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1.
Plant Mol Biol ; 102(4-5): 447-462, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31898148

RESUMO

KEY MESSAGE: ZjICE2 works as a positive regulator in abiotic stress responses and ZjICE2 is a valuable genetic resource to improve abiotic stress tolerance in the molecular breeding program of Zoysia japonica. The basic helix-loop-helix (bHLH) family transcription factors (TFs) play an important role in response to biotic or abiotic stresses in plants. However, the functions of bHLH TFs in Zoysia japonica, one of the warm-season turfgrasses, remain poorly understood. Here, we identified ZjICE2 from Z. japonica, a novel MYC-type bHLH transcription factor that was closely related to ICE homologs in the phylogenetic tree, and its expression was regulated by various abiotic stresses. Transient expression of ZjICE2-GFP in onion epidermal cells revealed that ZjICE2 was a nuclear-localized protein. Also, ZjICE2 bound the MYC cis-element in the promoter of dehydration responsive element binding 1 of Z. japonica (ZjDREB1) using yeast one-hybrid assay. A phenotypic analysis showed that overexpression of the ZjICE2 in Arabidopsis enhanced tolerance to cold, drought, and salt stresses. The transgenic Arabidopsis and Z. japonica accumulated more transcripts of cold-responsive DREB/CBFs and their downstream genes than the wild type (WT) after cold treatment. Furthermore, the transgenic plants exhibited an enhanced Reactive oxygen species (ROS) scavenging ability, which resulted in an efficient maintenance of oxidant-antioxidant homeostasis. In addition, overexpression of the ZjICE2 in Z. japonica displayed intensive cold tolerance with increases in chlorophyll contents and photosynthetic efficiency. Our study suggests that ZjICE2 works as a positive regulator in abiotic stress responses and the ICE-DREB/CBFs response pathway involved in cold stress tolerance is also conserved in Z. japonica. These results provide a valuable genetic resource for the molecular breeding program especially for warm-season grasses as well as other leaf crop plants.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/fisiologia , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/fisiologia , Poaceae/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Estresse Fisiológico , Arabidopsis/genética , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/fisiologia , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Temperatura Baixa , Resposta ao Choque Frio , Secas , Filogenia , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/fisiologia , Poaceae/genética , Regulon , Tolerância ao Sal , Fatores de Transcrição/genética , Fatores de Transcrição/fisiologia , Ativação Transcricional
2.
J Agric Food Chem ; 68(5): 1169-1185, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31922733

RESUMO

Epichloë endophytes in forage grasses have attracted widespread attention and interest of chemistry researchers as a result of the various unique chemical structures and interesting biological activities of their secondary metabolites. This review describes the diversity of unique chemical structures of taxa from Epichloë endophytes and grass infected with Epichloë endophytes and demonstrates their reported biological activities. Until now, nearly 160 secondary metabolites (alkaloids, peptides, indole derivatives, pyrimidines, sesquiterpenoids, flavonoids, phenol and phenolic acid derivatives, aliphatic metabolites, sterols, amines and amides, and others) have been reported from Epichloë endophytes and grass infected with Epichloë endophytes. Among these, non-alkaloids account for half of the population of total metabolites, indicating that they also play an important role in Epichloë endophytes and grass infected with Epichloë endophytes. Also, a diverse array of secondary metabolites isolated from Epichloë endophytes and symbionts is a rich source for developing new pesticides and drugs. Bioassays disclose that, in addition to toxic alkaloids, the other metabolites isolated from Epichloë endophytes and symbionts have notable biological activities, such as antifungal, anti-insect, and phytotoxic activities. Accordingly, the biological functions of non-alkaloids should not be neglected in the future investigation of Epichloë endophytes and symbionts.


Assuntos
Alcaloides/metabolismo , Endófitos/química , Epichloe/química , Poaceae/microbiologia , Simbiose , Alcaloides/química , Alcaloides/toxicidade , Animais , Endófitos/fisiologia , Epichloe/metabolismo , Insetos/efeitos dos fármacos , Gado/metabolismo , Poaceae/fisiologia
3.
Environ Sci Pollut Res Int ; 26(33): 34658-34669, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31654305

RESUMO

A 2-year field experiment was carried out with aim to assess the phytoremediation potential of Miscanthus × giganteus cultivated on the flotation tailings and to evaluate the effects of mineral NPK fertilizer on metal accumulation and plant physiological parameters and growth. Flotation tailings of the mine Rudnik (Serbia) are burdened with Pb, Cu and Zn and cause heavy metal pollution and deterioration of the surrounding ecosystems. In the second year of growth, plants retained the major portion of metals within their roots, with bioconcentration factor > 1 for Cu and Zn and < 1 for Pb. Their translocation factors were far below 1, showing that M. × giganteus acts as excluder of Cu, Zn and especially Pb. Higher amounts of Pb and Zn in leaves reduced the photosynthetic rate and total antioxidative capacity, but increased lipid peroxidation level. Changes at physiological level resulted in pronounced leaf senescence, reduced plant growth rate and annual biomass yield. Fertilization enhanced metal uptake by plant roots, but had no effect on their translocation to leaves. It improved chlorophyll a content, potential efficiency of Photosystem II photochemistry and biomass yield. Overall results indicate that M. × giganteus can be cultivated on the abandoned flotation tailings and that fertilization had positive effects on its physiology and growth.


Assuntos
Biodegradação Ambiental , Poaceae/fisiologia , Poluentes do Solo/metabolismo , Biomassa , Clorofila A , Ecossistema , Fertilizantes/análise , Metais Pesados/análise , Fotossíntese , Folhas de Planta/química , Raízes de Plantas/química , Plantas , Poaceae/crescimento & desenvolvimento , Sérvia , Solo/química , Poluentes do Solo/análise
4.
BMC Plant Biol ; 19(1): 418, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31604418

RESUMO

BACKGROUND: So far, little is known in detail about mating systems of woody bamboos. Paternity analysis of offspring improved our understanding of these systems, and contributed to their germplasm conservation and genetic improvement. RESULTS: In this study, a paternity analysis of offspring from two consecutive mass or sporadically flowering events of Dendrocalamus membranaceus and D. sinicus were conducted to determine their mating system and pollen dispersal using the program COLONY based on simple sequence repeat (SSR) markers. Two sporadically flowering populations of D. sinicus (C1, C2) obtained relatively high paternity assignments rates (69.0-71.4%). Meanwhile, among three populations of D. membranaceus, the sporadically flowering population A also had much higher paternity assignments rates (56.4%) than mass flowering populations B1(28.6%) and B2 (42.5%). Both D. membranaceus and D. sinicus had mixed mating systems while their mating patterns were variable depending on pollination conditions. The maximum pollen dispersal distances were 90 m and 4378 m for D. membranaceus and D. sinicus populations, respectively, and the mating distances of these two species focused on ranges of ca. 0-50 m and 0-1500 m, respectively. CONCLUSIONS: These results revealed for the first time variable mating patterns in woody bamboos. This suggests half-sib seeds from the same bamboo clump may have different male parents and it is crucial to clarify genetic origin in woody bamboos' breeding programs. The results also indicate the importance of pollinators in the mating systems of tropical woody bamboos.


Assuntos
Poaceae/fisiologia , Polinização , Marcadores Genéticos , Repetições de Microssatélites , Poaceae/genética , Reprodução/genética , Especificidade da Espécie
5.
Plant Sci ; 289: 110254, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31623785

RESUMO

ICE1 (Inducer of CBF Expression 1) is a regulator of cold-induced transcriptome, which plays an important role in plant cold response pathway. To enhance the cold tolerance of Zoysia japonica, one of the warm-season turfgrasses, it is helpful to understand the cold response mechanism in Zoysia japonica. We identified stress-responsive ZjICE1 from Zoysia japonica and characterized its function in cold stress. Our results showed that ZjICE1 shared the typical feature of ICE homolog proteins belonging to a nucleic protein. Transactivation activity assay revealed that ZjICE1 bound to the MYC cis-element in the ZjDREB1's promotor. The ZjICE1 overexpressed transgenic Arabidopsis showed enhanced tolerance to cold stress with an increases in SOD, POD, and free proline content and reduction in MDA content. They also induced the transcripts abundance of cold-responsive genes (CBF1, CBF2, CBF3, COR47A, KIN1, and RD29A) after cold treatment. These results suggest that ZjICE1 is a positive regulator in Zoysia japonica plant during cold stress and can be a useful gene for the molecular breeding program to develop the cold tolerant zoysiagrass. Furthermore, the ZjICE1 also conferred resistance to salt and drought stresses, providing the better understanding of the basic helix-loop-helix (bHLH) gene family in abiotic stress responses.


Assuntos
Aclimatação/genética , Arabidopsis/fisiologia , Resposta ao Choque Frio/genética , Proteínas de Plantas/genética , Poaceae/fisiologia , Fatores de Transcrição/genética , Sequência de Aminoácidos , Arabidopsis/genética , Temperatura Baixa , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/fisiologia , Poaceae/genética , Alinhamento de Sequência , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo
6.
Plant Sci ; 289: 110260, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31623790

RESUMO

The potential of Arundo donax to grow in degraded soils, characterized by excess of salinity (Na+), and phosphorus deficiency (-P) or excess (+P) also coupled with salinity (+NaP), was investigated by combining in vivo plant phenotyping, quantification of metabolites and ultrastructural imaging of leaves with a transcriptome-wide screening. Photosynthesis and growth were impaired by + Na, -P and + NaP. While + Na caused stomatal closure, enhanced biosynthesis of carotenoids, sucrose and isoprene and impaired anatomy of cell walls, +P negatively affected starch production and isoprene emission, and damaged chloroplasts. Finally, +NaP largely inhibited photosynthesis due to stomatal limitations, increased sugar content, induced/repressed a number of genes 10 time higher with respect to + P and + Na, and caused appearance of numerous and large plastoglobules and starch granules in chloroplasts. Our results show that A. donax is sensitive to unbalances of soil ion content, despite activation of defensive mechanisms that enhance plant resilience, growth and biomass production of A. donax under these conditions.


Assuntos
Fósforo/metabolismo , Poaceae/fisiologia , Estresse Salino , Sódio/metabolismo , Fósforo/deficiência , Poaceae/genética , Sódio/efeitos adversos , Solo/química
7.
Arq. bras. med. vet. zootec. (Online) ; 71(5): 1703-1711, set.-out. 2019. tab, graf
Artigo em Português | LILACS, VETINDEX | ID: biblio-1038652

RESUMO

Este trabalho teve como objetivo avaliar o valor nutritivo e a força de cisalhamento da cultivar de Urochloa brizantha (syn Brachiaria brizantha) cv Xaraés submetida a três intensidades luminosas e quatro cortes. O experimento foi conduzido na FMVZ - Unesp de Botucatu, com delineamento experimental em blocos ao acaso, sendo os tratamentos: luminosidade natural, redução de 30% e 60% de luz, com quatro cortes e três repetições. As análises realizadas foram: composição bromatológica, digestibilidade e a força de cisalhamento. Não houve diferença na digestibilidade entre os tratamentos em nenhum dos cortes, mas a qualidade forrageira foi influenciada pelos níveis de intensidade de luz, tendo o tratamento com 60% de redução de luminosidade apresentado maiores concentrações de proteína bruta e cinzas, menores teores de fibra em detergente neutro, hemicelulose, celulose e força de cisalhamento. Em relação aos cortes estudados, o primeiro teve o menor intervalo de corte e produziu forragem com qualidade superior em comparação ao último, pois obteve menor teor de fibra em detergente ácido, lignina, hemicelulose, celulose e consequente menor força de cisalhamento. Portanto, a redução de 60% de luminosidade é benéfica à qualidade e à força de cisalhamento da cultivar Xaraés.(AU)


This study aimed to evaluate the nutritive value and shear strength of the Xaraés grass (Urochloa brizantha) under the three intensities of light and four cuts. The experiment was conducted at FMVZ - UNESP, Botucatu, with a randomized block design, with the following treatments: natural luminosity, 30% and 60% light reduction, with four cuts and three replications. The analyzes were bromatological composition, digestibility, and shearing strength. There was no difference in digestibility between the treatments in any of the cuts, forage quality was influenced by the light intensity levels, and the treatment with 60% of light reduction produced higher concentrations of crude protein and ash, lower levels of neutral detergent fiber, hemicellulose, cellulose and shear strength. According to the studied cuts, the first one had the lowest cut interval and produced superior forage compared with the last one, as it obtained lower fiber content in acid detergent, lignin, hemicellulose, cellulose and consequent lower shear force. Therefore, the reduction of 60% of luminosity is beneficial to the quality and shear force of the Xaraés palisade grass.(AU)


Assuntos
Pastagens/análise , Pastagens/métodos , Análise de Alimentos/métodos , Poaceae/crescimento & desenvolvimento , Poaceae/fisiologia , Luz
8.
Ying Yong Sheng Tai Xue Bao ; 30(9): 2949-2954, 2019 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-31529869

RESUMO

Monthly phytolith-occluded organic carbon (PhytOC) content in living leaves and litterfall of Moso bamboo (Phyllostachys edulis) were measured for a year. The PhytOC sequestration rate in living leaves of different months were compared with that in annual litterfall to determine the optimum sampling time of living leaves for estimating PhytOC sequestration rate of Moso bamboo. The contents of phytoliths and PhytOC in living leaves of Moso bamboos were 23.45-101.07 g·kg-1 and 0.73-1.98 g·kg-1, respectively, with significant difference among different months. The monthly PhytOC sequestration rates of living leaves of Moso bamboo in different months ranged from 0.75 to 7.68 kg·hm-2·a-1. The maximum and minimum rates of the PhytOC sequestration occurred in December and April respectively, with significant difference between them. There was no difference between the PhytOC sequestration rate in living leaves of Moso bamboos in February or December and that of litterfall in the whole year. Therefore, February or December should be the optimal month of sampling living leaves for estimating the PhytOC sequestration rate of Moso bamboo stands.


Assuntos
Sequestro de Carbono , Poaceae/fisiologia , Carbono , Folhas de Planta/fisiologia
9.
Ying Yong Sheng Tai Xue Bao ; 30(9): 3046-3056, 2019 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-31529880

RESUMO

This study evaluated the changes of spatial distribution of the constructive species Stipa breviflora in the desert steppe under different grazing intensities (control, light, moderate, and heavy grazing) in Siziwang, Inner Mongolia. The small-scale spatial distribution of S. breviflora was measured. Results showed that population density of S. breviflora was following the order: heavy grazing (27.81 individuals·m-2) > moderate grazing (22.17 individuals·m-2) > control (11.31 individuals·m-2) > light grazing (10.76 individuals·m-2). The moderate and heavy grazing significantly increased population density of S. breviflora. According to the model fitting by semi-variance function, the population density of S. breviflora under the control, light, moderate and heavy gra-zing treatments were consistent with the exponential model, spherical model, exponential model and spherical model, respectively. Results from spatial distribution pattern analysis showed that structural ratio of S. breviflora population was control (99.7%) > heavy grazing (94.7%) > light grazing (92.7%) > moderate grazing (87.9%). Such a result indicated that the spatial autocorrelation of the four treatments was high, which were mainly affected by structural factors. In comparison, S. breviflora population structure ratio under moderate grazing treatment was the smallest, and partly affected by random factors. Based on fractal dimension analysis, spatial structure of the four treatments was good with simple spatial distribution. With the increases of grazing intensity, the spatial distribution was simpler and more homogeneous. Combined with 2D and 3D views, both light and heavy grazing changed spatial distribution of S. breviflora population from gradient distribution to patch distribution and resulted in the reduction of spatial heterogeneity.


Assuntos
Ecossistema , Meio Ambiente , Herbivoria , Poaceae/fisiologia , China , Análise Espacial
10.
Ecotoxicology ; 28(9): 1063-1074, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31531801

RESUMO

The oil industry has inherent risks of spills or leaks due to natural or anthropogenic causes, which cause alterations in the soil and damage to the plant. An experiment was carried to investigate the effect of oil on the growth, biomass production, biosynthesis of crude protein of Leersia hexandra grass and the remove of oil from the soil. The results showed different responses by L. hexandra depending on the age, low concentrations of oil induced a significant increase in stolon length, in relative growth rate, in dry matter production and in the biosynthesis of crude protein. The same parameters decreased at high concentrations of oil. However, at the end of the evaluation period of 180 days, high concentrations of oil induced a significant increase in the number of young plants and secondary roots, the terminal third of the main root and root dry matter. The dose response curves had the shape of an inverted U, showing that at days 15, 45, 90 and 180, in stolon length, aerial dry matter production, crude protein (day 90) and young plants (days 45 and 90) exhibited a typical biphasic response. The increase in oil concentration correlated with increases in young plants, number of secondary roots, number of roots at the middle, terminal third and root dry matter. After 180 days exposure the rhizosphere of L. hexandra a total oil removal of oil of 76.7 ± 4 was achieved; 61.7, 51, 44.6, 38 and 52% in soils that initially contained 7.9, 54, 102, 126, 145 and 238 g oil.


Assuntos
Hormese/fisiologia , Poluição por Petróleo/efeitos adversos , Poaceae/fisiologia , Rizosfera , Poluentes do Solo/efeitos adversos , Biodegradação Ambiental , Argila , México , Solo/química , Estresse Fisiológico
11.
J Environ Sci (China) ; 85: 107-118, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31471017

RESUMO

Biochar (BC) and rhamnolipid (RL) is used in bioremediation of petroleum hydrocarbons, however, the combined effect of BC and RL in phytoremediation has not been studied until now. In this paper, the phytoremediation of petroleum hydrocarbon-contaminated soil using novel plant Spartina anglica was enhanced by the combination of biochar (BC) and rhamnolipid (RL). Samples of petroleum-contaminated soil (10, 30 and 50 g/kg) were amended by BC, BC+ RL and rhamnolipid modified biochar (RMB), respectively. After 60 day's cultivation, the removal rate of total petroleum hydrocarbons (TPHs) for unplanted soil (UP), planted soil (P), planted soil with BC addition (P-BC), planted soil with BC and RL addition (P-BC + RL) and planted soil with addition of RMB (P-RMB) were 8.6%, 19.1%, 27.7%, 32.4% and 35.1% in soil with TPHs concentration of 30 g/kg, respectively. Compared with UP, the plantation of Spartina anglica significantly decreased the concentration of C8-14 and tricyclic PAHs. Furthermore, the application of BC and RMB alleviated the toxicity of petroleum hydrocarbons to Spartina anglica via improving plant growth with increasing plant height, root vitality and total chlorophyll content. High-throughput sequencing result indicated that rhizosphere microbial community of Spartina anglica was regulated by the application of BC and RMB, with increase of bacteria and plant mycorrhizal symbiotic fungus in biochar and RMB amended soil.


Assuntos
Biodegradação Ambiental , Petróleo/análise , Poaceae/fisiologia , Poluentes do Solo/análise , Carvão Vegetal/química , Glicolipídeos/química , Petróleo/metabolismo , Hidrocarbonetos Policíclicos Aromáticos , Rizosfera , Microbiologia do Solo , Poluentes do Solo/metabolismo
12.
Sci Total Environ ; 693: 133548, 2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-31369894

RESUMO

Plant invasion typically alters the microbial communities of soils, which affects ecosystem carbon (C) and nitrogen (N) cycles. The responses of the soil fungal communities to plant invasion along its chronosequence remain poorly understood. For this study, we investigated variations in soil fungal communities through Illumina MiSeq sequencing analyses of the fungal internal transcribed spacer (ITS) region, and quantitative polymerase chain reaction (qPCR), along a chronosequence (i.e., 9-, 13-, 20- and 23-year-old) of invasive Spartina alterniflora. We compared these variations with those of bare flat in a Chinese Yellow Sea coastal wetland. Our results highlighted that the abundance of soil fungi, the number of operational taxonomic units (OTUs), species richness, and Shannon diversity indices for soil fungal communities were highest in 9-year-old S. alterniflora soil, which gradually declined along the invasion chronosequence. The relative abundance of copiotrophic Basidiomycota revealed significant decreasing trend, while the relative abundance of oligotrophic Ascomycota gradually increased along the S. alterniflora invasion chronosequence. The relative abundance of soil saprotrophic fungi (e.g., undefined saprotrophs) was gradually reduced while symbiotic fungi (e.g., ectomycorrhizal fungi) and pathotrophic fungi (e.g., plant and animal pathogens) progressively increased along the S. alterniflora invasion chronosequence. Our results suggested that S. alterniflora invasion significantly altered soil fungal abundance and diversity, community composition, trophic modes, and functional groups along a chronosequence, via substantially reduced soil litter inputs, and gradually decreased soil pH, moisture, and soil nutrient substrates along the invasion chronosequence, from 9 to 23 years. These changes in soil fungal communities, particularly their trophic modes and functional groups along the S. alterniflora invasion chronosequence could well impact the decomposition and accumulation of soil C and N, while potentially altering ecosystem C and N sinks in a Chinese Yellow Sea coastal wetland.


Assuntos
Espécies Introduzidas , Poaceae/fisiologia , Microbiologia do Solo , Áreas Alagadas , Biomassa , Carbono , China , Microbiota , Micobioma , Micorrizas , Nitrogênio , Plantas , Solo/química
13.
BMC Plant Biol ; 19(1): 355, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31416418

RESUMO

BACKGROUND: To compensate for the lack of information about the molecular mechanism involved in Arundo donax L. response to salt stress, we de novo sequenced, assembled and analyzed the A. donax leaf transcriptome subjected to two levels of long-term salt stress (namely, S3 severe and S4 extreme). RESULTS: The picture that emerges from the identification of differentially expressed genes is consistent with a salt dose-dependent response. Hence, a deeper re-programming of the gene expression occurs in those plants grew at extreme salt level than in those subjected to severe salt stress, probably representing for them an "emergency" state. In particular, we analyzed clusters related to salt sensory and signaling, transcription factors, hormone regulation, Reactive Oxygen Species (ROS) scavenging, osmolyte biosynthesis and biomass production, all of them showing different regulation either versus untreated plants or between the two treatments. Importantly, the photosynthesis is strongly impaired in samples treated with both levels of salinity stress. However, in extreme salt conditions, a dramatic switch from C3 Calvin cycle to C4 photosynthesis is likely to occur, this probably being the more impressive finding of our work. CONCLUSIONS: Considered the distinct response to salt doses, genes either involved in severe or in extreme salt response could constitute useful markers of the physiological status of A. donax to deepen our understanding of its biology and productivity in salinized soil. Finally, many of the unigenes identified in the present study have the potential to be used for the development of A. donax varieties with improved productivity and stress tolerance, in particular the knock out of the GTL1 gene acting as negative regulator of water use efficiency has been proposed as good target for genome editing.


Assuntos
Folhas de Planta/fisiologia , Poaceae/fisiologia , RNA de Plantas/análise , Estresse Salino/genética , Transcriptoma/fisiologia , Folhas de Planta/efeitos dos fármacos , Poaceae/efeitos dos fármacos , Poaceae/genética , Estresse Salino/efeitos dos fármacos , Análise de Sequência de RNA , Transcriptoma/efeitos dos fármacos
14.
Artigo em Inglês | MEDLINE | ID: mdl-31362358

RESUMO

Seagrasses are a crucial indicator species of coastal marine ecosystems that provide substratum, shelter, and food for epiphytic algae, invertebrates, and fishes. More accurate mapping of seagrasses is essential for their survival as a long-lasting natural resource. Before reflectance spectra could properly be used as remote sensing endmembers, factors that may obscure the detection of reflectance signals must be assessed. The objectives in this study are to determine the influence of (1) epiphytes, (2) water depth, and (3) seagrass genus on the detection of reflectance spectral signals. The results show that epiphytes significantly dampen bottom-type reflectance throughout most of the visible light spectrum, excluding 670-679 nm; the depth does influence reflectance, with the detection of deeper seagrasses being easier, and as the depth increases, only Heterozostera increase in the exact "red edge" wavelength at which there is a rapid change in the near-infrared (NIR) spectrum. These findings helped improve the detection of seagrass endmembers during remote sensing, thereby helping protect the natural resource of seagrasses.


Assuntos
Clorófitas/fisiologia , Ecossistema , Poaceae/fisiologia , Tecnologia de Sensoriamento Remoto , Análise Espectral/métodos , Animais , Demografia , Oceanos e Mares , Austrália do Sul
15.
Mar Pollut Bull ; 146: 857-864, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31426229

RESUMO

Understanding plant traits in response to physical stress has been an important issue in the study of coastal saltmarshes. For plants that reproduce both sexually and asexually, whether and how seedlings (sexual reproduction) and clonal ramets (asexual reproduction) may differentially respond to tidal inundation is still unclear. We investigated the growth and morphology of sexual and asexual propagules of an exotic saltmarsh plant (Spartina alterniflora) along a gradient of tidal submergence in the Yellow River Delta. Our results showed that the density, height and basal diameter of clonal ramets or sexual seedlings increased with tidal inundation. The patch amplification edge clonal ramets are superior than patch center plants. The differences response of plants to tidal inundation highlight the sensitivity of S. alterniflora to future tidal regime shifts and can help predict and evaluate the impacts of changes in inundation conditions due to sea level rise, coastal erosion and human activities.


Assuntos
Poaceae/crescimento & desenvolvimento , China , Atividades Humanas , Poaceae/fisiologia , Rios/química , Áreas Alagadas
16.
Sci Total Environ ; 690: 27-39, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31284192

RESUMO

Improving our understanding of the impacts of climate variation and human activities on grassland dynamics is heightened by expectations that climate variation and human activities may induce grassland degradation. An accurate evaluation of the respective impacts of climate variation and human activities on grassland dynamics is crucial to understand the grassland degradation mechanism and to control the degraded grassland. In this study, net primary productivity (NPP) was selected as an indicator to reflect grassland dynamics. Meanwhile, the potential NPP (PNPP) and human-induced NPP (HNPP) calculated as the difference of PNPP and actual ANPP (ANPP) were used to assess the relative effects of climate variation and human activities on grassland NPP changes in China during 2000-2013. Results of grassland ANPP showed an overall increase than decrease in productivity (81.21% vs 18.79%) from 2000 to 2013. For the increase of ANPP, the relative contribution of climate variation and human activities to grassland NPP changes were 41.45% and 45.22%, respectively. Climate variation was the dominant factor that induced the increase in ANPP mainly in areas of Sichuan, Gansu, Ningxia and Inner Mongolia. An increase in Human-dominated ANPP mainly occurred in Tibet, Qinghai and Xinjiang. The decrease in ANPP is principally controlled by the effect of human activities than that of climate variation, especially in Inner Mongolia. Meanwhile, climate-dominated ANPP increase and human-dominated ANPP decrease mainly occurred in plain grassland, desert grassland and meadow across the six types of grasslands in China. Furthermore, in alpine sub-alpine meadow and alpine sub-alpine, while climate-dominated ANPP of grassland was found to be decreased, an increase in human-dominated ANPP was detected. The increase in precipitation and the implementation of ecological restoration programs were found to be effective in inducing the noticeable increased grassland ANPP since 2003. The findings of the current research recommend that the Chinese government should continue to implement the prohibiting graze policy across the country and extensively strengthen the implementation of the policy in Inner Mongolia and North Xinjiang, particularly in plain grassland, desert grassland and meadow.


Assuntos
Mudança Climática , Monitoramento Ambiental , Pradaria , China , Atividades Humanas , Poaceae/fisiologia
17.
Sci Total Environ ; 690: 7-15, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31284196

RESUMO

Coastal wetlands have been identified as vital global carbon (C) sinks; however, soil C sequestration in these ecosystems is susceptible to impacts of non-native species invasion and climate change worldwide. Although their potential impacts on soil organic C (SOC) storage have been reported in previous literature, the well-established mechanisms that control SOC storage response, especially in relation to soil depths, is still limited. To fill this knowledge gap, we developed a structural equation model (SEM) to identify mechanisms that account for SOC changes in topsoil (0-0.3 m) and subsoil (0.3-0.6 m) on coastal wetland of the East China Sea, where SOC in both depths increased with exotic Spartina alterniflora invasion. In the initial model, we hypothesized that there were a set of direct and indirect effects of the invasion, climate, and soil physicochemical properties on SOC storage. By evaluating the interactions of these factors, we found relatively complex patterns that vary with depth. For topsoil, the invasion had not only direct effects on SOC storage, but also indirect effects through mediating effects of soil water content (SWC) that was linked to fine soil fractions. For subsoil, the invasion was indirectly related to SOC storage through mediating effects of SOC in topsoil, SWC, and salinity. SOC in subsoil was also affected by temperature. Our results highlight that the response of SOC storage to the invasion and climate change results from the interacting effects of climate-plant-soil system.


Assuntos
Sequestro de Carbono , Mudança Climática , Poaceae/fisiologia , China , Espécies Introduzidas , Solo/química
18.
PLoS One ; 14(7): e0218741, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31291260

RESUMO

BACKGROUND: Many studies have analysed the effect of browsing by large herbivores on tree species but far fewer studies have studied their effect on understorey shrubs and herbs. Moreover, while many studies have shown that forest features and management intensity strongly influence understorey vegetation, the influence of such variation on the effect of large-herbivore exclusion is not known. THIS STUDY: In this study, we analysed changes of species richness, Shannon diversity, evenness and cover of understorey herbs and shrubs after excluding large herbivores for seven years on 147 forest sites, differing in management intensity and forest features, in three regions of Germany (Schwäbische Alb, Hainich-Dün, Schorfheide-Chorin). Further, we studied how the effect of large-herbivore exclusion on understorey vegetation was influenced by forest management intensity and several forest features. RESULTS: As expected, exclusion of large herbivores resulted in highly variable results. Nevertheless, we found that large-herbivore exclusion significantly increased cover and Shannon diversity of shrub communities, while it did not affect herb communities. Forest management intensity did not influence the effect of large-herbivore exclusion while some forest features, most often relative conifer cover, did. In forests with high relative conifer cover, large-herbivore exclusion decreased species richness and cover of herbs and increased Shannon diversity of herbs and shrubs, while in forests with low relative conifer cover large-herbivore exclusion increased species richness and cover of herbs, and decreased Shannon diversity of herbs and shrubs. CONCLUSION: We suggest that browsing by large herbivores should be included when studying understorey shrub communities, however when studying understorey herb communities the effects of browsing are less general and depend on forest features.


Assuntos
Cadeia Alimentar , Poaceae/fisiologia , Traqueófitas/fisiologia , Árvores/fisiologia , Biodiversidade , Agricultura Florestal/métodos , Florestas , Alemanha , Herbivoria/fisiologia
19.
Rev Environ Health ; 34(3): 283-291, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31318698

RESUMO

The impact of plant growth regulators (PGRs) "Stimpo" and "Regoplant" on Miscanthus x giganteus (Mxg) biomass parameters was investigated when the plant was grown in military soils with different properties from Dolyna, Ukraine and Hradcany, Czech Republic. The results showed that PGRs positively influenced the biomass parameters when the plant was grown in soil in Dolyna with good agricultural characteristics, the influence of "Regoplant" was higher and the best results were obtained with combined treatment: application to rhizomes before planting and spraying on the biomass during vegetation. Using of PGRs did not improve the biomass parameters when the plant was grown in poor soil in Hradcany. In parallel the peculiarities of the metals uptake process were studied for the following metals: chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), strontium (Sr) and lead (Pb). The uptake behavior of the monitored elements differed based on the soil quality. According to the bioconcentration factor uptake of the abiogenic elements, Cr and Pb, was dominant in the plant roots in both soils, whereas Ni was not detected in any plant tissues. The behavior of biogenic elements (Mn, Cu, Zn) and their analogs (Sr) was different. Those elements were more intensively taken up in shoot tissues in low-nutrient sandy Hradcany soils, while they were mainly taken up in plant roots in fertile Dolyna soils. The unusual behavior of biogenic elements in the low-nutrient soils may be explained by the effect of stress. However, more research is needed focused mainly on soil properties and nutrient availability in order to confirm or disprove this hypothesis and to explore the cause of the stress. The summarized results here show that soil properties influenced Mxg biomass parameters, affected the uptake behavior of metals significantly and tested PGRs cannot be utilized universally in the production of Mxg in the poor military soils.


Assuntos
Biomassa , Metais Pesados/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Poaceae/fisiologia , Poluentes do Solo/metabolismo , Solo/química , Bioacumulação , República Tcheca , Militares , Poaceae/crescimento & desenvolvimento , Poaceae/metabolismo , Ucrânia
20.
BMC Genomics ; 20(1): 589, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31315555

RESUMO

BACKGROUND: Puccinellia tenuiflora is the most saline-alkali tolerant plant in the Songnen Plain, one of the three largest soda saline-alkali lands worldwide. Here, we investigated the physicochemical properties of saline-alkali soils from the Songnen Plain and sequenced the transcriptomes of germinated P. tenuiflora seedlings under long-term treatment (from seed soaking) with saline-alkali soil extracts. RESULTS: We found that the soils from Songnen Plain were reasonably rich in salts and alkali; moreover, the soils were severely deficient in nitrogen [N], phosphorus [P], potassium [K] and several other mineral elements. This finding demonstrated that P. tenuiflora can survive from not only high saline-alkali stress but also a lack of essential mineral elements. To explore the saline-alkali tolerance mechanism, transcriptional analyses of P. tenuiflora plants treated with water extracts from the saline-alkali soils was performed. Interestingly, unigenes involved in the uptake of N, P, K and the micronutrients were found to be significantly upregulated, which indicated the existence of an efficient nutrition-uptake system in P. tenuiflora. Compared with P. tenuiflora, the rice Oryza sativa was hypersensitive to saline-alkali stress. The results obtained using a noninvasive microtest techniques confirmed that the uptake of NO3- and NH4+ and the regulatory flux of Na+ and H+ were significantly higher in the roots of P. tenuiflora than in those of O. sativa. In the corresponding physiological experiments, the application of additional nutrition elements significantly eliminated the sensitive symptoms of rice to saline-alkali soil extracts. CONCLUSIONS: Our results imply that the survival of P. tenuiflora in saline-alkali soils is due to a combination of at least two regulatory mechanisms and the high nutrient uptake capacity of P. tenuiflora plays a pivotal role in its adaptation to those stress. Taken together, our results highlight the role of nutrition uptake in saline-alkali stress tolerance in plants.


Assuntos
Álcalis/farmacologia , Poluição Ambiental , Germinação , Poaceae/fisiologia , Tolerância ao Sal , Sementes/fisiologia , Solo/química , Adaptação Fisiológica , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Oryza/crescimento & desenvolvimento , Raízes de Plantas/fisiologia , Poaceae/genética , Poaceae/crescimento & desenvolvimento , Poaceae/metabolismo , Estresse Fisiológico
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