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Non-destructive analysis of photosynthetic pigments in cotton plants
Brito, Giovani Greigh;Sofiatti, Valdinei;Brand?o, Ziany Neiva;Silva, Vivianny Belo;Silva, Franklin Magnum;Silva, Dalva Almeida;
Acta Scientiarum. Agronomy , 2011, DOI: 10.4025/actasciagron.v33i4.10926
Abstract: analytical techniques used to extract chlorophyll from plant leaves are destructive and based on the use of organic solvents. this study proposes a non-destructive quantification of the photosynthetic pigment concentration in cotton leaves using two portable chlorophyll meters, the spad-502 and the clorofilog 1030. after obtaining 200 leaf discs, each with an area of 113 mm2, the greening rate in each disc was determined by the average of five readings from both meters. immediately after measurement, 5 ml of dimethyl sulfoxide (dmso) was added, and the samples were kept in a water bath at 70oc for 30 min. after cooling, 3 ml of the liquid extract was used for analyses by spectrophotometry at 470, 646 and 663 nm. mathematical models were adjusted from analytical results using the reading index obtained from both devices to predict the contents of chlorophyll a, chlorophyll b, total chlorophyll and carotenoids. based on these results, it was concluded that both portable chlorophyll meters are an effective way to estimate the concentration of photosynthetic pigments in cotton leaves, thus saving time, space and the resources that are often required for these analyses.
Non-destructive determination of photosynthetic pigments in the leaves of castor oil plants
Rigon, Jo?o Paulo Gonsiorkiewicz;Capuani, Silvia;Beltr?o, Napole?o de Esberard Macêdo;Brito Neto, José Félix de;Sofiatti, Valdinei;Fran?a, Fabíola Vanessa de;
Acta Scientiarum. Agronomy , 2012, DOI: 10.4025/actasciagron.v34i3.13872
Abstract: the aim of the present work was to determine the relationship between photosynthetic pigments extracted in dimethyl sulfoxide (dmso) and readings obtained by the portable chlorophyll meter, clorofilog? 1030, to generate mathematical models that are able to report the contents of chlorophyll and carotenoids in the leaves of the castor oil plant. this work was conducted at embrapa cotton, located in the city of campina grande, state of paraíba, brazil, in october 2010. for the indirect analysis, portable equipment was used to read leaf discs of different shades of green. the chlorophyll in these discs was then determined using a classical method: 5 ml of dmso was added, the samples were incubated in a water bath at 70oc for 30 minutes, and a 3 ml aliquot was removed for spectrophotometric measurements at 470, 646 and 663 nm. the data were subjected to analysis of variance and regression analyses in which the readings obtained using the portable chlorophyll meter were the dependent variable and the photosynthetic pigments that were determined by the classical method were the independent variable. the results indicated that, with the exception of chlorophyll b, the clorofilog? 1030 portable chlorophyll meter estimated the concentration of photosynthetic pigments with high precision, thus saving time and the chemical reagents that are typically used in conventional procedures.
Optimal number of pigments in photosynthetic complexes  [PDF]
Simon Jesenko,Marko Znidaric
Physics , 2012, DOI: 10.1088/1367-2630/14/9/093017
Abstract: We study excitation energy transfer in a simple model of photosynthetic complex. The model, described by Lindblad equation, consists of pigments interacting via dipole-dipole interaction. Overlapping of pigments induces an on-site energy disorder, providing a mechanism for blocking the excitation transfer. Based on the average efficiency as well as robustness of random configurations of pigments, we calculate the optimal number of pigments that should be enclosed in a pigment-protein complex of a given size. The results suggest that a large fraction of pigment configurations are efficient as well as robust if the number of pigments is properly chosen. We compare optimal results of the model to the structure of pigment-protein complexes as found in nature, finding good agreement.
Photosynthetic efficiency in rhizophoracean mangroves with reference to compartmentalization of photosynthetic pigments
Moorthy,P.; Kathiresan,K.;
Revista de Biología Tropical , 1999,
Abstract: photosynthetic pigments are localized in protein complexes of chloroplast membranes and their role in photosynthesis has long been established but their efficiency has not been measured in many species. the photosynthetic efficiency of four rhizophoracean mangroves, rhizophora apiculata, r. mucronata, bruguiera cylindrica and ceriops decandra was studied in randomly collected propagules from pichavaram mangrove forest (southeast coast of india) by estimating the concentration of photosynthetic pigments in protein complexes of the thylakoid membrane. reaction centre chlorophyll (rc-chl) was maximum in b. cylindrica and minimum in r. mucronata. of the total amount of chlorophylls, rc-chl constitutes about 50%. the light harvesting complex chlorophyll (lhc-chl) was highest in c. decandra and lowest in r. mucronata. net photosynthesis was found to be higher in b. cylindrica and lower in r. mucronata with the respective co2 fixation of 20.52 and 10.83 m mol m-2 s-1. a positive correlation was obtained between rc-chl and net photosynthesis. the stomatal conductance to co2 influx was also found to be high and low in b. cylindrica and r. mucronata respectively. we refer the chlorophylls present in the reaction centre and light harvesting complex as " membrane bound chlorophyll" and propose to use this as an index for measuring the productivity of mangrove species.
Photosynthetic efficiency in rhizophoracean mangroves with reference to compartmentalization of photosynthetic pigments  [cached]
P. Moorthy,K. Kathiresan
Revista de Biología Tropical , 1999,
Abstract: Photosynthetic pigments are localized in protein complexes of chloroplast membranes and their role in photosynthesis has long been established but their efficiency has not been measured in many species. The photosynthetic efficiency of four rhizophoracean mangroves, Rhizophora apiculata, R. mucronata, Bruguiera cylindrica and Ceriops decandra was studied in randomly collected propagules from Pichavaram mangrove forest (southeast coast of India) by estimating the concentration of photosynthetic pigments in protein complexes of the thylakoid membrane. Reaction centre chlorophyll (RC-chl) was maximum in B. cylindrica and minimum in R. mucronata. Of the total amount of chlorophylls, RC-chl constitutes about 50%. The light harvesting complex chlorophyll (LHC-chl) was highest in C. decandra and lowest in R. mucronata. Net photosynthesis was found to be higher in B. cylindrica and lower in R. mucronata with the respective CO2 fixation of 20.52 and 10.83 m mol m-2 s-1. A positive correlation was obtained between RC-chl and net photosynthesis. The stomatal conductance to CO2 influx was also found to be high and low in B. cylindrica and R. mucronata respectively. We refer the chlorophylls present in the reaction centre and light harvesting complex as " membrane bound chlorophyll" and propose to use this as an index for measuring the productivity of mangrove species.
Multiple Roles of Photosynthetic and Sunscreen Pigments in Cyanobacteria Focusing on the Oxidative Stress  [PDF]
Naoki Wada,Toshio Sakamoto,Seiichi Matsugo
Metabolites , 2013, DOI: 10.3390/metabo3020463
Abstract: Cyanobacteria have two types of sunscreen pigments, scytonemin and mycosporine-like amino acids (MAAs). These secondary metabolites are thought to play multiple roles against several environmental stresses such as UV radiation and desiccation. Not only the large molar absorption coefficients of these sunscreen pigments, but also their antioxidative properties may be necessary for the protection of biological molecules against the oxidative damages induced by UV radiation. The antioxidant activity and vitrification property of these pigments are thought to be requisite for the desiccation and rehydration processes in anhydrobiotes. In this review, the multiple roles of photosynthetic pigments and sunscreen pigments on stress resistance, especially from the viewpoint of their structures, biosynthetic pathway, and in vitro studies of their antioxidant activity, will be discussed.
Full quantum dynamics of the electronic coupling between photosynthetic pigments  [PDF]
María Belén Oviedo,Cristián G. Sánchez
Physics , 2015,
Abstract: From studying the time evolution of the single electron density matrix within a density functional tight-binding formalism we study in a fully atomistic picture the electronic excitation transfer between two photosynthetic pigments in real time. This time-dependent quantum dynamics is based on fully atomistic structural models of the photosynthetic pigment. We analyze the dependence of the electronic excitation transfer with distance and orientation between photosynthetic pigments. We compare the results obtained from full quantum dynamics with analytical ones, based on a two level system model were the interaction between the pigments is dipolar. We observed that even when the distance of the photosynthetic pigment is about $30$ \AA\ the deviation of the dipolarity is of about $15$ percent.
Evaluation of Efficient Extraction Methods for Recovery of Photosynthetic Pigments from Microalgae  [PDF]
A. Ilavarasi,D. Pandiaraj,D. MubarakAli,M.H. Mohammed Ilyas
Pakistan Journal of Biological Sciences , 2012,
Abstract: Microalgal species are known to have pigments in their cellular constitute at the maximum and are valuable bioactive products. In the present study focused was on the evaluation of efficient extraction methods for photosynthetic pigments from microalgal species. They are, Chlorella sp., Acrochaete sp., Phormidium chlorinum, Jaaginema pseudogeminatum and Chroococcus sp. There are four different extraction methods were adopted for active recovery and are economically feasible such as direct extraction, mechanical grinding, heating and preheated solvent method. It was found that mechanical grinding method has extract two fold increased amount than the other methods. Additionally, this methods is inexpensive, less laborious and active extraction. It is suggested that this method could be used for the extraction of photosynthetic pigments from microalgae for pharmaceutical to biotechnological purpose.
Pepper plants growth, yield, photosynthetic pigments, and total phenols as affected by foliar application of potassium under different salinity irrigation water  [PDF]
M. M. Hussein, S. Y. El-Faham, A. K. Alva
Agricultural Sciences (AS) , 2012, DOI: 10.4236/as.2012.32028
Abstract: Irrigation with high salinity water influences plant growth, production of photosynthetic pigments and total phenols, leading to reduction in crop yield and quality. The objective of this study was to investigate the effects of potassium (K) foliar application in mitigating the negative effects of salt stress on pepper plants. A greenhouse experiment was conducted to investigate the effects of foliar application of potassium (K) on pepper plants grown with different salinity water irrigation (3000 and 6000 ppm as compared to tap water with salinity level of 300 ppm). Irrigation using high salinity water decreased plant height, biomass production, and fruit yield as compared to those of the plants irrigated by tap water. Photosynthetic pigments and total phenols increased in the former as compared to those of the latter plants. The most serious affect was for the plants under highest salinity irrigation (6000 ppm) as compared to that of the plants under moderate salinity irrigation (3000 ppm). Foliar application of potassium mono phosphate (KMP) at 200ppm concentration increased the plant growth, biomass production, and fruit yield. Chlorophyll_a content and total phenols increased significantly with foliar application of 100 ppm KMP. Further increase in foliar KMP concentration to 200 ppm had no significant benefits on photosynthetic pigments and total phenols content. This study demonstrated that foliar application of KMP, to some extent, mitigated the negative effects of high salinity water irrigation on pepper plant growth and fruit yield.
Effect of salt stress on nutrient concentration, photosynthetic pigments, proline and foliar morphology of Salvinia auriculata Aubl.
Gomes, Maria Angélica da Concei??o;Suzuki, Marina Satika;Cunha, Maura da;Tullii, Cristiane Ferrante;
Acta Limnologica Brasiliensia , 2011, DOI: 10.1590/S2179-975X2011000200007
Abstract: aim: this study aimed to investigate the effects of naci and na2so4 salts on ca, ci, k, mg n, p, s and na content as well as on the content of photosynthetic pigments (chlorophyll-a, chlorophyll-b and carotenoids), proline content and on the foliar morphology of salvinia auriculata aubl. methods: the plants were collected in jacu lagoon, located in the north of rio de janeiro state, and after a five-day-acclimation period, experiments were performed in the greenhouse with 0, 100, 200 mm concentrations of naci and na2so4 salts and the usual techniques for light and electron microscopy. results: after seven days of experiment, a decrease in the content of ca2+, k+, mg2+, p, n ions as well as in the content of photosynthetic pigments (chlorophyll-a,b and carotenoids) in salvinia auriculata under saline treatments was observed. the proline content showed an upward tendency as compared to the control. under transmission electron microscopy, it was observed that, on the foliar limb, there was a membrane system disorder, mainly of chloroplasts, with higher presence of starch grains of plant cells subjected to salinity. under scanning electron microscope, the integrity of trichomes and foliar limb cells of salvinia auriculata subjected to the control treatment as well as the changes caused by salinization on the surface of cells were observed. conclusion: as for all the salinization effects evaluated, it was noticed that the increase in na2so4 salt concentration resulted in higher morphological and nutritional alterations in the floating aquatic macrophyte, salvinia auriculata.
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