A new plant growth system rig based on thermodynamic solar energy: a study for energy efficiency assessment

At the present there is a high pressure toward the improvement of all production processes. Those improvements can target distinct factors along the production chain. In particular, and due to recent tight energy efficiency policies, those that involve energy efficiency. As can be expected, agricultural processes are not immune to this tendency. Even more when dealing with indoor productions. In this context, this work presents an innovative system that aims to improve the energy efficiency of a trees growing platform. This improvement in energy consumption is accomplished by replacing an electric heating system by one based on thermodynamic panels. The assessment of the heating fluid caudal and its temperature was experimentally obtained by means of a custom made scaled prototype whose actuators status are commanded by a Fuzzy-based controller. The obtained results suggest that the change in the heating paradigm will lead to overall savings that can easily reach 60% on the energy bill.

Measuring the Impact of Melaleuca quinquenervia Biochar Application on Soil Quality, Plant Growth, and Microbial Gas Flux

Biochar has been heralded a mechanism for carbon sequestration and an ideal amendment for improving soil quality. Melaleuca quinquenervia is an aggressive and wide-spread invasive species in Florida. The purpose of this research was to convert M. quinquenervia biomass into biochar and measure how application at two rates (2% or 5% wt/wt) impacts soil quality, plant growth, and microbial gas flux in a greenhouse experiment using Phaseolus vulgaris L. and local soil. Plant growth was measured using height, biomass weight, specific leaf area, and root-shoot ratio. Soil quality was evaluated according to nutrient content and water holding capacity. Microbial respiration, as carbon dioxide (CO2), was measured using gas chromatography. Biochar addition at 5% significantly reduced available soil nutrients, while 2% biochar application increased almost all nutrients. Plant biomass was highest in the control group, p2 flux decreased significantly in both biochar groups, but reductions were not long term.

Effects of plant density and the number of emitters on plant growth and nitrate concentration in spinach cultivated in substrate

The effects of plant density and the number of emitters per Styrofoam box on plant growth and nitrate (NO3-) concentration were evaluated in spinach (Spinacia oleracea L. cv. Tapir). Spinach seedlings were transplanted at 45 days after emergence into Styrofoam boxes filled with the substrate and were grown during winter in an unheated greenhouse with no supplemental lighting. The experiment was carried out with four treatments, including two plant densities (160 and 280 plants/m2) and two number of emitters per Styrofoam box (4 and 8 emitters). Each planting box was irrigated daily and fertigated with a complete nutrient solution. Shoot dry weight was not affected by plant density. However, yield increased with plant density and emitter number. Leaf-blade NO3- concentration was not affected by the interaction between plant density and number of emitters, but petioles NO3- concentration was greater in treatment with 160 plants/m2 and 8 emitters. Although leaf-blade NO3- concentration was not affected by plant density, it decreased with the number of emitters. On the other hand, petiole NO3- concentration was not affected by plant density or number of emitters. Leaf-blade NO3- concentration ranged from 3.2 to 4.1 mg/g fresh weight, occurring the highest value in the treatment with 280 plants/m2 and 4 emitters. Petiole NO3- concentration ranged from 3.5 to 5.3 mg/g fresh weight, values that were higher than allowed by EU regulation.

Effects of substrate type on plant growth and nitrogen and nitrate concentration in spinach

Abstract The effects of three commercial substrates (a mixture of forest residues, composted grape husks, and white peat, black peat and coir) on plant growth and nitrogen (N) and nitrate (NO3) concentration and content were evaluated in spinach (Spinacia oleracea L. cv. Tapir). Spinach seedlings were transplanted at 45 days after emergence into Styrofoam boxes filled with the substrates and were grown during winter and early spring in an unheated greenhouse with no supplemental lighting. Each planting box was irrigated daily by drip and fertilized with a complete nutrient solution. The NO3 content of the drainage water was lower in coir than in the other substrates. However, shoot NO3 concentration was not affected by substrate type, while yield and total shoot N and NO3 content were greater when plants were grown in peat than in the mixed substrate or the coir. Leaf chlorophyll meter readings provided a good indication of the amount of N in the plants and increased linearly with total shoot N. Keywords Spinacia oleracea; chlorophyll meter; coir; peat; soilless culture systems

Effects of substrate type on plant growth and nitrogen and nitrate concentration in spinach.

The effects of three commercial substrates (a mixture of forest residues, composted grape husks, and white peat, black peat and coir) on plant growth and nitrogen (N) and nitrate (NO3) concentration and content were evaluated in spinach (Spinacia oleracea L. cv. Tapir). Spinach seedlings were transplanted at 45 days after emergence into Styrofoam boxes filled with the substrates and were grown during winter and early spring in an unheated greenhouse with no supplemental lighting. Each planting box was irrigated daily by drip and fertilized with a complete nutrient solution. The NO3 content of the drainage water was lower in coir than in the other substrates. However, shoot NO3 concentration was not affected by substrate type, while yield and total shoot N and NO3 content were greater when plants were grown in peat than in the mixed substrate or the coir. Leaf chlorophyll meter readings provided a good indication of the amount of N in the plants and increased linearly with total shoot N.

Diversitet och tillväxtfrämjande egenskaper hos Stenotrophomonas-endofyter isolerade från Calliandra calothyrsus Meisn. rotknölar

The bacterial genus Stenotrophomonas comprises 12 species. They are widely found throughout the environment and particularly S. maltophilia, S. rhizophila and S. pavanii are closely associated with plants. Strains of the most common Stenotrophomonas species, S. maltophilia, promote plant growth and health, degrade natural and man-made pollutants and produce biomolecules of biotechnological and economical value. Many S. maltophilia –strains are also multidrug resistant and can act as opportunistic human pathogens. During an INCO-project (1998-2002) rhizobia were collected from root nodules of the tropical leguminous tree Calliandra calothyrsus Meisn. from several countries in Central America, Africa and New Caledonia. The strains were identified by the N2-group (Helsinki university) and some strains turned out to be members of the genus Stenotrophomonas. Several Stenotrophomonas strains induced white tumor- or nodule-like structures on Calliandra?s roots in plant experiments. The strains could, besides from root nodules, also be isolated from surface sterilized roots and stems. The purpose of my work was to investigate if the Stenotrophomonas strains i) belong to a new Stenotrophomonas species, ii) have the same origin, iii) if there are other differences than colony morphology between phase variations of the same strain, iv) have plant growth-promoting (PGP) activity or other advantageous effects on plants, and v) like rhizobia have ability to induce root nodule formation. The genetic diversity and clustering of the Stenotrophomonas strains were analyzed with AFLP fingerprinting to get indications about their geographical origin. Differences in enzymatic properties and ability to use different carbon and energy sources were tested between the two phases of each strain with commercial API tests for bacterial identification. The ability to infect root hairs and induce root nodule formation was investigated both using plant tests with the host plant Calliandra and PCR amplification of nodA and nodC genes for nodulation. The PGP activity of the strains was tested in vitro mainly with plate methods. The impact on growth, nitrogen content and nodulation in vivo was investigated through greenhouse experiments with the legumes Phaseolus vulgaris and Galega orientalis. Both the genetic and phenotypic diversity among the Stenotrophomonas strains was small, which proposes that they have the same origin. The strains brought about changes on the root hairs of Calliandra and they also increased the amount of root hairs. However, no root nodules were detected. The strains produced IAA, protease and lipase in vitro. They also showed plant a growth-promoting effect on G. orientalis, both alone and together with R. galegae HAMBI 540, and also activated nodulation among efficient rhizobia on P. vulgaris in greenhouse. It requires further research to get a better picture about the mechanisms behind the positive effects. The results in this thesis, however, confirm earlier studies concerning Stenotrophomonas positive impact on plants.

PGPRs and nitrogen-fixing legumes: a perfect team for efficient Cd phytoremediation?

Cadmium (Cd) is a toxic, biologically non-essential and highly mobile metal that has become an increasingly important environmental hazard to both wildlife and humans. In contrast to conventional remediation technologies, phytoremediation based on legume rhizobia symbiosis has emerged as an inexpensive decontamination alternative which also revitalize contaminated soils due to the role of legumes in nitrogen cycling. In recent years, there is a growing interest in understanding symbiotic legume rhizobia relationship and its interactions with Cd. The aim of the present review is to provide a comprehensive picture of the main effects of Cd in N-2-fixing leguminous plants and the benefits of exploiting this symbiosis together with plant growth promoting rhizobacteria to boost an efficient reclamation of Cd-contaminated soils.

Effect of planting methods and cyanobacterial inoculants on yield, water productivity and economics of rice cultivation

The impact of two crop planting methods and of the application of cyanobacterial inoculants on plant growth, yield, water productivity and economics of rice cultivation was evaluated with the help of a split plot designed experiment during the rainy season of 2011 in New Delhi, India. Conventional transplanting and system of rice intensification (SRI) were tested as two different planting methods and seven treatments that considered cyanobacterial inoculants and compost were applied with three repetitions each. Results revealed no significant differences in plant performance and crop yield between both planting methods. However, the application of biofilm based BGA bio-fertiliser + 2/3 N had an overall positive impact on both, plant performance (plant height, number of tillers) and crop yield (number and weight of panicles) as well as on grain and straw yield. Higher net return and a higher benefit-cost ratio were observed in rice fields under SRI planting method, whereas the application of BGA + PGPR + 2/3 N resulted in highest values. Total water productivity and irrigation water productivity was significantly higher under SRI practices (5.95 and 3.67 kg ha^(-1) mm^(-1)) compared to practices of conventional transplanting (3.36 and 2.44), meaning that using SRI method, water saving of about 34 % could be achieved and significantly less water was required to produce one kg of rice. This study could show that a combination of plant growth promoting rhizobacteria (PGPR) in conjunction with BGA and 2/3 dose of mineral N fertiliser can support crop growth performance, crop yields and reduces overall production cost, wherefore this practices should be used in the integrated nutrient management of rice fields in India.

Avaliação de populações de possíveis rizobactérias em solos sob espécies florestais

Embora estudos recentes relatem a utilização de RCPC (Rizobactérias Promotoras de Crescimento de Plantas) no Brasil, raríssimos trabalhos avaliam a presença natural dessas espécies bacterianas no solo. O objetivo deste trabalho foi avaliar a ocorrência de RPCP em duas amostras de solo sob diferentes tipos de manejo, através da construção e do seqüenciamento de bibliotecas de DNA metagenômico. Utilizaram-se oligonucleotídeos específicos para amplificação da região hipervariável do espaço intergênico dos genes ribossomais 16S-23S de DNA extraído de diferentes solos, sob Eucalyptus sp. e sob mata. Os fragmentos obtidos foram inseridos em vetor e clonados. As bibliotecas geraram 495 clones, que foram seqüenciados e identificados através de comparações realizadas pelo software Blast. O solo sob Eucalyptus sp. apresentou maior número de RPCP do que sob mata. Os filos Actinobacteria e Proteobacteria eram maiores no solo sob Eucalyptus sp., estando o filo Firmicutes ausente no solo sob mata. Somente oito espécies diferentes de RPCP foram detectadas: Bacillus subtilis, Bacillus megaterium, Bradyrhizobium japonicum, Bradyrhizobium elkanii, Bradyrhizobium sp., Frankia sp., Pseudomonas fluorescens e Pseudomonas gladioli. O trabalho forneceu valiosos dados sobre a presença de RPCP em solos com espécies florestais e sua possível utilização em reflorestamentos, assim como para o melhor conhecimento desses microrganismos nos solos do Brasil.

Cyanobacteria in mangrove ecosystems

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Innovative techniques for sport turf managing: Agronomic and phyisiological implications

The growing substrate of the putting greens is considered a key factor for a healthy turf ecosystem. Actually detailed study on the effects of growth promoting bacteria and biostimulants on a professional sport turf are very limited. This thesis aimed to study the effectiveness of different microorganisms and biostimulants in order to improve the knowledge relative to the relationship between the beneficial microflora and root apparatus of sport turfs. The research project was divided in three principal steps: Initially, commercial products based on biostimulants and microorganisms were tested on a Lolium perenne L. essence grown in a controlled-environment. The principal evaluations were the study of the habitus of plants, biomass production and length of leaves and roots. Were studied the capacity of colonization of microorganisms within root tissues and rhizosphere. In the second step were developed two different biostimulant solutions based on effective microorganisms, mycorrhizae and humic acids. This test was conducted both on an Agrostis stolonifera putting green (Modena Golf & Country Club) in a semi-field condition and within a growth chamber on a Lolium perenne L. essence. Fungicide and chemicals applications were suspended in order to assess the effectiveness of the inoculants for nutrition and control of pests. In the last step, different microorganism mixes and biostimulants were tested on an experimental putting green in the Turf Research Center (TRC) (Virginia Tech, United States) in a real managing situation. The effects of different treatments were studied maintaining all chemicals and mechanicals managements scheduled during a sport season. Both growth-chamber and field results confirmed the capacity of microorganisms based biostimulants to promote the physiologic conditions of the plants, improve the growth of the roots and enhance the aesthetic performance of the turf. Molecular analysis confirmed the capacity of microorganisms to colonize the root tissues.

Uso de Metarhizium spp. na produção de mudas pré-brotadas de cana-de-açúcar e seus efeitos na planta, em pragas e doenças

Os fungos do gênero Metarhizium são entomopatogênicos e ainda apresentam relações endofíticas e podem viver saprofiticamente no solo. A associação desses microrganismos com insetos é bem conhecida, mas as interações diretas com as plantas ainda são incipientes. Objetivou-se com este estudo, determinar a capacidade de colonização endofítica em raízes de cana-de-açúcar (Saccharum spp.) de M. robertsii, M. anisopliae e três linhagens brasileiras recém-descobertas, bem como revelar o potencial destes fungos como antagonistas a dois fungos fitopatogênicos responsáveis pela podridão-vermelha (Fusarium moniliforme e Colletotrichum falcatum) e no controle de duas importantes pragas, a broca da cana-de-açúcar, Diatraea saccharalis e o nematóide-das-galhas, Meloidogyne javanica. Foram utilizados 24 isolados de Metarhizium spp. nos experimentos de promoção de crescimento de plantas após a inoculação em gemas de cana-de-açúcar em condições de casa-de-vegetação e campo. O efeito da inoculação do fungo em mudas de cana-de-açúcar foi investigado quanto a mortalidade e redução no desenvolvimento de D. saccharalis e redução nas populações de M. javanica. Experimentos de inibição in vitro em cultivo pareado foram conduzidos com os fungos F. moniliforme e C. falcatum e Trichoderma harzianum. Além disto, foram realizados testes qualitativos \"in vitro\" para avaliar a capacidade desses fungos em produzir β-1,3-Glucanase e Sideróforos. A inoculação de Metarhizium de todas as espécies testadas promoveu o crescimento de parte aérea, peso úmido e seco de raízes em relação ao controle (água). Enquanto o tratamento de gemas rotineiramente usado na usina onde se realizou a produção de mudas pré-brotadas com aplicação do fungicida Comet® + o fertilizante Biozyme TF resultou em pegamento de 32% e 59,6%, apenas com o uso de isolados de Metarhizium spp. estes valores foram de até 50% e 86,4%, nos dois experimentos em campo, respectivamente. As mortalidades observadas em lagartas de D. saccharalis que se alimentaram das plantas inoculadas com isolados de Metarhizium spp. atingiram valores de até 80%, sendo a mortalidade confirmada pela esporulação do fungo de até 55%. As lagartas sobreviventes apresentaram menor peso do que aquelas do controle não tratado. A inoculação de Metarhizium spp. em mudas de cana-de-açúcar conferiu proteção a M. javanica, resultando em uma densidade de massa de ovos por grama de raiz nas mudas inoculadas com o fungo até 59,8% menor no primeiro experimento e 64,1% menor no segundo em relação as mudas sem inoculação. Os ensaios de antagonismo mostraram que, todos os isolados de Metarhizium spp. apresentaram alguma forma de inibição tanto para F. moniliforme como para C. falcatum. Dos 24 isolados testados, 20,8% produziram a enzima hidrolítica, β-1,3-glucanase, o que pode estar associado a capacidade de inibição dos fungos fitopatogênicos. Constatou-se que 8 (33,3%) dos isolados produziram sideróforos e sugere que esses fungos apresentam mecanismos de disponibilização do ferro. O conhecimento gerado com este estudo poderá subsidiar novas estratégias de utilização de Metarhizium spp. em campo na produção de MPB de cana-de-açúcar.

Sequencing and functional analysis of the genome of a nematode egg-parasitic fungus, Pochonia chlamydosporia

Pochonia chlamydosporia is a worldwide-distributed soil fungus with a great capacity to infect and destroy the eggs and kill females of plant-parasitic nematodes. Additionally, it has the ability to colonize endophytically roots of economically-important crop plants, thereby promoting their growth and eliciting plant defenses. This multitrophic behavior makes P. chlamydosporia a potentially useful tool for sustainable agriculture approaches. We sequenced and assembled ∼41 Mb of P. chlamydosporia genomic DNA and predicted 12,122 gene models, of which many were homologous to genes of fungal pathogens of invertebrates and fungal plant pathogens. Predicted genes (65%) were functionally annotated according to Gene Ontology, and 16% of them found to share homology with genes in the Pathogen Host Interactions (PHI) database. The genome of this fungus is highly enriched in genes encoding hydrolytic enzymes, such as proteases, glycoside hydrolases and carbohydrate esterases. We used RNA-Seq technology in order to identify the genes expressed during endophytic behavior of P. chlamydosporia when colonizing barley roots. Functional annotation of these genes showed that hydrolytic enzymes and transporters are expressed during endophytism. This structural and functional analysis of the P. chlamydosporia genome provides a starting point for understanding the molecular mechanisms involved in the multitrophic lifestyle of this fungus. The genomic information provided here should also prove useful for enhancing the capabilities of this fungus as a biocontrol agent of plant-parasitic nematodes and as a plant growth-promoting organism.

Inducción sistémica de la biosintesis de metabolitos secundarios en plantas aromáticas mediada por rizobacterias

El uso de microorganismos como inoculantes para incrementar la disponibilidad y toma de nutrientes por parte de los cultivos, es una nueva tecnología que ha dado buenos resultados, observándose un incremento en la emergencia, vigor, mayor desarrollo en la parte aérea y de raíces, registrándose aumentos considerables de los rendimientos en cultivos de interés comercial. Esto es debido a que los microorganismos PGPR (Plant Growth promoting rhizobacteria) sintetizan ciertas sustancias reguladoras del crecimiento como giberelinas, citoquininas y auxinas; las cuales estimulan la densidad y longitud de los pelos radicales, aumentando así la cantidad y longitud de las raíces de los vegetales. Así, se incrementa la capacidad de absorción de agua y nutrientes, haciendo que las plantas sean más vigorosas, productivas y tolerantes a condiciones climáticas adversas, como sequías o heladas. Otro factor benéfico es que ciertos microorganismos solubilizan nutrientes poco móviles en el suelo como el caso del fósforo, segundo nutriente, después del nitrógeno en importancia para el crecimiento de los cultivos. Estos microorganismos también tienen una función muy importante en el control natural de agentes patógenos, a través de la inducción del sistema de defensa en las plantas, aumentando su resistencia a enfermedades, a través de la producción de compuestos bacterianos como antibióticos y sideróforos. Los variados mecanismos mediante los cuales la acción PGPR se lleva a cabo no son plenamente conocidos y, por lo tanto, es necesario determinar con precisión su efecto particular en la biología de la planta beneficiada. Las plantas aromáticas y medicinales inoculadas con microorganismos (rizobacterias) registran un incremento en varios parámetros de crecimiento vegetal (peso fresco parte aérea, peso seco de raíz, número de hojas, etc) y en el rendimiento de aceite esencial (AE). El aumento de la síntesis, y la variación de los porcentajes relativos de los componentes principales de AE en plantas aromáticas, como efecto de la inoculación, podría considerarse como una respuesta defensiva de la planta frente a la colonización de microorganismos dado que varios AE poseen propiedades antimicrobianas. El incremento de estos metabolitos también se ha registrado como respuesta frente a la herbivoría. En el presente proyecto se propone dilucidar la existencia de una relación entre las defensas inducidas por rizobacterias con la producción de metabolitos secundarios en plantas aromaticas y medicinales.

Organic fertilization of peach trees: implication on nitrogen availability, root growth and carbon distribution within plant

In the last years, sustainable horticulture has been increasing; however, to be successful this practice needs an efficient soil fertility management to maintain a high productivity and fruit quality standards. For this purpose composted organic materials from agri-food industry and municipal solid waste has been used as a source to replace chemical fertilizers and increase soil organic matter. To better understand the influence of compost application on soil fertility and plant growth, we carried out a study comparing organic and mineral nitrogen (N) fertilization in micro propagated plants, potted trees and commercial peach orchard with these aims: 1. evaluation of tree development, CO2 fixation and carbon partition to the different organs of two-years-old potted peach trees. 2. Determination of soil N concentration and nitrate-N effect on plant growth and root oxidative stress of micro propagated plant after increasing rates of N applications. 3. Assessment of soil chemical and biological fertility, tree growth and yield and fruit quality in a commercial orchard. The addition of compost at high rate was effective in increasing CO2 fixation, promoting root growth, shoot and fruit biomass. Furthermore, organic fertilizers influenced C partitioning, favoring C accumulation in roots, wood and fruits. The higher CO2 fixation was the result of a larger tree leaf area, rather than an increase in leaf photosynthetic efficiency, showing a stimulation of plant growth by application of compost. High concentrations of compost increased total soil N concentration, but were not effective in increasing nitrate-N soil concentration; in contrast mineral-N applications increased linearly soil nitrate-N, even at the lowest rate tested. Soil nitrate-N concentration influenced positively plant growth at low rate (60- 80 mg kg-1), whereas at high concentrations showed negative effects. In this trial, the decrease of root growth, as a response to excessive nitrate-N soil concentration, was not anticipated by root oxidative stress. Continuous annual applications of compost for 10 years enhanced soil organic matter content and total soil N concentration. Additionally, high rate of compost application (10 t ha-1 year-1) enhanced microbial biomass. On the other hand, different fertilizers management did not modify tree yield, but influenced fruit size and precocity index. The present data support the idea that organic fertilizers can be used successfully as a substitute of mineral fertilizers in fruit tree nutrient management, since they promote an increase of soil chemical and biological fertility, prevent excessive nitrate-N soil concentration, promote plant growth and potentially C sequestration into the soil.