Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 8.944
Filtrar
1.
Chemosphere ; 242: 125261, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31896178

RESUMO

Seedling establishment consists of the former stage (i.e. skotomorphogenesis) and the latter stage (i.e. photomorphogenesis). Due to specific developmental processes in plants, the two stages may have different sensitivities to antibiotics. Tetracycline (TC), for example, is a major-use antibiotic. Radicle length, the relatively sensitive endpoint in plant skotomorphogenesis, is less sensitive than all of the indices of cotyledon colour and pigments in plant photomorphogenesis to TC stress. In conclusion, we suggest that plant photomorphogenesis may be more sensitive than plant skotomorphogenesis to stresses of antibiotics, but which needs further studies.


Assuntos
Antibacterianos/toxicidade , Brassica rapa/efeitos dos fármacos , Desenvolvimento Vegetal/efeitos dos fármacos , Plântula/efeitos dos fármacos , Poluentes do Solo/toxicidade , Tetraciclina/toxicidade , Proteínas de Arabidopsis/genética , Brassica rapa/crescimento & desenvolvimento , Brassica rapa/efeitos da radiação , Cotilédone/efeitos dos fármacos , Cotilédone/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Luz , Pigmentos Biológicos/biossíntese , Plântula/crescimento & desenvolvimento , Plântula/efeitos da radiação
2.
World J Microbiol Biotechnol ; 36(2): 26, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31997078

RESUMO

Salinity stress is one of the key constraints for sustainable crop production. It has gained immense importance in the backdrop of climate change induced imbalanced terrestrial water budgets. The traditional agronomic approaches and breeding salt-tolerant genotypes have often proved insufficient to alleviate salinity stress. Newer approaches like the use of bacterial endophytes associated with agricultural crops have occupied center place recently, owing to their advantageous role in improving crop growth, health and yield. Research evidences have revealed that bacterial endophytes can promote plant growth by accelerating availability of mineral nutrients, helping in production of phytohormones, siderophores, and enzymes, and also by activating systemic resistance against insect pest and pathogens in plants. These research developments have opened an innovative boulevard in agriculture for capitalizing bacterial endophytes, single species or consortium, to enhance plant salt tolerance capabilities, and ultimately lead to translational refinement of crop-production business under salty environments. This article reviews the latest research progress on the identification and functional characterization of salt tolerant endophytic bacteria and illustrates various mechanisms triggered by them for plant growth promotion under saline environment.


Assuntos
Bactérias/metabolismo , Endófitos/fisiologia , Desenvolvimento Vegetal/fisiologia , Tolerância ao Sal/fisiologia , Plantas Tolerantes a Sal/microbiologia , Produtos Agrícolas/metabolismo , Produtos Agrícolas/microbiologia , Microbiota , Reguladores de Crescimento de Planta/metabolismo , Raízes de Plantas/microbiologia , Salinidade , Sideróforos/metabolismo , Microbiologia do Solo
3.
J Environ Manage ; 254: 109779, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31726280

RESUMO

Rapid industrialization, modern agricultural practices and other anthropogenic activities add a significant quantity of toxic heavy metals into the environment, which induces severe toxic effects on all form of living organisms, alter the soil properties and its biological activity. Remediation of heavy metal contaminated sites has become an urgent necessity. Among the existing strategies, phytoremediation is an eco-friendly and much convincing tool for the remediation of heavy metals. However, the applicability of phytoremediation in contaminated sites is restricted by two prime factors such as i) slow growth rate at higher metal contaminated sites and ii) metal bioavailability. This circumstance could be minimized and accelerate the phytoremediation efficiency by incorporating the potential plant growth promoting rhizobacterial (PGPR) as a combined approach. PGPR inoculation might improve the plant growth through the production of plant growth promoting substances and improve the heavy metal remediation efficiency by the secretion of chelating agents, acidification and redox changes. Moreover, rhizobacterial inoculation consolidates the metal tolerance and uptake by regulating the expression of various metal transporters, tolerant and metal chelator genes. However, the exact underlying molecular mechanism of PGPR mediated plant growth promotion and phytoremediation of heavy metals is poorly understood. Thus, the present review provides clear information about the molecular mechanisms excreted by PGPR strains in plant growth promotion and phytoremediation of heavy metals.


Assuntos
Metais Pesados , Poluentes do Solo , Biodegradação Ambiental , Desenvolvimento Vegetal , Solo
4.
Rev Environ Contam Toxicol ; 252: 1-50, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31451946

RESUMO

Microbe-assisted organopollutant removal, or in planta crop decontamination, is based on an interactive system between organopollutant-degrading endophytic bacteria (DEBOP) and crops in alleviating organic toxins in plants. This script focuses on the fast-growing body of literature that has recently bloomed in organopollutant control in agricultural plants. The various facets of DEBOP under study include their colonization, distribution, plant growth-promoting mechanisms, and modes of action in the detoxification process in plants. Also, an assessment of the biotechnological advances, advantages, and bottlenecks in accelerating the implementation of this decontamination strategy will be undertaken. The highlighted key research directions from this review will shape the future of agro-environmental sustainability and preservation of human health.


Assuntos
Bactérias , Produtos Agrícolas/microbiologia , Endófitos , Poluentes do Solo/metabolismo , Agricultura , Produtos Agrícolas/metabolismo , Inativação Metabólica , Desenvolvimento Vegetal
5.
Chemosphere ; 240: 124891, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31574442

RESUMO

We investigated the effects of endophytes inoculation on ecological factors such as root morphology, rhizosphere soil properties, heavy metal speciation, and rhizosphere and endophytic bacterial communities and their role on phytoremediation. Indian mustards were grown for two months in V-contaminated soil with three treatments (control, inoculation with Serratia PRE01 or Arthrobacter PRE05). Inoculation with PRE01 and PRE05 increased organic matter content by 6.94% and 4.6% respectively and significantly increased bioavailability of heavy metals in rhizosphere soils. Despite the endophyte inocula failed to flourish as stable endophytes, they significantly affected the specific composition and diversity of endophytic bacterial communities in roots, with no significant effect on rhizosphere bacterial communities. The test strains could greatly increase plant growth promotion-related biomarkers in the endosphere, especially those associated with Pseudomonas and Microbacterium genera. PICRUSt analysis predicted high relative abundances of functional genes related to environmental information processing especially in the endophytic microbiota. More biomass production (12.0%-17.4%) and total metals uptake (24.2%-32.0%) were acquired in inoculated treatments. We conclude that endophyte PRE01 or PRE05 inoculation could effectively enhance phytoremediation of V-contaminated soil by improving the rhizosphere and endosphere microecology without causing any ecological damage.


Assuntos
Bactérias/metabolismo , Biodegradação Ambiental , Endófitos/crescimento & desenvolvimento , Mostardeira/metabolismo , Rizosfera , Poluentes do Solo/toxicidade , Vanádio/toxicidade , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Mostardeira/efeitos dos fármacos , Mostardeira/microbiologia , Desenvolvimento Vegetal/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Microbiologia do Solo , Poluentes do Solo/análise , Vanádio/análise
6.
Chemosphere ; 240: 124895, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31550588

RESUMO

Rapid industrialization and anthropogenic activities have produced huge amount of noxious Cr(VI), which accumulate in the soil for longer period. As a consequence, that decreases rice plant productivity in contiguous agricultural field of Sukinda mining area, Odisha. Thus, the high Cr(VI) resistant native bacterial strain CTWI-06 was selected for the study, which depicted resistance to 3500 ppm of Cr(VI) and wide array of other metals. Under optimized condition, the multi-metal resistant bacteria reduced 94% Cr(VI) within 92 h and Cr(VI) reduction was confirmed by FTIR and XRD analysis. Plant growth promoting traits like N2 fixation; phosphate (146.87 ppm), potassium (12.55 ppm) and Zn solubilization; ammonification; IAA production (114 µg mL-1) and suppression of fungal phytopathogens such as Rhizoctonia solani (ITCC 2060) and Phytium debaryanum (ITCC 5488) were also recorded. The bacterial strain was identified as Enterobacter cloacae CTWI-06 by 16S rDNA sequence (Accession No. MG757378). It significantly improved growth traits as well as productivity of Mahalakshmi rice variety in pot culture. Thus, the potential Cr(VI) reducing and PGPB strain may be utilized for long term bioremediation of Cr(VI) in chromium contaminated soil and to maintain soil fertility.


Assuntos
Biodegradação Ambiental , Cromo/metabolismo , Enterobacter cloacae/fisiologia , Oryza/microbiologia , Poluentes do Solo/metabolismo , Bactérias , Fungos , Mineração , Fosfatos , Desenvolvimento Vegetal , Solo , Microbiologia do Solo
7.
Chemosphere ; 240: 124944, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31726591

RESUMO

The present study explores the potential of two chromium tolerant and plant growth promoting bacterial strains, Klebsiella sp. and Enterobacter sp. in luxuriant growth of tomato plants under chromium stress conditions. For the assessment of potentiality of the two selected strains, a pot scale experiment was setup with tomato plant under different levels of chromium contamination. In pot experiment, different plant growth parameters, oxidative stress tolerance and chromium bioremediation potential were studied upon inoculation of the selected bacterial strains. The results of pot experiment showed that both the strains were effective in promotion of plant growth and enhanced the plant biomass but Enterobacter sp. was more prominent in enhancement of root length, shoot length, fresh and dry weight, and nutrient uptake in tomato plant. The enhancement of enzymes to combat oxidative stress in tomato plant under chromium stress was also observed for both the strains. Both strains enhanced the levels of superoxide dismutase, catalase, peroxidase, total phenolic, and ascorbic acid in tomato plant under different levels of chromium stress conditions. The chromium phytoremediation potential of tomato plant upon inoculation of both the strains was also studied. The results of phytoremediation showed greater chromium accumulation in roots with poor translocation in shoot upon inoculation of Klebsiella sp. while no significant enhancement in chromium uptake by tomato plant was observed on inoculation of Enterobacter sp. compared to control. Thus, these two strains can effectively be used in luxuriant growth of tomato plant under metal stress conditions.


Assuntos
Cromo/toxicidade , Enterobacter/fisiologia , Klebsiella/fisiologia , Lycopersicon esculentum/fisiologia , Poluentes do Solo/toxicidade , Biodegradação Ambiental , Biomassa , Catalase/metabolismo , Enterobacter/metabolismo , Klebsiella/metabolismo , Lycopersicon esculentum/efeitos dos fármacos , Lycopersicon esculentum/microbiologia , Estresse Oxidativo , Desenvolvimento Vegetal , Raízes de Plantas/metabolismo , Superóxido Dismutase/metabolismo
8.
Chemosphere ; 238: 124682, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31524619

RESUMO

Plant growth-promoting bacteria (PGPB) are considered a promising tool to improve biomass production and water remediation by the aquatic plant, duckweed; however, no effective methodology is available to utilize PGPB in large hydroponic systems. In this study, we proposed a two-step cultivation process, which comprised of a "colonization step" and a "mass cultivation step," and examined its efficacy in both bucket-scale and flask-scale cultivation experiments. We showed that in the outdoor bucket-scale experiments using three kinds of environmental water, plants cultured through the two-step cultivation method with the PGPB strain, Acinetobacter calcoaceticus P23, yielded 1.9 to 2.3 times more biomass than the control (without PGPB inoculation). The greater nitrogen and phosphorus removals compared to control were also attained, indicating that this strategy is useful for accelerating nutrient removal by duckweed. Flask-scale experiments using non-sterile pond water revealed that inoculation of strain P23 altered duckweed surface microbial community structures, and the beneficial effects of the inoculated strain P23 could last for 5-10 d. The loss of the duckweed growth-promoting effect was noticeable when the colonization of strain P23 decreased in the plant. These observations suggest that the stable colonization of the plant with PGPB is the key for maintaining the accelerated duckweed growth and nutrient removal in this cultivation method. Overall, our results suggest the possibility of an improved duckweed production using a two-step cultivation process with PGPB.


Assuntos
Acinetobacter calcoaceticus/metabolismo , Araceae/crescimento & desenvolvimento , Araceae/microbiologia , Hidroponia/métodos , Microbiota/fisiologia , Biomassa , Água Doce , Nitrogênio/análise , Nutrientes , Fósforo/análise , Desenvolvimento Vegetal , Purificação da Água/métodos
9.
Chemosphere ; 238: 124710, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31545216

RESUMO

The purpose of study was to examine the residual effects of two types of biochar amendments, two phosphorus (P) fertilizer levels, phosphorus solubilizing bacteria (PSB) and arbuscular mycorrhizal fungs (AMF) on plant growth, nutrients absorption and root architecture of Zea mays L. in texturally different soils. Biochar signficantly increased nutrients absorption and plant biomass production with P-fertilization and microbial inoculantion. Texturally different soils enhanced the plant biomass and nutrients absorption in their independent capacity on addition of biochar, microbial inoculants and P-fertilization. It was shown that mycorrhizal inoculation had positive influence on plant root and shoot biomass in both soils irrespective to the biochar type used. Root colonization was notably increased in biochar + mycorrhizae (B + M) inocultaed plants. It was shown that mycorrhizal inoculation had positive influence on nutrients absorption by plant roots and it had high content of P, potassium, calcium and magnesium in plants at all biochar and P levels. Without P fertilization, biochar amendments significantly promoted shoot P content and root colonization. The P application significantly influenced soil microbial activity in terms of nutrient concentration and plant growth. Root attributes were significantly inclined by microbial inoculation. Residual effects of biochar and P significantly enhanced the nutreints absorption and maize plant growth. Thus, we concluded that residual biochar and P fertilizer showed positive effects on nutrients absorption and maize plant growth promotion in differently textured soils. Microbial inoculants further stimulated the plant biomass production and nutrients absorption due to effective root colonization.


Assuntos
Bactérias/metabolismo , Carvão Vegetal/farmacologia , Fungos/metabolismo , Fósforo/farmacologia , Zea mays/crescimento & desenvolvimento , Inoculantes Agrícolas , Biomassa , Fertilizantes/análise , Micorrizas/efeitos dos fármacos , Nutrientes , Desenvolvimento Vegetal/efeitos dos fármacos , Raízes de Plantas/química , Raízes de Plantas/microbiologia , Solo/classificação , Poluentes do Solo/análise , Zea mays/metabolismo
10.
Sci Total Environ ; 700: 134453, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31670196

RESUMO

Heat stress induces secondary metabolic changes in plants, channeling photosynthetic carbon and energy, away from primary metabolic processes, including, growth. Use of ACC (1-aminocyclopropane-1-carboxylate) deaminase containing plant growth promoting bacteria (PGPB) in conferring heat resistance in plants and the role of PGPB, in altering net carbon assimilation, constitutive and stress volatile emissions has not been studied yet. We exposed leaves of Eucalyptus grandis inoculated and non-inoculated with PGPB Brevibacterium linens RS16 to two levels of heat stress (37 °C and 41 °C for 5 min) and quantified temporal changes in foliage photosynthetic characteristics and volatile emission rates at 0.5 h, day 1 and day 5 after the stress application. Heat stress resulted in immediate reductions in dark-adapted photosystem II (PSII) quantum yield (Fv/Fm), net assimilation rate (A), stomatal conductance to water vapor (gs), and enhancement of stress volatile emissions, including enhanced emissions of green leaf volatiles (GLV), mono- and sesquiterpenes, light weight oxygenated volatile organic compounds (LOC), geranyl-geranyl diphosphate pathway volatiles (GGDP), saturated aldehydes, and benzenoids, with partial recovery by day 5. Changes in stress-induced volatiles were always less in leaves inoculated with B. linens RS16. However, net assimilation rate was enhanced by bacterial inoculation only in the 37 °C treatment and overall reduction of isoprene emissions was observed in bacterially-treated leaves. Principal component analysis (PCA), correlation analysis and partial least squares discriminant analysis (PLS-DA) indicated that different stress applications influenced specific volatile organic compounds. In addition, changes in the expression analysis of heat shock protein 70 gene (DnaK) gene in B. linens RS16 upon exposure to higher temperatures further indicated that B. linens RS16 has developed its own heat resistance mechanism to survive under higher temperature regimes. Taken together, this study demonstrates that foliar application of ACC deaminase containing PGPB can ameliorate heat stress effects in realistic biological settings.


Assuntos
Brevibacterium/fisiologia , Eucalyptus/fisiologia , Resposta ao Choque Térmico , Estresse Fisiológico , Compostos Orgânicos Voláteis/análise , Carbono-Carbono Liases , Fotossíntese , Desenvolvimento Vegetal , Folhas de Planta
11.
World J Microbiol Biotechnol ; 35(12): 195, 2019 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-31784916

RESUMO

The search for effective plant-growth-promoting strains of rhizospheric bacteria that would ensure the resistance of plant-microbial associations to environmental stressors is essential for the design of environmentally friendly agrobiotechnologies. We investigated the interaction of potato (cv. Nevsky) microplants with the plant-growth-promoting bacteria Azospirillum brasilense Sp245 and Ochrobactrum cytisi IPA7.2 under osmotic stress in vitro. The bacteria improved the physiological and biochemical variables of the microplants, significantly increasing shoot length and root number (1.3-fold, on average). Inoculation also led a more effective recovery of the plants after stress. During repair, inoculation contributed to a decreased leaf content of malonic dialdehyde. With A. brasilense Sp245, the decrease was 1.75-fold; with O. cytisi IPA7.2, it was 1.4-fold. During repair, the shoot length, node number, and root number of the inoculated plants were greater than the control values by an average of 1.3-fold with A. brasilense Sp245 and by an average of 1.6-fold with O. cytisi IPA7.2. O. cytisi IPA7.2, previously isolated from the potato rhizosphere, protected the physiological and biochemical processes in the plants under stress and repair better than did A. brasilense Sp245. Specifically, root weight increased fivefold during repair, as compared to the noninoculated plants, while chlorophyll a content remained at the level found in the nonstressed controls. The results indicate that these bacteria can be used as components of biofertilizers. A. brasilense Sp245 has favorable prospects for use in temperate latitudes, whereas O. cytisi IPA7.2 can be successfully used in saline and drought-stressed environments.


Assuntos
Interações entre Hospedeiro e Microrganismos/fisiologia , Pressão Osmótica , Desenvolvimento Vegetal , Solanum tuberosum/microbiologia , Estresse Fisiológico/fisiologia , Azospirillum brasilense/fisiologia , Clorofila A , Contagem de Colônia Microbiana , Secas , Malonatos , Ochrobactrum/fisiologia , Folhas de Planta , Raízes de Plantas/microbiologia , Brotos de Planta , Rizosfera
12.
World J Microbiol Biotechnol ; 36(1): 8, 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31858273

RESUMO

The application of chemical fertilizers to enhance crop production is a major concern due to associated environmental pollution and health hazards. Hence, there is an urgent need to develop an eco-friendly solution to improve crop production and promote sustainable agriculture simultaneously. Stevia rebaudiana is an important medicinal crop being substitute for sugar, superior flavor outline, extensive medicinal properties, and also of agronomic interest. In the present study, bacterium STJP isolated from the rhizospheric soil of S. rebaudiana and identified as Bacillus safensis on the basis of 16S rRNA gene sequencing, showed good amount of zinc (4.4 mg/L) and potassium (5.4 mg/L) solubilization. Paneer-whey (a dairy waste) based bioformulation (P-WBF) was developed utilizing isolate B. safensis STJP (accession number NAIMCC TB-2833) and inspected for the quality and ability to enhance the growth, nutrients uptake, and stevioside content in S. rebaudiana. The application of P-WBF displayed a significantly higher concentration (153.12%) of stevioside in S. rebaudiana as compared to control. P-WBF treated Stevia plants showed significantly higher fresh and dry weight as well (as compared to control). Further, enhancement of phosphorous, nitrogen, potassium, and zinc uptake in plant tissue was also recorded by application of P-WBF. This study suggests the use of P-WBF based biofertilizer using B. safensis STJP to increase stevioside content in Stevia plant by a nutrient(s) linked mechanism. This novel approach can also be beneficial for utilization of a dairy waste in preparation of bioformulation and, for enhancement of crop yield by an ecofriendly manner leading to sustainable agriculture.


Assuntos
Bacillus/fisiologia , Diterpenos de Caurano/química , Fertilizantes/análise , Glucosídeos/química , Nutrientes/química , Desenvolvimento Vegetal , Stevia/crescimento & desenvolvimento , Agricultura , Bacillus/genética , Nitrogênio/análise , Fósforo/análise , RNA Ribossômico 16S/genética
13.
World J Microbiol Biotechnol ; 35(11): 172, 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31673798

RESUMO

The present study was designed with the objective of improving growth and nodulation of soybean [Glycine max (L.) Merill] with co-inoculation of native Bradyrhizobium sp. (LSBR-3) (KF906140) and non-rhizobial nodule endophytic diazotroph Leclercia adecarboxylata (LSE-1) (KX925974) with multifunctional plant growth promoting (PGP) traits in cereal based cropping system (Rice-Wheat). A total of 40 endophytic bacteria from cultivated and wild sp. of soybean were screened for multifarious PGP traits and pathogenicity test. Based on PGP traits, antagonistic activities and bio-safety test; L. adecarboxylata (LSE-1) was identified with 16 S rRNA gene sequencing along with the presence of nifH (nitrogen fixation) and ipdc (IAA production) genes. Dual inoculant LSE-1 and LSBR-3 increased indole acetic acid (IAA), P & Zn-solubilization, 1-aminocyclopropane-1-carboxylate deaminase (ACCD) activity, siderophore, biofilm formation and exo-polysaccharides in contrast to single inoculation treatment. Further, assessment of dual inoculant LSBR-3 + LSE-1 improved growth parameters, nodulation, soil enzymes activities, nutrient accumulation and yield as compared to single as well as un-inoculated control treatment under field conditions. Single inoculant LSBR-3 improved yield by 8.84% over control. Further, enhancement of 4.15% grain yield was noticed with LSBR-3 + LSE-1 over LSBR-3 alone treatment. Application of LSBR-3 + LSE-1 gave superior B:C ratio (1.29) and additional income approximately 116 USD ha-1 in contrast to control treatment. The present results thus, is the first report of novel endophytic diazotroph L. adecarboxylata (LSE-1) as PGPR from Indian conditions particularly in Punjab region for exploiting as potential PGPR along with Bradyrhizobium sp. (LSBR-3) in soybean.


Assuntos
Bradyrhizobium/isolamento & purificação , Bradyrhizobium/fisiologia , Enterobacteriaceae/isolamento & purificação , Enterobacteriaceae/fisiologia , Desenvolvimento Vegetal , Raízes de Plantas/microbiologia , Soja/crescimento & desenvolvimento , Soja/microbiologia , Proteínas de Bactérias/genética , Biofilmes/crescimento & desenvolvimento , Bradyrhizobium/classificação , Bradyrhizobium/genética , Endófitos , Enterobacteriaceae/classificação , Enterobacteriaceae/genética , Fertilizantes , Ácidos Indolacéticos/metabolismo , Fixação de Nitrogênio/genética , Nutrientes , Oryza/microbiologia , Oxirredutases/genética , Filogenia , RNA Ribossômico 16S/genética , Nódulos Radiculares de Plantas/microbiologia , Sideróforos , Soja/química , Triticum/microbiologia
14.
World J Microbiol Biotechnol ; 35(11): 177, 2019 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-31696403

RESUMO

Plant biostimulants are defined as materials containing microorganisms or substances whose function when applied to plants or the rhizosphere is to stimulate natural mechanisms to enhance plant growth, nutrient use efficiency, tolerance to abiotic stressors and crop quality, independent of their nutrient content. In agriculture, seaweeds (Macroalgae) have been used in the production of plant biostimulants while microalgae still remain unexploited. Microalgae are single cell microscopic organisms (prokaryotic or eukaryotic) that grow in a range of aquatic habitats, including, wastewaters, pounds, lakes, rivers, oceans, and even humid soils. These photosynthetic microorganisms are widely described as renewable sources of biofuels, bioingredients and biologically active compounds, such as polyunsaturated fatty acids (PUFAs), carotenoids, phycobiliproteins, sterols, vitamins and polysaccharides, which attract considerable interest in both scientific and industrial communities. Microalgae polysaccharides have so far proved to have several important biological activities, making them biomaterials and bioactive products of increasing importance for a wide range of applications. The present review describes microalgae polysaccharides, their biological activities and their possible application in agriculture as a potential sustainable alternative for enhanced crop performance, nutrient uptake and resilience to environmental stress. This review does not only present a comprehensive and systematic study of Microalgae polysaccharides as plant biostimulants but considers the fundamental and innovative principles underlying this technology.


Assuntos
Produtos Agrícolas/efeitos dos fármacos , Microalgas/metabolismo , Desenvolvimento Vegetal/efeitos dos fármacos , Polissacarídeos/metabolismo , Produtos Biológicos/metabolismo , Biotecnologia/métodos , Produtos Agrícolas/metabolismo , Estresse Fisiológico/efeitos dos fármacos
15.
Environ Monit Assess ; 191(12): 740, 2019 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-31712911

RESUMO

The aim of this study was to assess the effects of stone crushing dust pollution on three commonly cultivated fruit plant species (Vitis vinifera L., Morus alba L., and Prunus armeniaca L.) and on the health of workers working at crushing plants. The trial was carried out on fruit plant species grown close to the stone crushing units located near the northwestern (Brewery) bypass of Quetta city, Pakistan, near National Highway NH-25. Plant materials were collected from three polluted sites at a distance of 500, 1000, and 1500 m, respectively, away from the stone crushing units and one locality of comparatively clean air considered a control at 4000 m away from these crushing components. To know the status of air disorder near the experimental sites, the suspended particulate matters and both oxides of sulfur and nitrogen were also noted during operating hours. Consequences of the study indicated that during the crushing process, a fine aerosol of stone dust is often generated which could cause a significant health hazard to workers and also affect plant productivity due to the smothering of plant stomata. Environmental data designated that the average highest evaluated total suspended particulate matter (TSPM), NOx, and SOx were 7400 µg/m3, 803.7 µg/m3, and 216 µg/m3, respectively, at 500-m distance which gradually decreases as the distance increases-all of these pose a health risk to operators. The maximum deposit dust washed from the plant leaf surface under study was found to be 8.2, 4.6, and 4.4 at the distance of 500 m in all the investigated plant species which was highly significantly higher than that of the control site (4000 m). Among the plant species, the maximum dust fall was noted on the leaves of Vitis vinifera L., and minimum was on the leaves of Prunus armeniaca. The locations affected by more stone dust pollution (500 m) were leading to a reduction in the yield and quality of fruits. The studied stone crushing units had high percentages of closed stomata both on the upper sides (Us) and lower sides (Ls) of leaves at 500-m distance from stone crushing installations. Data regarding workers' health indicated the maximum age distribution among the workers was between the age groups of 20-35 years (46.15%). Results also showed that stone crushing workers suffered from symptoms of respiratory diseases (82.17%), allergies (72.13%), headaches (75.09%), coughing (78.36%), and tiredness (92.31%).


Assuntos
Poluentes Ocupacionais do Ar/análise , Poeira/análise , Exposição Ambiental/análise , Plantas , Adulto , Aerossóis , Exposição Ambiental/estatística & dados numéricos , Monitoramento Ambiental/métodos , Poluição Ambiental , Humanos , Exposição Ocupacional , Paquistão , Material Particulado/análise , Desenvolvimento Vegetal , Adulto Jovem
16.
World J Microbiol Biotechnol ; 35(12): 181, 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31728652

RESUMO

Root-associated fungi and bacteria play a pivotal role in the plant-soil ecosystem by influencing both plant growth and immunity. The aim of this study was to unravel the biodiversity of the bacterial and fungal rhizosphere (RS) and rhizoplane (RP) microbiota of Zhukovskij rannij potato (Solanum tuberosum L.) cultivar growing in the Alfisol of Tatarstan, Russia. To assess the structure and diversity of microbial communities, we employed the 16S rRNA and internal transcribed spacer gene library technique. Overall, sequence analysis showed the presence of 3982 bacterial and 188 fungal operational taxonomic units (OTUs) in the RP, and 6018 bacterial and 320 fungal OTUs for in the RS. Comparison between microbial community structures in the RS and RP showed significant differences between these compartments. Biodiversity was higher in the RS than in the RP. Although members of Proteobacteria (RS-59.1 ± 4.9%; RP-54.5 ± 9.2%), Bacteroidetes (RS-23.19 ± 10.2%; RP-34.52 ± 10.4%) and Actinobacteria (RS-11.55 ± 4.9%; RP-7.7 ± 5.1%) were the three most dominant phyla, accounting for 94-98% of all bacterial taxa in both compartments, notable variations were observed in the primary dominance of classes and genera in RS and RP samples. In addition, our results demonstrated that the potato rhizoplane was significantly enriched with the genera Flavobacterium, Pseudomonas, Acinetobacter and other potentially beneficial bacteria. The fungal community was predominantly inhabited by members of the Ascomycota phylum (RS-81.4 ± 8.1%; RP-81.7 ± 5.7%), among which the genera Fusarium (RS-10.34 ± 3.41%; RP-9.96 ± 4.79%), Monographella (RS-7.66 ± 4.43%; RP-9.91 ± 5.87%), Verticillium (RS-4.6 ± 1.43%; RP-8.27 ± 3.63%) and Chaetomium (RS-4.95 ± 2.07%; RP-8.33 ± 4.93%) were particularly abundant. Interestingly, potato rhizoplane was significantly enriched with potentially useful fungal genera, such as Mortierella and Metacordiceps. A comparative analysis revealed that the abundance of Fusarium (a cosmopolitan plant pathogen) varied significantly depending on rotation variants, indicating a possible control of phytopathogenic fungi via management-induced shifts through crop rotational methods. Analysis of the core microbiome of bacterial and fungal community structure showed that the formation of bacterial microbiota in the rhizosphere and rhizoplane is dependent on the host plant.


Assuntos
Bactérias/classificação , Biodiversidade , Fungos/classificação , Microbiota/fisiologia , Raízes de Plantas/microbiologia , Solo/química , Solanum tuberosum/microbiologia , Bactérias/genética , Fungos/genética , Microbiota/genética , Filogenia , Desenvolvimento Vegetal , RNA Ribossômico 16S/genética , Rizosfera , Federação Russa , Microbiologia do Solo , Solanum tuberosum/crescimento & desenvolvimento
17.
Environ Pollut ; 255(Pt 3): 113354, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31629223

RESUMO

Agricultural soil is one of the main sink for both heavy metals and nanomaterials (NMs). Whether NMs can impact heavy metals uptake or bioaccumulation in plants is unknown. Here, cucumber plants were cultivated in a multi-heavy metals contaminated soil amended with four types of NMs (SiO2, TiO2, ZnS and MoS2) separately for four weeks. Physiological and biochemical parameters were determined to investigate the impact of NMs on plant growth. Inductively coupled plasma mass spectrometry was employed to determine the metal content in plants. Results showed that none of the tested NMs impacted plants biomass, but all the NMs showed different degrees of reduction in heavy metals bioaccumulation in plant roots, stems and leaves. However, four NMs showed different degrees of reduction in macro and micro nutrients uptake. MoS2 decreased the bioaccumulation of heavy metals (As, Cd, Cr, Cu, Ni, Al, Ti and Pb) for 36.4-60.6% and nutrients (Mg, Fe, K, Si and Mn) for 40.1%-50.1% in roots. Exposure to MoS2 NMs also significantly increased 23.4% of Si in leaves, 205.6% and 83.9% of Mo in roots and stems, respectively. In general, the results of this study showed promising potential for NMs to reduce uptake of heavy metals in crop plants, especially MoS2 NMs. However, the negative impacts of perturbing nutrients uptake should be paid attention as well.


Assuntos
Cucumis sativus/química , Metais Pesados/análise , Nanoestruturas/análise , Poluentes do Solo/análise , Agricultura , Biomassa , Cucumis sativus/crescimento & desenvolvimento , Óxidos/análise , Desenvolvimento Vegetal , Raízes de Plantas/química , Dióxido de Silício/análise , Solo/química , Sulfetos/análise
18.
J Environ Manage ; 251: 109604, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31569025

RESUMO

Traditional revegetation techniques employed to restore seagrass meadows and coastal dunes have recently been criticized for their impact on donor populations as well as for the installation of plant anchoring structures made of non-biodegradable or not natural materials in recipient habitats. To improve the ecological sustainability of restoration practices, a novel plantable biodegradable container made of beach-cast seagrass wrack and a bio-based polymer was produced. The long-term performance of two seagrasses, Cymodocea nodosa and Zostera noltei, and two dune plants, Euphorbia paralias and Thinopyrum junceum, grown in nurseries from seeds using the bio-container or a non-biodegradable container of equal size/form made of a conventional plastic (control) was also examined. In addition, the development of bio-container-raised C. nodosa plants in the field was compared to that of plants removed from control containers at the installation and anchored with a traditional system. The bio-container degraded slowly in seawater and in sand and lost its functionality after about three years. In nurseries, all the tested species grown in bio-containers performed as well as, or better than, those raised in non-biodegradable ones. Six months after transplanting into the field, 80% of the C. nodosa nursery-raised plants installed with their bio-container have colonized the surrounding substrate while most of those planted with the traditional system was lost. These results indicate that the new bio-container may support plant growth, and it may also provide protection and anchorage to plants in the field. The use of this bio-container in combination with nursery techniques could improve the environmental sustainability of coastal restoration interventions by providing large plant stocks from seed, thus reducing the impact of collection on donor populations. This approach would also limit the introduction of extraneous materials in recipient habitats and offer an opportunity for valorizing seagrass beach-cast material.


Assuntos
Alismatales , Zosteraceae , Ecossistema , Desenvolvimento Vegetal , Plásticos
19.
Plant Sci ; 288: 110220, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31521220

RESUMO

Plants are sessile photo-autotrophic organisms continuously exposed to a variety of environmental stresses. Monitoring the sugar level and energy status is essential, since this knowledge allows the integration of external and internal cues required for plant physiological and developmental plasticity. Most abiotic stresses induce severe metabolic alterations and entail a great energy cost, restricting plant growth and producing important crop losses. Therefore, balancing energy requirements with supplies is a major challenge for plants under unfavorable conditions. The conserved kinases target of rapamycin (TOR) and sucrose-non-fermenting-related protein kinase-1 (SnRK1) play central roles during plant growth and development, and in response to environmental stresses; these kinases affect cellular processes and metabolic reprogramming, which has physiological and phenotypic consequences. The "yin-yang" model postulates that TOR and SnRK1 act in opposite ways in the regulation of metabolic-driven processes. In this review, we describe and discuss the current knowledge about the complex and intricate regulation of TOR and SnRK1 under abiotic stresses. We especially focus on the physiological perspective that, under certain circumstances during the plant stress response, the TOR and SnRK1 kinases could be modulated differently from what is postulated by the "yin-yang" concept.


Assuntos
Regulação da Expressão Gênica de Plantas/fisiologia , Magnoliopsida/fisiologia , Proteínas de Plantas/genética , Proteínas Serina-Treonina Quinases/genética , Estresse Fisiológico/genética , Serina-Treonina Quinases TOR/genética , Magnoliopsida/genética , Magnoliopsida/crescimento & desenvolvimento , Desenvolvimento Vegetal/genética , Desenvolvimento Vegetal/fisiologia , Proteínas de Plantas/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais/genética , Serina-Treonina Quinases TOR/metabolismo
20.
J Environ Manage ; 250: 109530, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31521922

RESUMO

This work aimed at elucidating the role of bacteria present in the gut of the earthworm Metaphire posthuma in plant growth promotion and toxic trace elements (TTEs) bioremediation. We isolated and identified three bacterial strains Bacillus safensis (MF 589718), Bacillus flexus (MF 589717) and Staphylococcus haemolyticus (MF 589719) among which the Bacillus strains appeared to be significantly more potent than the Staphylococcus strain (P < 0.05) in promoting plant growth and removing TTE (Cr(VI), Cu(II) and Zn(II)) from aqueous media. These strains exhibited several plant growth promoting traits (e.g., indole acetic acid (IAA), gibberellic acid (GA) and ammonium ion production, 1-aminocyclopropane- 1-carboxylic acid (ACC) deaminase activity, and phosphate solubilizing potential). In a pot trial, the gut isolates improved Vigna radiata seed germination, and enhanced the leaf area (30-79%), total chlorophyll content (26-67%) and overall root-shoot biomass (32-83%) as compared to the control. Bacillus safensis and Bacillus flexus were equipotent in removing Cr(VI) (40.5 and 40.3%) from aqueous media; the former triumphed for Zn(II) removal (52.8%), while the latter performed better for Cu(II) removal (43.5%). The gut isolates successfully solubilized phosphate even in TTE-contaminated conditions. The results demonstrate that the earthworm's enteric bacteria possess inherent plant growth promoting, TTE resistance and phosphate solubilization (even under TTE stress) properties which can be further explored for their application in sustainable crop production and environmental management.


Assuntos
Microbioma Gastrointestinal , Oligoquetos , Oligoelementos , Animais , Biodegradação Ambiental , Ácidos Indolacéticos , Desenvolvimento Vegetal , Raízes de Plantas , Microbiologia do Solo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA