Chlorophyll Fluorometer Research Articles

Response of boreal lakes to episodic weather-induced events

Weather-induced episodic mixing events in lake ecosystems are often unpredictable, and their impacts are therefore poorly known. The impacts can be short-lived, including changes in water temperature and stratification, but long-lasting effects on the lake’s biology may also occur. In this study we used automated water quality monitoring (AWQM) data from 8 boreal lakes to examine how the episodic weather-induced mixing events influenced thermal structure, hypolimnetic dissolved oxygen (DO), fluorometric chlorophyll estimates (Chl-a), and lake metabolism and how these events varied in frequency and magnitude in lakes with different characteristics. Rise in wind speed alone had an effect on the lakes with the weakest thermal stability, but a decrease in air temperature together with strong wind induced mixing events in all lakes. The return period of these mixing events varied widely (from 20 to 92 d) and was dependent on the magnitude of change in weather. In lakes with strong stability, thermal structure and hypolimnetic DO concentration were only slightly affected. Weather-induced mixing in the upper water column diluted the surface water Chl-a repeatedly, whereas seasonal maximum occurred in late summer on each lake. Although Finnish lakes have been characterized with stable stratification during summer, we observed many substantial mixing events of relatively short return periods relevant to both chemical and biological properties of the lakes.

Interference of heavy metals on the photosynthetic response from a Cr(VI)-resistant Dictyosphaerium chlorelloides strain.

The successful selection of a particular type of bioelement and its association to the appropriate transducer determines the specificity of a biosensor. Therefore, from a strain of chloroficea Dictyosphaerium chlorelloides, modified in laboratory to tolerate high Cr(VI) concentrations, the possible interferences of other heavy metals on photosynthetic activity were studied. After exposing wild type and Cr(VI)-resistant cells to increasing Ag(+1), Co(+2), Hg(+2), Cr(+3), Cu(+2), Zn(+2), Fe(+3) and Cd(+2) concentrations, both photosynthetic quantum yields was compared. Photosynthetic electron transport rates were measured with a TOXY-PAM chlorophyll fluorometer, non-linear regression analysis of each of the toxicity tests was done, and means of both groups were compared using unpaired t test. The results show no significant differences between both cell types when they were exposed to Ag(+1), Co(+2), Hg(+2), Cr(+3), Cu(+2), Fe(+3) and Cd(+2) metal ions, and extremely significant differences (p<0.0001) to Zn(+2) exposures. These results demonstrate the suitability of this Cr(VI)-resistant type D. chlorelloides strain as a suitable bioelement to be coupled to a biosensor based on dual-head microalgae strategy to detect and quantify Cr(VI) in water courses and waste water treatment plants. However, some disturbance may be expected, especially when certain analyte species such as zinc are present in water samples tested. The analysis of binary mixtures between Zn(+2) and other heavy metals showed a slight antagonistic phenomenon in all cases, which should not alter the potential Zn(+2) interference in the Cr(+6) detection process.

In vivo evaluation of the high-irradiance effects on PSII activity in photosynthetic stems of Hexinia polydichotoma

Green photosynthetic stems are often responsible for photosynthesis due to the reduction of leaves in arid and hot climates. We studied the response of PSII activity to high irradiance in the photosynthetic stems of Hexinia polydichotoma in the Taklimakan Desert by analysis of the fast fluorescence transients (OJIP). Leaf clips of a chlorophyll fluorometer were used in conjunction with a sponge with a 4-mm-width groove to prevent light leakage for precise in vivo measurements. High irradiance reduced performance indices, illustrating the photoinhibition of PSII to some extent. However, the decrease in active reaction centers (RC) per PSII absorption area and maximum quantum yield indicated a partial inactivation of RCs and an increase in excitation energy dissipation, resulting in downregulation of photosynthetic excitation pressure. In addition, the increased efficiency of electron transport to PSI acceptors alleviated overexcitation energy pressure on PSII. These mechanisms protected the PSII apparatus as well as PSI against damages from excessive excitation energy. We suggested that H. polydichotoma exhibited rather photoadaptation than photodamage when exposed to high irradiance during the summer in the Taklimakan Desert. The experiment also demonstrated that the modified leaf clip can be used for studying dark adaptation in a photosynthetic stem.

Research on Accuracy and Stability of Inversing Vegetation Chlorophyll Content by Spectral Index Method

Spectral index method was widely applied to the inversion of crop chlorophyll content. In the present study, PSR3500 spectrometer and SPAD-502 chlorophyll fluorometer were used to acquire the spectrum and relative chlorophyll content (SPAD value) of winter wheat leaves on May 2nd 2013 when it was at the jointing stage of winter wheat. Then the measured spectra were resampled to simulate TM multispectral data and Hyperion hyperspectral data respectively, using the Gaussian spectral response function. We chose four typical spectral indices including normalized difference vegetation index (NDVD, triangle vegetation index (TVI), the ratio of modified transformed chlorophyll absorption ratio index (MCARI) to optimized soil adjusted vegetation index (OSAVI) (MCARI/OSAVI) and vegetation index based on universal pattern decomposition (VIUPD), which were constructed with the feature bands sensitive to the vegetation chlorophyll. After calculating these spectral indices based on the resampling TM and Hyperion data, the regression equation between spectral indices and chlorophyll content was established. For TM, the result indicates that VIUPD has the best correlation with chlorophyll (R2 = 0.819 7) followed by NDVI (R2 = 0.791 8), while MCARI/OSAVI and TVI also show a good correlation with R2 higher than 0.5. For the simulated Hyperion data, VIUPD again ranks first with R2 = 0.817 1, followed by MCARI/OSAVI (R2 = 0.658 6), while NDVI and TVI show very low values with R2 less than 0.2. It was demonstrated that VIUPD has the best accuracy and stability to estimate chlorophyll of winter wheat whether using simulated TM data or Hyperion data, which reaffirms that VIUPD is comparatively sensor independent. The chlorophyll estimation accuracy and stability of MCARI/OSAVI also works well, partly because OSAVI could reduce the influence of backgrounds. Two broadband spectral indices NDVI and TVI are weak for the chlorophyll estimation of simulated Hyperion data mainly because of their dependence on few bands and the strong influence of atmosphere, solar altitude, viewing angle of sensor, background and so on. In conclusion, the stability and consistency of chlorophyll estimation is equally important to the estimation accuracy by spectral index method. VIUPD introduced in the study has the best performance to estimate winter wheat chlorophyll, which illustrates its potential ability in the area of estimating vegetation biochemical parameters.

Automated integrative high-throughput phenotyping of plant shoots: a case study of the cold-tolerance of pea (Pisum sativum L.).

BackgroundRecently emerging approaches to high-throughput plant phenotyping have discovered their importance as tools in unravelling the complex questions of plant growth, development and response to the environment, both in basic and applied science. High-throughput methods have been also used to study plant responses to various types of biotic and abiotic stresses (drought, heat, salinity, nutrient-starving, UV light) but only rarely to cold tolerance.ResultsWe present here an experimental procedure of integrative high-throughput in-house phenotyping of plant shoots employing automated simultaneous analyses of shoot biomass and photosystem II efficiency to study the cold tolerance of pea (Pisum sativum L.). For this purpose, we developed new software for automatic RGB image analysis, evaluated various parameters of chlorophyll fluorescence obtained from kinetic chlorophyll fluorescence imaging, and performed an experiment in which the growth and photosynthetic activity of two different pea cultivars were followed during cold acclimation. The data obtained from the automated RGB imaging were validated through correlation of pixel based shoot area with measurement of the shoot fresh weight. Further, data obtained from automated chlorophyll fluorescence imaging analysis were compared with chlorophyll fluorescence parameters measured by a non-imaging chlorophyll fluorometer. In both cases, high correlation was obtained, confirming the reliability of the procedure described.ConclusionsThis study of the response of two pea cultivars to cold stress confirmed that our procedure may have important application, not only for selection of cold-sensitive/tolerant varieties of pea, but also for studies of plant cold-response strategies in general. The approach, provides a very broad tool for the morphological and physiological selection of parameters which correspond to shoot growth and the efficiency of photosystem II, and is thus applicable in studies of various plant species and crops.

Chlorophyll fluorescence in guanandi tree (Calophyllum brasiliense) after herbicide application

Chlorophyll fluorescence is currently used as a rapid diagnostic and nondestructive method to detect and quantify damage on the photosynthetic apparatus of leaves on weeds, crops and ornamental/coniferous trees in response to both environmental stress and herbicides. This study aimed to evaluate chlorophyll fluorescence in guanandi plants (Calophyllum brasiliense) after application of different postemergence herbicides. The experiment was performed in a completely randomized design, with six treatments (control, bentazon, sulfentrazone, isoxaflutole, atrazine and glyphosate) and five replications. The herbicide treatments were applied with a stationary sprayer, and electron transport rate (ETR) was subsequently analyzed with OS5p Multi-Mode Chlorophyll Fluorometer. In the monitored period, guanandi plants subjected to atrazine showed higher sensitivity to chlorophyll fluorescence than the other treatments. Although bentazon is a photosystem II inhibitor, it showed no major changes in electron transport for the studied species and in the monitored period. In summary, ETR is a good parameter to evaluate the effect of some herbicides on Calophyllum brasiliense plants.

盐胁迫对“鄞红”葡萄光合特性及叶片细胞结构的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 盐胁迫对‘鄞红’葡萄光合特性及叶片细胞结构的影响 DOI: 10.5846/stxb201409141821 作者: 作者单位: 1.上海海洋大学; 2.浙江万里学院,浙江万里学院,浙江万里学院,1.上海海洋大学; 2.浙江万里学院,浙江万里学院,浙江万里学院 作者简介: 通讯作者: 中图分类号: 基金项目: 宁波市科技创新团队项目(2011B82019);浙江省科技厅项目(2011C32008);宁波市科技项目(2013C10009) Effects of salt stress on photosynthetic characteristics and leaf cell structure of ‘Yinhong’ grape seedlings Author: Affiliation: 1.Shanghai Ocean University; 2.Zhejiang Wanli University,Zhejiangwanli University,Zhejiangwanli University,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:采用水培法,研究了不同浓度(0%、0.2%、0.4%、0.6%、0.8%)NaCl处理对1年生‘鄞红’葡萄幼苗生长、光合特性及叶片细胞结构的影响,为盐碱地‘鄞红’葡萄的栽培提供参考。结果表明:低浓度盐分(NaCl≤0.4%)对葡萄生长、叶绿素含量、叶片细胞结构、气体交换参数以及叶绿素荧光参数影响不显著。随着盐浓度增大,葡萄生长受到抑制,叶片表皮层、栅栏组织、海绵组织变厚,海绵组织和栅栏组织细胞间隙变大,栅栏组织细胞叶绿体肿胀,内含淀粉粒和嗜锇颗粒变大且增多;同时,叶绿素含量、净光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)、蒸腾速率(Tr)、PSⅡ最大光化学效率(Fv/Fm)、PSⅡ潜在活性(Fv/Fo)、光化学电子传递效率(ETR)、光化学猝灭系数qP以及栅栏组织/海绵组织比逐渐下降,非光化学猝灭系数qN逐渐上升;尤其在0.8%NaCl浓度胁迫下,葡萄生长、叶绿素含量、叶片细胞结构、气体交换参数以及叶绿素荧光参数均发生显著性变化。由此表明,‘鄞红’葡萄能在较低含盐量(NaCl ≤ 0.4%)的基质中正常生长。 Abstract:Salt stress is one of the major environmental factors affecting plants; it causes many changes in plant metabolism, such as decreasing the capacity and efficiency of photosynthesis and inhibiting growth. Salt stress also changes leaf cell structure. Therefore, plant growth, photosynthesis, and leaf cell structure are often used as indicators of salt stress injury in plants. In response to salt stress, plants have evolved diverse mechanisms that can mitigate the effects of stress and lead to improved plant tolerance. In this study, 1-year-old potted seedlings of ‘Yinghong’ grape were used to examine their changes in growth, photosynthetic characteristics, and leaf cell structure under different levels of salt stress, ranging from NaCl concentrations of 0% to 0.8%. The goal of this experiment was to provide reference information for grape cultivation in salty soils. Because of the complexity of the soil composition in the natural state, the actual salt concentration of soil is difficult to control. Thus, to investigate the responses of grape seedlings to specific and precise salt concentration conditions, a total of 100 potted seedlings were divided into five groups, and 20 seedlings each were placed into Hoagland hydroponic culture with one of five salt concentrations, specifically 0%, 0.2%, 0.4%, 0.6%, and 0.8% NaCl. The chlorophyll content, gas exchange parameters, and chlorophyll fluorescence parameters of the grape seedlings were measured every 15 days, and the characteristics of the growth and leaf cell structure were measured after 45 days. In this study, the LA-S plant image analysis system was used to measure the growth traits, such as the length, average diameter, surface area, volume of the root system, and leaf area. Chlorophyll content was measured with a SPAD-502+PLUS chlorophyll meter. The GFS-3000 portable photosynthesis system was used to measure gas exchange parameters, such as the net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), and intercellular CO2 concentration (Ci). The JUNIOR-PAM chlorophyll fluorometer was employed to measure chlorophyll fluorescence parameters, such as the maximum photochemical efficiency of photosystem Ⅱ (PSⅡ) (Fv/Fm), PSⅡ potential activity (Fv/Fo), electron transport rate (ETR), photochemical quenching (qP), and non-photochemical quenching (qN). Finally, leaf cell microstructure and palisade tissue chloroplast ultrastructure were observed with an OLYMPUS optical microscope and a HITACHI-7650 transmission electron microscope. Grape seedlings in the low salt treatments (0.2% and 0.4% NaCl) grew normally, and the chlorophyll content, leaf cell structure, gas exchange parameters, and chlorophyll fluorescence parameters were not significantly different in these treatments from those of the control (0% NaCl). At higher NaCl concentrations (0.6% and 0.8% NaCl), plant growth was significantly constrained. The epidermis cells, palisade tissue, and spongy tissue in the leaves were thicker, the intercellular space within the palisade tissue and spongy tissue was larger, the chloroplasts became swollen, and the numbers and sizes of starch grains and plastoglobules were greater compared with the control. In addition, the chlorophyll content, Pn, Gs, Tr, Ci, Fv/Fm, Fv/Fo, ETR, qP, and thickness ratio of the palisade/spongy tissue were lower and qN was higher relative to the control. In particular, compared with the control, significant changes in plant growth status, chlorophyll content, leaf cell structure, gas exchange parameters, and chlorophyll fluorescence parameters were observed under high salt stress (0.8% NaCl). Therefore, 1-year-old potted seedlings of grape ‘Yinghong’ could grow normally under low salinity stress(NaCl ≤ 0.4%). 参考文献 相似文献 引证文献

Phalaenopsis efficiently acclimate to highlight environment through orchid mycorrhization

Phalaenopsis (Phalaenopsis amabilis ‘KC1410’) grow slowly and experience photoinhibition during the daytime. Thus, this study used orchid mycorrhizal (OM) fungus to promote orchid growth hypothetically via increasing the photoacclimation capacity of Phalaenopsis in response to high light (HL). By combining chlorophyll fluorometer and spectral reflectance techniques, the influences of OM colonization on the growth potentials and the photosynthetic performance of HL-grown Phalaenopsis were investigated. OM symbiosis significantly promoted the growth of HL-grown orchids, such as leaf span, fresh weight, and dry weight. Consistent with these observations, OM symbiosis obtained higher value of normalized difference vegetation index (NDVI) and enhanced CO2 uptake rate. This could be attributed to an increase in photosynthetic performance in OM plants. Notably, maximum quantum efficiency of PSII photochemistry (Fv/Fm) was not altered by OM symbiosis, however, the light-adapted fluorescence measurements of PSII operating efficiency (ФPSII) and electron transport rate (ETR) were increased. Nevertheless, OM orchids had higher photochemical quenching (qP) and lower non-photochemical quenching (NPQ). This indicates a relative higher photosynthetic performance and radiation-use efficiency (RUE) in OM plants. The photochemical reflectance index (PRI) as a photoprotection indicator was also enhanced. Based on these results, we proposed that OM symbiosis increases both the photosynthetic performance and the RUE in the HL-acclimated Phalaenopsis, resulting in an advantage to the OM plants to survive the HL stress.

Ocean acidification and warming alter photosynthesis and calcification of the symbiont-bearing foraminifera Marginopora vertebralis

The impact of elevated CO2 and temperature on photosynthesis and calcification in the symbiont-bearing benthic foraminifer Marginopora vertebralis was studied. Individual specimens of M. vertebralis were collected from Heron Island on the southern Great Barrier Reef (Australia). They were maintained for 5 weeks at different temperatures (28, 32 °C) and pCO2 (400, 1,000 µatm) levels spanning a range of current and future climate-change scenarios. The photosynthetic capacity of M. vertebralis was measured with O2 microsensors and a pulse-amplitude-modulated chlorophyll (Chl) fluorometer, in combination with estimates of Chl a and Chl c2 concentrations and calcification rates. After 5 weeks, control specimens remained unaltered for all parameters. Chlorophyll a concentrations significantly decreased in the specimens at 1,000 µatm CO2 for both temperatures, while no change in Chl c2 concentration was observed. Photoinhibition was observed under elevated CO2 and temperature, with a 70–80 % decrease in the maximum quantum yield of PSII. There was no net O2 production at elevated temperatures in both CO2 treatments as compared to the control temperature, supporting that temperature has more impact on photosynthesis and O2 flux than changes in ambient CO2. Photosynthetic pigment loss and a decrease in photochemical efficiency are thus likely to occur with increased temperature. The elevated CO2 and high temperature treatment also lead to a reduction in calcification rate (from +0.1 to >−0.1 % day−1). Thus, both calcification and photosynthesis of the major sediment-producing foraminifer M. vertebralis appears highly vulnerable to elevated temperature and ocean acidification scenarios predicted in climate-change models.

The effect of irradiance and temperature responses and the phenology of a native alga, Undaria pinnatifida (Laminariales), at the southern limit of its natural distribution in Japan

Phenology, irradiance, and temperature characteristics of an edible brown alga, Undaria pinnatifida (Laminariales), were examined from the southernmost natural population in Japan, both by culturing gametophytes and examining the photosynthetic activity of sporophytes using dissolved oxygen sensors and pulse amplitude-modulated chlorophyll fluorometer (IMAGING-PAM). Our surveys confirmed that sporophytes were present between winter and early summer, but absent by July. IMAGING-PAM experiments were used to measure maximum effective quantum yield (ΦII at 0 μmol photons m−2 s−1) for each of 14 temperatures (8–36 °C). Oxygen production was also determined over a coarser temperature gradient. Net photosynthesis and ΦII (at 0 μmol photons m−2 s−1) were observed to be temperature-dependent; the maximum ΦII was estimated to be 0.67, occurred at 21.2 °C, and was nearly identical to the optimal temperature of the net photosynthetic rate (21.7 °C). A net photosynthesis–irradiance (P–E) model revealed that saturation irradiance (Ek) was 119.5 μmol photons m−1 s−1, and the compensation irradiance (Ec) was 17.4 μmol photons m−1 s−1. Culture experiments on the gametophytes revealed that most individuals could not survive temperatures over 28 °C and that growth rates were severely inhibited. Based on our observations, temperatures greater than 20 °C are likely to influence photosynthetic activity and gametophyte survival, and therefore, it is possible that this species might become locally extinct if seawater temperatures in this region continue to rise.

海盐对绿竹叶片反射光谱及叶绿素荧光参数的影响

沿海防护林是海岸生态系统中最基本的生物资源，由于沿海地区地下水位高，土壤含盐量高，肥力低，生态环境恶劣等特点，所以优良植物种选择是加快沿海优良防护林体系建设的关键。为了探讨绿竹耐盐性以及为沿海地区防护林选择优良植物种，以2 年生绿竹 （<em>Bambusa oldhamii</em>） 为材料，采用水培法进行不同浓度的海盐处理，利用 Unispec-SC 型单通道光纤光谱仪和非调制式叶绿素荧光仪对绿竹叶片反射光谱和叶绿素荧光参数等进行测定。结果表明：当海盐浓度小于1.2%时，绿竹叶片中叶绿素a、叶绿素b和类胡萝卜素含量，以及"三边"参数与对照无显著差异，当海盐浓度升高到1.6%时，色素与对照相比分别降低了63.2%、62.8%和47.2% （<em>P</em> < 0.01），红边位置 （<em>λ</em>_red） 和红边面积 （<em>S</em>_red） 相比对照显著减小 （<em>P</em> < 0.05）。1.2%浓度的海盐处理，红边归一化指数 （<em>rNDVI</em>）、绿度归一化指数 （<em>gNDVI</em>）、类胡萝卜素反射指数2 （<em>CRI</em>₇₀₀） 和光化学反射指数 （<em>PRI</em>） 显著降低 （<em>P</em> < 0.05），与对照相比分别降低了27.3%、23.3%、19.5%和43.9%；当海盐浓度增加到1.6%时，<em>rNDVI</em> 、改良红边比值指数 （<em>mND</em>）、<em>gNDVI</em> 、改良归一化差值指数 （<em>mSR</em>₇₀₀）、类胡萝卜素反射指数1 （<em>CRI</em>₅₅₀）、<em>CRI</em>₇₀₀和<em>PRI</em> 等参数与对照相比分别下降了42.4%、43.9%、32.6%、21.5%、47.2%、49.9%和58.5%。绿竹叶片PSⅡ最大量子产率 （<em>F</em>_v/<em>F</em>_m）、电子传递的量子产额 （<em>ΦE</em><em>_o</em>）、单位反应中心捕获的用于电子传递的能量 （<em>ET</em>_<em>o</em>/<em>RC</em>）、单位面积反应中心数目 （<em>RC/CS</em>） 和叶片性能指数 （<em>PI</em>_ABS） 等参数，1.6%海盐处理与对照相比分别降低了50.8%、28.6%、21.7%、52.1%和92.3%，单位反应中心复合体吸收的能量 （<em>ABS/RC</em>） 比对照提高了96.9%。说明绿竹具有一定的耐盐性。;The coastal protection forest is the most basic living resources in the coastal ecosystem. Due to the high underground water level, high soil salt content, low fertility, and deteriorated ecological environment in the coastal area, the selection of plant species is the key to speed up the construction of coastal protection forest system. To evaluate the salt tolerance of <em>Bambusa oldhamii</em> and provide plant species for coastal protection forest in the coastal area, we investigated reflectance spectra and chlorophyll fluorescence parameters in the leaves of 2 years <em>B. oldhamii</em> under sea salt stress by hydroponics using Unispec-SC spectrometer and non-modulated chlorophyll fluorometer, respectively. Results showed that when the sea salt concentration was under 1.2%, the contents of chlorophyll a, chlorophyll b and carotenoids, and reflectance spectra parameters were not significantly different with that under control. However, when the sea salt concentration was 1.6%, the contents of chlorophyll a, chlorophyll b and carotenoids were decreased by 63.2%, 62.8%, and 47.2% (<em>P</em> < 0.01), respectively and reflectance spectra parameters red wavelength (<em>λ</em>_red) and red area (<em>S</em>_red) were significantly reduced (<em>P</em> < 0.05) compared with control. The red-edge normalized difference vegetation index (<em>rNDVI</em>), greenness normalized index (<em>gNDVI</em>), carotenoids reflectance indexes Ⅱ (<em>CRI</em>₇₀₀) and photochemical reflectance index (<em>PRI</em>) under 1.2% sea salt concentration was reduced by 27.3%、23.3%、19.5% and 43.9%, respectively compared with control. The <em>rNDVI</em>, modified red-edge normalized difference vegetation index (<em>mND</em>), <em>gNDVI</em>, modified red-edge ratio (<em>mSR</em>₇₀₀), carotenoids reflectance indexesⅠ (<em>CRI</em>₅₅₀),<em>CRI</em>₇₀₀ and <em>PRI</em> under 1.6% sea salt concentration was reduced by 42.4%, 43.9%, 32.6%, 21.5%, 47.2%, 49.9% and 58.5%, respectively compared with control. The maximum quantum yield of photosystemⅡ (<em>F</em>_v<em>/F</em>_m), quantum yield for electron transport (<em>ΦE</em>_o), electron transport flux per reaction center (<em>ET</em>_o<em>/RC</em>), density of reaction center (QA-reducing PSⅡ reaction centers) (<em>RC/CS</em>) and performance index on absorption basis (<em>PI</em>_ABS) under 1.6% sea salt concentration was reduced by 50.8%, 28.6%, 21.7%, 52.1%, and 92.3% respectively while the absorption flux per reaction center (<em>ABS/RC</em>) increased 96.9% compared with control. The above results showed that high salt stress inhibited the synthesis of the chlorophyll, reduced the absorption of the light energy, resulted in light inhibition and the damage of the acceptor side from PSⅡ, reaction center degradation or inactivation, and inhibited directly growth and development of bamboo. While under low salt stress, the salt tolerance of bamboo was improved by increasing chlorophyll content, light absorption, <em>F</em>_v/<em>F</em>_m, <em>ΦE</em>_o, <em>ET</em>_o/<em>RC</em>, <em>RC</em>/<em>CS</em> and <em>PI</em>_ABS.

Photosynthetic responses of the heteromorphic leaves in Populus euphratica to light intensity and CO&lt;inf&gt;2&lt;/inf&gt; concentration

Aims Populus euphratica is an important tree species and its leaf shape changes along the growth stages. Adult trees commonly comprise polymorphic leaves, including lanceolate, oval and serrated broad-oval leaves. Our objective were to elucidate the ecophysiological mechanisms of P. euphratica adapting to high temperature and strong light environment and its survival strategy by comparing photosynthetic efficiency and chlorophyll fluorescence parameters in heteromorphic leaves in an extremely arid desert area, and to explore the causes of changes in leaf shape in P. euphratica, in order to provide a scientific basis for the protection of desert P. euphratica forests. Methods Individuals with 10 cm diameter at breast height from a planted P. euphratica forest were selected. Measurements were made on the parameters of gas changes and chlorophyll fluorescence of three different leaf shapes on branches at the similar height using a LI-6400 Portable Photosynthesis System and a PAM-2100 chlorophyll fluorometer. The light/CO2 response curves of net photosynthetic rate(Pn) and rapid light curves of chlorophyll fluorescence in heteromorphic leaves were fitted and analyzed. Important findings The light and CO2 response curves, rapid light curves of the three different leaf shapes in P. euphratica were better fitted by the modified rectangular hyperbola models, and the model values of key photosynthetic parameters were very close to the measured data. There were significant differences in the light responses, biochemical parameters and the parameters of rapid light curves among the oval, serrated broad-oval leaves and lanceolate leaves, but the heteromorphic leaves did not significantly differ in carbon assimilationefficiency. The maximum net photosynthetic rate(Pnmax) of the heteromorphic leaves under saturated intercellular CO2 concentration was higher than under saturated irradiance, indicating that photosynthetic efficiency was limited to the great extent by CO2 supply and regeneration rate of ribulose biphosphate(RuBP). Initial quantum yield(α), initial carboxylation efficiency(CE), Pnmax, photosynthetic capacity(Amax), maximum carboxylation rate(Vcmax) were greater in the oval and serrated broad-oval leaves than in the lanceolate leaves; the serrated broad-oval leaves had the highest light saturation point(LSP), photosynthetic electron transportation rate(ETRmax) and rate of photorespiration(Rp), whereas the lanceolate leaves had the lowest light compensation point(LCP), LSP, α and CE. All the results above indicate that the serrated broad-oval leaves having greater resistance to strong light and higher Rp may be an important mechanism for dissipating excessive light energy and protecting the photosynthetic apparatus from light damage. In contrast, the oval leaves had higher values in α, CE, triose-phosphate utilization efficiency(TPU), PSII actual photochemical efficiency(ΦPSII), leaf nitrogen allocation strategy and low LCP and therefore could maintain high photosynthetic rate in extremely arid areas. The lanceolate leaves had the lowest values in Pn, ΦPSII, and ETR, which would be difficult to meet the individual growth demand because of the low production of photosynthate, and their number declined with growth and distributed mainly toward the lower tree crowns.

紫花苜蓿对牛角花齿蓟马为害的光合生理响应

PDF HTML阅读 XML下载 导出引用 引用提醒 紫花苜蓿对牛角花齿蓟马为害的光合生理响应 DOI: 10.5846/stxb201301250157 作者: 作者单位: 甘肃农业大学 草业学院,甘肃农业大学 草业学院,甘肃农业大学 草业学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家现代牧草产业技术体系建设专项（CARA-35）；教育部高校博士学科点基金项目（20106202110003）；国家自然科学基金项目（31260579） Photosynthetic physiological response of Medicago sativa to Odontothrips loti damage Author: Affiliation: College of Grassland Science, Gansu Agricultural University,College of Grassland Science, Gansu Agricultural University, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为了探索紫花（Medicago sativa L.）苜蓿对优势种害虫——牛角花齿蓟马（Odontothrips loti Haliday）为害的光合生理响应机制，揭示苜蓿对牛角花齿蓟马为害的补偿机制，以抗蓟马苜蓿无性系R-1和感蓟马苜蓿无性系I-1为材料，测定不同虫口密度牛角花齿蓟马为害后R-1、I-1无性系气体交换参数、叶绿素荧光诱导动力学参数的变化。结果表明：随着牛角花齿蓟马虫口密度的增加，R-1无性系叶绿素含量先升高后降低，I-1无性系叶绿素含量降低，R-1、I-1无性系的净光合速率（Pn）和水分利用效率（WUE）降低，胞间CO2浓度（Ci）、气孔导度（Gs）和蒸腾速率（Tr）升高；在相同虫口密度下，R-1无性系的叶绿素含量、Pn、WUE均高于I-1无性系。随着虫口密度的增加，R-1、I-1无性系的初始荧光（F0）升高，PSⅡ实际光合效率（ФPSⅡ）、非光化学淬灭系数（NPQ）、光化学淬灭系数（qP）、PSⅡ潜在活性（Fv/F0）和PSⅡ原初光能转化效率（Fv/Fm）均降低；在相同虫口密度下，R-1无性系的F0低于I-1无性系，R-1无性系的ФPSⅡ、qP、Fv/F0和Fv/Fm均高于I-1无性系。从各个指标的变化幅度来看，随着虫口密度的增加，R-1无性系气体交换参数和绿素荧光动力学参数的增幅、降幅均小于I-1无性系。说明牛角花齿蓟马为害造成了紫花苜蓿PSⅡ反应中心受损，使得紫花苜蓿对光能的利用能力下降，光合效率降低。但在低虫口密度（1、3头/枝条）下，R-1无性系具有较高的光合效率，光合补偿效应显著大于I-1无性系，说明R-1无性系对牛角花齿蓟马为害具有较强的抗性。 Abstract:Plant photosynthetic capability usually changes after damage by a herbivorous pest. Photosynthetic compensation is the physiological response of the plant to pest damage with the level of compensation varying with the change in pest damage. This paper explores the photosynthetic response mechanism of alfalfa to the dominant insect-Odontothrips loti -and explains the compensatory mechanism of alfalfa to thrip damage. The thrip resistant clone, R-1 and susceptible clone, I-1 were used to investigate the gas exchange and chlorophyll fluorescence parameter changes under different insect densities (0, 1, 3, 5, and 7 per branch, respectively), Photosynthesis equipment, GFS-3000 (Walz,Germany) and modulated chlorophyll fluorometer imaging-PAM (Walz,Germany) were used. For the 7 per branch treatment, the results indicate that the chlorophyll content of R-1 initially increased and then decreased, while the chlorophyll content of I-1 decreased. For R-1, the chlorophyll content was 11.32% lower than CK (0 thrip per branch), and for the 3, 5, and 7 per branch treatments of I-1, the chlorophyll contents were 14.05%, 22.02% and 26.27% lower than CK, respectively. For both R-1 and I-1, the net photosynthetic rate (Pn) and water use efficiency (WUE) decreased, while the intracellular concentration of CO2 (Ci), stomatal conductance (Gs) and transpiration rate (Tr) increased. For R-1, the Pn of 3, 5, and 7 per branch treatments were 6.98%, 19.03% and 20.11% lower than CK, and the WUE of all the treatments were 16.32%, 23.95%, 37.12% and 45.89% lower than CK. For I-1 treatments, the Pn of all the treatments were 5.38%, 8.77%, 22.47% and 35.66% lower than CK, and the WUE were 25.23%, 31.05%, 45.78% and 61.81% lower than CK, respectively. The chlorophyll content, WUE and Pn of R-1 were all greater than I-1 under the same insect density. As insect density increased, the initial fluorescence (F0) increased, which for the R-1 clone resulted in F0 for 5 and 7 per branch treatments of 6.99% and 9.13% higher than CK, respectively. For the I-1 clone, all the treatments were 2.81%, 6.45%, 12.36% and 14.93% higher than CK, respectively. The actual photosynthetic efficiency (ФPSⅡ) of PSⅡ, non-photochemical quenching coefficient (NPQ), photochemical quenching coefficient (qP), potential activity (Fv/F0) of PSⅡ and original light transformation efficiency (ФPSⅡ) of PSⅡ decreased for both R-1 and I-1. Among which the Fv/F0 of 3, 5 and 7 per branch treatments for the R-1 clone were 5.07%, 16.74% and 21.19% lower than CK and the Fv/Fm of 5 and 7 per branch treatments were 3.50% and 4.63% lower than CK, respectively. For the I-1 clone, Fv/F0 of all the treatments were 8.24%, 13.68%, 22.88% and 28.04% lower than CK, and the Fv/Fm were 1.67%, 2.91%, 5.31% and 6.86% lower than CK, respectively. Under the same insect density, R-1 was found to have a lower F0 but higher ФPSⅡ, qP, Fv/F0 and Fv/Fm, when compared with I-1. As a rule, the gas exchange parameter and chlorophyll fluorescence kinetic parameter of R-1 fluctuated less than I-1, indicating that the thrip's rasping-sucking damage had injured the chloroplast tissue of alfalfa leaves, decreased the anabolism of chlorophyll, aggravated leaf transpiration, decreased WUE, and therefore affected alfalfa photosynthesis. The thylakoid membrane in the alfalfa leaves and PSⅡ reaction center were injured, which decreased the absorption of light energy, and impeded the photosynthetic electron transport, reducing its photosynthetic efficiency. While under lower insect densities (1 per branch, 3 per branch), the R-1 clone had a stronger capability to adjust for water loss and usage after being damaged by the thrip, demonstrating adaptability to the thrip's rasping-sucking damage through internal regulation, lowering PSⅡ damage, with higher absorption, transmission, use and conversion efficiency. Therefore the R-1 clone was found to have a stronger resistance to thrips when compared with the I-1 clone, as expressed by the higher photosynthetic efficiency and photosynthetic compensation effect. 参考文献 相似文献 引证文献

In-situ optical and acoustical measurements of the buoyant cyanobacterium p. Rubescens: spatial and temporal distribution patterns.

Optical (fluorescence) and acoustic in-situ techniques were tested in their ability to measure the spatial and temporal distribution of plankton in freshwater ecosystems with special emphasis on the harmful and buoyant cyanobacterium P. rubescens. Fluorescence was measured with the multi-spectral FluoroProbe (Moldaenke FluoroProbe, MFP) and a Seapoint Chlorophyll Fluorometer (SCF). In-situ measurements of the acoustic backscatter strength (ABS) were conducted with three different acoustic devices covering multiple acoustic frequencies (614 kHz ADCP, 2 MHz ADP, and 6 MHz ADV). The MFP provides a fast and reliable technique to measure fluorescence at different wavelengths in situ, which allows discriminating between P. rubescens and other phytoplankton species. All three acoustic devices are sensitive to P. rubescens even if other scatterers, e.g., zooplankton or suspended sediment, are present in the water column, because P. rubescens containing gas vesicles has a strong density difference and hence acoustic contrast to the ambient water and other scatterers. After calibration, the combination of optical and acoustical measurements not only allows qualitative and quantitative observation of P. rubescens, but also distinction between P. rubescens, other phytoplankton, and zooplankton. As the measuring devices can sample in situ at high rates they enable assessment of plankton distributions at high temporal (minutes) and spatial (decimeters) resolution or covering large temporal (seasonal) and spatial (basin scale) scales.

Effects of habitat light conditions on the excitation quenching pathways in desiccating Haberlea rhodopensis leaves: An Intelligent FluoroSensor study

Resurrection plants can survive dehydration to air-dry state, thus they are excellent models of understanding drought and dehydration tolerance mechanisms. Haberlea rhodopensis, a chlorophyll-retaining resurrection plant, can survive desiccation to relative water content below 10%. Leaves, detached from plants of sun and shade habitats, were moderately (∼50%) dehydrated in darkness. During desiccation, chlorophyll a fluorescence was detected by the recently innovated wireless Intelligent FluoroSensor (IFS) chlorophyll fluorometer, working with three different detectors: a pulse-amplitude-modulated (PAM) broadband channel and two channels to measure non-modulated red and far-red fluorescence. No change in area-based chlorophyll content of leaves was observed. The maximal quantum efficiency of photosystem II decreased gradually in both shade and sun leaves. Shade leaves could not increase antennae-based quenching, thus inactivated photosystem II took part in quenching of excess irradiation. Sun leaves seemed to be pre-adapted to quench excess light as they established an intensive increase in antennae-based non-photochemical quenching parallel to desiccation. The higher far-red to red antennae-based quenching may sign light-harvesting complex reorganization. Thus, compared to PAM, IFS chlorophyll fluorometer has additional benefits including (i) parallel estimation of changes in the Chl content and (ii) prediction of underlying processes of excitation energy quenching.

Comparison of chlorophyll in the Red Sea derived from MODIS-Aqua and in vivo fluorescence

The Red Sea is a unique marine environment but relatively unexplored. The only available long-term biological dataset at large spatial and temporal scales is remotely-sensed chlorophyll observations (an index of phytoplankton biomass) derived using satellite measurements of ocean colour. Yet such observations have rarely been compared with in situ data in the Red Sea. In this paper, satellite chlorophyll estimates in the Red Sea from the MODIS instrument onboard the Aqua satellite are compared with three recent cruises of in vivo fluorometric chlorophyll measurements taken in October 2008, March 2010 and September to October 2011. The performance of the standard NASA chlorophyll algorithm, and that of a new band-difference algorithm, is found to be comparable with other oligotrophic regions in the global ocean, supporting the use of satellite ocean colour in the Red Sea. However, given the unique environmental conditions of the study area, regional algorithms are likely to fare better and this is demonstrated through a simple adjustment to the band-difference algorithm.

Excitation kinetics of chlorophyll fluorescence during light-induced greening and establishment of photosynthetic activity of barley seedlings

Excitation kinetics based on feedback regulation of chlorophyll (Chl) fluorescence of leaves measured with the chlorophyll fluorometer, FluoroMeter Modul (FMM), are presented. These kinetics showed the variation of excitation light (laser power, LP) regulated by the feedback mechanism of the FMM, an intelligent Chl fluorometer with embedded computer, which maintains the fluorescence response constant during the 300-s transient between the dark- and lightadapted state of photosynthesis. The excitation kinetics exhibited a rise of LP with different time constants and fluctuations leading to a type of steady state. The variation of excitation kinetics were demonstrated using the example of primary leaves of etiolated barley seedlings (Hordeum vulgare L. cv. Barke) during 48 h of greening in the light with gradual accumulation of Chl and development of photosynthetic activity. The excitation kinetics showed a fast rise followed by a short plateau at ca. 30 s and finally a slow constant increase up to 300 s. Only in the case of 2 h of greening in the light, the curve reached a stable steady state after 75 s followed by a slight decline. The final LP value (at 300 s of illumination) increased up to 12 h of greening and decreased with longer greening times. The active feedback mechanism of the FMM adjusted the excitation light during the measurement to the actual photosynthetic capacity of the individual leaf sample. In this way, the illumination with excessive light was avoided. The novel excitation kinetics can be used to characterize health, stress, disease, and/or product quality of plant material.

Wavelength-dependent photodamage to Chlorella investigated with a new type of multi-color PAM chlorophyll fluorometer

A new type of multi-color PAM chlorophyll fluorometer (Schreiber et al. 2012) was applied for measurements of photodamage to photosystem II (PS II) in optically thin suspensions of Chlorella (200 μg Chl l(-1)) in the presence of 1 mM lincomycin. An action spectrum of the relative decrease of F(v)/F(m) in the 440-625 nm range was measured, which not only showed the expected high activity in the blue, but at a lower level also substantial activity above 540 nm. With the same dilute suspension, a PS II absorption spectrum was derived via measurements of the O-I(1) rise kinetics induced by differently colored strong light at defined incident quantum flux densities. After normalization of the two spectra at 625 nm, the relative extent of photodamage at 440-480 nm proved substantially higher than absorption by PS II, whereas the two spectra were close to identical in the 540-625 nm range. Hence, overall photodamage to PS II appears to consist of two components, one of which is due to light absorbed by PS II pigments, whereas the other one is likely to involve direct light absorption by Mn in the oxygen-evolving complex (Hakala et al. Biochim Biophys Acta 1706:68-80, 2005). Based on this rationale, an action spectrum of the Mn mechanism of photodamage was deconvoluted from the overall action spectrum, declining steeply above 480 nm. An almost identical Mn-spectrum was derived by another approach with the PAR of the various colors being adjusted to give identical rates of PS II turnover, PAR (II). The tentative, basic assumption of negligibly small contribution of the Mn mechanism to photodamage above 540 nm was supported by supplementary measurements using an external 665 nm lamp. 665 nm not only gave about two times PS II turnover as compared to 625 nm, but also about two times photodamage.

Effects of bisphenol A on growth, photosynthesis and chlorophyll fluorescence in above-ground organs of soybean seedlings

Bisphenol A (BPA) is a representatively endocrine disruptor, which shows a highly toxic effect on life system. Its potential toxicity on plants that are the primary producers in earth’s ecosystem is not well documented. Here, the effects of BPA on the growth, photosynthesis, content of chlorophyll (Chl), initial fluorescence (F0), maximal photochemical efficiency (Fv/Fm), effective quantum yield of photosystem II (ΦPSII) and photosynthetic electron transport rate (ETR) in soybean seedlings were investigated by using gas exchange measurement system and chlorophyll fluorometer to understand the toxic effect of BPA on plants. It was found that when soybean seedlings were treated with BPA at the low concentration (1.5mgL−1), the growth indices (the plant height, fresh and dry weights of stems, fresh and dry weights of leaves, leaf area) were increased obviously compared with those of the control, which was not related with the photosynthesis, the content of Chl and the chlorophyll fluorescence. When soybean seedlings were treated with BPA at the high concentrations (7.0, 12.0, 17.2 and 50.0mgL−1), the growth indices, net photosynthetic rate, the content of chlorophyll, Fv/Fm, ΦPSII, ETR were decreased, while F0 was increased, compared with those of the control. Obviously, BPA at the high concentrations showed the toxic effect on soybean seedlings. The results from correlation analysis indicated that the inhibition in the growth of soybean seedlings treated with BPA was related to the decrease in photosynthesis because of the decrease in the content of chlorophyll and the change in chlorophyll fluorescence.

Assessment of wavelength-dependent parameters of photosynthetic electron transport with a new type of multi-color PAM chlorophyll fluorometer

Technical features of a novel multi-color pulse amplitude modulation (PAM) chlorophyll fluorometer as well as the applied methodology and some typical examples of its practical application with suspensions of Chlorella vulgaris and Synechocystis PCC 6803 are presented. The multi-color PAM provides six colors of pulse-modulated measuring light (peak-wavelengths at 400, 440, 480, 540, 590, and 625 nm) and six colors of actinic light (AL), peaking at 440, 480, 540, 590, 625 and 420–640 nm (white). The AL can be used for continuous illumination, maximal intensity single-turnover pulses, high intensity multiple-turnover pulses, and saturation pulses. In addition, far-red light (peaking at 725 nm) is provided for preferential excitation of PS I. Analysis of the fast fluorescence rise kinetics in saturating light allows determination of the wavelength- and sample-specific functional absorption cross section of PS II, Sigma(II)λ, with which the PS II turnover rate at a given incident photosynthetically active radiation (PAR) can be calculated. Sigma(II)λ is defined for a quasi-dark reference state, thus differing from σPSII used in limnology and oceanography. Vastly different light response curves for Chlorella are obtained with light of different colors, when the usual PAR-scale is used. Based on Sigma(II)λ the PAR, in units of μmol quanta/(m2 s), can be converted into PAR(II) (in units of PS II effective quanta/s) and a fluorescence-based electron transport rate ETR(II) = PAR(II) · Y(II)/Y(II)max can be defined. ETR(II) in contrast to rel.ETR qualifies for quantifying the absolute rate of electron transport in optically thin suspensions of unicellular algae and cyanobacteria. Plots of ETR(II) versus PAR(II) for Chlorella are almost identical using either 440 or 625 nm light. Photoinhibition data are presented suggesting that a lower value of ETR(II)max with 440 nm possibly reflects photodamage via absorption by the Mn-cluster of the oxygen-evolving complex.