Number of results to display per page
Search Results
3202. Chlorophyll fluorescence and gas exchange measurements in field research: an ecological case study
- Creator:
- Bucher, S. F., Bernhardt-Römermann, M., and Römermann, C.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorofyl, fluorescence, chlorophyll, Aposeris foetida, carbon isotope discrimination, Knautia dipsacifolia, leaf nitrogen, Mercurialis perennis, Trifolium pratense, 2, and 581
- Language:
- Multiple languages
- Description:
- We tested whether cheap and quick chlorophyll (Chl) fluorescence can be used in ecophysiological field studies as proxies for gas-exchange measurements. We measured net photosynthetic rate at saturating irradiance and ambient atmospheric CO2 concentrations (PNsat), maximum carboxylation rate (Vcmax), maximum quantum yield of PSII (Fv/Fm), the performance index (PIabs), leaf nitrogen (Narea), and carbon isotope discrimination (Δ13C) within four herbaceous species along two elevational gradients. We analysed the relationship between Chl fluorescence and gas-exchange parameters and their link to indirect assessment of plant performance via ecophysiological traits. Fv/Fm showed no relationship to PNsat and only weak relationships to Vcmax. PIabs was positively related to PNsat and Vcmax. PIabs, PNsat, and Vcmax were positively associated with Narea and negatively to Δ13C, whereas Fv/Fm showed no relationship to Narea and a positive to Δ13C. Thus, PIabs might be suitable to characterize the photosynthetic activity when aiming on large numbers of samples., S. F. Bucher, M. Bernhardt-Römermann, C. Römermann., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3203. Chlorophyll fluorescence characteristics and the growth response of Elaeocarpus glabripetalus to simulated acid rain
- Creator:
- Liu, M. H., Yi, L. T., Yu, S. Q., Yu, F., and Yin, X. M.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, kyselé deště, photosynthesis, acid rain, Čína, China, acid stress, growth adaptability, photosynthetic efficiency, Elaeocarpus glabripetalus, 2, and 581
- Language:
- Multiple languages
- Description:
- Acid rain causes damages to forest ecosystems. Here, we reported that acid rain could promote plant growth. From 2006 to 2009, one-year-old Elaeocarpus glabripetalus seedlings were sprayed with simulated acid rain (AR) (pH 2.5, 4.0, and 5.6). The maximum quantum yield efficiency of PSII and the actual photochemical quantum efficiency of PSII increased with rising AR acidity, which facilitated chlorophyll fluorescence and plant growth, as shown by a declining minimal fluorescence yield of dark-adapted state with little damage to the PSII reaction center. After the second experimental year, the plant height and ground diameter were greater at pH 2.5 than those found at pH 4.0 and 5.6. This showed the positive effects of AR on the seedling growth and photosynthesis of E. glabripetalus, revealing that this species exhibited a stronger resistance to acid deposition than some other tree species. This implies that E. glabripetalus is an acid-tolerant species., M.H. Liu, L.T. Yi, S.Q. Yu, F. Yu, X.M. Yin., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3204. Chlorophyll fluorescence emission spectroscopy of oxygenic organisms at 77 K
- Creator:
- Lamb, J. J., Røkke, G., and Hohmann-Marriott, M. F.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fluorescence, nízké teploty, fotosyntéza, low temperatures, photosynthesis, 2, and 581
- Language:
- Multiple languages
- Description:
- Photosynthetic fluorescence emission spectra measurement at the temperature of 77 K (-196°C) is an often-used technique in photosynthesis research. At low temperature, biochemical and physiological processes that modulate fluorescence are mostly abolished, and the fluorescence emission of both PSI and PSII become easily distinguishable. Here we briefly review the history of low-temperature chlorophyll fluorescence methods and the characteristics of the acquired emission spectra in oxygen-producing organisms. We discuss the contribution of different photosynthetic complexes and physiological processes to fluorescence emission at 77 K in cyanobacteria, green algae, heterokont algae, and plants. Furthermore, we describe practical aspects for obtaining and presenting 77 K fluorescence spectra., J. J. Lamb, G. Røkke, M. F. Hohmann-Marriott., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3205. Chlorophyll fluorescence imaging can reflect development of vascular connection in grafting union in some Solanaceae species
- Creator:
- Penella, C., Pina, A., San Bautista, A., López-Galarza, S., and Calatayud, Á.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- obecná botanika, pepper, callus, compatibility, graft, photochemical quenching, vascular connections, 2, and 581
- Language:
- Multiple languages
- Description:
- Graft union development in plants has been studied mainly by destructive methods such as histological studies. The aim of this work was to evaluate whether the chlorophyll fluorescence imaging (CFI) technique is sensitive enough to reflect changes at the cellular level in different Solanaceae grafted plants 30 d after grafting, when both grafted partners were well fused and strong enough in all plant combinations. The pepper cultivar ‘Adige’ was grafted onto different Capsicum spp. accessions typified with different compatibility degrees; eggplant was grafted on Solanum torvum and pepper homografts as compatible unions; pepper was grafted on S. torvum and on tomato as incompatible unions. ‘Adige’/’Adige’ and ‘Adige’/pepper A25 showed a higher maximum quantum efficiency of PSII associated with higher values of actual quantum efficiency of PSII and photochemical quenching as well as with vascular regeneration across the graft interface. Our results highlighted that CFI changes reflected histological observations in grafted Solanaceae plants., C. Penella, A. Pina, A. San Bautista, S. López-Galarza, Á. Calatayud., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3206. Chlorophyll fluorescence in the fleld grown sorghum. Instrument discrepancies
- Creator:
- Corlett, J. E., Jones, H. G., Masojídek, J. M., and Massacci, A.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- Two types of fluorimeter (inductíon and modulated) were employed to compare the intrinsic photosystem 2 efSciency of sun-exposed and shaded flag leaves of two cultivars (ICSV112 and Aralba) of sorghum, in the irrigated and unirrígated fleld plots at Monterotondo, Rome. Generally there was a good correlation between instruments, but for the irrigated sun adapted leaves of both cultivars much larger ratios were recorded with the modulated fluorimeter than with the inductíon one. This discrepancy was attributed to an insufficient flash intensity in the inductíon systém when measuring the healthy leaves adapted to a high irradiance.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3207. Chlorophyll fluorescence upper-to-lower-leaf ratio for determination of irrigation time for Pentas lanceolata
- Creator:
- Wu, C. W., Lee, M. C., Peng, Y. L., Chou, T. Y., Lin, K. H., and Chang, Y. S.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, nondestructive technique, reflectance spectroscopy, rewatering, water status, water stress, 2, and 581
- Language:
- Multiple languages
- Description:
- The objective of this study was to use nondestructive measurements as the precise irrigation indices for potted star cluster (Pentas lanceolata). Drought stress was imposed on plants for 0, 3, 5, 7, 12, and 16 d by withholding water. Measurements were conducted on the third leaf counted from the apex (upper leaves) and on the third leaf from the bottom (lower leaves). Within the range of soil water content (SWC) from 10 to 45%, leaf water potential (WP), SWC, and soil matric potential (SMP), chlorophyll fluorescence, photochemical reflectance index (PRI), adjusted normalized difference vegetation index (aNDVI), and the reflectance (R) at 1950 nm (R1950) were measured. The plants reached the temporary wilting point at -3.87 MPa of leaf WP; the maximal fluorescence yield of the light-adapted state (Fm′) ratio of upper-to-lower leaves was 1.7. When the Fm′ ratio was 1.3, it corresponded to lower-leaf WP < -2.27 MPa, SWC < 21%, SMP < -20 kPa, PRI < 0.0443, aNDVI < 0.0301, and R1950 > 8.904; it was the time to irrigate. In conclusion, the Fm′ ratio of upper-to-lower leaves was shown to be a nondestructive predictor of leaf WP and can be used to estimate irrigation timing., C. W. Wu, M. C. Lee, Y. L. Peng, T. Y. Chou, K. H. Lin, Y. S. Chang., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3208. Chlorophyll fluorescence, yield and yield components of bread wheat affected by phosphate bio-fertilizer, zinc and boron under late-season heat stress
- Creator:
- Eisvand, H. R., Kamaei, H., and Nazarian, F.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, výživa rostlin, photosynthesis, plant nutrition, Triticum aestivum L, 2, and 581
- Language:
- Multiple languages
- Description:
- We examined effects of late-season heat stress (L-SHS) on chlorophyll (Chl) fluorescence parameters and yield of bread wheat as well as roles of phosphate bio-fertilizer (PB-F) and Zn and B to compensate for the likely effects of heat stress. Factors were planting date (21 November and 5 January to coincide with grain filling to L-SHS) as the main factor, no inoculation (control) and inoculation of the seeds with PB-F as the sub-factor, and foliar application of water (control), Zn, B, and Zn + B as 3 L ha-1 as sub-sub factor. Results revealed that L-SHS reduced maximal quantum yield of PSII photochemistry, effective quantum yield of PSII photochemistry, efficiency of PSII in the light-adapted state, and the grain yield. Moreover, L-SHS increased the nonphotochemical quenching. The PB-F mitigated the effects of L-SHS on Chl fluorescence, yield, and yield components. Among nutrients, the combined Zn + B was more effective in reducing the effects of L-SHS than that of Zn and B alone. Nevertheless, there was an interaction between foliar nutrients application and PB-F, suggesting that Zn application alone had a profound influence on improving Chl fluorescence parameters and increased yield in combination with PB-F., H. R. Eisvand, H. Kamaei, F. Nazarian., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3209. Chlorophyll α fluorescence induction: Can just a one-second measurement be used to quantify abiotic stress responses?
- Creator:
- Stirbet, A., Lazár, D., Kromdijk, J., and Govindjee
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- abiotické faktory, abiotic factors, tolerance to stress, JIP-test, Kautsky effect, performance index, 2, and 581
- Language:
- Multiple languages
- Description:
- Chlorophyll (Chl) α fluorescence induction (transient), measured by exposing dark-adapted samples to high light, shows a polyphasic rise, which has been the subject of extensive research over several decades. Several Chl fluorescence parameters based on this transient have been defined, the most widely used being the FV [= (FM-F0)]/FM ratio as a proxy for the maximum quantum yield of PSII photochemistry. However, considerable additional information may be derived from analysis of the shape of the fluorescence transient. In fact, several performance indices (PIs) have been defined, which are suggested to provide information on the structure and function of PSII, as well as on the efficiencies of specific electron transport reactions in the thylakoid membrane. Further, these PIs have been proposed to quantify plant tolerance to stress, such as by high light, drought, high (or low) temperature, or N-deficiency. This is an interesting idea, since the speed of the Chl α fluorescence transient measurement (<1 s) is very suitable for high-throughput phenotyping. In this review, we describe how PIs have been used in the assessment of photosynthetic tolerance to various abiotic stress factors. We synthesize these findings and draw conclusions on the suitability of several PIs in assessing stress responses. Finally, we highlight an alternative method to extract information from fluorescence transients, the Integrated Biomarker Response. This method has been developed to define multi-parametric indices in other scientific fields (e.g., ecology), and may be used to combine Chl α fluorescence data with other proxies characterizing CO2 assimilation, or even growth or grain yield, allowing a more holistic assessment of plant performance., A. Stirbet, D. Lazár, J. Kromdijk, Govindjee., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3210. Chlorophyllase activity: effects of heavy metals and calcium
- Creator:
- Abdel-Basset, R., Issa, A.A., and Adam, M.S.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- Cd2+, Pb2+, Kirchneriella lunaris, Co2+, chlorophylls a and &, and Chlorella fusca
- Language:
- Multiple languages
- Description:
- Chlorophyllase (Chlase) actívity measured as the in vitro degradation of chlorophyll (Chl) was variably enhanced by various heavy metals (Cd2+, Pb2+, Mn2+, Co^"*", Ni2+ and their mixture). The en2yme actívity on Chl a was higher than that on Chl b. Chlase isolated from Chlorella fusca oř Kirchneriella lunaris responded differently to the heavy metals. The inclusion of Ca2+ in the assay media affected the enzyme actívity. While some concentrations were stimulatory, others were inhibitory depending on partícular heavy metal, the algal species, and the Chl a oř b.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public