Search results for "Photosynthesi"
showing 10 items of 310 documents
Three-dimensional crystallization of the light-harvesting complex from Mantoniella squamata (Prasinophyceae) requires an adequate purification proced…
1995
Abstract We present a new purification procedure for the light-harvesting complex of Mantoniella squamata whereupon three-dimensional crystallization succeeded. Previous purification methods were based on density centrifugations as the only separating principle. We have extended this preparation procedure by applying anion-exchange and molecular-sieve chromatography techniques. Purity and stability of the complex were proved by denaturing and non-denaturing polyacrylamide-gel electrophoresis, and spectroscopic measurements. With respect to contaminating lipids the purified pigment-protein complex was examined by thin-layer chromatography and the aggregation and/or oligomeric states were inv…
Linking photosynthesis and sun-induced fluorescence at sub-daily to seasonal scales
2018
Abstract Due to its close link to the photosynthetic process, sun-induced chlorophyll fluorescence (F) opens new possibilities to study dynamics of photosynthetic light reactions and to quantify CO2 assimilation rates. Although recent studies show that F is linearly related to gross primary production (GPP) on coarse spatial and temporal scales, it is argued that this relationship may be mainly driven by seasonal changes in absorbed photochemical active radiation (APAR) and less by the plant light use efficiency (LUE). In this work a high-resolution spectrometer was used to continuously measure red and far-red fluorescence and different reflectance indices within a sugar beet field during t…
Remote sensing of solar-induced chlorophyll fluorescence (SIF) in vegetation: 50 years of progress
2019
Remote sensing of solar-induced chlorophyll fluorescence (SIF) is a rapidly advancing front in terrestrial vegetation science, with emerging capability in space-based methodologies and diverse application prospects. Although remote sensing of SIF – especially from space – is seen as a contemporary new specialty for terrestrial plants, it is founded upon a multi-decadal history of research, applications, and sensor developments in active and passive sensing of chlorophyll fluorescence. Current technical capabilities allow SIF to be measured across a range of biological, spatial, and temporal scales. As an optical signal, SIF may be assessed remotely using high-resolution spectral sensors in …
Priming maritime pine megagametophytes during somatic embryogenesis improved plant adaptation to heat stress
2021
In the context of global climate change, forest tree research should be addressed to provide genotypes with increased resilience to high temperature events. These improved plants can be obtained by heat priming during somatic embryogenesis (SE), which would produce an epigenetic-mediated transgenerational memory. Thereby, we applied 37 °C or 50 °C to maritime pine (Pinus pinaster) megagametophytes and the obtained embryogenic masses went through the subsequent SE phases to produce plants that were further subjected to heat stress conditions. A putative transcription factor WRKY11 was upregulated in priming-derived embryonal masses, and also in the regenerated P37 and P50 plants, suggesting …
Strategies to Mitigate the Salt Stress Effects on Photosynthetic Apparatus and Productivity of Crop Plants
2018
Soil salinization represents one of the major limiting factors of future increase in crop production through the expansion or maintaining of cultivation area in the future. High salt levels in soils or irrigation water represent major environmental concerns for agriculture in semiarid and arid zones. Recent advances in research provide great opportunities to develop effective strategies to improve crop salt tolerance and yield in different environments affected by the soil salinity. It was clearly demonstrated that plants employ both the common adaptative responses and the specific reactions to salt stress. The review of research results presented here may be helpful to understand the physi…
C4-like photosynthesis and the effects of leaf senescence on C4-like physiology in Sesuvium sesuvioides (Aizoaceae).
2019
Sesuvium sesuvioides represents a young C4 lineage with C4-like metabolism: CO2 compensation points range between C4 and C3–C4 intermediate values, and Rubisco was detected in bundle sheath and mesophyll.
What is Vipp1 good for?
2018
While Vipp1 (also known as IM30) clearly is essential for proper biogenesis of thylakoid membranes in chloroplasts and cyanobacteria, the exact function of Vipp1/IM30 still remains unclear. The recent in vivo study of Gutu et al. now demonstrates that Vipp1/IM30 forms localized puncta specifically at highly curved membrane regions at the cell periphery. These Vipp1/IM30 puncta were found being highly dynamic under normal growth conditions, while it has recently been shown that they stably associate with membranes under high-light conditions. These observations, together with the observation that other Vipp1/IM30 homologous proteins also form puncta under stress conditions, indicate a protec…
Synthetic conversion of leaf chloroplasts into carotenoid-rich plastids reveals mechanistic basis of natural chromoplast development
2020
Plastids, the defining organelles of plant cells, undergo physiological and morphological changes to fulfill distinct biological functions. In particular, the differentiation of chloroplasts into chromoplasts results in an enhanced storage capacity for carotenoids with industrial and nutritional value such as beta-carotene (provitamin A). Here, we show that synthetically inducing a burst in the production of phytoene, the first committed intermediate of the carotenoid pathway, elicits an artificial chloroplast-to-chromoplast differentiation in leaves. Phytoene overproduction initially interferes with photosynthesis, acting as a metabolic threshold switch mechanism that weakens chloroplast i…
GreenCut proteinCPLD49 ofChlamydomonas reinhardtiiassociates with thylakoid membranes and is required for cytochromeb6fcomplex accumulation
2018
The GreenCut encompasses a suite of nucleus-encoded proteins with orthologs among green lineage organisms (plants, green algae), but that are absent or poorly conserved in non-photosynthetic/heterotrophic organisms. In Chlamydomonas reinhardtii, CPLD49 (Conserved in Plant Lineage and Diatoms49) is an uncharacterized GreenCut protein that is critical for maintaining normal photosynthetic function. We demonstrate that a cpld49 mutant has impaired photoautotrophic growth under high-light conditions. The mutant exhibits a nearly 90% reduction in the level of the cytochrome b6 f complex (Cytb6 f), which impacts linear and cyclic electron transport, but does not compromise the ability of the stra…
Opposite trends in the genus Monsonia (Geraniaceae): Specialization in the African deserts and range expansions throughout eastern Africa
2017
The African Austroerate Flora stands out by its important species richness. A distinctive element of this flora is Monsonia (Geraniaceae), mostly found in the Namib-Karoo but also in the Natal-Drakensberg, the Somalian Zambezian and the Saharo-Arabian regions. Here, we reconstruct the evolution and biogeographic history of Monsonia based on nuclear and plastid markers, and examine the role of morphological and niche evolution in its diversification using species distribution modeling and macroevolutionary models. Our results indicate that Monsonia first diversified in the Early Miocene c.21 Ma, coinciding with the start of desertification in southwestern Africa. An important diversification…