scholarly journals A Low Ratio of Red/Far-Red in the Light Spectrum Accelerates Senescence in Nest Leaves of Platycerium Bifurcatum

2017 ◽  
Vol 59 (2) ◽  
pp. 17-30 ◽  
Author(s):  
Jakub Oliwa ◽  
Andrzej Kornas ◽  
Andrzej Skoczowski
Keyword(s):  
Photochemical Efficiency ◽  
Anthropogenic Pressure ◽  
Light Spectrum ◽  
Photochemical Efficiency Of Psii ◽  
Lighting Conditions ◽  
Fluorescence Measurements ◽  
Platycerium Bifurcatum ◽  
Development And Aging ◽  
Non Destructive ◽  
Research Analysis

AbstractThe fern Platycerium bifurcatum is a valuable component of the flora of tropical forests, where degradation of local ecosystems and changes in lighting conditions occur due to the increasing anthropogenic pressure. In ferns, phytochrome mechanism responsible for the response to changes in the value of R/FR differs from the mechanism observed in spermatophytes. This study analyzed the course of ontogenesis of nest leaves in P. bifurcatum at two values of the R/FR ratio, corresponding to shadow conditions (low R/FR) and intense insolation (high R/FR). The work used only non-destructive research analysis, such as measurements of reflectance of radiation from the leaves, their blue-green and red fluorescence, and the chlorophyll a fluorescence kinetics. This allowed tracing the development and aging processes in the same leaves. Nest leaves are characterized by short, intense growth and rapid senescence. The study identified four stages of development of the studied leaves related to morphological and anatomical structure and changing photochemical efficiency of PSII. Under the high R/FR ratio, the rate of ontogenesis of the leaf lamina was much slower than under the low R/FR value. As shown, the rapid aging of the leaves was correlated with faster decline of the chlorophyll content. It was shown that leaf senescence was accompanied by accumulation of polyphenols, anthocyanins and carotenoids on the basis of reflectance and fluorescence measurements in the blue-green range.

Senior Living - Lighting, Circadian Rhythm and Dementia I

2019 ◽  
pp. 4-8
Author(s):  
Tadej Glažar ◽  
Marjeta Zupancic ◽  
Samo Kralj ◽  
Robert Peternelj
Keyword(s):  
The Elderly ◽  
Living Environment ◽  
Elderly Persons ◽  
Light Spectrum ◽  
Average Life Expectancy ◽  
The Real Estate ◽  
Lighting Conditions ◽  
Light Levels ◽  
Joint Fracture ◽  
Lease Contracts

The Real Estate Fund of Pension and Disability Insurance (Nepremicninski Sklad) in Slovenia, founded in1997 is the owner of 3255 properties in 116 locations throughout the country and is intended for solving housing issues of pensioners of 65 years or older and other elderly persons who are allowed independently to live. The lease contracts are concluded for an indefinite period of time. The aim and vision of the Fund is to improve the quality of life for the elderly tenants by adapting the living environment, the flats and surroundings according to the physical needs of aging tenants. Homes for seniors often have low light levels and poor light spectrum caused by fluorescent or incandescent lighting. Demographic changes in most European countries show rising average life expectancy which means that the number of people with weak visual capacity or visual impairment is increasing. Equally the risks of injuries due to poor lighting conditions are increasing, e.g. missing a step resulting in a hip joint fracture. Better lighting conditions are of critical importance for aging population, as stated also in the recently published CIE227:2017. To facilitate safe environment for the elderly, the Fund in 2013 initiated a lighting research study that should provide facts and evidence for a lighting standard for their own premises.

scholarly journals Physiological and Biochemical Responses ofUlva proliferaandUlva linzato Cadmium Stress

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
He-ping Jiang ◽  
Bing-bing Gao ◽  
Wen-hui Li ◽  
Ming Zhu ◽  
Chun-fang Zheng ◽  
...  
Keyword(s):  
Amino Acids ◽  
Photochemical Efficiency ◽  
Cadmium Stress ◽  
Nutrient Content ◽  
Ulva Prolifera ◽  
Cadmium Resistance ◽  
Relative Growth ◽  
Biochemical Responses ◽  
Photochemical Efficiency Of Psii ◽  
Physiological And Biochemical

Responses ofUlva proliferaandUlva linzato Cd2+stress were studied. We found that the relative growth rate (RGR), Fv/Fm, and actual photochemical efficiency of PSII (Yield) of twoUlvaspecies were decreased under Cd2+treatments, and these reductions were greater inU. proliferathan inU. linza.U. proliferaaccumulated more cadmium thanU. linzaunder Cd2+stress. WhileU. linzashowed positive osmotic adjustment ability (OAA) at a wider Cd2+range thanU. prolifera.U. linzahad greater contents of N, P, Na+, K+, and amino acids thanU. prolifera. A range of parameters (concentrations of cadmium, Ca2+, N, P, K+, Cl−, free amino acids (FAAs), proline, organic acids and soluble protein, Fv/Fm, Yield, OAA, and K+/Na+) could be used to evaluate cadmium resistance inUlvaby correlation analysis. In accordance with the order of the absolute values of correlation coefficient, contents of Cd2+and K+, Yield, proline content, Fv/Fm, FAA content, and OAA value ofUlvawere more highly related to their adaptation to Cd2+than the other eight indices. Thus,U. linzahas a better adaptation to Cd2+thanU. prolifera, which was due mainly to higher nutrient content and stronger OAA and photosynthesis inU. linza.

scholarly journals THE INFLUENCE OF BIO-ALGEEN S90 ON THE GROWTHOF MULTIFLORA ROSE SEEDLINGS (Rosa multiflora Thunb.)

2019 ◽  
Vol 18 (3) ◽  
pp. 35-43
Author(s):  
Mariusz Szmagara ◽  
Krystyna Pudelska ◽  
Wojciech Durlak ◽  
Barbara Marcinek ◽  
Kamila Rojek
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photochemical Efficiency ◽  
Morphological Characteristics ◽  
Rosa Multiflora ◽  
Plant Growth And Development ◽  
Agent Based ◽  
Photochemical Efficiency Of Psii ◽  
Stimulate Plant Growth ◽  
Maximum Photochemical Efficiency ◽  
Natural Agent

Striving to intensify horticultural production, new and more effective bio-preparations are being sought to stimulate plant growth and development. Bio-algeen S90 is a natural agent based on sea algae, the high bi- ological activity of which results from the high content of natural growth regulators. The aim of the study was to verify the influence of Bio-algeen S90 on the growth, morphological characteristics and chlorophyll fluorescence of Rosa multiflora seedlings. The bio-preparation was applied one, two and three times at con- centrations: 0.1, 0.2, 0.4 and 0.6 mg.dm−3. Following parameters were measured to evaluate the response of plants to the bio-preparation: F0 – initial fluorescence, Fm – maximal fluorescence in the dark-adapted state, Fv/Fm – maximum photochemical efficiency of PSII. All concentrations of the bio-preparation and frequency of its application stimulated the number of shoots in a bush, the length of shoots and the diameter of the root crown of plants intended for budding. The most beneficial was the two-fold bio-preparation application at a concentration of 0.4 mg.dm–3. Bio-algeen also positively influenced the chlorophyll fluorescence parame- ters. The highest mean F0 and Fm values were recorded with the two-fold preparation treatment. There was no significant effect of the bio-preparation on the Fv/Fm index, which was within the range of 0.75–0.66.

scholarly journals Photochemical efficiency in bean plants (Phaseolus vulgaris L. and Vigna unguiculata L. Walp) during recovery from high temperature stress

2002 ◽  
Vol 14 (2) ◽  
pp. 105-110 ◽  
Author(s):  
Ernany Santos Costa ◽  
Ricardo Bressan-Smith ◽  
Jurandi Gonçalves de Oliveira ◽  
Eliemar Campostrini ◽  
Carlos Pimentel
Keyword(s):  
High Temperature ◽  
Phaseolus Vulgaris ◽  
Temperature Stress ◽  
Vigna Unguiculata ◽  
Photochemical Efficiency ◽  
High Temperature Stress ◽  
Reaction Centre ◽  
Phaseolus Vulgaris L ◽  
Light Harvesting Complex ◽  
Photochemical Efficiency Of Psii

Bean (Phaseolus vulgaris L., cv. Carioca and cv. Negro Huasteco) and cowpea plants (Vigna unguiculata L. Walp cv. Epace 10) were grown in a growth chamber with PPF at leaf level of 200 mumol.m-2.s-1 and air temperature 25 + 1 ºC. The first fully expanded pair of leaves of 12-day-old plants was submitted to high temperature stress (25, 30, 35, 40, 45 and 48 ºC) for 1.5 h. The photochemical efficiency of PSII during recovery was monitored by means of chlorophyll a fluorescence at six different times (0.5, 1, 2, 4, 24, and 48 h) after stress, at 25 ºC, using a modulated fluorimeter. Increasing temperature promoted an increase in Fphi at 45 ºC, possibly associated with dissociation of the light harvesting complex from the reaction centre of PSII, but a decrease was observed at 48 ºC in all cultivars. Fmax decreased at 48 ºC in Carioca and Negro Huasteco, but not in Epace 10, showing a possible correlation between heat tolerance and Fmax for this cultivar. The low values of Fmax in Carioca and Negro Huasteco indicated a loss of PSII activity followed by death of these plants. Fv/Fmax did not vary in Epace 10 but varied in Carioca and Negro Huasteco with increasing temperatures.

scholarly journals Physiological Response of Cape Gooseberry Plants to Fusarium oxysporum f. sp. physali, Fusaric Acid, and Water Deficit in a Hydrophonic System

2021 ◽  
Vol 12 ◽  
Author(s):  
Luis Alberto Mendoza-Vargas ◽  
Wendy Paola Villamarín-Romero ◽  
Anderson Steven Cotrino-Tierradentro ◽  
Joaquín Guillermo Ramírez-Gil ◽  
Cristhian Camilo Chávez-Arias ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Water Deficit ◽  
Fusaric Acid ◽  
Photochemical Efficiency ◽  
Vascular Wilt ◽  
New Approach ◽  
Photochemical Efficiency Of Psii ◽  
Progress Curve ◽  
Solanaceae Family ◽  
Cape Gooseberry

Cape gooseberry production has been limited by vascular wilt caused by Fusarium oxysporum f. sp. physali (Foph). Fusaric acid (FA) is a mycotoxin produced by many Fusarium species such as F. oxysporum formae speciales. The effects of the interaction between this mycotoxin and plants (such as cape gooseberry) under biotic stress (water deficit, WD) have been little explored. Three experiments were carried out. The objectives of this study were to evaluate (i) different Foph inoculum densities (1 × 104 and 1 × 106 conidia ml−1; experiment (1); (ii) the effect of times of exposure (0, 6, 9, and 12 h) and FA concentrations (0, 12.5, 25, 50, and 100 mg L−1; experiment (2), and (iii) the interaction between Foph (1 × 104 conidia mL−1) or FA (25 mg L−1 × 9 h), and WD conditions (experiment 3) on the physiological (plant growth, leaf stomatal conductance (gs), and photochemical efficiency of PSII (Fv/Fm ratio) and biochemical [malondialdehyde (MDA) and proline] responses of cape gooseberry seedling ecotype Colombia. The first experiment showed that Foph inoculum density of 1 × 106 conidia ml−1 caused the highest incidence of the disease (100%). In the second experiment, gs (~40.6 mmol m−2 s−1) and Fv/Fm ratio (~0.59) decreased, whereas MDA (~9.8 μmol g−1 FW) increased in plants with exposure times of 9 and 12 h and an FA concentration of 100 mg L−1 compared with plants without FA exposure or concentrations (169.8 mmol m−2 s−1, 0.8, and 7.2 μmol g−1 FW for gs, Fv/Fm ratio and MDA, respectively). In the last experiment, the interaction between Foph or FA and WD promoted a higher area under the disease progress curve (AUDPC) (Foph × WD = 44.5 and FA × WD = 37) and lower gs (Foph × WD = 6.2 mmol m−2 s−1 and FA × WD = 9.5 mmol m−2 s−1) compared with plants without any interaction. This research could be considered as a new approach for the rapid scanning of responses to the effects of FA, Foph, and WD stress not only on cape gooseberry plants but also on other species from the Solanaceae family.

scholarly journals Photosynthetic performance in Eucalyptus clones cultivated in saline soil

2019 ◽  
pp. 368
Author(s):  
Jailma Ribeiro de Andrade ◽  
Sebastião de Oliveira Maia Júnior ◽  
Andrea Francisca da Silva Santos ◽  
Vicente Mota da Silva ◽  
L.T. Bezerra, J.R.R. da Silva, C.M. Santos, V.M. Ferreira, L. Endres
Keyword(s):  
Salt Stress ◽  
Block Design ◽  
Photosynthetic Pigment ◽  
Photochemical Efficiency ◽  
Dry Mass ◽  
Photosynthetic Performance ◽  
Saline Stress ◽  
Physiological Indicators ◽  
Photochemical Efficiency Of Psii ◽  
Randomized Block Design

The aim of this study was to evaluate the photosynthetic performance of Eucalyptus clones with the aim of identifying their tolerance to soil saline stress conditions. The experiment was arranged in a randomized block design with a 3 × 4 factorial arrangement: in five replications, totaling 60 plots, three Eucalyptus clones were used, VC865, I224, and I144, which were exposed to four concentrations of NaCl (0, 1, 2 and 3 g NaCl kg-1 of soil). Clone I144 shows mechanisms of salinity tolerance as smaller reductions in the stomatal conductance, transpiration, photosynthesis, photochemical efficiency of PSII, photosynthetic pigment content and total dry mass. On the other hand, clone I224 presents greater physiological damage, indicating high susceptibility to salt stress, while VC865 shows moderate sensitivity to salinity. Variables related to photosynthetic performance, such as gas exchange, photochemical efficiency of PSII and photosynthetic pigments are potentially reliable physiological indicators for selecting of tolerant Eucalyptus clones to salt stress.

scholarly journals Differences in photosynthetic capacity, chlorophyll fluorescence, and antioxidant system between invasive Alnus formosana and its native congener in response to different irradiance levels

Botany ◽  
2016 ◽  
Vol 94 (12) ◽  
pp. 1087-1101 ◽  
Author(s):  
Shi-liang Liu ◽  
Rong-jie Yang ◽  
Bo Ren ◽  
Mao-hua Wang ◽  
Ming-dong Ma
Keyword(s):  
Invasive Species ◽  
Chlorophyll Fluorescence ◽  
Antioxidant System ◽  
Photosynthetic Rate ◽  
Native Species ◽  
Antioxidant Activities ◽  
Photochemical Efficiency ◽  
High Irradiance ◽  
Invasion Success ◽  
Photochemical Efficiency Of Psii

We compared the invasive Alnus formosana (Burk.) Makino with its native congener (Alnus cremastogyne Burk.) at three irradiances in terms of photosynthesis, chlorophyll fluorescence, and antioxidant system. The increased light-saturated photosynthetic rate (Amax) and light saturation point (LSP) contributed directly to the increased performance of the invasive. The invasive species had also higher plasticity in carotenoid and total chlorophyll than the native species at 100% irradiance, potentially contributing to invasion success in high-irradiance locations via photoprotection. Moreover, the diurnal photoinhibition of photosynthesis, as judged by the maximum photochemical efficiency of PSII (Fv/Fm) of dark-adapted leaves, was more severe in the native species than in the invasive species. With increasing irradiance, the invasive exhibited increased antioxidant activities and higher antioxidant levels to support the adverse conditions of both low- and high-irradiance acclimation. In contrast, the intercellular CO2 concentration (Ci) and stomatal limitation (Ls) decreased with increases in the net photosynthetic rate (An), stomatal conductance (Gs), and transpiration rate (Tr). We speculated that Ls was the main factor inhibiting the An for both studied species. These results first indicated that the invasive may occupy new habitats successfully through tolerating shading at low irradiance and out-compete native species through higher Amax and antioxidant levels when irradiance is increased.

scholarly journals DAYTIME VARIATIONS OF CHLOROPHYLL A FLUORESCENCE IN PAU D'ALHO SEEDLINGS

2016 ◽  
Vol 40 (6) ◽  
pp. 1023-1030 ◽  
Author(s):  
Marcos Antonio Bacarin ◽  
Emanuela Garbin Martinazzo ◽  
Daniela Cassol ◽  
Antelmo Ralph Falqueto ◽  
Diolina Moura Silva
Keyword(s):  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Photochemical Efficiency ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Active Radiation ◽  
High Radiation ◽  
Active Radiation ◽  
Fluorescence Measurements ◽  
Subsequent Decrease ◽  
Modulated Fluorescence

ABSTRACT Analysis of transient and modulated fluorescence of chlorophyll a were made at one-hour intervals during an eight-hour period starting at 07:30h aiming to study mechanisms of photoprotection against high radiation and temperature in Gallesia integrifolia plants. Seeds were germinated inside plastic pots containing soil as substrate. At 120 days after emergence, chlorophyll fluorescence measurements were performed using Handy-PEA and FMS2 fluorometers. During the course of a day, an increase and a subsequent decrease in temperature and in photosynthetic active radiation were observed until 12:30h. Changes in transient kinetic curves of chlorophyll a fluorescence were identified. This resulted in changes in JIP test parameters. An increase during the period of high radiation and temperature may be stressed in relation to variables related to dissipation flux and appearance of positive -K and -L bands. Considering the modulated fluorescence, high values of non-photochemical quenching coefficients associated with lower values of effective photochemical efficiency of the photosystem II (FV'/ FM') and current photochemical efficiency of PSII (φPSII) could be observed during early morning. This was probably the result of an inhibition of the biochemical phase of photosynthesis. It can be concluded that Gallesia integrifolia decrease its photochemical activity with the increase in the photosynthetic active radiation, demonstrating a photoinhibitory effect under high irradiance conditions, but without irreversible damages to the photosynthetic apparatus.

scholarly journals Root Abscisic Acid Contributes to Defending Photoinibition in Jerusalem Artichoke (Helianthus tuberosus L.) under Salt Stress

2018 ◽  
Vol 19 (12) ◽  
pp. 3934 ◽  
Author(s):  
Kun Yan ◽  
Tiantian Bian ◽  
Wenjun He ◽  
Guangxuan Han ◽  
Mengxue Lv ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Salt Stress ◽  
Photochemical Efficiency ◽  
Jerusalem Artichoke ◽  
Photosynthetic Parameters ◽  
Synthesis Inhibitor ◽  
Potted Plants ◽  
Photochemical Efficiency Of Psii ◽  
Electron Donation ◽  
Aba Content

The aim of the study was to examine the role of root abscisic acid (ABA) in protecting photosystems and photosynthesis in Jerusalem artichoke against salt stress. Potted plants were pretreated by a specific ABA synthesis inhibitor sodium tungstate and then subjected to salt stress (150 mM NaCl). Tungstate did not directly affect root ABA content and photosynthetic parameters, whereas it inhibited root ABA accumulation and induced a greater decrease in photosynthetic rate under salt stress. The maximal photochemical efficiency of PSII (Fv/Fm) significantly declined in tungstate-pretreated plants under salt stress, suggesting photosystem II (PSII) photoinhibition appeared. PSII photoinhibition did not prevent PSI photoinhibition by restricting electron donation, as the maximal photochemical efficiency of PSI (ΔMR/MR0) was lowered. In line with photoinhibition, elevated H2O2 concentration and lipid peroxidation corroborated salt-induced oxidative stress in tungstate-pretreated plants. Less decrease in ΔMR/MR0 and Fv/Fm indicated that PSII and PSI in non-pretreated plants could maintain better performance than tungstate-pretreated plants under salt stress. Consistently, greater reduction in PSII and PSI reaction center protein abundance confirmed the elevated vulnerability of photosystems to salt stress in tungstate-pretreated plants. Overall, the root ABA signal participated in defending the photosystem’s photoinhibition and protecting photosynthesis in Jerusalem artichoke under salt stress.

Drought and cold stress responses in orostachys spinosa L.

2018 ◽  
Vol 22 (03) ◽  
pp. 77-81
Author(s):  
Otgonsuvd B ◽  
Ouyngerel Sh ◽  
Altanzaya T
Keyword(s):  
Electron Transfer ◽  
Drought Stress ◽  
Stress Responses ◽  
Photochemical Efficiency ◽  
Normal Growth ◽  
Growth Conditions ◽  
Photochemical Efficiency Of Psii ◽  
Succulent Plant ◽  
Drought Conditions ◽  
Long Time

Orostachys spinosa L. is a succulent plant native to predominantly East Asia. The objective of this study was to identify physiological and morphological responses of O. spinosa L. species to cold, drought stress in laboratory conditions. Exposure of plants to a drought stress for 28 days slightly decreased the photochemical efficiency of PSII and the Fv/Fm values were 10-15% lower (0.75±0.01) compared with the control plants (0.85±0.01). For cold treatments, plants were exposed to 4°C for 60 days and for recovery transferred to normal growth conditions for 14 days. Fv/Fm photochemical efficiency of PSII can be used to monitor PSII photoinhibition. This parameter describes the efficiency of the electron transfer within PSII.The results of this study demonstrated that O. spinosa L. plants were better adapted to cold and drought conditions as they showed less visible symptoms and highest Fv/Fm levels at the long time chilling and drought stress.

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