Salt Tolerance Mechanisms of Plants van Zelm, Eva; Zhang, Yanxia; Testerink, Christa
Annual review of plant biology,
04/2020, Letnik:
71, Številka:
1
Journal Article
Recenzirano
Crop loss due to soil salinization is an increasing threat to agriculture worldwide. This review provides an overview of cellular and physiological mechanisms in plant responses to salt. We place ...cellular responses in a time- and tissue-dependent context in order to link them to observed phases in growth rate that occur in response to stress. Recent advances in phenotyping can now functionally or genetically link cellular signaling responses, ion transport, water management, and gene expression to growth, development, and survival. Halophytes, which are naturally salt-tolerant plants, are highlighted as success stories to learn from. We emphasize that (
a
) filling the major knowledge gaps in salt-induced signaling pathways, (
b
) increasing the spatial and temporal resolution of our knowledge of salt stress responses, (
c
) discovering and considering crop-specific responses, and (
d
) including halophytes in our comparative studies are all essential in order to take our approaches to increasing crop yields in saline soils to the next level.
As there has been an explosive increase in wireless data traffic, mmw communication has become one of the most attractive techniques in the 5G mobile communications systems. Although mmw ...communication systems have been successfully applied to indoor scenarios, various external factors in an outdoor environment limit the applications of mobile communication systems working at the mmw bands. In this article, we discuss the issues involved in the design of antenna array architecture for future 5G mmw systems, in which the antenna elements can be deployed in the shapes of a cross, circle, or hexagon, in addition to the conventional rectangle. The simulation results indicate that while there always exists a non-trivial gain fluctuation in other regular antenna arrays, the circular antenna array has a flat gain in the main lobe of the radiation pattern with varying angles. This makes the circular antenna array more robust to angle variations that frequently occur due to antenna vibration in an outdoor environment. In addition, in order to guarantee effective coverage of mmw communication systems, possible solutions such as distributed antenna systems and cooperative multi-hop relaying are discussed, together with the design of mmw antenna arrays. Furthermore, other challenges for the implementation of mmw cellular networks, for example, blockage, communication security, hardware development, and so on, are discussed, as are potential solutions.
When plants face an environmental stress such as water deficit, soil salinity, high temperature, or shade, good communication between above- and belowground organs is necessary to coordinate growth ...and development. Various signals including hormones, peptides, proteins, hydraulic signals, and metabolites are transported mostly through the vasculature to distant tissues. How shoots and roots synchronize their response to stress using mobile signals is an emerging field of research. We summarize recent advances on mobile signals regulating shoot stomatal movement and root development in response to highly localized environmental cues. In addition, we highlight how the vascular system is not only a conduit but is also flexible in its development in response to abiotic stress.
Limitations in water uptake in roots and sucrose supply from shoots under abiotic stress can be encoded into signals that regulate the growth and development of distant tissues.Root-localized stress signals trigger changes in xylem hydraulics, mobile peptides, reactive oxygen species (ROS), and Ca2+, which lead to remote effects and induce shoot stomatal closure.The mobility of HY5 protein and its downstream targets via the phloem conveys shoot-sensed light and temperature information to affect both primary and lateral root growth.Shoot-derived sucrose loading/unloading in the phloem is highly responsive to environmental changes, and triggers signaling pathways that regulate root development.Developmental plasticity of the vasculature in response to abiotic stresses is of key importance for long-distance transport of substances to assist plant stress resilience.
Increasing soil salinization largely impacts crop yield worldwide. To deal with salinity stress, plants exhibit an array of responses, including root system architecture remodelling. Here, we review ...recent progress in physiological, developmental and cellular mechanisms of root growth responses to salinity. Most recent research in modulation of root branching, root tropisms, as well as in root cell wall modifications under salinity stress, is discussed in the context of the contribution of these responses to overall plant performance. We highlight the power of natural variation approaches revealing novel potential pathways responsible for differences in root salt stress responses. Together, these new findings promote our understanding of how salt shapes the root phenotype, which may provide potential avenues for engineering crops with better yield and survival in saline soils.
This review highlights recent research on the effect of soil salinity on root growth modulation. We discuss root architecture plasticity, root tropisms and root cell wall modifications under salinity stress in Arabidopsis thaliana and several crop species.
•The energy transmission characteristics of overhead and cable hybrid HVDC lines are obtained by theoretical analysis.•A fault segment identification method based on the energy ratio at both ends of ...the hybrid HVDC transmission line is proposed, and the auxiliary criterion to prevent the misjudgment of line connection point fault is given.•Utilize the relationship between energy ratio and fault point distance to realize fault location within fault segment. The principle of fault location method is clear and easy to implement.
This paper proposes a fault location method for overhead and cable hybrid line in VSCHVDC system. Firstly, the energy transmission characteristics in overhead and cable hybrid DC line is analyzed respectively. Secondly, the change of energy ratio at both ends of the line with fault points is studied, a fault segment identification method based on the energy ratio of two ends is proposed, and the auxiliary criterion to prevent misjudgment of line connection point fault is given. On this basis, the relationship between the energy ratio and the fault distance is derived, and the fault location equation is established to locate the fault within the segment. In the paper, the influence of unsynchronous sampling data on fault location accuracy is also analyzed, and a simulation model is built using PSCAD/EMTDC to verify the effectiveness of the proposed fault location method for overhead and cable hybrid line in VSCHVDC system.
Using the wide area information obtained from phasor measurement units, a novel out-of-step splitting protection is proposed. In order to analyze the different characteristic of bus voltage phase ...angles, a new coordinate system is introduced. In this coordinate system, all of the converted bus voltage phasor ends are stable, while only the common beginning is moving during the out-of-step oscillation process. Its conformal property guarantees the voltage phase angle differences in the old and new coordinate systems are equal. After the coordinate transformation, the formula about the converted power network neutral point trajectory is derived. The intersection of the trajectory and the broken line which connects the bus voltage phasor ends is the out-of-step center. All of the buses are divided into two parts by the out-of-step center. Through a series of proofs, it is found that the absolute values of the bus voltage phase angles in one part are always smaller than 110°, while the voltage phase angles of the rest buses vary from -180° to 180°. These different characteristics could be used to group these buses and locate the out-of-step center. It is very simple because only the voltage phase angle information is applied, and there are no complex mathematical operations. Finally, a novel out-of-step splitting protection scheme is given. The digital simulation results prove the proposed scheme is efficient.
Abstract
A H
ii
region is a kind of emission nebula, and more definite samples of H
ii
regions can help study the formation and evolution of galaxies. Hence, a systematic search for H
ii
regions is ...necessary. The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) conducts medium-resolution spectroscopic surveys and provides abundant valuable spectra for unique and rare celestial body research. Therefore, the medium-resolution spectra of LAMOST are an ideal data source for searching for Galactic H
ii
regions. This study uses the LAMOST spectra to expand the current spectral sample of Galactic H
ii
regions through machine learning. Inspired by deep convolutional neural networks with wide first-layer kernels (WDCNN), a new spectral-screening method, multihead WDCNN, is proposed and implemented. Infrared criteria are further used for the identification of Galactic H
ii
region candidates. Experimental results show that the multihead WDCNN model is superior to other machine-learning methods and it can effectively extract spectral features and identify H
ii
regions from the massive spectral database. In the end, among all candidates, 57 H
ii
regions are identified and known in SIMBAD, and four objects are identified as “to be confirmed” Galactic H
ii
region candidates. The known H
ii
regions and H
ii
region candidates can be retrieved from the LAMOST website.
Recent studies show that international trade affects global distributions of air pollution and public health. Domestic interprovincial trade has similar effects within countries, but has not been ...comprehensively investigated previously. Here we link four models to evaluate the effects of both international exports and interprovincial trade on PM
pollution and public health across China. We show that 50-60% of China's air pollutant emissions in 2007 were associated with goods and services consumed outside of the provinces where they were produced. Of an estimated 1.10 million premature deaths caused by PM
pollution throughout China, nearly 19% (208,500 deaths) are attributable to international exports. In contrast, interprovincial trade leads to improved air quality in developed coastal provinces with a net effect of 78,500 avoided deaths nationwide. However, both international export and interprovincial trade exacerbate the health burdens of air pollution in China's less developed interior provinces. Our results reveal trade to be a critical but largely overlooked consideration in effective regional air quality planning for China.International and domestic interprovincial trade of China are entangled, but their health impacts have been treated separately in earlier studies. Here Wang. quantify the complex impacts of trade on public health across China within an integrative framework.
Jasmonates are plant signalling molecules that play key roles in defence against insects and certain pathogens, among others by controlling the biosynthesis of protective secondary metabolites. In ...Catharanthus roseus, the AP2/ERF-domain transcription factor ORCA3 controls the jasmonate-responsive expression of several genes encoding enzymes involved in terpenoid indole alkaloid biosynthesis. ORCA3 gene expression is itself induced by jasmonate. The ORCA3 promoter contains an autonomous jasmonate-responsive element (JRE) composed of a quantitative sequence responsible for the high level of expression and a qualitative sequence that acts as an on/off switch in response to methyl-jasmonate (MeJA). Here, we identify the basic helix-loop-helix (bHLH) transcription factor CrMYC2 as the major activator of MeJA-responsive ORCA3 gene expression. The CrMYC2 gene is an immediate-early jasmonate-responsive gene. CrMYC2 binds to the qualitative sequence in the ORCA3 JRE in vitro, and transactivates reporter gene expression via this sequence in transient assays. Knock-down of the CrMYC2 expression level via RNA interference caused a strong reduction in the level of MeJA-responsive ORCA3 mRNA accumulation. In addition, MeJA-responsive expression of the related transcription factor gene ORCA2 was significantly reduced. Our results show that MeJA-responsive expression of alkaloid biosynthesis genes in C. roseus is controlled by a transcription factor cascade consisting of the bHLH protein CrMYC2 regulating ORCA gene expression, and the AP2/ERF-domain transcription factors ORCA2 and ORCA3, which in turn regulate a subset of alkaloid biosynthesis genes.
Abstract
Despite paramount applications of chiral trifluoromethylated compounds in medicinal chemistry and materials science, limited strategies have been developed for catalytic asymmetric synthesis ...of such valuable fluorinated structures. Here, we report a nickel catalyzed enantioselective dicarbofunctionalization of inexpensive industrial chemical 3,3,3-trifluoropropene (TFP) with readily available tertiary alkyl and aryl iodides. The reaction overcomes the β-F elimination side reaction of TFP, and proceeds efficiently under mild reaction conditions. The protocol possesses advantages, such as synthetic convenience, high enantioselectivity, and excellent functional group tolerance, providing rapid and straightforward access to chiral trifluoromethylated compounds of medicinal interest.
PDF
