Effects of Homologous Genome 7 on Gas Exchange and Chlorophyll Fluorescence Parameters of Wheat

[Objective]To study the effects of homologous chromosomes 7 （7A,7B and 7D） on wheat photosynthesis and provide theoretical basis for breeding high photosynthetic efficiency wheat by genetic,physiological and biochemical means. [Method]The Triticum asetivum cultivar Chinese Spring wheat and nullisomic wheat （N7A,N7B and N7D） were planted in greenhouse. The photosynthetic indexes were determined at early filling stage. [Result]The photosynthetic rate （Pn）,stomatal conductance （Gs）,primary photochemical efficiency （Fv/Fm）,actual chemical efficiency of photosystem II （ФPS II） and apparent electron transfer rate of photosystem II （ETR） were significantly lower in the N7A and N7B than in the Chinese Spring （P0.05）. The photosynthetic rate and stomatal conductance was significantly lower in the N7D than in the Chinese Spring （P0.05）. The Fv/Fm,ФPS II,ETR of N7D were higher than that of the Chinese Spring without significant difference. [Conclusion]The homologous chromosomes 7A and 7B have positive effects on photosynthetic rate and have relationship with stomatal conductance and photoreaction （chlorophyll fluorescence parameters）. The homologous chromosome 7D has negative effects on photosynthetic rate,which is mainly related to stomatal conductance rather than photoreaction.

Effects of NaCl Stress on Chlorophyll Fluorescence Parameters in Cinnamomum japonicum var. chenii

[ Objective ] Study on the changes of chlorophyll fluorescence parameters in Cinnamomumjaponicum var. chenii under NaCl stress. [ Method ] The seedling growth increment, chlorophyll content and chlorophyll fluorescence parameters in leaves of 1-year old Cinnamomum japonicum var. chenii were investigated in field experiment. [ Result] Under NaC1 stress, seedling growth increment reduced and the chlorophyll content decreased to a stable value ; changes of Fv/Fm and Fv/Fo showed identical increasing trend and double peak type. With the aggravation of salt stress, most variations were observed in Fo, correlations among chlorophyll fluorescence parameters presented ＂rise-drop＂ trend （in.the treatment of 7 g/L NaCl）. [ Conclusion] Cirmamomum japonicum vat. chenii is endowed with strong salt resistance and wide adaptability.

Evaluation of Chlorophyll Content and Fluorescence Parameters as Indicators of Drought Tolerance in Barley

Drought is a major abiotic stress that severely affects food production worldwide. Agronomic and physiological traits associated with drought tolerance are suitable indicators for selection of drought tolerance genotypes to reduce the impact of water deficit on crop yield in breeding program. The objective of this study was to identify indicators related to drought tolerance through analysis of photosynthetic traits in barley （Hordeum vulgare L.）. These traits included chlorophyll content, initial fluorescence （Fo）, maximum primary yield of photochemistry of photosystem Ⅱ （Fv /Fo） and maximum quantum yield of photosystem Ⅱ （Fv/Fm）. Four genotypes （Tadmor, Arta, Morocco9-75 and WI2291） variable in drought tolerance were used to investigate the correlation between these traits and drought tolerance. The results reflected that all of these traits were affected negatively in the four genotypes at different levels of post-anthesis drought stress, but the decrease in drought tolerant genotypes was much less than that of drought sensitive genotypes. The results further revealed that the components of the photosynthetic apparatus could be damaged significantly in drought sensitive genotypes, while drought tolerant genotypes were relatively less affected. On the other hand, the values of chlorophyll content, Fo, Fv/Fo and Fv/Fm in drought tolerance genotypes were significantly higher than those in drought sensitive genotypes under drought stress. It was concluded that chlorophyll content, Fo, Fv/Fo and Fv/Fm could be considered as reliable indicators in screening barley germplasm for drought tolerance.

Effects of Illumination Intensity, 5-aminolevulinic Acid Concentration and Their Interaction on Chlorophyll Fluorescence Parameters and Yield of Summer Maize

[Objective] This study aimed to investigate the influence of illumination intensity, 5-aminolevulinic acid （ALA） concentration and their interaction on chlorophyll fluorescence parameters and yield of summer maize. [Method] Two illumination intensity levels and five ALA concentrations were applied in the experiment using 2x5 completely balanced program. The two illumination intensity levels were natural light （So） and 60% shade （SO, and five ALA concentrations were 0, 1, 10, 25 and 50 mg/L. [Result] The relative chlorophyll content of leaf （SPAD）, the optimal/maximal quantum yield of PS II （Fv/Fm）, the photochemical quenching coefficient （qP）, electron transport rate （ETR）, grain number per cob and grain weight per cob in $1 treatment were significantly reduced compared with that in So. However, the non- photochemical quenching coefficient （qN） was significantly increased. The responses of these parameters to ALA were different under So and $1 treatments. The SPAD, Fv/Fm, qP, ETR, grain number and grain weight per cob were firstly increased, but then decreased following the raise of ALA concentration, ranging from 0 to 50 mg/L, whereas qN showed opposite trend. The effect of the interaction of illumination in- tensity and ALA concentration on these parameters was significant （P〈0.05）. Under natural light, summer maize could obtain higher SPAD, Fv/Fm, qP and ETR and lower qN combined with low concentration of ALA. However, high concentration of ALA was needed under shading to get the same results. [Conclusion] Soaking seed in suitable concentration of ALA can reduce the yield loss of summer maize caused by short-term shading in seedling stage.

Differences in Chlorophyll Fluorescence Parameters, Yield and Its Components Between Different Genotypes of Wheat Under Waterlogging Conditions at Anthesis

Waterlogging is one of the most factors limiting wheat production in the middle and lower reaches of the Yangtze River Plain of China,especially in the middle and late stages of wheat.Wheat varieties‘Jingmai102’(JM102)and‘Yangmai158’(YM158)were planted to study the dynamic changes of photosynthetic characteristics in flag leaf and the influence of waterlogging at anthesis on the yield and components and dry matter accumulation and remobilization of winter wheat in above ground.The results showed that the SPAD values slightly increased at 1 day after anthesis(d),and then kept decreasing with the increase of waterlogging time.The decrease in SPAD value was more remarkably in YM158 than that in JM102.As for the chlorophyll fluorescence parameters,the photochemical efficiency(Fv/Fm),potential activity(Fv/Fo)of photosystem II,and electronic transmission(Fm/Fo)on photosystem II increased first and then decreased with the increase of waterlogging days after anthesis.The quantum ratio of heat dissipation(Fo/Fm)had a tendency opposite to that of Fv/Fm,and the change range of JM102 was lower than that of YM158.For the grain yield and components,waterlogging at anthesis decreased the dry weight of single stem,grain yield,1 000-kernel weight,spikelet per panicle,and harvest index,and the reduction of JM102 was smaller than that of YM158.As for the accumulation and remobilization of dry matter,the accumulation of dry matter after anthesis decreased significantly under waterlogging condition(WL),and the reduction of JM102 was smaller than that of YM158.In conclusion,waterlogging at anthesis significantly affected the photosynthetic characteristics,yield and components in both varieties,but different varieties exhibited different tolerances to waterlogging stress and YM158 was more sensitive to water stress than JM102.

Genome-wide Association Analysis of Fast Chlorophyll Fluorescence Parameters in Maize

Fast chlorophyll fluorescence parameters are widely used to characterize the photosynthetic efficiency of plants. In this study, a genome-wide association analysis was used to detect key single-nueleotide polymorphisms （SNPs） associated with fast chlorophyll fluorescence parameters using more than 560 000 SNPs in a maize panel consisting of 404 inbred lines. In four fidd environments, 41 SNPs were detected to be associated with five fast chlorophyll fluorescence parameters, including ABS/CS0, ET0/CS0, TR0/ABS, ET0/TR0 and Pies. Among these identified SNPs, 8, 6, 18, 4 and 5 were significantly associated with ET0/TR0, ABS/ CS0, TR0/ABS, ET0/CS, and Plcs, respectively. These SNPs will help to discover genes for chlorophyll fluorescence parameters, better understand the genetic basis of photosynthesis, and assist in developing marker-assisted selection breeding programs in maize.

K Shell Fluorescence Parameters by Impact of 5.96 keV Photons on Ti and Its Compounds

K shell fluorescence parameters of pure Ti and some of its compounds have been determined experimentally using an Ultra-LEGe detector with resolution 150 eV at 5.9keV.The samples were excited 5.96 keV photons emitted from a ^(55) Fe radioisotope source with 50 mCi activity.The experimental values of the K shell fluorescence parameters have been compared with the experimental and theoretical values available in the literature for pure Ti.

温度和光强对海带新品系“黄官2号”幼孢子体的生长和生理生化特性的影响

为探明“黄官2号”海带(Saccharinajaponica)幼孢子体(3~4cm)生长适宜的光、温条件及其生理生化机制,本研究开展“黄官2号”海带幼孢子体在不同光强和温度下相对生长速率(RGR)、叶绿素荧光参数、色素/蛋白含量、活性氧含量、抗氧化剂含量和抗氧化酶活性等生长和生理生化特性的相关研究。结果显示,RGR受光强、温度及二者交互作用影响显著,影响程度由大到小依次为温度、光强、二者交互作用。在10~13℃、60~90μmol photons/(m^(2)·s)条件下,“黄官2号”海带幼孢子体RGR较高,高温(16℃和19℃)组的RGR则在30μmol photons/(m^(2)·s)下较高。在同一温度下,随光强升高,海带幼孢子体的叶绿素a和类胡萝卜素含量逐渐下降,超氧化物歧化酶(SOD)活性和抗坏血酸(AsA)含量呈上升趋势;在同一光强下,相对于10~13℃,高温组可溶性蛋白含量减少,丙二醛和过氧化氢含量显著升高,抗氧化酶(SOD、谷胱甘肽过氧化物酶、抗坏血酸过氧化物)活性和抗氧化物质(AsA和类胡萝卜素)含量均较高。高温和高光[120μmol photons/(m^(2)·s)]组的光系统Ⅱ最大量子产量(Fv/Fm)均显著降低,表明藻体在高温高光胁迫下光能转换效率降低。而高光组的调节性能量耗散的量子产量显著增大,且快速光曲线初始斜率(α)显著降低,表明“黄官2号”幼孢子体的光保护系统对高光胁迫产生了积极响应,并通过降低光能利用效率降低了对光能的吸收,从而减少光损伤。高光、高温组的关键抗氧化酶活性和抗氧化物质含量均显著升高,表明“黄官2号”海带幼孢子体的抗氧化系统均对高光、高温逆境产生了积极响应以降低活性氧损害。低光[10μmol photons/(m^(2)·s)]组的Fv/Fm、α、光系统Ⅱ实际量子产量和叶绿素a含量均显著升高,表明“黄官2号”海带幼孢子体在弱光环境下的光能转换效率和光能利用效率均显著提升,从而增加对光能的吸收。上述对“黄官2号”海带幼孢子体在温度和光强条件下的生理、生态适应性研究为其海上栽培技术的优化提供了理论依据。

Enzymatic activity and chlorophyll fluorescence imaging of maize seedlings (Zea mays L.) after exposure to low doses of chlorsulfuron and cadmium

The aim of this research was to study the influence of chlorsulfuron residue and cadmium on the enzymatic activity and photosynthetic apparatus of maize(Zea mays L.) plants. Chlorsulfuron and cadmium at 0.001 and 5.0 mg kg–1, respectively, were mixed and applied to soil prior to planting. The levels of chlorsulfuron-and cadmium-induced stress to plants were estimated by growth, chlorophyll content, lipid peroxide content, enzyme activities, and major fluorescence parameters of chlorophyll(revealed by the fluorescence imaging system Fluor Cam). Chlorsulfuron negatively affected the chlorophyll content, photochemical efficiency of photosystem II in the dark-adapted state, the maximum efficiency of photosystem II, photochemical quenching coefficient, and steady-state fluorescence decline ratio in the leaves of maize seedlings. However, cadmium did not produce noticeable changes. Plants that were exposed to both chlorsulfuron and cadmium showed an obvious increase in the steady-state fluorescence decline ratio. These results implied that the seedlings possessed more resistance to cadmium than to chlorsulfuron and their resistance to chlorsulfuron toxicity was enhanced by the presence of cadmium. The results also suggested that chlorophyll fluorescence imaging reveals overall alterations within the leaves but may not reflect small-scale effects on tissues, as numeric values of specific parameters are averages of the data collected from the whole leaf.

Quantitative energy-dispersive X-ray fluorescence analysis for unknown samples using full-spectrum least-squares regression

The full-spectrum least-squares(FSLS) method is introduced to perform quantitative energy-dispersive X-ray fluorescence analysis for unknown solid samples.Based on the conventional least-squares principle, this spectrum evaluation method is able to obtain the background-corrected and interference-free net peaks, which is significant for quantization analyses. A variety of analytical parameters and functions to describe the features of the fluorescence spectra of pure elements are used and established, such as the mass absorption coefficient, the Gi factor, and fundamental fluorescence formulas. The FSLS iterative program was compiled in the C language. The content of each component should reach the convergence criterion at the end of the calculations. After a basic theory analysis and experimental preparation, 13 national standard soil samples were detected using a spectrometer to test the feasibility of using the algorithm. The results show that the calculated contents of Ti, Fe, Ni, Cu, and Zn have the same changing tendency as the corresponding standard content in the 13 reference samples. Accuracies of 0.35% and 14.03% are obtained, respectively, for Fe and Ti, whose standard concentrations are 8.82% and 0.578%, respectively. However, the calculated results of trace elements (only tens of lg/g) deviate from the standard values. This may be because of measurement accuracy and mutual effects between the elements.

Changes in Chlorophyll Fluorescence of Rice Mutants Induced by High Hydrostatic Pressure

Three mutants of rice (Oryza sativa L. ), Mutant 1, Mutant 2 and Mutant 3, which were selected by high hydrostatic pressure (75 MPa), and their parent Yuexiangzhan were used to study the changes in chlorophyll fluorescence during different growth stages. In all the three mutants, the function of PSⅡ was improved, F_v/F_m ratio of mutants increased compared to their parent at tillering and heading stage, and ΦPSⅡ also improved except for Mutant 2 at heading stage. Similar to their parent, the mutants exhibited slight photoinhibition at noon and almost complete recovery to initial levels of 6:00 after 18:00 at heading stage. At milking stage, the photoinhibition in the mutants was obvious, and recovered rapidly compared to the parent. Yields of individual plant and grain/straw ratio were also higher in three mutants than the parent. Results indicated that characteristics of chlorophyll fluorescence in leaves of mutants and their photoinhibition in the field had changed. It is suggested that high hydrostatic pressure induction could be applied as a new effective approach in high-yield rice breeding in the future.

Relationships between leaf color changes,pigment levels,enzyme activity,photosynthetic fluorescence characteristics and chloroplast ultrastructure of Liquidambar formosana Hance

Liquidambar formosana Hance is an attractive landscape tree species because its leaves gradually change from green to red,purple or orange in autumn.In this study,the red variety of L.formosana was used to establish a quantitative model of leaf color.Physiological changes in leaf color,pigment levels,enzyme activity,photosynthetic fluorescence characteristics and chloroplast ultrastructure were monitored.The relationship between leaf color and physiological structure indices was quantitatively analyzed to systematically explore the mechanisms behind leaf color.Our data showed that with a decrease in external temperatures,chloroplast numbers and sizes gradually decreased,thylakoid membranes became distorted,and chlorophyll synthesis was blocked and gradually decreased.As a result,chloroplast membranes could not be biosynthesized normally;net photosynthesis,maximum and actual photochemical efficiency,and rate of electron transfer decreased rapidly.Excess light energy caused leaf photoinhibition.With intensification of photoinhibition,leaves protected themselves using two mechanisms.In the first,anthocyanin synthesis was promoted by increasing chalcone isomerase and flavonoid glycosyltransferase activities and soluble sugar content so as to increase anthocyanin to filter light and eliminate reactive oxygen species to reduce photoinhibition.In the second,excessive light energy was consumed in the form of heat energy by increasing the non-photochemical quenching coefficient.These processes tuned the leaves red.

Effects of Different Potassium Stress on Leaf Photosynthesis and Chlorophyll Fluorescence in Maize (Zea Mays L.) at Seedling Stage

Leaf early senescence caused by nutrition deficiency is one of the major limitation reasons in the world crop production. Potassium (K) is one of important nutrient elements in crop growth, which modifies dozens of enzyme activations and controls stomatal movement of photosynthesis. The yield and quality of maize (Zea Mays L.) have been limited due to K deficiency in plough layer soil. However, the mechanism of K deficiency tolerance is not fully understood in maize. In this study, two inbred lines, 099 (tolerance to potassium deficiency) and 835 (sensitive to potassium deficiency) were carried out to investigate the variations of chlorophyll content, photosynthetic and chlorophyll fluorescence parameters related with senescence under different K+ concentrations in maize at seedling stage. The results showed that the Chlorophyll a, b and (a + b) of 835 were significantly decreased under different K deficiency treatments, whereas those of 099 were remained normal. In addition, 099 showed a lower stomatal restriction and higher electronic transition capacity under different K deficiency treatments. The variations of F0, Fv/Fm, ΦPSⅡ, qP and NPQ in 835 were largely higher than those in 099. These results indicated that the inbred line 099 tolerance to K deficiency could keep chlorophyll content to maintain photosynthesis and to alleviate the injury of PSII under K deficiency condition. This study should contribute to explaining the physiological mechanism tolerance nutrition deficiency and improving breeding program in maize.

pharmacognostical study and establishment of quality parameters of aerial parts of Costus speciosus-a well known tropical folklore medicine

Objective:To evaluate the diagnostic pharmacognostical characters of Costus speciosus(aerial parts)along with their physico-chemical parameters and fluorosence analysis.Method:The pharmacognostical characters were determined in terms of macroscopy,microscopy,powder microscopy,leaf constant,fluorescence analysis and preliminary phytochemical investigation.Results:The findings of macroscopy revealed that leaves elliptic to oblong or oblong-lancoelate,thick,spirally arranged,with stem clasping sheaths up to 4 cm,flowers large,white,conelike terminal spikes,with bright red bracts.Transverse section of leaflet showed the presence of cuticularised epidermis with polygonal cells on adaxial surface and bluntly angled cells on abaxial surface of lamina,mesophyll cells differentiated in to single layered palisade cells on each surface and 2-3 layered spongy parenchyma,unicellular and uniseriate multicellular covering trichomes,paracytic stomata and vascular bundles surrounded by sclerenchymatous multicellular sheath.Preliminary phytochemical screening exhibited the presence of various phytochemical groups like alkaloids,glycosides,steroids,phenolic constituents.Further,the leaf constants,powder microscopy and fluorescence characteristics indicated outstanding results from this investigation Conclusions:Various pharmacognostical and physico-chemical parameters have pivotal roles in identification,authentication and establishment of quality parameters of the species.

Fluorescence of Chlorophyll a for Discovering Inhibitors of Photosynthesis in Plant Extracts

Aims: Twelve crude extracts were prepared from different parts of Pluchea sagittalis, Cecropia palmata and Brachiaria brizantha, and their effect on the light reaction of photosynthesis. Study Design: Use of fluorescence of ChL a (Chlorophyll a) to detect inhibitors of photosynthesis in plant extracts. Place and Duration of Study: Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Departamento de Ciências Exatas e da Terra, Universidade Federal de Sao Paulo (UNIFESP), between July 2015 and January 2016. Methodology: The samples had their effect on the light reaction of photosynthesis studied by Chlorophyll a (Chl a) fluorescence transient by the use of chloroplasts isolated from spinach leaves. As negative controls we used the same amounts of DMSO that have been employed to solubilize the samples, and as positive control we have used 10 μM of the commercial herbicide DCMU (Diuron). Results: The extracts inhibited the photosynthesis, and their inhibition sites were located in the range of electron flow from OEC complex and between P680 to QA of PS II, and inhibited the photosystem II (PS II) by inducing the appearance of the transient bands K and J. Conclusion: Our results suggest an indicative that the photochemical apparatus probably is failing at the donor and acceptor sides of PSII, causing damage to electron transport during the photosynthesis phenomenon.

Quick Fluorescence Method for the Distinguishing of Vegetable Oils

This paper presents the possibilities offered by fluorescence spectroscopy for the identification of vegetable oils such as soybean, sunflower, flax, walnut, corn, almond, sesame, olive and pumpkin oils. The probes under study have been excited with two types of sources： a laser diode （LD） and light-emitting diodes （LEDs） emitting in the UV and in the visible range. Total luminescence spectra were recorded by measuring the emission spectra in the range 350-720 nm at excitation wavelengths from 375 to 450 nm. The excitation-emission matrices have been obtained and two basic fluorescence regions in the visible have been outlined. On this basis the fluorescence spectra of the oils have been subdivided into three categories depending on the prevalence of the fluorescence maxima. The samples show differences in their fluorescence spectra. The latter fact shows that fluorescence spectroscopy can be used for the quick identification of edible oils. The fatty acid, the tocopherol, the beta-carotene and chlorophyll contents in the analyzed oils have been studied. It is shown that some of the types of oils differ significantly from each other by the first derivatives of their fluorescence spectra. There also exist color differences between the groups of vegetable oils under study.

9个山茶品种对高温胁迫的光合生理响应及其耐热性综合评价

【目的】山茶的花型和花色丰富、花期长,其耐热性日益受到关注,筛选合适的评价方法和指标可为山茶属植物耐热性鉴定、种质发掘和新品种选育提供理论依据。【方法】以耐热性较强的单体红山茶和‘串花瀑布’为对照,7个自育束花茶花新品种为试验对象,采用瓶插方法,在短期(5 h)和长期(7 d)高温(42℃/35℃)处理后,考察各品种形态及光合生理标指标的变化,并综合评价其耐热性。【结果】(1)‘垂枝粉玉’和‘串花瀑布’在高温胁迫下叶绿素含量、类胡萝卜素含量、叶绿素a/b、净光合速率(Pn)和气孔导度(Gs)均上升,PSⅡ最大光化学效率(F_(v)/F_(m))、PSⅡ潜在活性(F_(v)/F_(o))和电子传递速率(ETR)维持在较高水平,且长期高温胁迫后均未出现热害。‘金叶粉玉’、‘上植华章’和‘玫瑰春’在高温胁迫下Pn和Gs均显著降低,而Ci升高,‘金叶粉玉’和‘上植华章’的F_(v)/F_(m)、F_(v)/F_(o)和ETR均大幅降低,且长期高温胁迫后出现较严重热害或死亡。(2)通过主成分分析将15个单项指标换算成4个独立的综合指标,累计贡献率可达90%;短期高温时以叶绿素含量、类胡萝卜素含量、叶黄素含量的综合权重值较高,长期高温时以叶绿素a/b、F_(v)/F_(m)、光化学淬灭系数(qP)、非光化学淬灭系数(qN)的综合权重值较高。【结论】新品种‘垂枝粉玉’耐热较强,‘上植月光曲’、‘上植欢乐颂’和‘玫玉’中等耐热,‘玫瑰春’、‘上植华章’和‘金叶粉玉’耐热性较弱;叶绿素、类胡萝卜素、叶黄素含量可作为山茶短期耐热性考察指标,而叶绿素a/b、F_(v)/F_(m)、qP、qN可作为山茶长期耐热性的考察指标。

盐胁迫下外源褪黑素和丛枝菌根真菌对月季幼苗生长生理特性的影响

【目的】盐胁迫易导致月季生长发育不良、观赏品质下降,严重影响其在高盐环境或沿海地区室外绿化应用,探究施用外源褪黑素(MT)和接种丛枝菌根真菌(AMF)对其幼苗生长、叶绿素荧光参数以及激素代谢的调控作用,解析它们促进月季适应盐胁迫的生理生化机制,对于增强月季抗盐性,扩大月季应用范围具有重要意义。【方法】以月季品种‘月月红’幼苗为试验材料,采用室内盆栽试验,设置对照(CK)、100 mol/L NaCl胁迫、根际施用MT、根际接种AMF幼套近明球囊霉(Claroideoglomus etunicatum)及其组合等8个处理,考察各处理对月季幼苗生长、叶绿素荧光参数、激素代谢及抗氧化系统的影响。【结果】(1)施用MT可以促进AMF对月季幼苗根系的侵染,提高侵染率、丛枝着生率、泡囊数和侵入点数;(2)月季幼苗株高、茎粗以及生物量等在盐胁迫下显著下降,在MT或AMF处理下均不同程度增加,而AMF+MT处理下株高、茎粗无显著变化,地上部干重、地下部干重分别显著增加24.1%和37.0%;(3)月季幼苗叶绿素含量在盐胁迫下显著下降,叶绿素荧光参数也降低,MT或AMF处理能提高盐胁迫月季幼苗叶绿素含量以及叶绿素荧光参数,AMF+MT处理则使叶绿素总量、叶绿素a/b分别增加46.2%和67.2%,PSⅡ最大光化学效率(F_(v)/F_(m))、潜在活性(F_(v)/F_(o))、实际光化学效率(ΦPSⅡ)、有效光化学量子效率(Fv'/Fm')、光化学淬灭系数(qP)分别增加4.9%、51.0%、175.0%、168.7%和92.5%,而NPQ下降42.7%;(4)在盐胁迫下,月季叶片中玉米素(ZT)、赤霉素(GA)、生长素(IAA)含量下降,而脱落酸(ABA)含量增加,MT或AMF处理有利于盐胁迫下ZT、GA、IAA含量的提高以及ABA含量的下降,AMF+MT处理后ZT、GA、IAA分别增加146.9%、116.9%、35.7%,ABA下降21.1%;(5)在盐胁迫下,抗氧化酶SOD、CAT活性增强,超氧阴离子(O_(2)^(-·))产生速率和H_(2)O_(2)累积大量增加,MT或AMF处理有助于增加抗氧化酶活性并减少O_(2)^(-·)产生速率和H_(2)O_(2)含量,而AMF+MT处理能够进一步激活SOD、CAT活性,降低O_(2)^(-·)产生速率和H_(2)O_(2)累积。【结论】接种AMF、添加MT或者AMF+MT处理均可以提高盐胁迫下月季幼苗叶绿素含量,保护叶绿素荧光系统,维持植物内源激素的平衡,激活SOD、CAT等抗氧化酶活性以及降低脂质过氧化和H_(2)O_(2)累积,以减轻盐胁迫对月季幼苗的伤害,促进月季生长,并以AMF+MT处理增强月季幼苗抗盐性的效果更佳。

外源镉和温度变化对不同品种水稻抽穗期光合特性的影响

探讨外源镉(Cd)和温度变化对水稻抽穗期光合特性的影响,为水稻生长过程中应对稻田土壤重金属污染和气候变暖的复合作用提供理论依据。通过添加外源Cd (0和2 mg/kg土)和模拟温度(白天/夜晚分别为30℃/25℃(CK)、33℃/28℃(T1)、36℃/31℃(T2)),研究外源Cd和温度变化对不同品种水稻(武运粳30号和新两优6号)抽穗期光合参数、荧光参数及其生物量的影响。结果表明,单一Cd处理显著降低了新两优6号的SPAD值,而单一增温处理则显著降低了武运粳30号的SPAD值(P<0.05)。虽然外源Cd和温度的复合作用未显著影响武运粳30号和新两优6号的净光合速率(Pn),但Cd处理显著降低了两品种的Pn,而增温处理则显著影响了新两优6号的Pn;大部分Cd和温度处理下,新两优6号的SPAD值和Pn大于武运粳30号。Cd处理和增温处理均影响了水稻叶绿素诱导动力学曲线的形状,O、K、J和I点的荧光因处理的不同而具有一定差异。Cd处理和增温处理对水稻Fv/Fm和比活度参数的影响与水稻品种有关,Cd处理未显著影响运粳30号和新两优6号的Fv/Fm值,而增温处理则显著减少了武运粳30号的Fv/Fm值;新两优6号的比活度参数ABS/RC、DIo/RC、TRo/RC、ET0/RC在Cd处理下显著降低,而武运粳30号的比活度参数在增温处理下则显著增加(P<0.05)。Cd处理显著降低了新两优6号的茎叶生物量,而增温处理则显著降低了武运粳30号茎叶生物量,然而两者的复合作用对水稻茎叶和根生物量的影响因品种不用而具有差异,新两优6号的茎叶和根干物质量在大部分处理下大于武运粳30号。综上可知,Cd和增温处理通过影响水稻的光合参数和荧光参数,从而影响水稻的生物量,但影响程度因品种不同而具有差异,其中,武运粳30号对Cd具有较强的抗性而新两优6号对增温有较强的抗性。因此,在实际的田间管理中,应选择合适的水稻品种,以应对土壤Cd污染和温度升高对水稻生长的影响。

Dual-parameter Correlation Analysis of the Fluorescence Data of 1-Methyl-2-formyl-5-substituted Pyrrole(4-nitrophenyl)hydrazones

By using 1-methyl-2-formyl-5 -Y-substituted pyrrole (4-nitrophenyl)hydrazones as a model for nitrogen-containing heterocyclic aromatic compounds, the emission wavelength [lambda(max(em))] values df their fluorescence spectra have been measured. Correlation results show that the Delta E-em values are mainly affected by polar effects, but spin-delocalizatin effects also exist.