scholarly journals Effects of sea salt stress on reflectance spectrum and chlorophyll fluorescence parameters inBambusa oldhamiileaves

2014 ◽  
Vol 34 (17) ◽  
Author(s):  
吴寿国 WU Shouguo ◽  
余学军 YU Xuejun ◽  
李凯 LI Kai ◽  
蒋玉俭 JIANG Yujian ◽  
张汝民 ZHANG Rumin
Keyword(s):  
Salt Stress ◽  
Chlorophyll Fluorescence ◽  
Reflectance Spectrum ◽  
Sea Salt ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters

Genetic variability and identification of quantitative trait loci affecting plant growth and chlorophyll fluorescence parameters in the model legume Medicago truncatula under control and salt stress conditions

2014 ◽  
Vol 41 (9) ◽  
pp. 983 ◽  
Author(s):  
Sarah Exbrayat ◽  
Georges Bertoni ◽  
Mohamad Reza Naghavie ◽  
Ali Peyghambari ◽  
Mounavar Badri ◽  
...  
Keyword(s):  
Salt Stress ◽  
Chlorophyll Fluorescence ◽  
Quantitative Trait Loci ◽  
Genetic Variability ◽  
Plant Growth ◽  
Medicago Truncatula ◽  
Quantitative Trait ◽  
Chlorophyll Fluorescence Parameters ◽  
Model Legume ◽  
Fluorescence Parameters

Salinity is one of the major stresses that limits crop production worldwide and affects most physiological activities in plants. In order to study the genetic control of salt stress in the model legume Medicago truncatula Gaertn., an experiment was undertaken to determine the genetic variability and to identify quantitative trait loci (QTLs) controlling several traits related to plant growth and physiology in a population of recombinant inbred lines. Shoot and root DW, relative water content, leaf area, chlorophyll content, chlorophyll fluorescence parameters, and Na+ and K+ in shoots and roots were measured. The experiment was carried out with three replications. ANOVA showed a large genetic variation and transgressive segregation for the traits studied, suggesting putative complex tolerance mechanisms. A total of 21 QTLs were detected under control conditions and 19 QTLs were identified under 100 mm salt stress conditions, with three QTLs being common to both situations. The percentage of total phenotypic variance explained by the QTLs ranged from 4.6% to 23.01%. Overlapping QTLs for different traits were also observed, which enables us to discriminate independent traits from linked ones. The results should be helpful information for further functional analysis of salt tolerance in M. truncatula.

scholarly journals Changes in chlorophyll fluorescence parameters during desiccation and osmotic stress of Hassallia antarctica culture

2018 ◽  
Vol 8 (2) ◽  
pp. 198-207
Author(s):  
Marta Campos Alonso
Keyword(s):  
Salt Stress ◽  
Chlorophyll Fluorescence ◽  
Osmotic Stress ◽  
Austral Summer ◽  
Rapid Decline ◽  
Filamentous Cyanobacterium ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
Fluorescence Measurements ◽  
James Ross Island

Hassallia antarctica is a terrestrial cyanobacterium colonizing various habitats in Antarctica such as soil surface, microbiological mats and seepages. H. antarctica represents one of the cyanobacterial species forming biodiversity of terrestrial autotrophs of James Ross Island, Antarctica. It is a filamentous cyanobacterium composing blackish fasciculated clusters thanks to false branching. In our study, sensitivity of the species to dehydration and salt stress was studied. We used H. antarctica culture (CCALA 956) grown on Z liquid medium. Clusters of H. antarctica were placed on wet filter paper and dried naturally at 5°C. During gradual dehydration, relative water content (RWC) was evaluated gravimetrically simultaneously with chlorophyll fluorescence measurements. Slow Kautsky kinetics and the chlorophyll fluorescence parameters (FV/FM, ФPSII) were used to assess dehydration-related decrease in primary photosynthetic processes. It was found that H. antarctica, contrastingly to other terrestrial cyanobacteria from polar habitats, was not able to maintain photosynthetic processes at RWCs as low as 20%. Even during initial phase of dehydration (RWC of 95%) rapid decline in FV/FM occured. Resistance of H. antarctica to osmotic stress was studied by time courses of the chlorophyll fluorescence parameter in response to 3.0, 0.3, and 0.03 M NaCl solution. Both shape of slow Kautsky kinetics and numeric values of chlorophyll fluorescence parameters were affected by osmotic stress. While full inhibitory effect was apparent in 3.0 M NaCl treatment immediately, the salt stress-induced decline in chlorophyll fluorescence parameters was observed at 0.03 M NaCl even after 8 hours of exposition. It was, therefore, concluded that H. antarctica exhibited high resistance to osmotic stress which may help the species to cope with repetitive dehydration events that happen in the field during austral summer season in Antarctica, James Ross Island in particular.

scholarly journals Differential responses of ribulose-1,5-bisphosphate carboxylase/oxygenase activities of two Vigna unguiculata cultivars to salt stress

2005 ◽  
Vol 17 (2) ◽  
pp. 207-212 ◽  
Author(s):  
Maria Erivalda Farias de Aragão ◽  
Marjorie Moreira Guedes ◽  
Maria de Lourdes Oliveira Otoch ◽  
Maria Izabel Florindo Guedes ◽  
Dirce Fernandes de Melo ◽  
...  
Keyword(s):  
Salt Stress ◽  
Chlorophyll Fluorescence ◽  
Chlorophyll Content ◽  
Vigna Unguiculata ◽  
Shoot Growth ◽  
Bisphosphate Carboxylase ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
Root And Shoot Growth ◽  
Specific Activities

Vita 3 and Vita 5 are two Vigna unguiculata cultivars that differ in their capacities for survival in saline environments; Vita 3 is more tolerant and Vita 5 more sensitive. Both cultivars were submitted to salt stress with 0.1 M NaCl. After 8 days, root and shoot growth from both cultivars was reduced but reduction was more pronounced in Vita 5. Furthermore, leaf area was also reduced in this cultivar. Chlorophyll content and chlorophyll fluorescence parameters were not affected by salt stress, but the specific activities of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) decreased in Vita 3 and increased in Vita 5. The use of immunological techniques also revealed that the Rubisco content from Vita 3 decreased while that of Vita 5 increased. The discussion of these results is aimed at reaching a better understanding of the differences between these cultivars in relation to salt stress.

Photoinduced toxicity of fluoranthene on primary processes of photosynthesis in lichens

2006 ◽  
Vol 39 (1) ◽  
pp. 91-100 ◽  
Author(s):  
Marie KUMMEROVÁ ◽  
štěpán ZEZULKA ◽  
Jana KRULOVÁ ◽  
Jan TŘÍSKA
Keyword(s):  
Chlorophyll Fluorescence ◽  
Bioconcentration Factor ◽  
Lichen Species ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
Photochemical Processes ◽  
Symbiotic Algae ◽  
Lasallia Pustulata ◽  
Photoinduced Toxicity ◽  
Umbilicaria Hirsuta

The effect of increasing concentrations (0·01, 0·1, 1 and 5 mg l−1) of intact (FLT) and photo-modified (phFLT) fluoranthene and the duration of exposure (1, 2, 3, 5 and 7 days) on the chlorophyll fluorescence parameters (F0, FV/FM, and ΦII) of symbiotic algae in the thalli of two foliose lichens Lasallia pustulata and Umbilicaria hirsuta was investigated. In addition the FLT concentration in thalli of both lichen species was determined and a bioconcentration factor (BCF) was calculated. The results obtained demonstrated that the concentrations of FLT and especially phFLT (1 and 5 mg l−1) applied affected primary photochemical processes of photosynthesis in the algae of both lichen species. The F0 value increased and the FV/FM and ΦII values decreased. The fluoranthene content in the thallus of both lichen species increased with increasing FLT concentration in the environment.

scholarly journals Photosynthetic response to nitrogen source and different ratios of nitrogen and phosphorus in toxic cyanobacteria, Microcystis aeruginosa FACHB-905

2016 ◽  
Author(s):  
Guotao Peng ◽  
Zhengqiu Fan ◽  
Xiangrong Wang ◽  
Chen Chen
Keyword(s):  
Chlorophyll Fluorescence ◽  
Algal Blooms ◽  
Freshwater Ecosystems ◽  
Cyanobacterial Blooms ◽  
Photosynthetic Response ◽  
Nitrogen And Phosphorus ◽  
Ammonium Toxicity ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
N Assimilation

<p>The frequent outbreak of cyanobacterial blooms has become a worldwide phenomenon in freshwater ecosystems. Studies have elucidated the close relationship between harmful algal blooms and nutrient contents, including the loading of nitrogen and the ratios of nitrogen (N) and phosphorus (P). In this study, the effect of inorganic (nitrate and ammonium) and organic (urea) nitrogen at varied N/P ratios on the <em>Microcystis</em> <em>aeruginosa</em> FACHB-905 accumulation and photosynthesis was investigated.  The optimal NO<sub>3</sub>/P in this study were 30~50 indicated by the cell abundance (4.1×10<sup>6</sup>/mL), pigment concentration (chlorophyll a 3.1 mg/L,  phycocyanin 8.3mg/L), and chlorophyll fluorescence parameters (<em>rETR</em>, <em>E<sub>k</sub>, α, φPSII</em> and <em>F<sub>v</sub>/F<sub>m</sub> </em>values), while too high NO<sub>3</sub>-N (N/P=100:1) would cause an intracellular nitrate inhibition, leading to a decrease of photosynthetic activity. In addition, low concentration of NH<sub>4</sub>-N (N/P=4:1) would favor the <em>M. aeruginosa </em>growth and photosynthesis, and high NH<sub>4</sub>/P ratio (&gt;16) would rise the ammonium toxicity of algal cells and affect the N assimilation. In urea treatments, <em>M. aeruginosa </em>responded similarly to the NH<sub>4</sub>-N treatments both in growth curves and pigment contents, and the favorable N/P ratio was between 16~30, suggested by the chlorophyll fluorescence parameters. The results demonstrated that the various chemical forms of N and N/P ratios have a significant impact on <em>Microcystis</em> abundance and photosynthesis. More work is needed to figure out the mechanism of nitrogen utilization by <em>Microcystis</em> and  the photosynthetic response to nutrient stress at the molecular level.</p>

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