叶绿素荧光分析技术在林木培育中的应用

叶绿素荧光分析技术是近年来在光合作用机理研究中发展起来的一种新型、快速、简便、精确且整体无损伤检测植物光合作用生理状况的新技术.叶绿素荧光信号包含了十分丰富的光合作用过程变化的信息,因而被视为植物光合作用与环境关系的内在探针.该项技术在农业、园艺等方面已得到广泛应用,而在林木培育中的应用较少.本文介绍了叶绿素荧光分析相关参数及其生物学意义,总结了国内外关于叶绿素荧光分析技术在林木栽培、林木逆境生理等方面的应用,并对该技术在林木培育中的应用提出一些初步建议.     

用叶绿素荧光分析技术鉴定植物抗寒性的剖析

在分析叶绿素荧光技术原理的基础上,从低温条件下叶绿素荧光参数的变化与处理温度、季节的关系、叶绿素荧光参数的变化与其它抗寒指标的相关性以及可用于筛选与鉴定抗寒植物的荧光参数3个方面介绍这一技术在抗寒植物筛选与鉴定中的应用现状,并指出这一技术的可取之处和存在问题。     

盐胁迫对植物叶绿素荧光影响的研究进展

盐胁迫是制约植物生长发育的主要非生物胁迫之一, 研究植物的耐盐机理对开发和有效利用盐碱地有重要的意义。叶绿素荧光动力技术作为研究植物光合生理状况及植物与逆境胁迫关系的理想方法, 可表明外界胁迫环境对植物光合器官的伤害程度。通过总结性阐述盐胁迫对植物叶绿素荧光的影响, 分别从盐分类型、植物类型、光照强度以及盐旱交互作用等方面分析了植物叶绿素荧光对盐胁迫的响应, 进而反映盐胁迫对植物光合能力的影响程度, 并提出增强植物抗盐性的途径, 包括施加外源物质、利用转基因技术、真菌的协同效应和培育耐盐品种。最后对叶绿素荧光动力技术在抗盐胁迫的运用前景进行了展望, 提出了当前研究需要解决的问题, 旨在为提高植物耐盐能力提供一定的理论依据。     

荧光显微分析技术在植物细胞学研究中的应用

论述了在植物细胞学研究中应用荧光显微分析技术时常用的荧光分析仪器以及近年来荧光显微分析技术在植物细胞学研究中的应用,并对其应用前景进行了展望.     

叶绿素荧光技术在植物环境胁迫研究中的应用

近年来叶绿素荧光技术在植物,包括藻类对各种环境胁迫响应的机理和应用研究中起着越来越重要的作用．本文简述了这方面的部分工作和进展．     

去镁叶绿素置换细菌去镁叶绿素对紫细菌反应中心皮秒荧光的影响

选择597 nm作为激发波长,探测范围为600～900 nm的荧光特性,分析了天然反应中心和两种去镁叶绿素置换的紫细菌反应中心的荧光发射光谱.借助细菌叶绿素、细菌去镁叶绿素和植物去镁叶绿素的荧光光谱,对相关组分进行了归类.实验结果表明选择性地置换细菌去镁叶绿素影响了荧光光谱的组成.在天然反应中心、BpheB置换的反应中心和BpheA,B置换的反应中心中可分别解析到4、3和2个荧光发射组分.研究肯定荧光发射组分与去镁叶绿素的结合存在对应关系.实验还分别在686.4、674.1和681.1 nm处测定了不同反应中心内的原初电子供体P的激发态通过荧光衰减的过程,观测到衰减动力学上的差异.说明去镁叶绿素置换影响了细菌反应中心内激发光能传递和原初光化学反应过程.     

叶绿素荧光主动与被动联合观测应用前景

叶绿素荧光是研究植物光合生理机制、量化植被光合作用时空格局以及准确理解气候变化背景下陆地生态系统生产力的关键。然而, 目前对于叶绿素荧光主动与被动联合观测的研究还较少。该文对比了叶绿素荧光主动观测与被动观测的优缺点, 展示了叶片尺度和冠层尺度主动与被动联合观测的仪器设备组成, 探讨了主动与被动联合观测在探索叶绿体尺度-叶片尺度-冠层尺度能量在光合、荧光以及热耗散中的分配, 阐明叶绿素荧光与总初级生产力的关联机制, 验证星基日光诱导叶绿素荧光, 解译叶绿素荧光光谱形状4个方面的应用前景。综上, 叶绿素荧光的主动与被动联合观测对于揭示各尺度上荧光与光合作用之间的关联机制, 改善全球尺度植被生产力模型至关重要。     

采煤沉陷裂缝区土壤含水量变化对柠条叶片叶绿素荧光的响应

采煤塌陷引起的土壤环境因子的变化对矿区植物生长的影响越来越受到人们的关注,快速叶绿素荧光诱导动力学分析技术被称为植物受胁迫状态的有效探针,能够快速获取胁迫下光系统II光化学活性和电子传递的信息。研究采煤塌陷裂缝区植物叶片叶绿素荧光的变化是揭示煤炭开采塌陷胁迫对植物个体生长影响的关键环节,能为大尺度下采煤沉陷区植物损伤机理研究提供基础。对于黄土高原半干旱矿区,土壤水分无疑是植物生长最重要的限制因素,而植物叶片叶绿素荧光变化采煤塌陷影响下土壤含水量变化的响应如何尚不清楚。为了弄清采煤沉陷裂缝影响下土壤含水量变化对柠条叶片叶绿素荧光响应的影响,选取神东煤田大柳塔矿区52302工作面为实验场地,在分析了采煤塌陷裂缝对土壤含水量的影响的基础上,以生态修复物种柠条为研究对象,对采煤塌陷裂缝区不同土壤含水量下柠条叶片快速叶绿素荧光诱导动力学曲线进行监测。结果显示:(1)由于煤炭井工开采在地表形成大量裂缝,破坏了土体结构,增加了土壤水分的蒸发面,加速了土壤水的散失。土壤水分含量随着与裂缝之间距离的增加而增加,从距离裂缝0 cm到300 cm,土壤平均含水量从5.63%增加到15.07%;(2)裂缝区土壤水分降低,柠条受到干旱胁迫程度加重,叶片快速叶绿素荧光诱导动力学曲线由O—J—I—P变形为O—K—J—I—P曲线。干旱胁迫通过干扰柠条叶片PSII电子供体侧、受体侧以及电子传递链的功能,严重的损害了柠条叶片光合机构的正常功能。     

荧光定量PCR技术在植物研究中的应用

荧光定量PCR技术是近年发展起来的一种用于基因定量分析的PCR方法,自同世以来在基础科学研究、临床诊断、疾病研究及药物研发等领域应用较为广泛.在植物研究方面应用起步较晚,现已开始用于植物基因表达分析、外源基因基因鉴定等方面的研究.介绍了实时荧光定量PCR技术的原理、优缺点和试验中潜在问题和条件的优化,并对其在植物研究中的应用及前景作了探讨.     

烟草腺毛发育过程中叶绿体形态学研究

应用荧光显微技术和电镜技术,对不同发育时期烟草叶面腺毛的叶绿素荧光和叶绿体结构进行了比较研究.结果发现,在腺毛发育初期,腺头细胞叶绿素荧光明显,叶绿体类囊体结构清晰;随着腺头细胞的分裂和生长,叶绿素荧光逐渐增强,叶绿体数目逐渐增多,类囊体发达,嗜锇颗粒产生;在腺毛发育成熟以后,叶绿素荧光减弱,类囊体膜降解,嗜锇颗粒增多;随着腺毛的分泌活动增强,叶绿体完全降解,磷脂双层膜消失,嗜锇颗粒扩散到细胞质中,并最终聚集在细胞质膜附近.     

Artificial leaf aids analysis of chlorophyll fluorescence and P700 absorbance in studies involving microalgae

Measuring chlorophyll fluorescence and P700 absorbance has been widely used to study photosynthesis in both terrestrial plants and algae. However, in order to apply these measurement techniques to study microalgae, a concentrated suspension of algae, which is usually prepared by centrifugation, is required. In this study, instead of using centrifugation, we concentrated microalgae on a nitrocellulose membrane using filtration to create an ‘artificial leaf’ before analysis. Overall, we were able to generate values of the appropriate photosynthetic parameters that were comparable to those obtained when chlorophyll fluorescence and P700 absorbance were measured following centrifugation. There were no statistically significant differences (P > 0.05) between the artificial leaf method and the traditional cuvette method for determining chlorophyll fluorescence or P700 absorbance at appropriate chlorophyll concentrations. We were also able to reduce background noise by using a filter membrane as a carrier. Therefore, an artificial leaf has the potential to be a valuable tool for phycologists interested in studying microalgal photosynthesis by enabling them to eliminate tedious centrifugation steps. In addition, fluorometers commonly used for studying the leaves of higher plants will also be suitable for studying microalgae.     

CO2 uptake and chlorophyll a fluorescence of Suaeda fruticosa grown under diurnal rhythm and after transfer to continuous dark

Photosynthesis Research - Although only 2–4% of absorbed light is emitted as chlorophyll (Chl) a fluorescence, its measurement provides valuable information on photosynthesis of the plant,...     

锰胁迫对垂序商陆光合特性及叶绿素荧光参数的影响

垂序商陆(Phytolacca americana L.)是我国首次发现的锰超富集植物。通过温室营养液培养实验,研究垂序商陆锰耐性与光合特性及叶绿素荧光参数的关系。结果表明,随着生长介质中锰浓度的升高,垂序商陆叶片的叶绿素a、叶绿素b和总叶绿素含量下降,净光合速率(Pn)和气孔导度(Gs)呈下降趋势,而胞间CO2浓度(Ci)却逐渐升高;叶绿素a/b值和蒸腾速率(Tr)在1 000μmol.L-1锰供应水平时达到最大值;叶片PSⅡ的最大量子产量(Fv/Fm)、PSⅡ有效光化学量子产量(EQY)和光合电子传递速率(ETR)呈下降趋势,而光化学淬灭系数(qP)和光合有效辐射(PAR)高于239μmol photons.m-.2s-1下的非光化学淬灭系数(NPQ)在5 000μmol.L-1锰供应水平时达到最大值。因此,垂序商陆在锰胁迫下可能具有一定的光合保护机制。     

A method for measuring whole plant photosynthesis in Arabidopsis thaliana

Measurement of photosynthesis of intact leaves of Arabidopsis thaliana has been prohibitive due to the small leaf size and prostrate growth habit. Because of the widespread use of Arabidopsis for plant science research it is important to have a procedure for accurate, nondestructive measurement of its photosynthesis. We developed and tested a method for analysis of photosynthesis in whole plants of Arabidopsis. Net carbon assimilation and stomatal conductance were measured with an open gas exchange system and photosynthetic oxygen evolution was determined from chlorophyll fluorescence parameters. Individual plants were grown in 50 cubic centimeter tubes that were attached with an air tight seal to an enclosed gas exchange chamber for measurement of carbon dioxide and water exchange by the whole plant. Chlorophyll fluorescence from intact leaves was simultaneously measured with a pulse modulated fluorometer. Photosynthetic CO₂ assimilation and stomatal conductance rates were calculated with established gas exchange procedures and O₂ evolution was determined from chlorophyll fluorescence measurement of Photosystem II yield. Carbon assimilation and oxygen evolution in response to light intensity and ambient CO₂ concentration was measured and is presented here to demonstrate the potential use of this method for investigation of photosynthesis of Arabidopsis plants in controlled environment conditions.     

Excess iron-induced changes in the photosynthetic characteristics of sweet potato

Iron (Fe) is an essential nutrient for plant growth and development. In plant tissues, approximately 80% of Fe is found in photosynthetic cells. This study was carried out to determine the effect of different iron concentrations on the photosynthetic characteristics of sweet potato plants. The fluorescence transient of chlorophyll a (OJIP), chlorophyll index and gas exchange were measured in plants grown for seven days in Hoagland solution containing an iron concentration of 0.45, 0.90, 4.50 or 9.00 mM Fe (as Fe-EDTA). The initial and maximum fluorescence increased in the plants receiving 9.00 mM Fe. In the analysis of the fluorescence kinetic difference, L- and K-bands appeared in all of the treatments, but the amplitude was higher in plants receiving 4.50 or 9.00 mM Fe. In plants grown in 9.00 mM Fe, the parameters of the JIP-Test indicated a better efficiency in the capture, absorption and use of light energy, and although the chlorophyll index was higher, the net photosynthesis was lower. The overall data showed that sweet potato plants subjected to high iron concentrations may not exhibit the toxicity symptoms, but the light reactions of photosynthesis can be affect, which may result in a declining net assimilation rate.     

不同水氮梯度下典型挺水植物叶绿素荧光的响应特性

叶绿素荧光测量分析可以揭示植物叶片光化学效率的变化,已越来越多地应用于植物生态监测。以再生水为主要补给水源的北京门城湖湿地公园为研究区,选取典型湿地挺水植物芦苇(Phragmites australis)、香蒲(Typha angustifolia)和茭白(Zizania latifolia)为研究对象,通过野外测量叶片尺度的叶绿素荧光参数和室内测定对应样点的水体总氮含量指标,研究了再生水补给条件下,不同水氮梯度植物叶绿素荧光的响应特性。结果表明,3种典型挺水植物的初始荧光(Fo)与最大荧光(Fm)随着水体总氮含量的增加呈现上升的趋势;PSII的量子效率(F_v/F_m)与实际量子效率(ΦPSII)受水氮含量的影响先升高,达到15–20 mg·L~(–1)区间时,则与之持平;光化学淬灭(qP)参数则呈现先升高后降低的变化趋势,而非光化学淬灭(NPQ)参数的变化没有明显的规律。当水氮含量为15–20 mg·L~(–1)时,光化学反应减弱,光合作用出现抑制。不同类型植物的荧光参数也有所不同,处于生长期(6月)植物的光合作用显著强于生长成熟期(9月)。     

The usefulness of the chlorophyll fluorescence parameters in harvest prediction in 10 genotypes of winter triticale under optimal growth conditions

The aim of the experiment was to detect differences in the activity of the photosynthetic apparatus in 10 genotypes of winter triticale. Measurements of gas exchange and chlorophyll fluorescence were performed. Among the tested genotypes, the photosynthetic apparatus of Timbo and Piano was the most active, while the photosynthesis of both Babor and Boreas was highly reduced. Additionally, we have found significant correlations between the yield and some parameters of chlorophyll fluorescence and leaf gas exchange. Parameters of chlorophyll fluorescence are useful for estimation of the functional state of the photosynthetic apparatus and could become selection criteria in plant breeding. Moreover, such parameters permit definition of the effectiveness of the utilization of chlorophyll a excitation energy and co‐operation of the light phase reactions, with reactions occurring during the dark phase of photosynthesis.     

Fog interception by Sequoia sempervirens (D. Don) crowns decouples physiology from soil water deficit

Although crown wetting events can increase plant water status, leaf wetting is thought to negatively affect plant carbon balance by depressing photosynthesis and growth. We investigated the influence of crown fog interception on the water and carbon relations of juvenile and mature Sequoia sempervirens trees. Field observations of mature trees indicated that fog interception increased leaf water potential above that of leaves sheltered from fog. Furthermore, observed increases in leaf water potential exceeded the maximum water potential predicted if soil water was the only available water source. Because field observations were limited to two mature trees, we conducted a greenhouse experiment to investigate how fog interception influences plant water status and photosynthesis. Pre-dawn and midday branchlet water potential, leaf gas exchange and chlorophyll fluorescence were measured on S. sempervirens saplings exposed to increasing soil water deficit, with and without overnight canopy fog interception. Sapling fog interception increased leaf water potential and photosynthesis above the control and soil water deficit treatments despite similar dark-acclimated leaf chlorophyll fluorescence. The field observations and greenhouse experiment show that fog interception represents an overlooked flux into the soil–plant–atmosphere continuum that temporarily, but significantly, decouples leaf-level water and carbon relations from soil water availability.     

Indirect suppression of photosynthesis on individual leaves by arthropod herbivory

BACKGROUND: Herbivory reduces leaf area, disrupts the function of leaves, and ultimately alters yield and productivity. Herbivore damage to foliage typically is assessed in the field by measuring the amount of leaf tissue removed and disrupted. This approach assumes the remaining tissues are unaltered, and plant photosynthesis and water balance function normally. However, recent application of thermal and fluorescent imaging technologies revealed that alterations to photosynthesis and transpiration propagate into remaining undamaged leaf tissue. SCOPE AND CONCLUSIONS: This review briefly examines the indirect effects of herbivory on photosynthesis, measured by gas exchange or chlorophyll fluorescence, and identifies four mechanisms contributing to the indirect suppression of photosynthesis in remaining leaf tissues: severed vasculature, altered sink demand, defence-induced autotoxicity, and defence-induced down-regulation of photosynthesis. We review the chlorophyll fluorescence and thermal imaging techniques used to gather layers of spatial data and discuss methods for compiling these layers to achieve greater insight into mechanisms contributing to the indirect suppression of photosynthesis. We also elaborate on a few herbivore-induced gene-regulating mechanisms which modulate photosynthesis and discuss the difficult nature of measuring spatial heterogeneity when combining fluorescence imaging and gas exchange technology. Although few studies have characterized herbivore-induced indirect effects on photosynthesis at the leaf level, an emerging literature suggests that the loss of photosynthetic capacity following herbivory may be greater than direct loss of photosynthetic tissues. Depending on the damage guild, ignoring the indirect suppression of photosynthesis by arthropods and other organisms may lead to an underestimate of their physiological and ecological impacts.