Selenium distribution and nitrate metabolism in hydroponic lettuce(Lactuca sativa L.): Effects of selenium forms and light spectra          下载免费PDF全文

BIAN Zhong-hua  LEI Bo  CHENG Rui-feng  WANG Yu  LI Tao  YANG Qi-chang 《农业科学学报》2020,19(1):133-144

A deficiency in selenium(Se) in the human diet is a worldwide problem. The intake of Se-rich vegetables can be a safe way to combat Se deficiency for humans. However, most leafy vegetables can accumulate a high content of nitrates, which poses a potential threat to human health. Light is an important environmental factor that regulates the uptake and distribution of mineral elements and nitrogen metabolism in plants. However, the effects of Se forms and light conditions, especially light spectra, on the uptake and translocation of Se and on nitrate reduction are poorly understood. In this study, lettuce(Lactuca sativa L.) was treated with exogenous Se applied as selenate(10 mmol L~(-1)) and selenite(0.5 mmol L~(-1)) and grown under five different light spectra: fluorescent light(FL), monochromatic red LED light(R), monochromatic blue LED light(B), and mixed red and blue LED light with a red to blue light ratio at 4(R/B=4), 8(R/B=8), and 12(R/B=12), respectively. The effects of light spectra and Se forms on plant growth, photosynthetic performance, Se accumulation and nitrate reduction were investigated. The results showed that the light spectra and Se forms had significant interactions for plant growth, foliar Se accumulation and nitrate reduction. The Se concentration and nitrate content in the leaves were negatively correlated with the percentage of red light from the light sources. Compared to Se applied as selenite, exogenous Se applied as selenate was more effective in reducing nitrate via promoting nitrate reductase and glutamate synthase activities. The lowest nitrate content and highest plant biomass were observed under R/B=8 for both the selenate and selenite treatments. The significant effect of the light spectra on the root concentration factor and translocation factor of Se resulted in marked variations in the Se concentrations in the roots and leaves. Compared with FL, red and blue LED light led to significant decreases in the foliar Se concentration. The results from this study suggest that the light spectra can contribute to Se distribution and accumulation to produce vegetables with better food quality.  相似文献   

环的幂等元与素谱的开闭集   总被引：1，自引：1，他引：0  

王景昕  张国印 《金陵科技学院学报》2007,23(3):5-8

设R是任意带单位元的结合环,L(R)表示Levitzki根,左素理想谱specl(R)是一个弱Zariski拓扑空间。本文主要研究所有包含L(R)的左素理想谱Sl(R)的正规性与环的Gelfand性、Sl(R)的开闭集与环的幂等元的关系。证明了:设R是任意环,对任意Sl(R)的开闭集U,都存在环R一个幂等元e,使得U=Ul(Re)∩Sl(R)。  相似文献   

利用紫外光谱等研究蒸爆过程中毛竹木质素基本化学结构的变化   总被引：1，自引：0，他引：1  

朱汤军  邵顺流  卢刚  柏明娥  金贞福 《竹子研究汇刊》2007,26(3):37-40

运用硝基苯氧化法、紫外光谱法研究了蒸煮爆破过程中毛竹木质素分子一些基本化学结构的降解特征。结果显示5年生毛竹材木质素及磨木木质素的硝基苯氧化产物产量分别为368和325 mmoL.(200g lignin)-1。压力2.0 MPa、时间5 min的蒸煮爆破条件能够导致木质素非缩合型结构较强烈的降解,有助于低分子苯酚类的形成。蒸爆未造成木质素分子重要组成部分的对-香豆酸和阿魏酸等显著的解离,但产生了一定程度的木质素-多糖复合物的降解或芳香环侧链结构的变化。  相似文献   

基于不同预处理的椴树木材基本密度近红外光谱估测及模型优化     

尹世逵  李春旭  孟永斌  王晨  赵婧含  李耀翔 《中南林业科技大学学报(自然科学版)》2020,(5):171-180

【目的】木材的基本密度在木材质量等级评定中起着重要的作用,是木材分流及精细化利用的重要依据。利用近红外光谱技术,实时监测木材性质,掌握木材性质的变化,为进一步制定和改善林木培育方法提供理论依据。【方法】借助树木生长锥对椴树活立木取样,以椴树样品基本密度真值和近红外光谱数据为输入,分别通过卷积平滑、一阶导数和二阶导数预处理方法来实现近红外光谱数据的预处理,建立了基于偏最小二乘法(PLS)的椴树木材基本密度的近红外估测模型。【结果】在350~2 500 nm波段范围内,一阶导数预处理的椴树木材基本密度模型是最优的,校正集相关系数为0.964 8,校正均方根误差为0.002 7,验证集相关系数为0.943 2,预测均方根误差为0.003 3。在对近红外光谱数据进行去噪优化处理,构建椴树木材基本密度模型后,在500~2 300 nm波段范围内,一阶导数预处理椴树木材基本密度模型依旧最优,其校正集相关系数为0.987 1,校正均方根误差为0.001 6,验证集的相关系数是0.948 6,预测的均方根误差是0.002 1。【结论】选择特定的预处理方法,结合样本特征,建立椴树木材基本密度模型,可以显著降低建模成本,提高模型预测精度,快速测定椴树木材的基本密度。  相似文献   

FTIR-PAS study of light-induced changes in the surface of acetylated or polyethylene glycol-impregnated wood     

Makoto Ohkoshi 《Journal of Wood Science》2002,48(5):394-401

The objective of this study was to characterize the surface changes in acetylated and polyethylene glycol (PEG)-impregnated wood caused during light irradiation by Fourier transformed infrared photoacoustic spectroscopy analysis to determine their effects on the reduction of light deterioration. Light irradiation made the color of the chemically modified wood lighter or more vivid, whereas it deepened the color of the untreated wood. The color difference during light irradiation was less in the chemically modified wood than the untreated wood. The color difference of PEG-impregnated wood increased with increasing irradiation time. The light irradiation generated much carbonyl and significantly degraded lignin in the untreated wood. The generation of carbonyl and lignin degradation diminished in the acetylated wood in comparison with the untreated wood, indicating that acetylation restrained the photochemical degradation of wood. Deacetylation did not occur during light irradiation of the acetylated wood. The PEG impregnation decreased the generation of carbonyl and degradation of lignin during light irradiation. However, the irradiation occurred a little photochemical degradation of PEG, generating the carbonyl. Therefore, longer light irradiation should increase the degradation of PEG, thus reducing the effect of treatment. The correlation between the color difference and lignin degradation was high, indicating that the color changes during light irradiation significantly depended on lignin degradation. The chemical modification reduced the degradation of lignin and consequently decreased the color difference. Some of the compounds containing the carbonyl generated during light irradiation were water-soluble.This paper was presented at the 50th Annual Meeting of the Japan Wood Research Society, Kyoto, April 2000  相似文献   

Pulse-Abnormality Analysis for Heroin Addicts     

ZHU Ying hu  CAI Kun bao  WANG Yong dong  SHI Yong zhi 《保鲜与加工》2001,(1):59-62

Extracting features from biomedical signals to provide some decision support for medical diagnoses is an important aspect in the development of biomedical engineering.Analyzing power spectra of pulse signals for 15 heroin addicts and 15 healthy persons and calculating the power distributions on specified frequency bands for every power spectrum based on spectral estimation in this paper,we find that the significant difference of power distributions exists between the heroin addicts and the healthy persons.A primary criterion is also obtained,upon which the 13 cases of 15 heroin addicts are identified.The research result of this paper shows that the frequency domain analysis for pulse signals of heroin addicts is really an effective method.  相似文献   

阳生植物与阴生植物光化学活性与荧光光谱的比较     

王俊玲  李晓峰  孟庆荣  李文平  高志奎 《湖北农业科学》2012,51(8):1612-1614,1621

以阳生植物月季、玫瑰和阴生植物酢浆草、半夏为试验材料,利用IMAGING-PAM MINI版WALZ新型调制叶绿素荧光成像系统和QE65000光谱仪对4种植物叶片的叶绿素荧光参数和荧光光谱进行了测定,分析了阴生植物与阳生植物光化学活性与荧光光谱的差异.结果表明,与阳生植物相比,阴生植物叶片测定的叶绿素荧光参数中,光合系统Ⅱ的实际光化学效率、原初光化学效率和电子传递速率较高,而调节性能量耗散的光化学效率、非调节性能量耗散的光化学效率、光化学性能指数、最大荧光值和初始荧光值均较低;4种植物在650～800nm波长处的荧光光谱图形相同,最高峰均出现在680 nm附近,在735 nm处伴有一弱峰出现,并且阳生植物的Fp680/Fp735比阴生植物低.  相似文献   

高效净化污水光合细菌的分离鉴定     

马姝萍  赵述淼  郭俊平  葛向阳 《饲料工业》2012,33(15):46-50

研究旨在筛选1株能够高效净化污水的光合细菌。通过对不同来源光合细菌的筛选分离以及比较菌株对水体有机质、氨态氮、可溶性磷的去除作用,综合比较得到1株最优菌株P1,该菌对水体有机质有很强的吸收能力,去除率可以达到66.87%,对水体氨态氮和磷有一定的吸收作用,去除率分别为3.33%和8.03%。经过16S rDNA测序以及生理生化实验鉴定,该菌为粪红假单胞菌(Rhodopseu-domonas faecalis)。药敏试验显示P1菌对常用抗生素均有一定的敏感性,其中对庆大霉素最敏感,其次是氨苄青霉素和链霉素,对卡那霉素最不敏感,显示在应用过程中要注意抗生素对该菌存活能力的影响。  相似文献   

基于反射光谱的不同播期冬小麦LAI监测研究     

王超  冯美臣  尹超  肖璐洁  杨武德 《山西农业大学学报(自然科学版)》2012,32(4):307-311

为利用遥感技术快速、无损伤监测不同播期冬小麦LAI,通过大田和室内试验,对5个不同播期处理的冬小麦LAI进行了测定,并在此基础上建立了基于反射光谱的不同播期冬小麦LAI监测模型。结果表明,在4个播期处理和一个所有播期组合下所建立的LAI监测光谱模型中,以播期3条件下的PVI(1460,460)和LAI相关性最好,决定系数可达0.8296,播期3是监测冬小麦LAI的最适播期,依此所建立的冬小麦LAI监测光谱模型是可行的。同时,所有播期组合的LAI与PVI(1460,460)也有较高的相关性,说明在此基础上所建立的模型具有较好的普适度,这为冬小麦品质的大尺度遥感监测和小麦生产的宏观管理调控提供理论依据。  相似文献   

TMV侵染后烟叶叶绿体的荧光光谱与生理学特性   总被引：3，自引：0，他引：3  

王继伟  李怀方  严衍录  程英豪 《植物保护学报》1995,22(4):315-318

作者研究了ＴＭＶ侵染后烟草叶片中完整叶绿体的荧光光谱与生理学特性：６８５ｎｍ与７４０ｎｍ荧光强度之比升高，放氧放降低，完整叶绿体数目下降，结合ＴＭＶ侵染后烟叶荧光主特征变化，分析讨论了ＴＭＶ侵染过程引起的病理变化及其机制。  相似文献