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We demonstrate high-performance photodetectors based on Eu-doped 2D perovskite nanowire arrays. The pure crystallographic orientation enables efficient carrier transport and the doped Eu ions effectively suppress the trap density in the nanowire arrays. As a result, the optimized Eu-doped photodetectors show an excellent responsivity of 6.24 A W

The application of selenium (Se) can promote the growth of potatoes and increase the Se content of potato tubers. Nitrogen (N) can promote nutrient absorption and potato yield. However, the effects of Se and N on the yield and Se content of potato tubers have not been reported. Field experiments were conducted in 2019–2020 and 2020–2021. Three N levels, i.e., 0 kg N ha−1 (N0), 150 kg N ha−1 (N1) and 200 kg N ha−1 (N2), and three Se levels, i.e., 0 g Se ha−1 (Se0), 500 g Se ha−1 (Se1) and 1000 g Se ha−1 (Se2), were set up. Potato yield, root dry weight, root activity, leaf area index (LAI), net photosynthetic rate (Pn), malondialdehyde (MDA) content, antioxidant enzyme activity and Se content were investigated. N application increased root dry weight and activity, LAI, antioxidant enzymes activities, Se content and decreased MDA content. Pn, total potato yield and commercial potato yield first increased and then decreased with the increase in N application level. Se application increased root activity, Pn, antioxidant enzyme activities, total yield, commercial potato yield, commercial potato rate, Se content and decreased MDA content. In general, compared with the single application, the combination of N and Se fertilizers further promoted the growth of potatoes, increased the yield of potatoes and the Se content of potato pieces.

Detecting conformational changes in protein is imperative due to its major role in neurodegenerative disorders. Here, we propose an alternative strategy for monitoring the structural change of proteins based on biological microlasers. Smart responsive protein-based microscale biolasers were constructed by incorporating organic gain medium into the microspheres of silk fibroin via emulsion-solvent evaporation. The lasing characteristic of the biolasers exhibited a sensitive response to the structural transformation of the silk fibroin. With narrowed linewidth, the as-prepared biolasers as sensing signals enable highly sensitive protein conformation detection. These results offer an effective approach to monitoring the protein conformational changes and provide valuable guidance for a better understanding of the relationship between bio-microstructures and their photonic properties.

Background Chenopodium quinoa is a crop with outstanding tolerance to saline soil, but long noncoding RNAs (LncRNAs) expression profile driven by salt stress in quinoa has rarely been observed yet. Based on the high-quality quinoa reference genome and high-throughput RNA sequencing (RNA-seq), genome-wide identification of LncRNAs was performed, and their dynamic response under salt stress was then investigated. Results In total, 153,751 high-confidence LncRNAs were discovered and dispersed intensively in chromosomes. Expression profile analysis demonstrated significant differences between LncRNAs and coding RNAs. Under salt stress conditions, 4,460 differentially expressed LncRNAs were discovered, of which only 54 were differentially expressed at all the stress time points. Furthermore, a weighted co-expression network was then constructed to infer the potential biological functions of LncRNAs. Seven modules were significantly correlated with salt treatments, resulting in 210 hub genes, including 22 transcription factors and 70 LncRNAs. These results indicated that LncRNAs might interact with transcription factors to respond to salinity stress. Gene ontology enrichment of the coding genes of these modules showed that they were highly related to regulating metabolic processes, biological regulation and response to stress. Conclusions This study is the first report on genome-wide analysis of the LncRNAs responding to salt stress in quinoa. The findings will provide a solid framework for further functional research of salt responsive LncRNAs, contributing to quinoa genetic improvement.

Micro/nanoscale photonic barcodes based on multicolor luminescent segmented heterojunctions hold potential for applications in information security. However, such multicolor heterojunctions reported thus far are exclusively based on static luminescent signals, thus restricting their application in advanced confidential information protection. Reported here is a strategy to design responsive photonic barcodes with heterobimetallic (Tb3+ /Eu3+ ) metal-organic framework multicolor heterostructures. The spatial colors could be precisely controlled by thermally manipulating the energy-transfer process between the two lanthanides, thus achieving responsive covert photonic barcodes. Also demonstrated is that spatially resolved responsive barcodes with multi-responsive features could be created in a single heterostructure. These findings offer unique opportunities to purposely design highly integrated responsive microstructures and smart devices toward advanced anti-counterfeiting applications.

Circularly polarized light (CPL) detection has emerged as a key technology for various optoelectronics. Chiral hybrid perovskites (CHPs) that combine CPL‐sensitive absorption induced by chiral organic ligands and superior photoelectric properties of perovskites are promising candidates for direct CPL detection. To date, most of the CHP detectors are made up of polycrystalline thin‐film, which results in a rather limited discrimination of CPL due to the existence of redundant impurities and intrinsic defect states originating from rapid crystallization process. Here, it is developed a direct CPL detector with high photocurrent and polarization selectivity based on low‐defect CHP single‐crystal nanowire arrays. Large‐scale CHP nanowires are obtained through a micropillar template‐assisted capillary‐bridge rise approach. Thanks to the high crystallinity and ordered crystallographic alignment of these arrays, a CPL photodetector with high light on/off ratio of 1.8 × 104, excellent responsivity of 1.4 A W−1, and an outstanding anisotropy factor of 0.24 for photocurrent has been achieved. These results would provide useful enlightenment for direct CPL detection in high‐performance chiral optoelectronics., An efficient circularly polarized light (CPL) detector is demonstrated with large‐scale chiral hybrid perovskite (CHP) nanowire arrays. Based on the high photocurrent and polarization selectivity of CHP single‐crystals, high‐performance CPL detectors with high light on/off ratio and excellent polarization distinguishability through arranging such single‐crystalline CHP nanowires into low‐defect arrays are achieved.

Potassium (K) is the essential element for plant growth. It is one of the critical factors that determine crop yield, quality, and especially leaf development in tobacco. However, the molecular mechanism of potassium use efficiency (KUE), especially non-coding RNA, is still unknown. In this study, tobacco seedlings were employed, and their hydro-cultivation with K treatments of low and sufficient concentrations was engaged. Physiological analysis showed that low potassium treatment could promote malondialdehyde (MDA) accumulation and antioxidant enzyme activities such as peroxidase (POD), ascorbate-peroxidase (APX). After transcriptomic analysis, a total of 10,585 LncRNA transcripts were identified, and 242 of them were significantly differently expressed under potassium starvation. Furthermore, co-expression networks were constructed and generated 78 potential regulation modules in which coding gene and LncRNAs are involved and functional jointly. By further module-trait analysis and module membership (MM) ranking, nine modules, including 616 coding RNAs and 146 LncRNAs, showed a high correlation with K treatments, and 20 hub K-responsive LncRNAs were finally predicted. Following gene ontology (GO) analysis, the results showed potassium starvation inducing the pathway of antioxidative stress which is consistent with the physiology result mentioned above. Simultaneously, a part of detected LncRNAs, such as

Secondary wall-associated NAC (SWN) genes are a subgroup of NAC (NAM, ATAF, and CUC) transcription factors (TF) that play a key role in regulating secondary cell wall biosynthesis in plants. However, this gene family has not been systematically characterized, and their potential roles in response to hormones are unknown in Nicotiana tabacum. In this study, a total of 40 SWN genes, of which 12 from Nicotiana tomentosiformis, 13 from Nicotiana sylvestris, and 15 from Nicotiana tabacum, were successfully identified. The 15 SWNs from Nicotiana tabacum were further classified into three groups, namely, vascular-related NAC domain genes (NtVNDs), NAC secondary wall thickening promoting factor genes (NtNSTs), and secondary wall-associated NAC domain genes (NtSNDs). The protein characteristic, gene structure, and chromosomal location of 15 NtSWNs (also named Nt1 to Nt15) were also analyzed. The NtVND and NtNST group genes had five conserved subdomains in their N-terminal regions and a motif (LP[Q/x] L[E/x] S[P/A]) in their diverged C- terminal regions. Some hormones, dark and low-temperature related cis-acting elements, were significantly enriched in the promoters of NtSWN genes. A comprehensive expression profile analysis revealed that Nt4 and Nt12 might play a role in vein development. Others might be important for stem development. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) revealed that in the NtNST group, genes such as Nt7, Nt8, and Nt13 were more sensitive than the genes in NtVND and NtSND groups under abiotic stress conditions. A transactivation assay further suggested that Nt7, Nt8, and Nt13 showed a significant transactivation activity. Overall, SWN genes were finally identified and characterized in diploid and tetraploid tobacco, revealing new insights into their evolution, variation, and homology relationships. Transcriptome, cis-acting element, qRT-PCR, and transactivation assay analysis indicated the roles in hormonal and stress responses, which provided further resources in molecular mechanism and genetic improvement.

Micro/nanoscale multicolor barcodes with unique identifiability and a small footprint play significant roles in applications such as multiplexed labeling and tracking systems. Now, a strategy is reported to design multicolor photonic barcodes based on 1D Ln-MOF multiblock heterostructures, where the domain-controlled emissive colors and different block lengths constitute the fingerprint of a corresponding heterostructure. The excellent heteroepitaxial growth characteristics of MOFs enable the effective modulation of the coding structures, thereby remarkably increasing the encoding capacity. The as-prepared multicolor barcodes enable an efficient authentication and exhibit great potential in fulfilling the functions of anti-counterfeiting, information security, and so on. The results will pave an avenue to novel hybrid MOFs for optical data recording and security labels.

Highly sensitive photodetectors play significant roles in modern optoelectronic integrated circuits. Constructing p-n junctions has been proven to be a particularly powerful approach to realizing sensitive photodetection due to their efficient carrier separation. Recently, p-n-junction photodetectors based on organic-inorganic hybrid perovskites, which combine favorable optoelectronic performance with facile processability, hold great potential in practical applications. So far, these devices have generally been made of polycrystalline films, which exhibit poor carrier-transport efficiency, impeding the further improvement of their photoresponsivities. Here, a type of ultrasensitive photodetector based on single-crystalline perovskite p-n-junction nanowire arrays is demonstrated. The single-crystalline perovskite p-n-junction nanowire arrays not only possess high crystallinity that enables efficient carrier transport but also form a built-in electric field facilitating effective carrier separation. As a result, the devices show excellent photosensitivity over a wide spectral range from 405 to 635 nm with an outstanding responsivity of 2.65 × 10

Organic materials are an important class of gain media for fabricating miniaturized lasers because they combine fabrication simplicity with wide spectral coverage and tunability. However, progress toward near-infrared (NIR) organic solid-state lasers has been limited because of serious nonradiative processes originating from the severe intermolecular interaction in the condensed state. Here, we develop a strategy to realize room-temperature NIR microscale lasers through encapsulating organic dyes into the cavities of metal-organic frameworks (MOFs). The spatial confinement of the dye molecules within the MOF pores contributes to suppressing the multiple nonradiative processes (i.e., aggregation-caused quenching and exciton-exciton annihilation). This results in a much higher radiative efficiency and thus much easier population inversion and low-threshold NIR lasing. Furthermore, the lasing wavelength can be further expanded based on the tailorable energy levels of the dye molecules. The results will provide useful enlightenment for the development of miniaturized NIR laser sources for new photonic applications.

Extreme drought is likely to become more frequent and intense as a result of global climate change, which may significantly impact plant root traits and responses (i.e., morphology, production, turnover, and biomass). However, a comprehensive understanding of how drought affects root traits and responses remains elusive. Here, we synthesized data from 128 published studies under field conditions to examine the responses of 17 variables associated with root traits to drought. Our results showed that drought significantly decreased root length and root length density by 38.29% and 11.12%, respectively, but increased root diameter by 3.49%. However, drought significantly increased root:shoot mass ratio and root cortical aerenchyma by 13.54% and 90.7%, respectively. Our results suggest that drought significantly modified root morphological traits and increased root mortality, and the drought-induced decrease in root biomass was less than shoot biomass, causing higher root:shoot mass ratio. The cascading effects of drought on root traits and responses may need to be incorporated into terrestrial biosphere models to improve prediction of the climate-biosphere feedback.

Point placement of urea is an efficient technology to improve urea use efficiency in transplanted rice (Oryza sativa L.), but it is largely unknown how nutrient composition in the point placement and the distance from placement site to the plant influence rice root distribution and growth, nutrient uptake, and rice grain yield. A controlled greenhouse experiment was conducted using both N- and P-deficient soil with point placement of N only or N and P together (N + P) at a distance close to or far from the plant, in comparison to an N-spilt application and a no-N control. Both nutrient composition and distance significantly affected rice root growth. Compared with the N point placement, the N + P point placement led to smaller root length and mass densities, higher specific root length (SRL) around the placement site, smaller root system, higher straw mass and grain yield, and higher N and P uptake. The difference between the N + P and N point placements was greater when close to the plant than when far from the plant. It is suggested that higher SRL around the placement site is essential for improving nutrient uptake and rice grain yield, and simultaneous point placement of N and P has a synergistic effect on rice growth.

Quinoa is a gluten-free food crop that contains all the essential amino acids and vitamins. The selection of proper housekeeping and tissue-specific genes is the crucial prerequisite for gene expression analysis using the common approach, real-time quantitative PCR (RT-qPCR). In this study, we identified 40 novel candidate housekeeping genes by the minimum transcript per million (TPM), coefficient of variation (CV) and maximum fold change (MFC) methods and 19 candidate tissue-specific genes by the co-expression network method based on an RNA-seq dataset that included 53 stem, leaf, flower and seed samples, as well as additional shoot and root samples under different stresses. The expression stability of 12 housekeeping and tissue-specific genes, as well as that of another two traditionally used housekeeping genes, was further evaluated using qPCR and ranked using NormFinder, BestKeeper and the comparative delta-Ct method. The results demonstrated that MIF, RGGA, VATE and UBA2B were ranked as the top four most stable candidate housekeeping genes. qPCR analysis also revealed three leaf-specific genes and five root-specific genes, but no stem-specific gene was identified. Gene Ontology (GO) enrichment analysis identified that housekeeping genes were mainly enriched in the small molecule metabolic process, organonitrogen compound metabolic process, NAD binding and ligase activity. In addition, tissue-specific genes are closely associated with the major functions of a specific tissue. Specifically, GO terms “photosynthesis” and “thylakoid” were most significantly overrepresented in candidate leaf-specific genes. The novel housekeeping and tissue-specific genes in our study will enable better normalization and quantification of transcript levels in quinoa.

We demonstrate the fabrication of organic high Q active whispering-gallery-mode (WGM) resonators from π-conjugated polymer by a controlled emulsion-solvent-evaporation method, which can simultaneously provide optical gain and act as an effective resonant cavity. By measuring the shift of their lasing modes on exposure to organic vapor, we successfully monitored the slight concentration variation in the chemical gas. These microlaser sensors demonstrated high detection sensitivity and good signal repeatability under continuous chemical gas treatments. The results offer an effective strategy to design miniaturized optical sensors.

Background Several studies have mined short-read RNA sequencing datasets to identify long non-coding RNAs (lncRNAs), and others have focused on the function of individual lncRNAs in abiotic stress response. However, our understanding of the complement, function and origin of lncRNAs – and especially transposon derived lncRNAs (TE-lncRNAs) - in response to abiotic stress is still in its infancy. Results We utilized a dataset of 127 RNA sequencing samples that included total RNA datasets and PacBio fl-cDNA data to discover lncRNAs in maize. Overall, we identified 23,309 candidate lncRNAs from polyA+ and total RNA samples, with a strong discovery bias within total RNA. The majority (65%) of the 23,309 lncRNAs had sequence similarity to transposable elements (TEs). Most had similarity to long-terminal-repeat retrotransposons from the Copia and Gypsy superfamilies, reflecting a high proportion of these elements in the genome. However, DNA transposons were enriched for lncRNAs relative to their genomic representation by ~ 2-fold. By assessing the fraction of lncRNAs that respond to abiotic stresses like heat, cold, salt and drought, we identified 1077 differentially expressed lncRNA transcripts, including 509 TE-lncRNAs. In general, the expression of these lncRNAs was significantly correlated with their nearest gene. By inferring co-expression networks across our large dataset, we found that 39 lncRNAs are as major hubs in co-expression networks that respond to abiotic stress, and 18 appear to be derived from TEs. Conclusions Our results show that lncRNAs are enriched in total RNA samples, that most (65%) are derived from TEs, that at least 1077 are differentially expressed during abiotic stress, and that 39 are hubs in co-expression networks, including a small number that are evolutionary conserved. These results suggest that lncRNAs, including TE-lncRNAs, may play key regulatory roles in moderating abiotic responses.

Several studies have mined short-read RNA sequencing datasets to identify lncRNAs, and others have focused on the function of individual lncRNA in abiotic stress response. However, our understanding of the complement, function and origin of long-non-coding RNA (lncRNAs) response to abiotic stress, especially transposon derived lncRNA (TE-lncRNA), is still in its infancy. To discover and study lncRNAs in maize (Zea mays ssp. mays), we utilized a dataset of 127 RNA sequencing samples that included PacBio fl-cDNA and total RNA-Seq datasets. Overall, we identified 23,309 candidate lncRNAs, 60% of which were identified in polyadenylated (polyA+) samples. The majority (65%) of the 23,309 lncRNAs had sequence similarity to transposable elements (TEs). Most had similarity to long-terminal-repeat retrotransposons from the Copia and Gypsy superfamilies, representing the high proportion of these elements in the genome, but class II, DNA transposons were enriched for lncRNAs relative to their genomic representation by 2-fold. By assessing the fraction of lncRNAs that respond to abiotic stresses like heat, cold, salt and drought, we identified 1,077 differentially expressed lncRNA transcripts. Their expression was correlated (r2=0.48) with their nearest gene, suggesting that lncRNAs are subject to some of the cis regulatory features as neighboring genes. By inferring co-expression networks across our large dataset, we found that 39 lncRNAs act as major hubs in co-expression networks, of which 18 appeared to be derived from TEs. These results suggest that lncRNAs, especially TE-lncRNAs, may play key regulatory roles in moderating abiotic responses.

We demonstrate efficient and stable dual-wavelength microlasers fabricated by encapsulating different organic dyes into metal–organic framework (MOF) microcrystals. The intermolecular interactions between the organic dyes are suppressed effectively by the spatial confinement effect of the MOF pores, enabling a simultaneously efficient optical gain, and therefore lasing at different wavelengths. The results represent an important step towards a function-oriented laser material design.

Additional file 1: Figure S1. A schematic showing the data used in this paper, the bioinformatic pipeline for lncRNA identification, numbers of genes and identified lcRNAs, and some features of downstream lncRNA analyses. Figure S2. The chromosomal distribution of lncRNAs. Density was plotted across each chromosome. Figure S3. Differential expressed genes (DEGs) under different abiotic stresses. A-D, Venn diagram of DEGs under different stresses across different development stage V3-V6. E-G, Venn diagram of DEGs under different stress conditions at one stage. Figure S4. The correlation values (r) between each of the inferred coexpression modules and the specific traits (e.g., Heat, Cold) at different development times (e.g., V3 to V6). A subset of these data for the top 16 stress-associated modules is provided as a heat map in Figure 3. Figures S5-S9. These figures are the same format as that of Figure 4, but represent cold (Figure S5), drought (Figure S6), salt (Figure S7), UV (Figure S8) and ozone stress (Figure S9). Each figure contains a heat map (top) and graphs of the expression of specific TElncRNAs (bottom) that were chosen because they overrepresented with high interconnectivity. The heat graph shows transcript expression levels for genes and lncRNAs in each module (y-axis) and across conditions (x-axis). The key to modules (yaxis) and stress conditions (x-axis) are shown on the right legend, with conditions also separated by developmental stage (bottom of x-axis). Warmer colors within the heat map indicate high expression, and cooler colors are under-expression. The bar plots below the heat graph are eigen-lncRNA expression values selected from the top overrepresented lncRNAs with high interconnectivity. The x-axis is the same as the heat map, and the id of the lncRNAs is provided by the color key.

Purpose To demonstrate a new MR imaging approach that unambiguously identifies and quantitates contrast agents based on intrinsic agent properties such as r1 , r2 , r2*, and magnetic susceptibility. The approach is referred to as magnetic barcode imaging (MBI). Methods Targeted and bioresponsive contrast agents were imaged in agarose phantoms to generate T1 , T2 , T2*, and quantitative susceptibility maps. The parameter maps were processed by a machine learning algorithm that is trained to recognize the contrast agents based on these parameters. The output is a quantitative map of contrast agent concentration, identity, and functional state. Results MBI allowed the quantitative interpretation of intensities, removed confounding backgrounds, enabled contrast agent multiplexing, and unambiguously detected the activation and binding states of bioresponsive and targeted contrast agents. Conclusion MBI has the potential to overcome significant limitations in the interpretation, quantitation, and multiplexing of contrast enhancement by MR imaging probes. Magn Reson Med 77:970-978, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Plant roots have been recognized to be modular, and a third order root cluster has been proposed to be the basic root module unit based upon the life cycle. This experiment examines root modularity of the nutrient-uptake function using stable isotope 15N. Solidago canadensis root clusters of second or third orders—from the same third or fourth order roots, respectively—were treated with 15NH 4 15 NO3, NH4NO3, and de-ionized water for 15 and 180 min. The δ15N values of the root clusters were then analyzed and compared. The δ15N values of 15N-treated root clusters of both second and third orders were hundreds of times higher than that of the 15N untreated root clusters. However, the differences of the δ15N values among 15N untreated root clusters (though expressed some significant variations), did not indicate the 15N shared by the sister root clusters came from a common higher-order root. These results demonstrated functional modularity of root nutrient uptake, revealed a second order root, perhaps even a first order root to be a base module unit in terms of root nutrient uptake. The results also suggested that the concept of root modularity is function-specific. This experiment further revealed the importance of treatment timing in stabilizing the internal 15N/14N ratio in roots and avoiding top-down transportation of 15N back into roots to secure unbiased measurements.

The very broad emission bands of organic semiconductor materials are, in theory, suitable for achieving versatile solid-state lasers; however, most of organic materials only lase at short wavelength corresponding to the 0-1 transition governed by the Franck-Condon (FC) principle. A strategy is developed to overcome the limit of FC principle for tailoring the output of microlasers over a wide range based on the controlled vibronic emission of organic materials at microcrystal state. For the first time, the output wavelength of organic lasers is tailored across all vibronic (0-1, 0-2, 0-3, and even 0-4) bands spanning the entire emission spectrum.

Extreme drought is likely to become more frequent and intense as a result of global climate change, which may significantly impact plant root traits and responses (i.e., morphology, production, turnover, and biomass). However, a comprehensive understanding of how drought affects root traits and responses remains elusive. Here, we synthesized data from 128 published studies under field conditions to examine the responses of 17 variables associated with root traits to drought. Our results showed that drought significantly decreased root length and root length density by 38.29% and 11.12%, respectively, but increased root diameter by 3.49%. However, drought significantly increased root:shoot mass ratio and root cortical aerenchyma by 13.54% and 90.7%, respectively. Our results suggest that drought significantly modified root morphological traits and increased root mortality, and the drought-induced decrease in root biomass was less than shoot biomass, causing higher root:shoot mass ratio. The cascading effects of drought on root traits and responses may need to be incorporated into terrestrial biosphere models to improve prediction of the climate-biosphere feedback.

Here we present the 15 pseudochromosomes of sweet potato, Ipomoea batatas, the seventh most important crop in the world and the fourth most significant in China. By using a novel haplotyping method based on genome assembly, we have produced a half haplotype-resolved genome from ~296 Gb of paired-end sequence reads amounting to roughly 67-fold coverage. By phylogenetic tree analysis of homologous chromosomes, it was possible to estimate the time of two recent whole-genome duplication events as occurring about 0.8 and 0.5 million years ago. This half haplotype-resolved hexaploid genome represents the first successful attempt to investigate the complexity of chromosome sequence composition directly in a polyploid genome, using sequencing of the polyploid organism itself rather than any of its simplified proxy relatives. Adaptation and application of our approach should provide higher resolution in future genomic structure investigations, especially for similarly complex genomes.Assembly of polyploid plant genomes has been technically challenging. Now, a study presents a half haplotype-resolved hexaploid genome of sweet potato, Ipomoea batatas, using a novel haplotyping method.

High N loss and low N use efficiency (NUE), caused by high N fertilizer inputs and inappropriate fertilization patterns, have become important issues in the rice (Oryza sativa L.) growing regions of southern China. Changing current farmer fertilizer practice (FFP, 225 kg ha–1 N as three applications, 40% as basal fertilizer, 30% as tillering fertilizer and 30% as jointing fertilizer) to one—time root—zone fertilization (RZF, 225 kg ha–1 N applied once into 10 cm deep holes positioned 5 cm from the rice root as basal fertilizer) will address this problem. A two—year field experiment covering two rice growing regions was conducted to investigate the effect of urea one—time RZF on rice growth, nutrient uptake, and NUE. The highest NH4+–N content for RZF at fertilizer point at 30 d and 60 d after fertilization were 861.8 and 369.9 mg kg–1 higher than FFP, respectively. Rice yield and total N accumulation of RZF increased by 4.3–44.9% and 12.7–111.2% compared to FFP, respectively. RZF reduced fertilizer—N loss by 56.3–81.9% compared to FFP. The NUEs following RZF (mean of 65.8% for the difference method and 43.7% for the labelled method) were significantly higher than FFP (mean of 35.7% for the difference method and 14.4% for the labelled method). In conclusion, RZF maintained substantial levels of fertilizer—N in the root—zone, which led to enhanced rice biomass and N uptake during the early growth stages, increased fertilizer—N residual levels and reduced fertilizer—N loss at harvest. RZF produced a higher yield increment and showed an increased capacity to resist environmental threats than FFP in sandy soils. Therefore, adopting suitable fertilizer patterns plays a key role in enhancing agricultural benefits.

Although the sweet potato, Ipomoea batatas, is the seventh most important crop in the world and the fourth most significant in China, its genome has not yet been sequenced. The reason, at least in part, is that the genome has proven very difficult to assemble, being hexaploid and highly polymorphic; it has a presumptive composition of two B1 and four B2 component genomes (B1B1B2B2B2B2). By using a novel haplotyping method based on de novo genome assembly, however, we have produced a half haplotype-resolved genome from ∼267Gb of paired-end sequence reads amounting to roughly 60-fold coverage. By phylogenetic tree analysis of homologous chromosomes, it was possible to estimate the time of two whole genome duplication events as occurring about 525,000 and 341,000 years ago. Our analysis also identified many clusters of genes for specialized compounds biosynthesis in this genome. This half haplotype-resolved hexaploid genome represents the first successful attempt to investigate the complexity of chromosome sequence composition directly in a polyploid genome, using direct sequencing of the polyploid organism itself rather than of any of its simplified proxy relatives. Adaptation and application of our approach should provide higher resolution in future genomic structure investigations, especially for similarly complex genomes.

Rapid evolutionary changes in invasion-related ecological traits of alien plants are receiving considerable attention in current ecological research. Tolerance to herbivory is of particular interest because of the potential for using biological agents to control the spread of invasive plants. In this study, we compared herbivory tolerance in six populations of tall form Spartina alterniflora : three from its introduced range in Jiangsu Province, China, and three from its native range in Georgia, USA. Plants were grown in a greenhouse and subjected to a full-factorial experimental design with three simulated leaf herbivory levels and two levels of nitrogen availability for 20 weeks. We found that native and invasive tall form S. alterniflora grown under different nitrogen conditions responded to simulated leaf herbivory differently with regard to underground and aboveground biomass and total culm height. Invasive S. alterniflora populations had a greater capacity to compensate for leaf damage than native populations in terms of underground biomass and aboveground biomass, particularly with low nitrogen availability. In addition, invasive S. alterniflora also showed higher compensatory capacity than native plants with regard to total culm height in both nitrogen treatments and with regard to tiller number in the high nitrogen treatment. Elevated nitrogen availability significantly increased the compensatory capacity of underground biomass in native S. alterniflora populations but did not affect any factor in invasive populations. Our results suggested a rapid evolutionary change in herbivory tolerance of invasive tall form S. alterniflora after its introduction to China. Understanding such changes in the tolerance to herbivory between native and invasive populations of alien plants has important implications for improving management efficiency.

The objective of this study was to compare various plant traits of native and invasive conspecifics of the tall form of Spartina alterniflora to test the genetic shift hypothesis, which predicts that due to genetic differences invasive plants may have different performance. We conducted a controlled experiment with six populations of the tall form of S. alterniflora : three transported from its introduced range in Jiangsu Province, China, and three from its native range in Georgia, USA. Plants were grown in a greenhouse and subjected to one of two levels of nitrogen availability for several months. Growth, biomass accumulation, biomass allocation, and photosynthetic and morphological traits, as well as the corresponding trait plasticities, were measured and compared between the populations. Nitrogen addition significantly affected individual traits of both invasive Jiangsu and native Georgia S. alterniflora populations, with invasive populations having stronger responses to nitrogen addition in RGR, total biomass, total leaf number (TLN), total leaf area (TLA) and maximum culm height (MxCH) than native populations according to the results of both reaction norms and the relative distance plasticity index (RDPI). Invasive S. alterniflora was more vigorous than its native conspecific as shown by greater total biomass and higher light-saturated photosynthetic rate ( P max ). Several morphological traits (MxCH, TLN and LAR) and most of the biomass allocation traits of invasive populations were found to differ from native populations. Our results indicated probable genetic shifts in plant traits in the introduced populations relative to the native populations of the tall form of S. alterniflora . Such genetic shifts may play a vital role in their success as invasive plants.

Ultrasmall (3, 4, 5, and 6 nm), water-soluble Fe3O4 magnetic nanoparticles were synthesized in diethylene glycol (DEG) via a facile one-pot reaction. Hydrodynamic size and relaxation time measurements did not show particle aggregation when Fe3O4 nanoparticles were dispersed in phosphate buffered saline, fetal bovine serum, or calf bovine serum for 1 week. Furthermore, the new Fe3O4 nanoparticles tolerated high salt concentrations (≤1 M NaCl) and a wide pH range from 5 to 11. Surface modification of the nanoparticles with poly(ethylene glycol) bis(carboxymethyl) ether (HOOC-PEG-COOH, 600 g/mol) was accomplished through a ligand-exchange reaction. The effects of PEG modification on magnetization and relaxivity of the Fe3O4 nanoparticles were investigated, and the results indicate that the increase in transverse relaxivity after PEG modification may be due to the increased volume of slowly diffusing water surrounding each nanoparticle. In vitro experiments showed that the DEG- and PEG-coated Fe3O4 nanoparticles have little effect on NIH/3T3 cell viability.

In order to make clear the relationships between photosynthesis and leaf N, leaf P and SLA of tropical trees, and test the differences in the relationships among life-form groups (trees, shrub-like trees and shrubs), seedlings and saplings of 101 species from a tropical montane rain forest, located in the Diaoluo Mountain of Hainan Island, were selected. The net photosynthesis based on area and mass (Aarea and Amass), leaf nitrogen content based on area and mass (Narea and Nmass), leaf phosphorus content based on area and mass (Parea and Pmass) and specific leaf area (SLA) were measured and/or calculated. The results showed that Aarea and Amass tended to follow the order of shrubs > trees > shrub-like trees. One-way ANOVA showed that the difference in Aarea between shrubs and shrub-like trees was significant (p 0.05). The relationship between Aarea and SLAwas highly significant in shrubs (p = 0.0006), trees (p 0.05). The relationships between Amass and leaf N and SLA were highly significant in all three life-form groups and for all species (p

By one-pot reaction, biocompatible magnetite nanocrystals with surface reactive moieties were prepared through the thermal decomposition of Fe(acac)3 in 2-pyrrolidone using α , ω -dicarboxyl-terminated poly(ethylene glycol) as surface capping molecule. The successful conjugation between the magnetite nanocrystals and 9-amino acridine on the one hand demonstrates the existence of free carboxylic groups from PEG binding on the particle surface, on the other hand may also lead to a new type of magneto-optical materials as well as magneto-drugs.