4种植物油热氧化同步荧光光谱分析     

李泳霖  谷宇欣  宫婷  王子健  潘政道  于修烛 《农产品加工．学刊》2020,(3):50-54,59

以亚麻籽油、大豆油、菜籽油与葵花籽油为原料,在不同温度条件下氧化并测定其不同时间的同步荧光光谱,分析同步荧光光谱及荧光物质变化情况。结果表明,4种植物油不同温度下的同步荧光光谱峰变化主要集中在300~415 nm内,且随着加热时间的延长存在波动现象;在50℃和150℃加热氧化条件下,300,330,375,415 nm这4个峰都存在明显的波动现象;二维相关分析表明,这4个峰的荧光强度变化速率不同,不同油变化差异较大;同种油在不同温度下,4个峰的波动情况、相互关系、变化速率均有明显差异。这些峰的变化与油脂氧化过程中荧光物质和油脂氧化程度的变化有关,可以利用同步荧光光谱的变化特性作为监控油脂氧化的依据。  相似文献   

长期施肥处理对双季晚稻叶绿素荧光特征及籽粒产量的影响   总被引：2，自引：0，他引：2  

HOU Hong-Qian  LIN Hong-Xin  LIU Xiu-Mei  JI Jian-Hua  LIU Yi-Ren  LAN Xian-Jin  LYU Zhen-Zhen  ZHOH Wei-Jun 《作物学报》2020,46(2):280-289

研究施肥模式对水稻叶绿素含量及荧光参数的调节作用,对提高水稻光能利用效率及籽粒产量具有重要意义。本研究以水稻品种赣929为试验材料,比较长期定位施磷钾肥(PK)、施氮磷钾肥(NPK)、等养分条件下70%氮磷钾肥配合施用30%有机肥(70F+30M)、50%氮磷钾肥配合施用50%有机肥(50F+50M)、30%氮磷钾肥配合施用70%有机肥(30F+70M)条件下水稻叶绿素荧光参数和产量变化特征。结果表明,水稻旗叶叶绿素含量从齐穗期到成熟期呈下降趋势,且表现为30F+70M50F+50M70F+30MNPKPK。水稻叶绿素荧光参数Fv/Fm随水稻生育期的推进呈降低趋势,其中PK处理Fv/Fm值最低,而施氮处理比不施氮处理Fv/Fm值增加了2.85%～4.18%。叶绿素荧光参数qL、ΦPSII在NPK处理中表现为齐穗期较高, 20 d之后显著降低;在50F+50M、30F+70M处理中表现为齐穗期较低, 20 d以后显著增加;在PK处理、70F+30M处理中一直处于较高水平。NPQ变化趋势与qL基本相反。ETR-PAR光响应曲线拟合结果表明, 70F+30M处理ETRmax、?和Ek值在齐穗期和20 d后值均最高。综合看来,等养分条件下配施30%有机肥具有最优的叶绿素荧光指标组合及籽粒产量;而配施超过50%有机肥由于前期热耗散增大使得用于光合作用的光能份额减少,而施用氮磷钾肥处理则由于后期的衰老使得光能利用效率下降。  相似文献   

钻头磨损在线监测研究     

尹向东  李传乾 《湖南农业大学学报(自然科学版)》1989,16(4)

本文研究了钻头磨损对钻削过程中振动加速度信号的动态特性的影响。发现加速度信号中敏感频率分量随着钻头磨损的增加呈明显的“碟形”规律变化。我们提出用敏感频率分量的自功率谱值(PSD)作为特征量。建立了特征量与钻孔数之间的状态空间方程;提出了钻头磨损在线自适应监测方法。该方法打破了故障诊断和状态识别中设置“阈值”的传统做法;另辟蹊径。  相似文献   

Rapid Screening for Aluminum Tolerance in Cereals by Use of the Chlorophyll Fluorescence Test   总被引：1，自引：0，他引：1  

M. Moustakas    G. Ouzounidou  R. Lannoye 《Plant Breeding》1993,111(4):343-346

The effects of aluminum on the photosynthetic apparatus were examined in cereals grown in nutrient solutions (pH 4.5) at two Al levels (0 and 148 μM). The chlorophyll fluorescence kinetics results confirmed that the soft wheat ‘BHG’ cultivar has the potential for growth on acid soils while triticale cultivars ‘Niovi’ and ‘Dada’ appeared to be relatively tolerant. The percentage decrease in F_v/F_m of the less tolerant cultivars after Al-treatment indicated a decrease in the efficiency of the primary photochemistry of PS II, while the decrease in the ratio F_V/F_osuggested that exposure of the cultivars ‘Dio’ and ‘Appulo E’ to aluminum caused injury to the thylakoid structure. The percentage fluctuations of the ratio F_v/F_mwere shown to correlate very closely with the assessment of injury as evaluated by the relative top fresh weight. Measurements of chlorophyll fluorescence in vivo could be used to monitor injury caused by “Al-stress”, and thus they may serve as a rapid screening test for Al tolerance.  相似文献   

水稻中系8541与中系8240光合特性的比较研究     

郭宗华  张其德 《北京农学院学报》1993,(2)

本文通过光合作用参数的测定,详细的研究了中系8541和8240两种不同产量水平的水稻品种的光合特性.论述了在含等量叶绿素的条件下,中系8541和中系8240之间在对光谱的吸收、叶片的光合作用量子转化效率,叶绿体的PSⅡ(光系统Ⅱ)潜在活性(Fv/F_0)和原初光能转化效率(Fv/Fm等的主要区别.实验结果说明,上述各光合作用参数中系8541都优于中系8240.不仅如此.在Mg~(2+)作用下,Fv/Fo和Fv/Fm比值的提高以及Mg~(2+)对两个光系统激发能分配的调节能力中系8541也强于中系8240.  相似文献   

Effect of phytoplasmal infection on photosystem II efficiency and thylakoid membrane protein changes in field grown apple (Malus pumila) leaves     

M. Bertamini  M. S. Grando  K. Muthuchelian  N. Nedunchezhian   《Physiological and Molecular Plant Pathology》2002,61(6):349

We have studied the effect of the apple proliferation phytoplasmal infection on some features of the thylakoids from field grown apple (Malus pumila) leaves. Changes in photosynthetic pigments, soluble proteins, ribulose-1,5-bisphosphate carboxylase, nitrate reductase, photosynthetic activities and thylakoid membrane proteins were investigated. The level of total chlorophyll and carotenoids were reduced in phytoplasma-infected leaves. Similar results were also observed for soluble proteins and ribulose- 1,5-bisphosphate carboxylase activity. The in vivo nitrate reductase activity was significantly reduced in infected leaves. When various photosynthetic activities were followed in isolated thylakoids, phytoplasmal infection caused marked inhibition of whole chain and photosystem II activity while the inhibition of photosystem I activity was only marginal. The artificial exogenous electron donors, diphenyl carbazide and hydroxylamine significantly restored the loss of photosystem II activity in infected leaves. The same results were obtained when F_v/F_m was evaluated by chlorophyll fluorescence measurements. The marked loss of photosystem II activity in infected leaves could be due to the loss of 47, 33, 28–25, 23 and 17 kDa polypeptides. It is concluded that phytoplasmal infection inactivates the donor side of photosystem II. This conclusion was confirmed by immunological studies showing that the content of the 33 kDa protein of the water-splitting complex was diminished significantly in infected leaves.  相似文献   

红肉脐橙(Citrus sinensis L.)果肉中特征色素提取方法探索   总被引：4，自引：0，他引：4  

徐娟  邓秀新 《果树学报》2002,19(4):223-226

红肉脐橙是目前为止惟一果肉呈粉红色或红色的脐橙,其呈色色素尚未见报道。为深入研究其果肉中特征色素的构成及在果实生长发育和贮存过程中色素含量的变化,本研究在对该色素初步定性的基础上对提取方法进行了探索。在分析红肉脐橙果肉中色素萃取液的紫外可见吸收光谱时发现,该色素有类胡萝卜素的特征吸收峰,将萃取液进行薄层层析则进一步证实其内含有番茄红素。在色素提取的前处理方式上,本研究认为冷冻干燥样品的浸提效果较真空干燥的样品稳定(变异系数小),且浸提率相差无几,所以选择冷冻干燥作为合适的样品前处理方式。色素浸提条件的正交实验结果表明,最佳浸提条件为50℃、1.5h内浸提4次,浸提的料液比为1:60。此外,浸提温度、浸提时间、浸提料液比和浸提次数对浸提率都有显著影响,影响最大的因素是浸提温度,最佳温度为50℃,随温度降低浸提率显著降低。其次是侵提时间的长短,最佳浸提时间为1.5h,延长或缩短0.5h都会使浸提率下降。浸提次数对浸提率的影响是最小的。  相似文献   

Footsteps from Insect Larvae Damage Leaf Surfaces and Initiate Rapid Responses   总被引：4，自引：0，他引：4  

Dawn E. Hall  Kennaway B. MacGregor  Jaap Nijsse  Alan W. Bown 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(4):441-447

Plant resistance to insect herbivory involves gene expression in response to wounding and the detection of insect elicitors in oral secretions (Kessler and Baldwin, 2002, Ann. Rev. Plant/ Biol. 53: 299–328). However, crawling insect larvae stimulate the synthesis of 4-aminobutyrate within minutes and imprints of larval footsteps can be visualized within seconds through superoxide production or transient increases in chlorophyll fluorescence (Bown et al., 2002, Plant Physiol. 129: 1430–1434). Here cryo-scanning electron microscopy was used to demonstrate that larval feet, which are equipped with a perimeter row of hook-like crochets, damage leaf tissue and result in larval footprints. Staining for cell death shows that areas of wounding correspond to footsteps detected through increased chlorophyll fluorescence. Superoxide production in response to footsteps was inhibited by diphenyleneiodonium, an inhibitor of the plasma membrane NADPH oxidase enzyme. Inhibition of superoxide production, however, did not eliminate the detection of cell death. The results demonstrate that larval footsteps damage leaf tissue, and initiate rapid local responses which are not dependent on herbivory or oral secretions. It is proposed that superoxide production at the wound site prevents opportunistic pathogen infection.  相似文献   

Growth- and leaf-temperature effects on photosynthesis of sweet orange seedlings infected with Xylella fastidiosa     

R. V. Ribeiro  E. C. Machado †  R. F. Oliveira 《Plant pathology》2004,53(3):334-340

The effects of growth and leaf temperature on photosynthesis were evaluated in sweet orange seedlings ( Citrus sinensis cv. Pera) infected with Xylella fastidiosa (the bacterium that causes citrus variegated chlorosis, CVC). Measurements of leaf gas exchange and chlorophyll  a fluorescence were taken at leaf temperatures of 25, 30, 35 and 40°C in healthy and infected (without visible symptoms) seedlings submitted to two temperature regimes (25/20 or 35/20°C, day/night), not simultaneously. The CO₂ assimilation rates ( A ) and stomatal conductance ( g _s) were higher in healthy plants in both temperature regimes. Values for A and g _s of infected and healthy plants were higher in the 35/20°C regime, decreasing with leaf temperature increase. In addition, differences between healthy and infected plants were higher at 35/20°C, while no differences in chlorophyll  a fluorescence parameters were observed except for potential quantum efficiency of photosystem II, which was higher in infected plants. Low A values in infected plants were caused by low g _s and probably by biochemical damage to photosynthesis. The high alternative electron sink of infected plants was another effect of reduced A . Both high growth and high leaf temperatures increased differences in A between healthy and infected plants. Therefore this feature may be partially responsible for lower growth and/or productivity of CVC-affected plants in regions with high air temperature.  相似文献   

X射线荧光光谱法快速测定稻谷中的镉     

李梅 《粮食储藏》2016,(1):46-48

探索了一种对稻谷中重金属镉的快速、直接的测定方法,以适用稻谷集中收购、存储和流通过程中快速检测的的需要。样品无需前处理,直接磨成粉状即可上机测定。该方法采用X射线荧光光谱分析的原理,样品中的待测元素受激产生特征X射线,并由高性能探测器接收,得到镉元素的信号强度,然后根据信号强度与浓度的比例关系,经过软件处理自动计算样品中镉的含量,20min内完成精确定量。检出限可达到0.034mg/kg,实物标样标准偏差为0.016。此方法简单快速,并且准确性高,重现性好,可广泛应用于稻谷中镉的快速检测。  相似文献