Light Adaptation and Senescence of the Photosynthetic Apparatus. Changes in Pigment Composition, Chlorophyll Fluorescence Parameters and Photosynthetic Activity

Author(s):  
Hartmut K. Lichtenthaler ◽  
Fatbardha Babani
2013 ◽  
Vol 85 (2) ◽  
pp. 665-670 ◽  
Author(s):  
DANIEL GONZALEZ-MENDOZA ◽  
FRANCISCO ESPADAS y GIL ◽  
FERNANDO ESCOBOZA-GARCIA ◽  
JORGE M. SANTAMARIA ◽  
OMAR ZAPATA-PEREZ

The effects of copper toxicity on the photosynthetic activities of Avicennia germinans was investigated using two CuSO4 concentrations (0.062 and 0.33 M) added in Hoagland's solution in an aerated hydroponic system. Photosynthesis and chlorophyll fluorescence were measured after 30 h of copper stress. Results obtained in this study show that increasing levels of Cu+2 of 0.062 and 0.33 M Cu+2 resulted in a general reduction of the stomatal conductance (28 and 18%, respectively) and 100% of inhibition of net photosynthesis. Additionally, at these concentrations of Cu+2, reductions of chlorophyll fluorescence parameters were also observed. These changes suggested that the photosynthetic apparatus of Avicennia germinans was the primary target of the Cu+2 action. It is concluded that Cu+2 ions causes a drastic decline in photosynthetic gas exchange and Chlorophyll fluorescence parameters in A. germinans leaves.


2020 ◽  
Author(s):  
Yanling Zheng ◽  
Meng Wang ◽  
Shijun Hu ◽  
Jianrong Wu ◽  
Zhixiang Yu

Abstract Background: Our previous work showed that freezing tolerance of Cycas panzhihuaensis was higher than that of C. bifida. However, the mechanisms underlying the differential freezing tolerance of the two species is not clear. Photosynthesis is one of the most temperature-sensitive processes. Lipids play important roles in membrane structure, signal transduction and energy storage which are closely related to stress response of plants. Hence, the chlorophyll fluorescence parameters and lipid profiles of the two species were characterized to explore the dynamic changes of photosynthetic activity and lipid metabolism following low temperature and subsequent recovery. Results: The photosynthetic activity decreased significantly with the decrease of temperatures in C. bifida, reaching to zero after recovery, which however, was little affected in C. panzhihuaensis. Lipid composition of C. bifida was more affected by cold and freezing treatments than C. panzhihuaensis. Compared to the control, the proportions of all the lipid categories recovered to the original level for C. panzhihuaensis but those of most lipid categories changed significantly for C. bifida after 3 d of recovery. Particularly, the glycerophospholipids and prenol lipids of C. bifida degraded severely during recovery period for C. bifida. The changes of acyl chain length and double bond index (DBI) occurred in more lipid classes immediately after low temperatures in C. panzhihuaensis than those in C. bifida. DBI of the total main membrane lipids of C. panzhihuaensis was significantly higher than that of C. bifida following all the treatments. Conclusions: The results of chlorophyll fluorescence parameters confirmed that the freezing tolerance of C. panzhihuaensis was higher than that of C. bifida. The lipid metabolism of the two species had differential responses to low temperatures. The homeostasis and plastic adjustment of lipid metabolism and the higher level of DBI of the main membrane lipids might contribute to the higher tolerance of C. panzhihuaensis to low temperature.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yanling Zheng ◽  
Yongqiong Yang ◽  
Meng Wang ◽  
Shijun Hu ◽  
Jianrong Wu ◽  
...  

Abstract Background C. panzhihuaensis is more tolerant to freezing than C. bifida but the mechanisms underlying the different freezing tolerance are unclear. Photosynthesis is one of the most temperature-sensitive processes. Lipids play important roles in membrane structure, signal transduction and energy storage, which are closely related to the stress responses of plants. In this study, the chlorophyll fluorescence parameters and lipid profiles of the two species were characterized to explore the changes in photosynthetic activity and lipid metabolism following low-temperature exposure and subsequent recovery. Results Photosynthetic activity significantly decreased in C. bifida with the decrease of temperatures and reached zero after recovery. Photosynthetic activity, however, was little affected in C. panzhihuaensis. The lipid composition of C. bifida was more affected by cold and freezing treatments than C. panzhihuaensis. Compared with the control, the proportions of all the lipid categories recovered to the original level in C. panzhihuaensis, but the proportions of most lipid categories changed significantly in C. bifida after 3 d of recovery. In particular, the glycerophospholipids and prenol lipids degraded severely during the recovery period of C. bifida. Changes in acyl chain length and double bond index (DBI) occurred in more lipid classes immediately after low-temperature exposure in C. panzhihuaensis compare with those in C. bifida. DBI of the total main membrane lipids of C. panzhihuaensis was significantly higher than that of C. bifida following all temperature treatments. Conclusions The results of chlorophyll fluorescence parameters confirmed that the freezing tolerance of C. panzhihuaensis was greater than that of C. bifida. The lipid metabolism of the two species had differential responses to low temperatures. The homeostasis and plastic adjustment of lipid metabolism and the higher level of DBI of the main membrane lipids may contribute to the greater tolerance of C. panzhihuaensis to low temperatures.


2006 ◽  
Vol 39 (1) ◽  
pp. 91-100 ◽  
Author(s):  
Marie KUMMEROVÁ ◽  
štěpán ZEZULKA ◽  
Jana KRULOVÁ ◽  
Jan TŘÍSKA

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.


Author(s):  
Guotao Peng ◽  
Zhengqiu Fan ◽  
Xiangrong Wang ◽  
Chen Chen

<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>


Agronomy ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 213 ◽  
Author(s):  
Cristhian C. Chávez-Arias ◽  
Sandra Gómez-Caro ◽  
Hermann Restrepo-Díaz

Cape gooseberry has coped with abiotic and biotic stresses such as prolonged waterlogging periods and vascular wilt in recent years. The aim of this study was to evaluate the influence of four waterlogging periods on stomatal conductance (gs), leaf water potential (Ψwf), plant growth, leaf photosynthetic pigments, malondialdehyde (MDA) production, proline content and chlorophyll fluorescence parameters in cape gooseberry plants infected with Fusarium oxysporum f. sp. physali (Foph). Two-month-old ecotype “Colombia” plants were arranged in a completely randomized factorial design in eight treatments: plants without waterlogging (control), plants with waterlogging for 4, 6 and 8 d with and without Foph, respectively. The area under the disease progress curve was higher in inoculated plants subjected to 6 and 8 d of waterlogging (55.25 and 64.25) compared to inoculated plants but without waterlogging (45.25). The results also showed a lower plant growth, gs, Ψwf, leaf photosynthetic pigments and chlorophyll fluorescence parameters (Fv/Fm, electron transport rate (ETR), Y (II) and qP) as waterlogging periods in plants with Foph increased. However, this group of plants showed a greater proline and malondialdehyde (MDA) accumulation and a higher NPQ. In conclusion, cape gooseberry shows a low acclimation to waterlogging conditions of more than 6 d in soils with Foph.


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