Plant's life history can evolve in response to variation in climate spatio‐temporally, but numerous multiple‐species studies overlook species‐specific (especially a foundation species) ecological ...effects and genetic underpinnings. For a species to successfully invade a region, likely to become a foundation species, life‐history variation of invasive plants exerts considerable ecological and evolutionary impacts on invaded ecosystems. We examined how an invasive foundation plant, Spartina alterniflora, varied in its life history along latitudinal gradient using a common gardens experiment. Two common gardens were located at range boundary in tropical zone and main distribution area of S. alterniflora in temperate zone in China. Within each population/garden, we measured the onset time of three successive phenological stages constituting the reproductive phase and a fitness trait. In the low‐latitude garden with higher temperature, we found that reproductive phase was advanced and its length prolonged compared to the high‐latitude garden. This could possibly due to lower plasticity of maturity time. Additionally, plasticity in the length of the reproductive phase positively related with fitness in the low‐latitude garden. Marginal population from tropic had the lowest plasticity and fitness, and the poor capacity to cope with changing environment may result in reduction of this population. These results reflected genetic divergence in life history of S. alterniflora in China. Our study provided a novel view to test the center–periphery hypothesis by integration across a plant's life history and highlighted the significance in considering evolution. Such insights can help us to understand long‐term ecological consequences of life‐history variation, with implications for plant fitness, species interaction, and ecosystem functions under climate change.
The ecological effects of the variation in the plant life history of specific species (e.g., foundation species) and genetic underpinnings therein were rarely studied. We found that geographic populations of invasive Spartina alterniflora had different plasticity in the reproductive phase in response to warming, and the lowest plasticity and fitness of southernmost population may suggest the slowdown of rapid dispersion of S. alterniflora in China. Our study provided a novel view to test the center–periphery hypothesis by integration across a plant's life history.
Growth regulating factors (GRFs) have been shown to play important roles in plant growth and development. GRF genes represent a large multigene family in plants. Recently, genome-wide structural and ...evolutionary analyses of the GRF gene families in Arabidopsis, rice, and maize have been reported. Chinese cabbage (Brassica rapa L. ssp. pekinensis) is one of the most important vegetables for agricultural production, and a full genome assembly for this plant has recently been released. However, to our knowledge, the GRF gene family from Chinese cabbage has not been characterized in detail.
In this study, genome-wide analysis was carried out to identify all the GRF genes in Chinese cabbage. Based on the complete Chinese cabbage genome sequence, 17 nonredundant GRF genes, named BrGRFs, were identified and classified into six groups. Phylogenetic analysis of the translated GRF protein sequences from Chinese cabbage, Arabidopsis, and rice indicated that the Chinese cabbage GRF proteins were more closely related to the GRF proteins of Arabidopsis than to those of rice. Expression profile analysis showed that the BrGRF genes had uneven transcript levels in different organs or tissues, and the transcription of most BrGRF genes was induced by gibberellic acid (GA3) treatment. Additionally, over-expression of BrGRF8 in transgenic Arabidopsis plants increased the sizes of the leaves and other organs by regulation of cell proliferation.
The data obtained from this investigation will contribute to a better understanding of the characteristics of the GRF gene family in Chinese cabbage, and provide a basis for further studies to investigate GRF protein function during development as well as for Chinese cabbage-breeding programs to improve yield and/or head size.
A single, low dose of the NMDA receptor antagonist ketamine produces rapid antidepressant actions in treatment-resistant depressed patients. Understanding the cellular mechanisms underlying this will ...lead to new therapies for treating major depression. NMDARs are heteromultimeric complexes formed through association of two GluN1 and two GluN2 subunits. We show that in vivo deletion of GluN2B, only from principal cortical neurons, mimics and occludes ketamine's actions on depression-like behavior and excitatory synaptic transmission. Furthermore, ketamine-induced increases in mTOR activation and synaptic protein synthesis were mimicked and occluded in 2BΔCtx mice. We show here that cortical GluN2B-containing NMDARs are uniquely activated by ambient glutamate to regulate levels of excitatory synaptic transmission. Together these data predict a novel cellular mechanism that explains ketamine's rapid antidepressant actions. In this model, basal glutamatergic neurotransmission sensed by cortical GluN2B-containing NMDARs regulates excitatory synaptic strength in PFC determining basal levels of depression-like behavior.
Concepts that draw inspiration from soft biological tissues have enabled significant advances in creating artificial materials for a range of applications, such as dry adhesives, tissue engineering, ...biointegrated electronics, artificial muscles, and soft robots. Many biological tissues, represented by muscles, exhibit directionally dependent mechanical and electrical properties. However, equipping synthetic materials with tissue-like mechanical and electrical anisotropies remains challenging. Here, we present the bioinspired concepts, design principles, numerical modeling, and experimental demonstrations of soft elastomer composites with programmed mechanical and electrical anisotropies, as well as their integrations with active functionalities. Mechanically assembled, 3D structures of polyimide serve as skeletons to offer anisotropic, nonlinear mechanical properties, and crumpled conductive surfaces provide anisotropic electrical properties, which can be used to construct bioelectronic devices. Finite element analyses quantitatively capture the key aspects that govern mechanical anisotropies of elastomer composites, providing a powerful design tool. Incorporation of 3D skeletons of thermally responsive polycaprolactone into elastomer composites allows development of an active artificial material that can mimic adaptive mechanical behaviors of skeleton muscles at relaxation and contraction states. Furthermore, the fabrication process of anisotropic elastomer composites is compatible with dielectric elastomer actuators, indicating potential applications in humanoid artificial muscles and soft robots.
We developed analytical models of flexibility and elastic-stretchability for self-similar interconnect. The analytic solutions agree very well with the finite element analyses, both demonstrating ...that the elastic-stretchability more than doubles when the order of self-similar structure increases by one. Design optimization yields 90% and 50% elastic stretchability for systems with surface filling ratios of 50% and 70% of active devices, respectively. The analytic models are useful for the development of stretchable electronics that simultaneously demand large coverage of active devices, such as stretchable photovoltaics and electronic eye-ball cameras.
Electrical interconnects that adopt self-similar, serpentine layouts offer exceptional levels of stretchability in systems that consist of collections of small, non-stretchable active devices in the so-called island–bridge design. This paper develops analytical models of flexibility and elastic stretchability for such structures, and establishes recursive formulae at different orders of self-similarity. The analytic solutions agree well with finite element analysis, with both demonstrating that the elastic stretchability more than doubles when the order of the self-similar structure increases by one. Design optimization yields 90% and 50% elastic stretchability for systems with surface filling ratios of 50% and 70% of active devices, respectively.
Stretchable electronic devices that exploit inorganic materials are attractive due to their combination of high performance with mechanical deformability, particularly for applications in biomedical ...devices that require intimate integration with human body. Several mechanics and materials schemes have been devised for this type of technology, many of which exploit deformable interconnects. When such interconnects are fully bonded to the substrate and/or encapsulated in a solid material, useful but modest levels of deformation (<30–40%) are possible, with reversible and repeatable mechanics. Here, the use of prestrain in the substrate is introduced, together with interconnects in narrow, serpentine shapes, to yield significantly enhanced (more than two times) stretchability, to more than 100%. Fracture and cyclic fatigue testing on structures formed with and without prestrain quantitatively demonstrate the possible enhancements. Finite element analyses (FEA) illustrates the effects of various material and geometric parameters. A drastic decrease in the elastic stretchability is observed with increasing metal thickness, due to changes in the buckling mode, that is, from local wrinkling at small thicknesses to absence of such wrinkling at large thicknesses, as revealed by experiment. An analytic model quantitatively predicts the wavelength of this wrinkling, and explains the thickness dependence of the buckling behaviors.
A prestrain strategy is introduced as a means for enhancing the stretchability of for serpentine metal interconnect structures bonded to soft elastomers. Systematic studies of the buckling physics include results from analytical models, finite element method computations, and quantitative experiments. The results have general utility for future work in stretchable inorganic device systems.
Cordgrass (
Spartina alterniflora
) was introduced to China in 1979 from the United States for reducing coastal erosion. It grows vigorously in China and has spread over much of the Chinese coast, ...from Leizhou Peninsula to Liaoning, a range of more than 19 degrees of latitude. On the southern coast of China,
S. alterniflora
has invaded mangrove-dominated habitats during the last two decades, but little is known about interactions between native mangroves and invasive
S. alterniflora
.
We studied the distribution and competitive interactions between native mangroves and
S. alterniflora
in the Zhangjiang Estuary at four tidal sites along a salinity gradient: oligohaline upstream, mesohaline, polyhaline, and euhaline downstream.
S. alterniflora
occurred at all four sites, and several mangrove species occurred at all but the downstream euhaline site.
S. alterniflora
has invaded the estuary widely and has spread to the lower tidal margins of mangroves. It has not invaded mangrove areas with a closed canopy but has established in the mangrove zone where the canopy was opened by human disturbance.
Ramets of
S. alterniflora
transplanted into the understory of mangrove stands with closed canopies died within 10 weeks, but 37.5% survived and grew well on open mud flats.
S. alterniflora
had virtually no competitive effect on mangrove seedlings planted at the upstream oligohaline site. However,
S. alterniflora
competitively reduced biomass of mangrove seedlings to 33% over a period of 14 weeks at the mesohaline and polyhaline sites where human disturbance has opened the mangrove canopy. In contrast,
S. alterniflora
marginally facilitated growth and survival of experimental seedlings at the downstream euhaline site.
In China, mangroves occur along the coastline south of Whenzhou, but they have been severely disturbed and removed widely, mainly by mariculture activities. Natural vegetation patterns and our experimental results suggest that, without intervention,
S. alterniflora
could gradually replace these mangroves in mid-salinity regions of Chinese estuaries.
In order to understand the effects of low nitrogen (LN) stress on the growth and development in different genotypes of Chinese cabbage, the L40 genotype with high nitrogen utilization and the L14 ...genotype with LN utilization were selected as experimental materials. Field experiments and indoor hydroponic methods were used to study the different responses of two Chinese cabbage genotypes to low nitrogen levels. In this study, we also analyzed the genome-wide gene expression profiles of L40 and L14 in response to LN stress by high-throughput RNA sequencing technology. The results reveal that the L40 root system responds better to LN compared with L14. After LN stress, L40 can effectively absorb and transport NO3- and store it in the ground. It is precisely because of this characteristic of the L40 genotype that LN treatment did not have a significant effect on the chlorophyll (Chl) content and net photosynthetic rate (Pn) of the L40 Chinese cabbage compared with the L14 Chinese cabbage. These two different Chinese cabbage genotypes were shown to have differently expressed genes related to nitrate transport, auxin synthesis, and glutamate dehydrogenase synthesis. These genes function in the nitrogen pathway, which are important candidates for understanding the molecular host-response mechanisms to LN stress.
Characterization of temperature and thermal transport properties of the skin can yield important information of relevance to both clinical medicine and basic research in skin physiology. Here we ...introduce an ultrathin, compliant skin-like, or 'epidermal', photonic device that combines colorimetric temperature indicators with wireless stretchable electronics for thermal measurements when softly laminated on the skin surface. The sensors exploit thermochromic liquid crystals patterned into large-scale, pixelated arrays on thin elastomeric substrates; the electronics provide means for controlled, local heating by radio frequency signals. Algorithms for extracting patterns of colour recorded from these devices with a digital camera and computational tools for relating the results to underlying thermal processes near the skin surface lend quantitative value to the resulting data. Application examples include non-invasive spatial mapping of skin temperature with milli-Kelvin precision (±50 mK) and sub-millimetre spatial resolution. Demonstrations in reactive hyperaemia assessments of blood flow and hydration analysis establish relevance to cardiovascular health and skin care, respectively.
Power systems are striving for the decarbonization goal for long‐term sustainability. As a result, the renewable energy sources (RES) have been playing an increasingly important role in the ...generation portfolio. Power system flexibility maintaining the power balance under uncertain and variable RES generation has become a major concern during the energy transition. This paper proposes to apply new energy vehicles (NEV) including electric vehicles (EVs) and fuel cell vehicles (FCVs) as day‐ahead flexibility resources to make revenue by providing comprehensive capacity/energy flexibility in the ancillary service market. First, the detailed joint optimized operational strategies of the NEV fleet and the EV charging/hydrogen refuelling stations are formulated. Second, the design and service clearing methodology of the ancillary service market for flexibility enhancement is introduced. A game‐theoretic model is applied to determine the equilibrium price for both the demand and suppliers (namely NEV fleets) of operational flexibility. Third, case studies using IEEE benchmark systems are provided to validate the proposed methods. The results demonstrate that the joint optimization of NEV fleets, charging stations, and hydrogen refuelling stations can improve the power system operational flexibility, reduce the charging expense of NEV owners, and reduce the carbon emission by utilizing the green hydrogen.
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