Search results for "photosynthesi"
showing 10 items of 310 documents
Diurnal Cycle Relationships between Passive Fluorescence, PRI and NPQ of Vegetation in a Controlled Stress Experiment
2017
In order to estimate vegetation photosynthesis from remote sensing observations; some critical parameters need to be quantified. From all absorbed light; the plant needs to release any excess that is not used for photosynthesis; by non-photochemical quenching; by fluorescence emission and unregulated thermal dissipation. Non-photochemical quenching (NPQ) processes are controlled photoprotective mechanisms which; once activated; strongly control the dynamics of photochemical efficiency. With illumination conditions increasing and decreasing during a diurnal cycle; photoprotection mechanisms needs to change accordingly. The goal of this work is to quantify dynamic NPQ; measured from active fl…
De novo Transcriptome Assembly and Comparison of C3, C3-C4, and C4 Species of Tribe Salsoleae (Chenopodiaceae)
2017
C4 photosynthesis is a carbon-concentrating mechanism that evolved independently more than 60 times in a wide range of angiosperm lineages. Among other alterations, the evolution of C4 from ancestral C3 photosynthesis requires changes in the expression of a vast number of genes. Differential gene expression analyses between closely related C3 and C4 species have significantly increased our understanding of C4 functioning and evolution. In Chenopodiaceae, a family that is rich in C4 origins and photosynthetic types, the anatomy, physiology and phylogeny of C4, C2, and C3 species of Salsoleae has been studied in great detail, which facilitated the choice of six samples of five representative …
De novo Transcriptome Assembly and Comparison of C3, C3-C4, and C4 Species of Tribe Salsoleae (Chenopodiaceae)
2017
C4 photosynthesis is a carbon-concentrating mechanism that evolved independently more than 60 times in a wide range of angiosperm lineages. Among other alterations, the evolution of C4 from ancestral C3 photosynthesis requires changes in the expression of a vast number of genes. Differential gene expression analyses between closely related C3 and C4 species have significantly increased our understanding of C4 functioning and evolution. In Chenopodiaceae, a family that is rich in C4 origins and photosynthetic types, the anatomy, physiology and phylogeny of C4, C2, and C3 species of Salsoleae has been studied in great detail, which facilitated the choice of six samples of five representative …
Terahertz Absorption change in Photosynthetic Reaction Center upon photoactivation
2012
Photosynthetic reaction center is a membrane protein which plays an important role in converting solar energy into chemical energy. Upon continuous illumination a charge separation occurs within the protein which is stable for several seconds [1]. The stability of this state is very important to protect the protein against the release of excess heat and an instable radical due to charge recombination. Absorption of terahertz radiation corresponds to the excitation of large vibrations in the protein and is thus suitable for studying its different dynamical states. Here we recorded terahertz absorption spectra of the dark and illuminated state of reaction centre from the purple membrane bacte…
The effect of wood ash application on growth, leaf morphological and physiological traits of trees planted in a cutaway peatland
2021
Management of cutaway peatlands is a key issue in many countries. Whilst afforestation has been considered as a suitable after use option for cutaway peatlands, growing conditions after peat harvest are often adverse. To increase soil fertility and neutralise soil acidity, wood ash, an energy production by-product, can be used. In this study, we examined whether wood ash fertiliser affects growth (survival, height, root collar diameter), leaf morphological (mass, specific leaf area, leaf water content) and physiological traits (chlorophyll concentration, fluorescence parameters, photosynthetic and transpiration rate) of planted deciduous trees in a cutaway peatland in the central part of La…
Physiological and Structural Responses to Prolonged Water Deficit in Young Trees of Two Olive Cultivars
2022
This study aimed to characterize the physiological and structural responses of potted one-year-old olive trees belonging to two olive cultivars—‘Nocellara del Belice’ and ‘Cerasuola’—exposed to prolonged drought under greenhouse conditions. Two irrigation treatments based on evapotranspiration (ET) were imposed for 69 days, i.e., well-watered (WW, 100% ET) and drought-stressed (DS, 10–30% ET). Leaf stomatal conductance (gs), stem water potential (Ψstem), transpiration (E), photosynthetic capacity (Amax), water use efficiency (WUE), stem (Kstem) and root (Kroot) hydraulic conductance, trunk diameter variations (TDV), and leaf patch attenuated pre…
Use of Biostimulants for Organic Apple Production: Effects on Tree Growth, Yield, and Fruit Quality at Harvest and During Storage
2018
The experiment was conducted during two consecutive seasons (years 2016 and 2017) in an organic apple orchard of the cultivar Jonathan. Several biostimulants were tested (10 in total), including humic acids, macro and micro seaweed extracts, alfalfa protein hydrolysate, amino acids alone or in combination with zinc, B-group vitamins, chitosan and a commercial product containing silicon. Treatments were performed at weekly intervals, starting from the end of May until mid-August. The macroseaweed extract was effective in stimulate tree growth potential in both years, as shown by a significantly larger leaf area (+20% as compared to control) and by an higher chlorophyll content and leaf photo…
Appraisal of Combined Applications of Trichoderma virens and a Biopolymer-Based Biostimulant on Lettuce Agronomical, Physiological, and Qualitative P…
2020
The current research elucidated the agronomical, physiological, qualitative characteristics and mineral composition of lettuce (Lactuca sativa L. var. longifolia) after treatments with a beneficial fungus Trichoderma virens (TG41) alone or in combination with a vegetal biopolymer-based biostimulant (VBP
Priming effect increases with depth in a boreal forest soil
2016
Abstract Climate warming increases labile carbon (C) inputs to soil through increased photosynthesis and C allocation belowground. This could counterintuitively lead to losses of soil C via priming effects (PE): the stimulation of soil organic matter (SOM) decomposition caused by labile C addition. Systematic quantification of PEs in different ecosystems is needed. We measured PEs of free-living soil microbes in different layers of a boreal forest soil, and found that the relative magnitude of the PE increased with soil depth. The relationship between relative PE and the added glucose amount also depended on the soil layer. Our results indicate that the decomposition of SOM in deeper soil l…
Determinants of the interannual relationships between remote sensed photosynthetic activity and rainfall in tropical Africa
2007
International audience; The response of photosynthetic activity to interannual rainfall variations in Africa South of the Sahara is examined using 20 years (1981-2000) of Normalised Difference Vegetation Index (NDVI) AVHRR data. Linear correlations and regressions were computed between annual NDVI and annual rainfall at a 0.5° latitude/longitude resolution, based on two gridded precipitation datasets (Climate Prediction Center Merged Analysis of Precipitation [CMAP] and Climatic Research Unit [CRU]). The spatial patterns were then examined to detect how they relate to the mean annual rainfall amounts, land-cover types as from the Global Land Cover 2000 data set, soil properties and soil typ…