As a new high-technology with an advantage of high temporal resolution,wide coverage and low cost,remote sensing is currently used in a wide arrange of earth observation activities and thus provides a useful tool to detect and monitor the spatial patterns of crop cultivation.Based on the systematic summary of the progress of studies in remote-sensing-based monitoring of spatial patterns of agricultural crops in the latest decade,including its theories,methods and applications,a series of problems that should be urgently resolved in the study are put forward,and some important study directions and priorities for future are viewed.Studies show that crop acreage can be monitored according to the differences in spectral characteristics of different crops,which are normally recorded by the satellite sensors.There are three major approaches used for crop acreage monitoring:spectral-based identification,phenology-based identification and multiple data-fusion-based identification methods.Mapping multiple cropping systems using remote sensing is mainly based on the crop growth curves,which can be derived from the smoothed time-series vegetation index(VI) data.Furthermore,cropping patterns can be also examined through discriminating the crop growth period from variations in time-series VI data and characteristics of different cropping patterns.How to construct the theoretical and technological systems,to develop and verify the image classification methods,to optimize the smoothing methods for time-series data and to improve the capability of automatic extraction of information could be the major development trends of this field in the future.
Abstract Objective The limited understanding of the molecular mechanism for oral submucosal fibrosis (OSF) poses challenges to the development of effective prevention and treatment strategies. The lack of suitable animal models is a major hindrance. Therefore, this study aimed to address this issue by comparing commonly used arecoline‐induced water drinking and injection mouse models. Materials and Methods The mice were subjected to two protocols: receiving 2 mg/mL arecoline in drinking water and 4 mg/mL arecoline saline solution injections every other day. Tissues were collected at regular 4‐week intervals, with a final time point of 20 weeks. Stereo microscopy and histomorphological analysis were performed on live and harvested tissues, respectively. Results During arecoline treatment, collagen deposition and myofibroblast proliferation progressively increased in both models. Changes in the collagen I/III ratio indicated that both models exhibited characteristics of the early and intermediate stages of OSF after 20 weeks of arecoline induction. The water‐drinking model also demonstrated multi‐organ fibrosis involving the tongue, lungs, and small intestine. Conclusion Both the water drinking and injection mouse models effectively induced OSF, but the water‐drinking model better mirrored the observed pathogenesis in patients with OSF. These models provide valuable tools for investigating the mechanisms underlying OSF.
We sequenced the complete plastid genome of Anomodon attenuatus. The genome size is 125,320 bp with two inverted repeat regions of 9,948 bp separated by a large single-copy region of 86,847 bp and a small single-copy region of 18,578 bp. It encodes 114 unique genes including 80 protein-coding genes, 30 tRNA genes and 4 rRNAgenes. The overall GC content is 29.5%, with 26.9, 26.5, and 43.9% in LSC, SSC, IR regions, respectively. 139 SSRs were identified in the genome. Phylogenetic anlysis showed that the position of A.attenuatus is closely related to S.uncinata, another pleurocarpous moss.
Abstract Two hypotheses have been used to explain the loss of plant diversity with nutrient addition. The nutrient identity hypothesis posits that biodiversity loss is due to a specific limiting nutrient, such as nitrogen (N) or phosphorus (P), while the niche dimension hypothesis posits that adding a larger number of limiting nutrients, regardless of their identity, results in biodiversity loss. These two hypotheses have not previously been tested together simultaneously. Here, we conduct that analysis to enable their relative effect sizes to be compared. We manipulated the supply of eight nutrients in the same experimental meadow grassland site to isolate the effects of the identity of added nutrients versus the number of added nutrients on biodiversity loss. We found support for both hypotheses, with the largest negative effects on biodiversity measures being due to N, or N and P treatment, with additional more minor effects of the number of added nutrients. Structural equation models (SEMs) suggested both identity and number of added nutrients had direct negative effects on biodiversity, likely caused by species' innate ability to competitively respond to nutrients, especially in response to disease, herbivory, and stress. SEMs also suggested indirect effects arising from nutrient‐driven increases in aboveground biomass, which resulted in intensified competition for light and the competitive exclusion of short‐statured species. These effects were exacerbated by the nutrients N and P which caused a shift in biomass accumulation from belowground to aboveground. The results highlight that a multi‐nutrient perspective will improve our ability to effectively manage, monitor, and restore ecosystems.
Abstract Exploring the frequency and distribution pattern of polyploid species in geographic parameters is of significance in understanding the mechanisms of polyploid speciation and evolutionary drivers of biodiversity. We here explored polyploid and paleopolyploid incidence frequency in a scale of 100 × 100 km grids in China. We found 33% of angiosperm species are polyploidy in China, and 23% of polyploid speciation. Western China and eastern China showed a significantly different polyploid and paleopolyploid frequency, with an evolutionary cradle of polyploid angiosperms in the Qinghai–Tibetan plateau. Herbaceous species exhibited higher polyploid frequency but lower paleopolyploid frequency than woody species, indicating the former experienced more rapid differentiation and speciation than the latter. Our results indicate that western China is an evolutionary cradle for polyploid angiosperms where harsh environment facilitates the establishment and survival of polyploids, while polyploid lineages tend to rediploidize to be diploids with sufficient time in suitable environment.
Plastid genomes are useful markers in resolving plant phylogenetic relationships for various taxonomic groups. Here, we sequenced and de novo assembled the complete plastid genome sequence of the fern Asplenium tenerum Forst. (Aspleniaceae, Polypodiales) using the genome skimming data. The newly generated plastid genome is conserved in structure and gene content compared with that of closely related species. Plastid phylogenetic analysis of Polypodiales ferns recovered a robust phylogeny, supporting the close relationship of A. tenerum with Asplenium prolongatum.
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