Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 9.848
Filtrar
1.
J Agric Food Chem ; 67(38): 10577-10586, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31490682

RESUMO

Root and rhizosphere is important for phosphorus (P) uptake in rice plants. However, little is known about the detailed regulation of irrigation regimes, especially frequently alternate wetting and drying (FAWD), on P usage of rice plants. Here, we found that compared with normal water and P dose, FAWD with a reduced P dose maintained the grain yield in two rice varieties. Compared to rice variety Gaoshan1, rice variety WufengyouT025 displayed a higher grain yield, shoot P content, rhizosphere acid phosphatase activity, abundance of bacteria, and bacterial acid phosphatase gene of rhizosphere. Moreover, the FAWD regime may increase the abundance of bacteria with acid phosphatase activity to release available phosphorus in the rhizosphere, which is associated with rice varieties. Our results suggest that an optimized management of irrigation and phosphorous application can enhance both water and phosphorus use efficiency without sacrificing the yield, which may contribute significantly to sustainable agriculture production.


Assuntos
Irrigação Agrícola/métodos , Produção Agrícola/métodos , Oryza/crescimento & desenvolvimento , Fósforo/metabolismo , Microbiologia do Solo , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Produção Agrícola/instrumentação , Fertilizantes/análise , Microbiota , Oryza/classificação , Oryza/metabolismo , Oryza/microbiologia , Rizosfera , Água/metabolismo
2.
BMC Plant Biol ; 19(1): 341, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31382871

RESUMO

BACKGROUND: Barley is a low phosphorus (P) demand cereal crop. Tibetan wild barley, as a progenitor of cultivated barley, has revealed outstanding ability of tolerance to low-P stress. However, the underlying mechanisms of low-P adaption and the relevant genetic controlling are still unclear. RESULTS: We identified low-P tolerant barley lines in a doubled-haploid (DH) population derived from an elite Tibetan wild barley accession and a high-yield cultivar. The tolerant lines revealed greater root plasticity in the terms of lateral root length, compared to low-P sensitive lines, in response to low-P stress. By integrating the QTLs associated with root length and root transcriptomic profiling, candidate genes encoding isoflavone reductase, nitrate reductase, nitrate transporter and transcriptional factor MYB were identified. The differentially expressed genes (DEGs) involved the growth of lateral root, Pi transport within cells as well as from roots to shoots contributed to the differences between low-P tolerant line L138 and low-P sensitive lines L73 in their ability of P acquisition and utilization. CONCLUSIONS: The plasticity of root system is an important trait for barley to tolerate low-P stress. The low-P tolerance in the elite DH line derived from a cross of Tibetan wild barley and cultivated barley is characterized by enhanced growth of lateral root and Pi recycling within plants under low-P stress.


Assuntos
Hordeum/fisiologia , Fósforo/metabolismo , Raízes de Plantas/fisiologia , Adaptação Fisiológica , Perfilação da Expressão Gênica , Genes de Plantas/genética , Genes de Plantas/fisiologia , Hordeum/genética , Hordeum/crescimento & desenvolvimento , Hordeum/metabolismo , Fósforo/deficiência , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Locos de Características Quantitativas/genética , Estresse Fisiológico
3.
Bioresour Technol ; 291: 121871, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31369924

RESUMO

Denitrifying Sulfur conversion-associated Enhanced Biological Phosphorus Removal (DS-EBPR) bioprocess has been recently developed for saline sewage treatment. This study investigated the applicability of granulation technology in DS-EBPR by long-term operation (272 days) of a lab-scale reactor to cultivate sludge granules, then analyzed important physicochemical and biological properties. The findings of this research showed that the net P removal and denitrification efficiencies in DS-EBPR were 80% and 98%, respectively. The average particle size was about 100 µm, and the ratio of SVI5 and SVI30 was <1.3, indicating the activated sludge was well aggregated as micro-granules. The dry density was between 32 and 56 mg/mL, and the specific surface area was 28 m2/g, demonstrating good microporous structure. FISH reveals absence of PAOs, but enriched with SRB (predominant) and denitrifying bacteria in the DS-EBPR granular sludge. Overall, this study provided essential characterization information of DS-EBPR granular sludge which can be used for future development.


Assuntos
Fósforo/metabolismo , Esgotos/microbiologia , Enxofre/metabolismo , Desnitrificação
4.
Bioresour Technol ; 291: 121783, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31326682

RESUMO

Microalgae are feedstocks for multiple product development based on algal biorefinery concept. The effects of light quality (white, red and blue light emitting diodes) and macro-element starvations on Chlorella sp. AE10 were investigated under 20% CO2 and 850 µmol m-2 d-1. Nitrogen and phosphorus starvations had negative effects on its growth rate. The biomass productivities were decreased from day 1 and the highest one was 1.90 g L-1 d-1 under white light conditions. Phosphorus starvation promoted carbohydrate accumulation under three LED light sources conditions and the highest carbohydrate content was 75.9% using red light. Blue light increased lutein content to 9.58 mg g-1. The content of saturated fatty acids was significantly increased from 37.51% under blue light and full culture medium conditions to 77.44% under blue light and nitrogen starvation conditions. Chlorella sp. AE10 was a good candidate for carbohydrate and lutein productions.


Assuntos
Carboidratos/biossíntese , Chlorella/metabolismo , Ácidos Graxos/biossíntese , Luteína/biossíntese , Biomassa , Chlorella/crescimento & desenvolvimento , Ácidos Graxos/análise , Luz , Nitrogênio/metabolismo , Fósforo/metabolismo
5.
Bioresour Technol ; 289: 121718, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31296361

RESUMO

There is an exponential increase in swine farms around the world to meet the increasing demand for proteins, resulting in a significant amount of swine/piggery wastewater. The wastewater produced in swine farms are rich in ammonia with high eutrophication potential and negative environmental impacts. Safe methods for treatment and disposal of swine wastewater have attracted increased research attention in the recent decades. Conventional wastewater treatment methods are limited by the high ammonia content and chemical/biological oxygen demand of swine wastewater. Recently, microalgal cultivation is being proposed for the phytoremediation of swine wastewater. Microalgae are tolerant to high ammonia levels seen in swine wastewater and they also ensure phosphorus removal simultaneously. This review first gives a brief overview on the conventional methods used for swine wastewater treatment. Microalgae-based processes for the clean-up of swine wastewater are discussed in detail, with their potential advantages and limitations. Future research perspectives are also presented.


Assuntos
Microalgas/metabolismo , Águas Residuárias/química , Amônia/metabolismo , Animais , Análise da Demanda Biológica de Oxigênio , Fósforo/metabolismo , Suínos
6.
Physiol Plant ; 166(4): 892-893, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31294874

RESUMO

Drought is an increasingly common climatic event that can devastate ecosystems, as well as surrounding agricultural and forestry industries. Few places face this challenge more than Australia, where millennia of droughts linked to geography and climatic drivers, such as El Niño, have shaped the flora and fauna into forms predicated on resilience and economy. How an organism responds to these cyclic challenges is a combination of the inherent tolerance mechanisms encoded in their genome and outside influences, such as the effect of nutrients and symbiotic interactions. In this issue of Physiologia Plantarum, Tariq et al. (2019) describes how the presence of the element phosphorus can bolster the physiological and biochemical response of eucalypt seedlings to severe drought conditions.


Assuntos
Secas , Genoma de Planta/genética , Fósforo/metabolismo , Plântula/genética , Plântula/metabolismo , Austrália
7.
Plant Mol Biol ; 101(1-2): 129-148, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31267256

RESUMO

Iron and phosphorus are abundant elements in soils but poorly available for plant nutrition. The availability of these two nutrients represents a major constraint for fruit tree cultivation such as apple (Malus × domestica) leading very often to a decrease of fruit productivity and quality worsening. Aim of this study was to characterize common and specific features of plant response to Fe and P deficiencies by ionomic, transcriptomic and exudation profiling of apple roots. Under P deficiency, the root release of oxalate and flavonoids increased. Genes encoding for transcription factors and transporters involved in the synthesis and release of root exudates were upregulated by P-deficient roots, as well as those directly related to P acquisition. In Fe-deficiency, plants showed an over-accumulation of P, Zn, Cu and Mn and induced the transcription of those genes involved in the mechanisms for the release of Fe-chelating compounds and Fe mobilization inside the plants. The intriguing modulation in roots of some transcription factors, might indicate that, in this condition, Fe homeostasis is regulated by a FIT-independent pathway. In the present work common and specific features of apple response to Fe and P deficiency has been reported. In particular, data indicate similar modulation of a. 230 genes, suggesting the occurrence of a crosstalk between the two nutritional responses involving the transcriptional regulation, shikimate pathway, and the root release of exudates.


Assuntos
Ferro/deficiência , Malus/fisiologia , Fósforo/deficiência , Transcriptoma , Transporte Biológico , Perfilação da Expressão Gênica , Homeostase , Ferro/metabolismo , Malus/genética , Fósforo/metabolismo , Exsudatos de Plantas/metabolismo , Folhas de Planta/genética , Folhas de Planta/fisiologia , Raízes de Plantas/genética , Raízes de Plantas/fisiologia , Análise de Sequência de RNA
8.
Ecol Lett ; 22(9): 1462-1471, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31270952

RESUMO

In subtropical oceans phytoplankton carbon: phosphorus (C : P) ratios are high, and these ratios are predicted to increase further with rising ocean temperatures and stratification. Prey stoichiometry may pose a problem for copepod zooplankton nauplii, which have high phosphorus demands due to rapid growth. We hypothesised that nauplii meet this demand by consuming bacteria. Naupliar bacterial and phytoplankton carbon and phosphorus ingestion, assimilation and incorporation were traced using 33 P and 14 C radioisotopes. Bacterial carbon was incorporated four times less efficiently into biomass than phytoplankton carbon. In contrast, bacterial and phytoplankton phosphorus were incorporated at similar efficiencies, and bacteria could meet a substantial amount of naupliar phosphorus requirements. As parts of the ocean become more oligotrophic, bacteria could help sustain naupliar growth and survival under suboptimal stoichiometric conditions. Thus, nauplii may be a shortcut for phosphorus from the microbial loop to the classical food web.


Assuntos
Bactérias/química , Copépodes/metabolismo , Cadeia Alimentar , Fósforo/metabolismo , Animais , Carbono/metabolismo , Radioisótopos de Carbono/análise , Oceanos e Mares , Radioisótopos de Fósforo/análise , Fitoplâncton/química
9.
Bioresour Technol ; 289: 121736, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31288961

RESUMO

This study investigated a new method of multiple-cycle operation of a sulphur-cycle-enhanced biological phosphorus (P) removal system to maintain good phosphorus removal performance at a high temperature (30 °C). The findings demonstrate that P removal was low and unstable under a normal cycle (77 ±â€¯18%), but multiple cycles resulted in a high and quite stable level of P removal (88 ±â€¯9%). Moreover, in the normal mode, the polyhydroxyalkanoate levels increased significantly from 2 to 15 mg C/g of VSS, the glycogen level doubled from 5 to 10 mg C/g of VSS and the polyhydroxyalkanoate and glycogen levels were maintained at considerably low levels after multiple cycles (only 5 C/g of VSS). The 16S rRNA high-throughput sequencing analysis revealed that the genera Thioalbus and Psychrobacter in the gamma-Proteobacteria class were the key functional communities. These findings suggest a high level of P removal with multiple cycles of sulphur-cycle enhanced biological phosphorus removal.


Assuntos
Fósforo/metabolismo , Enxofre/metabolismo , Reatores Biológicos , Glicogênio/metabolismo , Temperatura Alta , RNA Ribossômico 16S/genética
10.
Bioresour Technol ; 289: 121745, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31323724

RESUMO

The status of heavy metals and the P fractions in compost affects their environmental risk. The present study investigated the effects of different initial carbon to nitrogen (C/N) ratios (15, 22, 27) on redistribution of Cu, Zn, and P fractions during composting. The results showed that the composting process transformed Cu, Zn and P from mobile fractions to more stable fractions. Compost with an initial C/N of 22 showed the most effective immobilization of Cu, Zn and P because of yielding greatest degree of polymerization. Multivariate statistical analysis identified organic matter as the most critical factor for explaining the redistribution of Cu, Zn, and P fractions in composting. However, the degree of organic matter degradation (organic matter content and Humic acid/Fulvic acid) better explained the change of bioavailability factor for Cu and the mobility of P during composting. This research provided guidance for providing technology to reduce environmental risk in compost.


Assuntos
Carbono/metabolismo , Compostagem , Cobre/metabolismo , Nitrogênio/metabolismo , Fósforo/metabolismo , Zinco/metabolismo , Disponibilidade Biológica
11.
Sci Total Environ ; 691: 908-918, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31326814

RESUMO

Energy (photosynthetically active [PAR] and ultraviolet [UVR] radiation) and matter (organic and inorganic nutrients) fluxes regulate the ecosystem's stability. However, the mechanisms underpinning the potential interplay between resistance and resilience to shifts in nutrient inputs and UVR are poorly understood. To assess how the UVR × nutrients interaction alters ecosystem stability, we exposed in situ a microbial food web from an oligotrophic ecosystem to: (1) two light (UVR + PAR and PAR), and (2) four nutrient (ambient concentrations, phosphorus [P], carbon [C] and C × P addition) treatments for three weeks. During this period, we quantified the community composition and biomass, sestonic P and C:P ratio, primary [PP] and bacterial [BP] production, community [CR] and bacterial [BR] respiration, excreted organic carbon [EOC], as well as the commensalistic phytoplankton-bacteria interaction (i.e. bacterial carbon demand [BCD]:EOC ratio) and the metabolic balance of the ecosystem (i.e. [PP:R] ratio). The stability of all response variables under the four environmental scenarios tested (i.e. UVR, UVR × C, UVR × P, and UVR × C × P) was quantified by means of the resistance and resilience indexes. The microbial community was dominated by phototrophs during the experimental period regardless of the treatment considered. The most complex scenario, i.e. UVR × C × P, decreased the resistance for all variables, except for BR and the PP:R ratio. Despite that PP:R ratio showed the highest resistance under such scenario, it was >1 in all environmental scenarios (i.e. net autotrophic), except under the UVR × C interaction, where, concomitant with increased resilience, the balance shifted towards net heterotrophy (PP:R < 1). Under the UVR × C × P scenario, the metabolic balance of the ecosystem proved strongly resistant due mainly to high resistance of bacterial respiration and a firm stability of the commensalistic interaction. Our results evidence that the high resilience of phototrophs (favoring their predominance over mixo- and heterotrophs) may lead to the maintenance of the autotrophic nature and carbon (C) sink capacity of the ecosystem.


Assuntos
Cadeia Alimentar , Água Doce/microbiologia , Biomassa , Carbono/metabolismo , Ecossistema , Nitrogênio/metabolismo , Fósforo/metabolismo , Fitoplâncton
12.
Chemosphere ; 233: 216-222, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31173959

RESUMO

Considering the prevalence of eutrophication of water bodies, sustainable treatment technologies like constructed wetlands (CWs) have come up as a promising alternate for nutrient removal and wastewater treatment. The present study was undertaken to investigate the potential of Brachiaria-based constructed wetland for removal of phosphorus and nitrogen in different seasons of a sub-tropical region. The CW cell could efficiently remove phosphate and nitrogen under varying influent concentrations across different seasons. Average removal of total phosphate increased from 55.2% (winter) to 78.5% (spring), 80.7% (autumn), and 85.6% (summer), and maximum removal rate was 384.4 mg/m2-day during the summer season. The soluble/available phosphate was removed on priority owing to its easy bio-availability. The removal efficiency of Brachiaria increased with increasing influent phosphate concentration (5-20 mg/l), if supplemented with nitrogen maintaining the N:P ratio of 5:1. This highlighted the characteristic of Brachiaria to absorb chemical shocks w.r.t. phosphate. The neutral pH (6.2-8.3) and oxidising conditions in rhizosphere ruled out possibility of binding of phosphate with cations (Ca, Fe, and Al) in sediments. Ambient temperature and sunshine hours regulated evapotranspiration and hence nutrient removal. Simultaneous removal of nitrogen (75.6-84.6%) by Brachiaria indicated that it can serve dual purpose of nutrient removal and fodder-production for livestock, thus serving as a sustainable prototype for rural communities in sub-tropical regions.


Assuntos
Brachiaria/metabolismo , Nitrogênio/isolamento & purificação , Fósforo/isolamento & purificação , Eliminação de Resíduos Líquidos/métodos , Áreas Alagadas , Concentração de Íons de Hidrogênio , Índia , Nitrogênio/metabolismo , Fosfatos/metabolismo , Fósforo/metabolismo , Estações do Ano , Águas Residuárias , Qualidade da Água
13.
Plant Sci ; 285: 110-121, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31203875

RESUMO

In agricultural soil, the bioavailability of iron (Fe) and phosphorus (P) is often below the plant's requirement causing nutritional deficiency in crops. Under P-limiting conditions, white lupin (Lupinus albus L.) activates mechanisms that promote P solubility in the soil through morphological, physiological and molecular adaptations. Similar changes occur also in Fe-deficient white lupin roots; however, no information is available on the molecular bases of the response. In the present work, responses to Fe and P deficiency and their reciprocal interactions were studied. Transcriptomic analyses indicated that white lupin roots upregulated Fe-responsive genes ascribable to Strategy-I response, this behaviour was mainly evident in cluster roots. The upregulation of some components of Fe-acquisition mechanism occurred also in P-deficient cluster roots. Concerning P acquisition, some P-responsive genes (as phosphate transporters and transcription factors) were upregulated by P deficiency as well by Fe deficiency. These data indicate a strong cross-connection between the responses activated under Fe or P deficiency in white lupin. The activation of Fe- and P-acquisition mechanisms might play a crucial role to enhance the plant's capability to mobilize both nutrients in the rhizosphere, especially P from its associated metal cations.


Assuntos
Ferro/metabolismo , Lupinus/metabolismo , Fósforo/metabolismo , Raízes de Plantas/metabolismo , Fosfatase Ácida/metabolismo , FMN Redutase/metabolismo , Genes de Plantas/fisiologia , Ferro/deficiência , Lupinus/genética , Lupinus/fisiologia , Fósforo/deficiência , Raízes de Plantas/fisiologia , Rizosfera , Análise de Sequência de RNA , Transcriptoma
14.
Microbiol Res ; 223-225: 1-12, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31178042

RESUMO

Phosphorus (P) is an essential plant nutrient, but often limited in soils for plant uptake. A major economic constraint in the rice production is excessive use of chemical fertilizers to meet the P requirement. Bioaugmentation of phosphate solubilizing rhizobacteria (PSB) can be used as promising alternative. In the present study 11 mineral PSB were isolated from Basmati rice growing areas of Pakistan. In broth medium, PSB solubilized tricalcium phosphate (27-354 µg mL-1) with concomitant decrease in pH up to 3.6 due to the production of different organic acids, predominantly gluconic acid. Of these, 4 strains also have ability to mineralize phytate (245-412 µg mL-1). Principle component analysis showed that the gluconic acid producing PSB strains (Acinetobacter sp. MR5 and Pseudomonas sp. MR7) have pronounced effect on grain yield (up to 55%), plant P (up to 67%) and soil available P (up to 67%), with 20% reduced fertilization. For simultaneous validation of gluconic acid production by MR5 and MR7 through PCR, new specific primers were designed to amplify gcd, pqqE, pqqC genes responsible for glucose dehydrogenase (gcd) mediated phosphate solubilization. These findings for the first time demonstrated Acinetobacter soli as potent P solubilizer for rice and expands our knowledge about genus specific pqq and gcd primers. These two gcd containing PSB Acinetobacter sp. MR5 (DSM 106631) and Pseudomonas sp. MR7 (DSM 106634) submitted to German culture collection (DSMZ), serve as global valuable pool to significantly increase the P uptake, growth and yield of Basmati rice with decreased dependence on chemical fertilizer in P deficit agricultural soils.


Assuntos
Biofortificação , Glucose 1-Desidrogenase/genética , Oryza/crescimento & desenvolvimento , Fósforo/metabolismo , Acinetobacter/genética , Agricultura , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Bactérias/metabolismo , Proteínas de Bactérias/genética , Transporte Biológico , Meios de Cultura , Fertilizantes , Germinação , Gluconatos/metabolismo , Concentração de Íons de Hidrogênio , Paquistão , Fosfatos/metabolismo , Pseudomonas/genética , Sementes/crescimento & desenvolvimento , Solo/química , Microbiologia do Solo , Solubilidade
15.
Nat Commun ; 10(1): 2829, 2019 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-31249296

RESUMO

Extracellular vesicles (EVs) are involved in the regulation of cell physiological activity and the reconstruction of extracellular environment. Matrix vesicles (MVs) are a type of EVs released by bone-related functional cells, and they participate in the regulation of cell mineralization. Here, we report bioinspired MVs embedded with black phosphorus (BP) and functionalized with cell-specific aptamer (denoted as Apt-bioinspired MVs) for stimulating biomineralization. The aptamer can direct bioinspired MVs to targeted cells, and the increasing concentration of inorganic phosphate originating from BP can facilitate cell biomineralization. The photothermal effect of the Apt-bioinspired MVs can also promote the biomineralization process by stimulating the upregulated expression of heat shock proteins and alkaline phosphatase. In addition, the Apt-bioinspired MVs display outstanding bone regeneration performance. Our strategy provides a method for designing bionic tools to study the mechanisms of biological processes and advance the development of medical engineering.


Assuntos
Vesículas Extracelulares/metabolismo , Fósforo/metabolismo , Fosfatase Alcalina/genética , Fosfatase Alcalina/metabolismo , Animais , Aptâmeros de Nucleotídeos/genética , Aptâmeros de Nucleotídeos/metabolismo , Biomineralização , Osso e Ossos/química , Osso e Ossos/citologia , Osso e Ossos/metabolismo , Vesículas Extracelulares/química , Feminino , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Osteoblastos/química , Osteoblastos/metabolismo , Fosfatos/metabolismo , Fósforo/química , Ratos
16.
Sci Total Environ ; 684: 50-57, 2019 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-31150875

RESUMO

Urbanization, the migration of populations from rural to urban areas, has been causing great stress on natural environments, leading to air pollution and nitrogen (N) deposition, negatively affecting forest health. Although there is evidence that urbanization has changed forest N cycling, little is known about whether urbanization also changes the availability of phosphorus (P), which is important for plant growth and forest productivity. To address this question, we carried out a survey in the Pearl River Delta region, the world's largest urban area in southern China, using two types of representative forests, the evergreen broadleaf forests (BFs) and pine plantations (PPs). The leaf N:P ratios in the two forest types were high (20-50) with a significant increasing pattern along the rural-to-urban gradient. The ratios of leaf P:K and P:Na declined along the rural-to-urban gradient, whereas leaf P content did not change in BF but decreased in PP along the rural-to-urban gradient, suggesting that leaf P became limiting along urbanization. The abundance of actinomycetes and gram-negative bacteria decreased along the rural-to-urban gradient, indicating the negative effects of urbanization on soil microorganisms. Principal component analysis indicated that divergent key factors respond to the urbanization and affect plant P limitation in the two forest types. In BF, broadleaf trees showed a greater response to N deposition from urbanization indicating direct leaf N uptake from N deposition is a key factor for plant P limitation. Alternatively, in PP, our findings suggest soil acidification is an important factor accelerating plant P limitation. Our study revealed that urbanization intensifies plant P limitation in subtropical forests, and the effects vary depending on forest types. Our findings provide empirical information to support the management of forest ecosystems and evaluation of urbanization effects on forest health.


Assuntos
Florestas , Nitrogênio/metabolismo , Fósforo/metabolismo , Árvores/metabolismo , Urbanização , China , Folhas de Planta/anatomia & histologia , Folhas de Planta/metabolismo
17.
Plant Biol (Stuttg) ; 21(5): 805-812, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31050863

RESUMO

Identifying the mechanisms of compensation to insect herbivory remains a major challenge in plant biology and evolutionary ecology. Most previous studies have addressed plant compensatory responses to one or two levels of insect herbivory, and the underlying traits mediating such responses remain elusive in many cases. We evaluated responses associated with compensation to multiple intensities of leaf damage (0% control, 10%, 25%, 50%, 75% of leaf area removed) by means of mechanical removal of foliar tissue and application of a caterpillar (Spodoptera exigua) oral secretions in 3-month-old wild cotton plants (Gossypium hirsutum). Four weeks post-treatment, we measured plant growth and multiple traits associated with compensation, namely: changes in above- and belowground, biomass and the concentration of nutrients (nitrogen and phosphorus) and non-structural carbon reserves (starch and soluble sugars) in roots, stems and leaves. We found that wild cotton fully compensated in terms of growth and biomass allocation when leaf damage was low (10%), whereas moderate (25%) to high leaf damage in some cases led to under-compensation. Nonetheless, high levels of leaf removal (50% and 75%) in most cases did not cause further reductions in height and allocation to leaf and stem biomass relative to low and moderate damage. There were significant positive effects of leaf damage on P concentration in leaves and stems, but not roots, as well as a negative effect on soluble sugars in roots. These results indicate that wild cotton fully compensated for a low level of leaf damage but under-compensated under moderate to high leaf damage, but can nonetheless sustain growth despite increasing losses to herbivory. Such responses were possibly mediated by a re-allocation of carbohydrate reserves from roots to shoots.


Assuntos
Gossypium/fisiologia , Herbivoria , Animais , Gossypium/metabolismo , Nitrogênio/metabolismo , Fósforo/metabolismo , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Caules de Planta/metabolismo , Spodoptera
18.
Sci Total Environ ; 678: 551-558, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31078845

RESUMO

Legumes can increase nitrogen (N) input to soil via N2 fixation, and arbuscular mycorrhizal fungi (AMF) can colonize legumes, which further promotes the acquisition of nutrients such as phosphorus (P). Nevertheless, little is known about how different legume species or planting densities affect soil AMF communities. We measured soil AMF abundance, diversity, and community composition in two legume species that had been planted at two densities in a karst grassland. Five treatments were used: control (CK), Amorpha fruticosa at 1.5 × 2 m density (AFD1), A. fruticosa at 1 × 1 m density (AFD2), Indigofera atropurpurea at 1.5 × 2 m density (IAD1), and I. atropurpurea at 1 × 1 m density (IAD2). The results showed that A. fruticosa plots were significantly richer in Redeckera spp., while I. atropurpurea plots were richer in Septoglomus. AMF abundance in AFD1, AFD2, and IAD1 was significantly higher than in CK, but AMF abundance in IAD2 was significantly lower than that in the other treatments. AMF richness and Chao1 estimator in AFD1 were significantly higher than in CK. Funneliformis, Septoglomus, and Acaulospora were significantly more abundant in IAD2 than in the other treatments. The interaction between legume species and density had a significant effect on AMF abundance and community composition. AMF abundance and diversity were significantly negatively and positively correlated with available P and microbial biomass N, respectively. These results suggest that different species and densities of legumes may increase available N, which could improve AMF abundance and alleviate soil P deficiencies. Planting A. fruticosa or I. atropurpurea at a low density may be an effective method to increase AMF colonization of roots, and thus, nutrient transport in karst grasslands.


Assuntos
Fabaceae/metabolismo , Pradaria , Microbiota , Micorrizas/fisiologia , Solo/química , China , Nitrogênio/metabolismo , Nutrientes/metabolismo , Fósforo/metabolismo , Densidade Demográfica , Especificidade da Espécie
19.
Environ Sci Pollut Res Int ; 26(20): 20961-20968, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31115809

RESUMO

This study compared the efficiency of nutrient removal and lipid accumulation by a monoculture of Scenedesmus obliquus and mixed cultures of microalgae. The highest removal efficiencies of ammonium (99.2%), phosphate (91.2%), and total organic carbon (83.6%) occurred in the monoculture. All the mixed cultures were dominated by S. quadricauda; in some mixed cultures, the proportions of Chlamydomonas reinhardtii and C. microsphaera reached > 20%. The lipid content and lipid production in the monoculture were 15.9% and 52.3 mg kg-1, respectively, significantly higher than those in all the mixed cultures of microalgae. In all the mixed cultures, the proportion of palmitic acid was > 50%. The results suggest that the monoculture had advantages over the mixed culture of microalgae in terms of nutrient removal and lipid production.


Assuntos
Metabolismo dos Lipídeos , Microalgas/metabolismo , Nutrientes/isolamento & purificação , Scenedesmus/metabolismo , Poluentes Químicos da Água/isolamento & purificação , Biocombustíveis/análise , Carbono/isolamento & purificação , Carbono/metabolismo , Lipídeos/química , Microalgas/classificação , Microalgas/crescimento & desenvolvimento , Nitrogênio/isolamento & purificação , Nitrogênio/metabolismo , Nutrientes/metabolismo , Fósforo/isolamento & purificação , Fósforo/metabolismo , Scenedesmus/crescimento & desenvolvimento , Poluentes Químicos da Água/metabolismo
20.
Chemosphere ; 229: 132-141, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31078028

RESUMO

Simultaneous nitrogen and phosphorus removal in winter is one of the great challenges in wastewater treatment processes due to the poor bioactivity of microbial communities. In this study, excellent performance of simultaneous nitrification, denitrification and phosphorus removal (SNDPR) was achieved at low temperature of 10 °C and COD/N ratio of 6 in a lab-scale sequencing batch reactor. Total nitrogen (TN) and phosphorus (TP) removal efficiency reached 89.6% and 97.5%, respectively, accompanied with N2O emission of 7.46% TN due to the primary contribution (70%) of nitrifier denitrification. It was further confirmed that polyphosphate accumulating organisms (PAOs) were dominant in microbial communities revealed by fluorescence in situ hybridization and 16S rRNA amplicon sequencing. Moreover, denitrifying phosphorus removal by PAOs through nitrite pathway was found to be the main reason for the high efficiency of this SNDPR process. Denitrifying PAOs, especially the subgroup PAOII capable of utilizing nitrite to take up phosphorus, played a significant role in highly efficient TN and TP removal at low temperature. Furthermore, genus Propionivibrio was enriched (48.9%) in the bacterial community based on the 16S rRNA analysis, which was proposed to be a crucial member involved in the nitrogen and phosphorus removal simultaneously at low temperature in this system.


Assuntos
Reatores Biológicos/microbiologia , Desnitrificação , Nitrificação , Fósforo/isolamento & purificação , Fósforo/metabolismo , Temperatura Ambiente , Eliminação de Resíduos Líquidos/métodos , Bactérias/metabolismo , Nitrogênio/isolamento & purificação , Nitrogênio/metabolismo , Águas Residuárias/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA