Ontogenetic changes of the water status and accumulated soluble compounds in developing and ripening mume (Prunus mume) fruit measured by 1H-NMR analysis

The physiological changes of intact mume (Prunus mume Sieb. et Zucc. cv. Rinshu) fruit tissues were examined by measuring the physical states of cell-associated water in the fruit tissues with developing and ripening using 1H-NMR spectroscopy. We found that the water molecules in mume fruit tissues existed in several different compartments with different mobilities. Additionally, spectral recovery in the water proton indicated reverse relationships between the pericarps and seeds at the immature and mature stages. In the pericarp tissues, the longest T1 and longer T2 markedly increased, while those in the seeds decreased. From these results, the change in the water status with growth stage had reverse trajectories in the pericarp and seed of the fruit. In the pericarp tissues, both water uptake and dry weight prominently increased with ripening. The epidermis and inner parenchymal cells of the pericarp tissues remarkably enlarged as a sigmoidal growth curve. Membrane permeability, indicating a loss of membrane integrity, increased in the pericarp tissues. The elongation in the fully vacuolated cells and changes in the membrane permeability in the pericarp tissues with ripening correlated to the longest T1. In contrast, the high mobility of water in the seeds began to decrease with maturation, while oil began to accumulate. Thus, the mobility of water, as analyzed in this study, is considered to reflect the results of physiological changes such as cellular heterogeneity and spatial arrangements both in the pericarp and in seed tissues for mume fruit with development and ripening

Mechanism of delayed seed germination caused by high temperature during grain filling in rice (Oryza sativa L.)

High temperature during grain filling considerably reduces yield and quality in rice (Oryza sativa L.); however, how high temperature affects seed germination of the next generation is not yet well understood. Here, we report that seeds from plants exposed to high temperature during the grain filling stage germinated significantly later than seeds from unstressed plants. This delay remained even after dormancy release treatments, suggesting that it was not due to primary seed dormancy determined during grain filling. In imbibed embryos of heat-stressed seeds, expression of abscisic acid (ABA) biosynthesis genes (OsNCEDs) was higher than in those of control seeds, whereas that of ABA catabolism genes (OsABA8′OHs) was lower. In the aleurone layer, despite no change in GA signaling as evidenced by no effect of heat stress on OsGAMYB gene expression, the transcripts of α-amylase genes OsAmy1C, OsAmy3B, and OsAmy3E were significantly down-regulated in heat-stressed seeds in comparison with controls. Changes in promoter methylation levels were consistent with transcriptional changes of ABA catabolism-related and α-amylase genes. These data suggest that high temperature during grain filling results in DNA methylation of ABA catabolism-related and α-amylase gene promoters, delaying germination of heat-stressed seeds

Trehalose Metabolism: From Osmoprotection to Signaling

Trehalose is a non-reducing disaccharide formed by two glucose molecules. It is widely distributed in Nature and has been isolated from certain species of bacteria, fungi, invertebrates and plants, which are capable of surviving in a dehydrated state for months or years and subsequently being revived after a few hours of being in contact with water. This disaccharide has many biotechnological applications, as its physicochemical properties allow it to be used to preserve foods, enzymes, vaccines, cells etc., in a dehydrated state at room temperature. One of the most striking findings a decade ago was the discovery of the genes involved in trehalose biosynthesis, present in a great number of organisms that do not accumulate trehalose to significant levels. In plants, this disaccharide has diverse functions and plays an essential role in various stages of development, for example in the formation of the embryo and in flowering. Trehalose also appears to be involved in the regulation of carbon metabolism and photosynthesis. Recently it has been discovered that this sugar plays an important role in plant-microorganism interactions

Increased Anion Channel Activity Is an Unavoidable Event in Ozone-Induced Programmed Cell Death

Ozone is a major secondary air pollutant often reaching high concentrations in urban areas under strong daylight, high temperature and stagnant high-pressure systems. Ozone in the troposphere is a pollutant that is harmful to the plant. generation by salicylic and abscisic acids. Anion channel activation was also shown to promote the accumulation of transcripts encoding vacuolar processing enzymes, a family of proteases previously reported to contribute to the disruption of vacuole integrity observed during programmed cell death.-induced programmed cell death. Because ion channels and more specifically anion channels assume a crucial position in cells, an understanding about the underlying role(s) for ion channels in the signalling pathway leading to programmed cell death is a subject that warrants future investigation

Search for Eccentric Black Hole Coalescences during the Third Observing Run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass $M>70$ $M_\odot$) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities $0 < e \leq 0.3$ at $0.33$ Gpc$^{-3}$ yr$^{-1}$ at 90\% confidence level.Comment: 24 pages, 5 figure

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M&gt;70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0&lt;e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM