辐射增强20%条件下,大豆幼苗期、分枝-开花期和结荚期的叶绿素含量分别降低了5.03%、 7.70%和10.38%;分枝-开花期,F_v/F_m值降低了6.13%;幼苗期和分枝-开花期,有效量子产量(Y)在PAR>366 μmol·(m~2·s)~(-1)时显著降低,最大潜在相对电子传递速率(P_m)分别降低了28.92%和15.49%;但对三叶期和结荚期的Y和P_m无显著影响.UV-B辐射增强使三叶期和幼苗期半饱和光强(l_k)分别降低了21.18%和23.17%;使分枝-开花期的初始斜率(α)降低了21.05%;并显著降低了幼苗期PAR>366 μmol·(m~2·s)~(-1)的非光化学淬灭(NPQ)和分枝-开花期PAR>366 μmol·(m~2·s)~(-1)的光化淬灭(qP).本研究意味着UV-B辐射增强抑制了PSⅡ的电子传递活性,损伤了捕光系统和耗散保护机制,破坏了大豆光合系统,使其光合效率下降.
Effects of Exogenous Nitric Oxide on Wheat Exposed to Enhanced Ultraviolet-B Radiation  [PDF]
Liyan Yang, Rong Han, Yi Sun
American Journal of Plant Sciences (AJPS) , 2013, DOI: 10.4236/ajps.2013.46159

We explored the use of exogenous nitric oxide (NO) on alleviating effects of UV-B light on winter wheat development. Triticum aestivum L. cv. Linyou 7287 seeds were irradiated with UV-B (10.08 kJ·m2·d–1) (enhanced UV-B) and watered with either water or 100 μmol·L–1 SNP solution. Plants were also watered with the SNP alone. The results showed that enhanced UV-B produced negative effects on seedling development. Leaf length decreased and seedling biomass dropped significantly compared with the control. Photochemical efficiency (Fv/Fm) dropped, and chlorophyll and carotenoid content as well as the ATPase activity declined. Content of UV-absorbing compounds and activity of the POD increased compared to the control. Application of the SNP, a NO donor partially protected wheat seedlings exposed to elevated UV-B radiation in that their leaf lengths and biomass accumulation were enhanced compared to the UV-B treatment alone. SNP also improved the contents of chlorophyll, carotenoid and UV-absorbing compounds in leaves. ATPase activity was enhanced but no influence on POD activity. Furthermore, the application of SNP alone showed a favorable effect on seedling growth compared with the control.

Influence of Enhanced UV-B Radiation and Straw Application on Soil Respiration in Soybean Field

HU Zheng-hu,LI Han-mao,YANG Yan-ping,CHEN Shu-tao,LI Cen-zi,SHEN Shuang-he,

环境科学 , 2010,
Abstract: Field experiment was carried out in 2008 in order to investigate the effects of enhanced UV-B radiation and straw application on soil respiration in soybean field. LI-8100 automated soil CO2 flux system was used to measure soil respiration under 20% enhanced UV-B radiation, straw application, 20% enhanced UV-B radiation + straw application and control. Environmental factors such as air temperature, soil temperature and moisture were also measured. Results indicated that supplemental UV-B radiation reduced soil respiration rate by 30.31%, straw application increased soil respiration rate by 14.51%, while enhanced UV-B radiation + straw application combined treatment had no significant effect on soil respiration. Enhanced UV-B radiation enhanced the carbon conversion rate of straw. Significant relationship were found between soil respiration rate and soil temperature under the control, enhanced UV-B, straw application, and enhanced UV-B + straw application, the fitting equation determined coefficients R2 were 0.434, 0.563,0.451 and 0.513. The Q10(temperature sensitivity coefficients) for soil respiration were 1.55, 1.91, 1.80 and 1.71, respectively. It was reflected that enhanced UV-B radiation, straw application and enhanced UV-B radiation + straw returning increased the Q10 for soil respiration.
Validation of Spectral and Broadband UV-B (290 - 325 nm) Irradiance for Canada  [PDF]
Jacqueline Binyamin, John Davies, Bruce McArthur
Atmospheric and Climate Sciences (ACS) , 2011, DOI: 10.4236/acs.2011.13008
Abstract: Stratospheric ozone depletion, as a result of increasing chlorofluorocarbons in the stratosphere, allows more UV-B irradiance (290 - 325 nm) to reach the earth’s surface with possible detrimental biological effects. Be-cause there are few UV-B radiation stations, irradiance models are useful tools for estimating irradiances where measurements are not made. Estimates of spectral and broadband irradiances from a numerical model are compared with Brewer spectrophotometer measurements at nine Canadian stations (Alert, Resolute Bay, Churchill, Edmonton, Regina, Winnipeg, Montreal, Halifax and Toronto) and 26 years of data. The model uses either the discrete ordinate radiative transfer (DISORT) or the delta-Eddington algorithms to solve the radiative transfer equation for a 49-layer, vertically inhomogeneous, plane-parallel atmosphere, with cloud inserted between the 2 and 3 km heights. Spectral calculations are made at 1 nm intervals. The model uses extraterrestrial spectral irradiance, spectral optical properties for each atmospheric layer for ozone, air mole-cules, and aerosol and surface albedo. A fixed broadband cloud optical depth of 27 was satisfactory for cal-culating cloudy sky irradiances at all stations except in the arctic. Comparisons are made both for daily totals and for monthly averaged spectral and broadband irradiances. The delta-Eddington method is shown to be unsuitable for calculating spectral irradiances under clear skies, at wavelengths less than 305 nm where absorption by ozone is high, and at large solar zenith angles. The er-rors are smaller for overcast conditions. The method is adequate for daily total and monthly averaged spec-tral (? 305 nm) and broadband calculations for all sky conditions, although consistently overestimating ir-radiances. There is a good agreement between broadband measurements and calculations for both daily totals and monthly averages with mean bias error mainly less than 5% of the mean measured daily irradiance and root mean square error less than 25%, decreasing to below 15% for monthly averages.
The Effect of Enhanced UV-B Radiation on the Growth of Cotton in Oasis Cotton Field

王进, 白丽, 杨明凤
Hans Journal of Agricultural Sciences (HJAS) , 2015, DOI: 10.12677/HJAS.2015.53017
在大田试验条件下,研究UV-B辐射增强对棉花生长发育的影响。通过人工增加对棉花UV-B辐射,设置4个处理,每个处理的辐射剂量分别为0 W/m2 (R0)、0.5 W/m2 (R1)、1.0 W/m2 (R2) 和1.5 W/m2 (R3),研究了UV-B辐射增强对棉花株高、茎粗、叶面积、叶片表观伤害、产量和品质的影响。结果表明:随着UV-B辐射增强,R1、R2和R3处理组的株高、茎粗、叶面积分别与对照达到了极显著水平(P < 0.01),R3与各个处理之间差异均达到了极显著水平(P < 0.01);棉花叶片可见伤害症状越来越严重,各个处理的棉花产量和品质显著低于对照。UV-B辐射增强使棉花形态、产量和品质之间存在密切的直接关系,UV-B辐射强度越大对棉花的影响就越大。
The objectives of this research were to study the influences of enhanced ultraviolet radiation (UV-B, 280 - 320 nm) on physiological indicator, yield and quality of cotton. We set four treatments of 0 w/m2 (R0), 0.5w/m2 (R1), 1w/m2 (R2), 1.5 w/m2 (R3) by increasing artificial UV-B radiation and studied the effect of enhanced Ultraviolet-B radiation on plant height, stem diameter, leaf area index (LAI), apparent injure in leaf, yield and quality of cotton. The results showed that the plant height, stem diameter and LAI had significant correlation with the increasing Ultraviolet- B radiation (P < 0.01), and the difference between R3 and other treatments also had statistically significance (P < 0.01). The apparent injury in leaf of cotton became more serious and the quantity and quality was also at the lowest level as followed. The relationship between UV-B radiation and cotton growth was closer. The higher intensity of UV-B radiation would have more negative effects on cotton growth.
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