scholarly journals Combining Heat Stress with Pre-Existing Drought Exacerbated the Effects on Chlorophyll Fluorescence Rise Kinetics in Four Contrasting Plant Species

2021 ◽  
Vol 22 (19) ◽  
pp. 10682
Author(s):  
Lingling Zhu ◽  
Wei Wen ◽  
Michael R. Thorpe ◽  
Charles H. Hocart ◽  
Xin Song
Keyword(s):  
Heat Stress ◽  
Chlorophyll Fluorescence ◽  
Plant Species ◽  
Tree Species ◽  
Heat Dissipation ◽  
Principal Component ◽  
Dynamic Responses ◽  
Future Research ◽  
Psii Photochemistry ◽  
Fluorescence Rise

Although drought and high temperature are two main factors affecting crop productivity and forest vegetation dynamics in many areas worldwide, little work has been done to describe the effects of heat combined with pre-existing drought on photochemical function in diverse plant species. This study investigated the biophysical status of photosystem II (PSII) and its dynamic responses under 2-day heat stress during a 2-week drought by measuring the polyphasic chlorophyll fluorescence rise (OJIP) kinetics. This study examined four contrasting species: a C3 crop/grass (wheat), a C4 crop/grass (sorghum), a temperate tree species (Fraxinus chinensis) and a tropical tree species (Radermachera sinica). Principal component analysis showed that the combination of heat and drought deviated from the effect of heat or drought alone. For all four species, a linear mixed-effects model analysis of variance of the OJIP parameters showed that the deviation arose from decreased quantum yield and increased heat dissipation of PSII. The results confirmed, in four contrasting plant species, that heat stress, when combined with pre-existing drought, exacerbated the effects on PSII photochemistry. These findings provide direction to future research and applications of chlorophyll fluorescence rise OJIP kinetics in agriculture and forestry, for facing increasingly more severe intensity and duration of both heat and drought events under climate change.

scholarly journals Chlorophyll fluorescence of tropical tree species in a semi-deciduous forest gap

2004 ◽  
Vol 28 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Rafael Vasconcelos Ribeiro ◽  
Gustavo Maia Souza ◽  
Angelo Gilberto Manzatto ◽  
Eduardo Caruso Machado ◽  
Ricardo Ferraz de Oliveira
Keyword(s):  
Chlorophyll Fluorescence ◽  
Tree Species ◽  
Deciduous Forest ◽  
Fluorescence Emission ◽  
Principal Component ◽  
Tropical Tree ◽  
Ecological Groups ◽  
Tropical Tree Species ◽  
Potential Tool

The characterization of different ecological groups in a forest formation/succession is unclear. To better define the different successional classes, we have to consider ecophysiological aspects, such as the capacity to use or dissipate the light energy available. The main objective of this work was to assess the chlorophyll fluorescence emission of tropical tree species growing in a gap of a semi-deciduous forest. Three species of different ecological groups were selected: Croton floribundus Spreng. (pioneer, P), Astronium graveolens Jacq. (early secondary, Si), and Esenbeckia febrifuga A. Juss. (late secondary, St). The potential (Fv/Fm) and effective (deltaF/Fm') quantum efficiency of photosystem II, apparent electron transport rate (ETR), non-photochemical (qN) and photochemical (qP) quenching of fluorescence were evaluated, using a modulated fluorometer, between 7:30 and 11:00 h. Values of Fv/Fm remained constant in St, decreasing in P and Si after 9:30 h, indicating the occurrence of photoinhibition. Concerning the measurements taken under light conditions (deltaF/Fm', ETR, qP and qN), P and Si showed better photochemical performance, i.e., values of deltaF/Fm', ETR and qP were higher than St when light intensity was increased. Values of qN indicated that P and Si had an increasing tendency of dissipating the excess of energy absorbed by the leaf, whereas the opposite was found for St. The principal component analysis (PCA), considering all evaluated parameters, showed a clear distinction between St, P and Si, with P and Si being closer. The PCA results suggest that chlorophyll fluorescence may be a potential tool to differentiate tree species from distinct successional groups.

scholarly journals Chlorophyll Fluorescence Imaging Analysis for Elucidating the Mechanism of Photosystem II Acclimation to Cadmium Exposure in the Hyperaccumulating Plant Noccaea caerulescens

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2580 ◽  
Author(s):  
Gülriz Bayçu ◽  
Julietta Moustaka ◽  
Nurbir Gevrek ◽  
Michael Moustakas
Keyword(s):  
Chlorophyll Fluorescence ◽  
Quantum Yield ◽  
Photosystem Ii ◽  
Fluorescence Imaging ◽  
Heat Dissipation ◽  
Chlorophyll Fluorescence Imaging ◽  
Imaging Analysis ◽  
Noccaea Caerulescens ◽  
Psii Photochemistry ◽  
Cd Exposure

We provide new data on the mechanism of Noccaea caerulescens acclimation to Cd exposure by elucidating the process of photosystem II (PSII) acclimation by chlorophyll fluorescence imaging analysis. Seeds from the metallophyte N. caerulescens were grown in hydroponic culture for 12 weeks before exposure to 40 and 120 μM Cd for 3 and 4 days. At the beginning of exposure to 40 μM Cd, we observed a spatial leaf heterogeneity of decreased PSII photochemistry, that later recovered completely. This acclimation was achieved possibly through the reduced plastoquinone (PQ) pool signaling. Exposure to 120 μM Cd under the growth light did not affect PSII photochemistry, while under high light due to a photoprotective mechanism (regulated heat dissipation for protection) that down-regulated PSII quantum yield, the quantum yield of non-regulated energy loss in PSII (ΦNO) decreased even more than control values. Thus, N. caerulescens plants exposed to 120 μM Cd for 4 days exhibited lower reactive oxygen species (ROS) production as singlet oxygen (1O2). The response of N. caerulescens to Cd exposure fits the ‘Threshold for Tolerance Model’, with a lag time of 4 d and a threshold concentration of 40 μM Cd required for the induction of the acclimation mechanism.

Combining Gas Exchange and Chlorophyll Fluorescence to Assess the Adaptability of Medicinal Plant Aesculus chinensis Compared to Two Imported Aesculus Species

2013 ◽  
Vol 726-731 ◽  
pp. 4330-4336
Author(s):  
Hai Yan Fu ◽  
Fu Qiang Song ◽  
Jia Sen Wu ◽  
Xiang Shi Kong ◽  
Dan Dan Qi
Keyword(s):  
Chlorophyll Fluorescence ◽  
Electron Transport ◽  
Gas Exchange ◽  
Tree Species ◽  
Light Energy ◽  
The Other ◽  
Photochemical Quenching ◽  
Chlorophyll Fluorescence Parameters ◽  
Psii Photochemistry

Analysis of gas exchange and determination of chlorophyll fluorescence parameters in leaves of three tree species including Aesculus chinensis, A. octandra and A. hybrida were conducted under field conditions and then comparison was carried out. The results showed that the light compensation point (LCP) was significantly different among the three tree species, of which the LCP of A. chinensis with 12.53 μmol·m-2·s-1 that of the lowest was notable lower than that of the other two species (36.11 and 46.41 μmol·m-2·s-1respectively). On the other hand, the light saturation point (LSP) of the three tree species also showed remarked different and the LSP of A. chinensis was 1475 μmol·m-2·s-1 which was dramatic higher than that of the other two species respective to 1366.67 and 1025 μmol·m-2·s-1. Beside, the maximum net photosynthetic rate (MNPR) was different too, MNPR of A. chinensis was 9.47μmol CO 2·m-2·s-1which was higher than the other two species (5.91 and 2.30 μmol CO 2·m-2·s-1 respectively), indicating A. chinensis had a higher photosynthetic capacity and stronger utilization ability for light energy. Moreover, the electron transport rate (ETR) of A. chinensis was higher than A. octandra and A. hybrida, the ETR of the former was 55.800 that were 1.33 and 1.44 times of the later two respectively. Quantum yield of PSII photochemistry (ФPSII) in A. chinensis was higher than A. octandra and A. hybrida, the ФPSII of the former was 0.470 that were 1.21 and 1.15 times of the later two respectively. Furthermore, the photochemical quenching (qP) of A. chinensis was 0.975 much higher than A. octandra and A. hybrida respective to 1.10 and 1.10 times of the later two respectively. These three photochemical parameters with dramatic different among the three different tree species suggested A. chinensis had a high activity of electron transport and conversion efficiency for light energy.

Pharmacological Uses of the Plants Belonging to the Genus Commiphora

2020 ◽  
Vol 18 ◽  
Author(s):  
Subbiah Latha ◽  
Palanisamy Selvamani ◽  
Thangavelu Prabha
Keyword(s):  
Secondary Metabolites ◽  
Plant Species ◽  
Dna Cleavage ◽  
Structural Information ◽  
Chemical Constituents ◽  
Future Research ◽  
Pharmacological Properties ◽  
Chemical Structures ◽  
Indigenous Uses ◽  
Available Information

: Natural products have a unique place in the healthcare industry. The genus Commiphora emerged as a potential medicinal with huge benefits as evidenced through its use in various traditional and modern systems of medicine. Therefore, we aimed to prepare a concise review on the pharmacological activities and the indigenous uses of various plant species belonging to the genus Commiphora along with the structural information of various active botanical ingredients present in these plants based on the published literatures and scientific reports. To collect the various published literatures on Commiphora in various journals; to study and classify the available information on the pharmacological uses and chemical constituents; and to present the gathered information as a precise review to serve as a potential reference for future research. Pharmacological and phytochemical data on Commiphora plant species were collected from various journals, books, reference materials, websites including scientific databases, etc for compilation. This review article describes the various pharmacological properties of plants of Commiphora species viz., Anti-arthritic and anti-inflammatory, Anti-atherogenic, Antibacterial, Anti-coagulant, Anti-dicrocoeliasis, Anti-epileptic, Anti-fascioliasis, Anti-fungal, Anti-heterophyidiasis, Anti-hyper cholesterolemic, Anti-hyperlipidemic, Anti-hypothyroidism, Anti-obesity, Anti-osteoarthritic, Anti-osteoclastogenesis, Anti-oxidant, Anti-parasitic, Anti-pyretic, Anti-schistosomiasis, Anti-septic, Anti-thrombotic, Anti-ulcer, Cardioprotective, COX enzyme inhibitory, Cytotoxic /Anti-carcinogenic/Anti-cancer, DNA cleavage, Hypotensive, Inhibits lipid peroxidation, Inhibits NO and NO synthase production, Insecticidal, Local anesthetic, Molluscicidal, Smooth muscle relaxant, Tick repellent activities along with toxicity studies. Furthermore, the review also included various secondary metabolites isolated from various species of Commiphora genus along with their chemical structures serve as a ready resource for researchers. We conclude that the plant species belonging to the genus Commiphora possesses abundant pharmacological properties with a huge treasure of diverse secondary metabolites within themselves. This review indicates the necessity of further in-depth research, pre-clinical and clinical studies with Commiphora genus which may help to detect the unidentified potential of the Commiphora plant species.

scholarly journals Exploring Morpho-Physiological Variation for Heat Stress Tolerance in Tomato

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 347
Author(s):  
Samikshya Bhattarai ◽  
Joshua Harvey ◽  
Desire Djidonou ◽  
Daniel Leskovar
Keyword(s):  
Heat Stress ◽  
Chlorophyll Fluorescence ◽  
Open Field ◽  
Electrolyte Leakage ◽  
Leaf Gas Exchange ◽  
Total Yield ◽  
Stress Conditions ◽  
Heat Injury ◽  
Injury Index ◽  
Heat Tolerant

Texas tomato production is vulnerable to extreme heat in the spring-summer cropping period, which is exacerbated by the lack of superior genetic materials that can perform well in such environments. There is a dire need for selecting superior varieties that can adapt to warm environments and exhibit high yield stability under heat stress conditions. This research aimed at identifying heat-tolerant varieties under heat-stress conditions in controlled and open-field environments and was carried out in three stages. For the first experiment, 43 varieties were screened based on yield responses in natural open-field environment. From those, 18 varieties were chosen and exposed to control (greenhouse: 26/20 °C) and constant heat-stress (growth-chamber: 34/24 °C) conditions for three months. Measurements were done for chlorophyll fluorescence, chlorophyll content (SPAD), plant height, stem diameter and heat injury index (HII). The last experiment was conducted in an open field with a pool of varieties selected from the first and second experiments. Leaf gas exchange, leaf temperature, chlorophyll fluorescence, SPAD value, electrolyte leakage, heat injury index and yield were assessed. From the combined studies, we concluded that heat-tolerant genotypes selected by using chlorophyll fluorescence and HII in controlled heat-stress conditions also exhibited heat-tolerance in open-field environments. Electrolyte leakage and HII best distinguished tomato varieties in open-field environments as plants with low electrolyte leakage and HII had higher total yield. 'Heat Master,' 'New Girl,' 'HM-1823,' 'Rally,' 'Valley Girl,' 'Celebrity,' and 'Tribeca' were identified as high heat-tolerant varieties. Through trait correlation analysis we provide a better understanding of which traits could be useful for screening and breeding other heat-tolerant tomato varieties.

scholarly journals Age, Sex and Cerebral Microbleed Effects On White Matter Degradation After Traumatic Brain Injury

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 886-887
Author(s):  
Andrei Irimia ◽  
Ammar Dharani ◽  
Van Ngo ◽  
David Robles ◽  
Kenneth Rostowsky
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
White Matter ◽  
Diffusion Tensor ◽  
Diffuse Axonal Injury ◽  
Principal Component ◽  
Older Age ◽  
Analysis Of Covariance ◽  
Future Research ◽  
Cerebral Microbleed

Abstract Mild traumatic brain injury (mTBI) affects white matter (WM) integrity and accelerates neurodegeneration. This study assesses the effects of age, sex, and cerebral microbleed (CMB) load as predictors of WM integrity in 70 subjects aged 18-77 imaged acutely and ~6 months after mTBI using diffusion tensor imaging (DTI). Two-tensor unscented Kalman tractography was used to segment and cluster 73 WM structures and to map changes in their mean fractional anisotropy (FA), a surrogate measure of WM integrity. Dimensionality reduction of mean FA feature vectors was implemented using principal component (PC) analysis, and two prominent PCs were used as responses in a multivariate analysis of covariance. Acutely and chronically, older age was significantly associated with lower FA (F2,65 = 8.7, p < .001, η2 = 0.2; F2,65 = 12.3, p < .001, η2 = 0.3, respectively), notably in the corpus callosum and in dorsolateral temporal structures, confirming older adults’ WM vulnerability to mTBI. Chronically, sex was associated with mean FA (F2,65 = 5.0, p = 0.01, η2 = 0.1), indicating males’ greater susceptibility to WM degradation. Acutely, a significant association was observed between CMB load and mean FA (F2,65 = 5.1, p = 0.009, η2 = 0.1), suggesting that CMBs reflect the acute severity of diffuse axonal injury. Together, these findings indicate that older age, male sex, and CMB load are risk factors for WM degeneration. Future research should examine how sex- and age-mediated WM degradation lead to cognitive decline and connectome degeneration after mTBI.

scholarly journals Dynamic Responses to Acute Heat Stress between 34 °C and 38.5 °C, and Characteristics of Heat Stress Response in Mice

2003 ◽  
Vol 26 (5) ◽  
pp. 701-708 ◽  
Author(s):  
Naoki Harikai ◽  
Kanji Tomogane ◽  
Mitsue Miyamoto ◽  
Keiko Shimada ◽  
Satoshi Onodera ◽  
...  
Keyword(s):  
Heat Stress ◽  
Stress Response ◽  
Dynamic Responses ◽  
Heat Stress Response ◽  
Acute Heat Stress

Effects of heat stress on PSII photochemistry in a cyanobacterium Spirulina platensis

Plant Science ◽  
2008 ◽  
Vol 175 (4) ◽  
pp. 556-564 ◽  
Author(s):  
Binbin Zhao ◽  
Jia Wang ◽  
Hongmei Gong ◽  
Xiaogang Wen ◽  
Haiyun Ren ◽  
...  
Keyword(s):  
Heat Stress ◽  
Spirulina Platensis ◽  
Psii Photochemistry

The psychology quadrant: an outcome measure based on the START risk assessment

2017 ◽  
Vol 19 (1) ◽  
pp. 14-22
Author(s):  
Matthew John Gill ◽  
Samantha Brookes
Keyword(s):  
Risk Assessment ◽  
Factor Structure ◽  
Psychiatric Rehabilitation ◽  
Principal Component ◽  
Future Research ◽  
Psychological Outcome ◽  
Content Type ◽  
Health Rehabilitation ◽  
Mental Health Rehabilitation ◽  
Outcome Tool

Purpose The purpose of this paper is to develop a psychological outcome tool which reflects the relationship between clusters of items on the Short Term Assessment of Risk and Treatability (START) risk assessment and different categories of psychological progress in male inpatient psychiatric services. Design/methodology/approach A principal component analysis (PCA) was conducted on data from 135 male psychiatric rehabilitation patients’ START risk assessments. Findings PCA identified four strength psychology quadrants which were explained by a five-factor structure and four vulnerability quadrants which were explained by a four-factor structure. The development of the psychology quadrant, its usefulness in establishing a treatment pathway and areas of future research are also discussed. Originality/value Developing accessible, transparent outcome measures using evidence-based practice is highly relevant within the field of mental health rehabilitation.

Estimating Store Brand Shelf Space: A New Framework Using Neural Networks and Partial Least Squares

2009 ◽  
Vol 51 (2) ◽  
pp. 1-19 ◽  
Author(s):  
Monica Gomez ◽  
Shintaro Okazaki
Keyword(s):  
Least Squares ◽  
Partial Least Squares ◽  
Structural Equation ◽  
Statistical Treatment ◽  
Principal Component ◽  
Future Research ◽  
Store Brand ◽  
Shelf Space ◽  
Managerial Implications ◽  
Space Data

Despite abundant research that examines the effects of store brands on retail decision making, little attention has been paid to the predictive model of store brand shelf space. This paper intends to fill this research gap by proposing and testing a theoretical model of store brand shelf space. From the literature review, 11 independent variables were identified (i.e. store format, reputation, brand assortment, depth of assortment, in-store promotions, leading national brands’ rivalry, retailers’ rivalry, manufacturers’ concentration, store brand market share, advertising, and innovation) and analysed as potential predictors of the dependent variable (i.e. store brand shelf space). Data were collected for 29 product categories in 55 retail stores. In designing the statistical treatment, a three-phase procedure was adopted: (1) interdependence analysis via principal component analysis; (2) dependence analysis via neural network simulation; and (3) structural equation modelling via partial least squares. The findings corroborate our proposed model, in that all hypothesised relationships and directions are supported. On this basis, we draw theoretical as well as managerial implications. In closing, we acknowledge the limitations of this study and suggest future research directions.

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