RESUMEN
Diseases and pests are a problem even in greenhouse crops, problem which has to be solved without threatening the plant. Crop protection requires frequent updates in information and therefore sensor networks that are real time monitoring systems are the ones that can deliver such information. The purpose of this paper is to present a way of preventing the appearance of diseases and pests in a greenhouse by using a monitoring system composed of an integrated sensor network. Our sensor system is doing a real time monitoring of the following parameters in the greenhouse: light intensity, soil moisture and temperature, air temperature and humidity and air temperature at canopy level; all of the data being stored using a software made by "Tedelco". A real time monitoring camera is also used for pest and disease detection. A pot experiment, using beans, was established inside the greenhouse to test the applicability of the system. In order to assure the optimal conditions for the inhibition of pests, the greenhouse is also equipped with an artificial lighting system specially designed for greenhouses, an irrigation system and an artificial fog system. Sensor systems are the ideal support for preventive monitoring and at the same time it offers all the support data necessary for decision making regarding crops development.
Asunto(s)
Agricultura/instrumentación , Agricultura/métodos , Control de Plagas , Enfermedades de las Plantas/prevención & control , Redes de Comunicación de Computadores/instrumentación , Monitoreo del Ambiente/métodos , Humedad , Luz , Suelo/química , TemperaturaRESUMEN
Arbuscular mycorrhizal fungi are forming the most wide-spread mycorrhizal relationships on Earth. Mycorrhiza contributes to phosphorous acquisition, water absorption and resistance to diseases. The fungus promotes the absorption of nutrients and water from soil, meanwhile the host plant offers photosynthetic assimilates in exchange, like carbohydrates, as energy source. The plant benefits from the contribution of symbiotic partner only when nutrients are in low concentrations in soil and the root system would not be able to absorb sufficiently the minerals. When the help of mycorrhizal fungi is not necessarily needed, the host plant is making an economy of energy, suppressing the development of fungi in the internal radicular space. In this moment, the nature of relationship turns from symbiotic to parasitic, triggering a series of defensive reactions from the plant. Also, there were several cases reported when the presence of arbuscular mycorrhizal fungi negatively influenced the host plant. For example, in adverse environmental conditions, like very high temperatures, instead of determining a higher plant biomass and flowering, the mycorrhiza reduces the growth of the host plant. We conducted a pot experiment with hydroponic culture to examine the effect of arbuscular mycorrhiza on development of French marigold as a host plant. As experimental variants, the phosphorous content in nutrient medium and temperature varied. Plants were artificially infected with arbuscular mycorrhizal fungi using a commercial inoculum containing three fungal species, as following: Glomus intraradices, Glomus etunicatum and Glomus claroideum. Colonization intensity and arbuscular richness were checked using root staining with aniline blue and estimation with the Trouvelot method. To observe the differences between plants from the experimental variants, we examined the number of side shoots, flower buds and fully developed flowers, fresh biomass and total leaf area. Results show that adverse climatic conditions, like temperature shock at the beginning of growing period modified the nature of symbiosis. In this case, the physiological parameters were reduced at colonized plants, while usual, constant growing conditions permitted the normal, efficient and beneficial development of symbiosis.
Asunto(s)
Micorrizas/fisiología , Simbiosis/fisiología , Tagetes/microbiologíaRESUMEN
Fungal contamination of plant products is an important risk factor for health, because of the high mycotoxin potential deriving from these contaminations with multiple effects: hepatic toxicity, teratogenic, mutagenic and carcinogenic. The contamination of cereals with mycotoxins has been a serious problem in Balkan communities. Several studies implicated mycotoxins, in endemic kidney disease geographically limited to Balkan region (Balkan endemic nephropathy). The trichothecenes are of particular concern because they are ubiquitous found in wheat, corn and barley throughout the world. Fumonisins have been isolated from certain Fusarium species of which FB1, FB2 and FB3 are the major ones produced in naturally contaminated foods.These mycotoxins are produced on cereal grains infected by Fusarium while being grown in-the-field. The aim of this study is to evaluate the presence of the Fusarium species in cereals from West side of Romania and to determinate the concentrations of deoxynivalenol (DON) and fumonisine (F1+F2). Identification of Fusarium species was done using the total number of fungal species determination method. The level of mycotoxins was determined with the immune-enzymatic method ELISA. 27 cereal samples from rural households in three counties in West Romania were analysed.
Asunto(s)
Grano Comestible/microbiología , Fusarium/metabolismo , Micotoxinas/química , Enfermedades de las Plantas/microbiología , Contaminación de Alimentos , Micotoxinas/metabolismo , RumaníaRESUMEN
Glyphosate applied to soils potentially affect microbial activity. A series of field and laboratory experiments assessed the effect of this herbicide on soil microorganisms. The aim of experiments was to evaluate the effect of glyphosate application on the soil microbial community structure, function and their activity. We studied "in vitro", changes in the microbial activity of typical Chernozem and Gleysol soils, with and without applied glyphosate. The herbicide was applied at a rate of 2, respectively 4 mg kg(-1) of soil and microbial activity were measured by fluorescein diacetate (FDA) hydrolysis. We found an increase of 9 to 13% in FDA hydrolyses in the presence of glyphosate in rate of 2 mg kg (-1) compared with the same type of soil which had never received herbicide. The double quantity of glyphosate decrease soil microbial activity; the amount of hydrolyzed fluorescein is lower than the addition of 2 ppm. The greater decrease was observed in the Gleysol type where the fluorescein hydrolyzed is with 4, 85% lower than version control without glyphosate. Chemical characters of soil, influence soil biological activity when herbicide is added. In Chemozem case, rich in humus, whose predominant micro flora is represented by actinomycetes through glyphosate treatment these organisms growths of as major producers of antibiotics actinomycetes determine an inhibitory effect on eubacteria and micromycetes growth, which is highlighted by estimating a relatively small number of them. After 10 days, once with decreasing of glyphosate content in soil, decreases the number of active actinomycetes, therefore we are witnessing to a numerical growth of bacterial population. In Gleysol type the indigenous micro flora is represented by eubacteria, so when the glyphosate is added it was registered a high growth of these organisms fraction.
Asunto(s)
Actinobacteria/efectos de los fármacos , Glicina/análogos & derivados , Herbicidas/toxicidad , Actinobacteria/metabolismo , Biodegradación Ambiental , Fluoresceínas/química , Glicina/análisis , Glicina/metabolismo , Glicina/toxicidad , Herbicidas/análisis , Herbicidas/metabolismo , Hidrólisis , Rumanía , Suelo/química , Microbiología del Suelo , Contaminantes del Suelo/análisis , Contaminantes del Suelo/metabolismo , Contaminantes del Suelo/toxicidad , GlifosatoRESUMEN
Glyphosate (N-phosphonomethyl-glycine), the active ingredient in several herbicide formulations, is a non-selective, post-emergent herbicide used in a variety of crop and non-crop situations. Glyphosate is a non-volatile herbicide that is relatively immobile in soil. Its degradation is due to microbiological processes and most laboratory studies have been conducted with 14C-glyphosate with the rate of 14CO2 evolution being used as an indication of herbicide breakdown. In this paper we have studied the glyphosate degradation in compost amendment soils using Scientilator Liquid TRIATHLER and Glyphosate-phosphonomethyl-14C-labeled with specific activity 2,2mCi/mmol. Four types of soils have been taken under study: Black Chernozem, Vertisol, Gleysol and Phaeozem with different characteristics. For the each type of soil have been realized four experimental variants (glyphosate blind sample with 1,5 ppm, concentration, autoclaved soil, soil with glyphosate and addition of compost in field concentration of 40 t/ha, respectively 60 t/ha. The mineralization curves of 14CO2 accumulated were compared during of 40 days. All the mineralization curves for the soils exhibited same patterns, with only two phases, the initial rapid phase of degradation, for about 20 days, attributed to microbial action on the free glyphosate and the second slow phase, when the curves attained plateaus. Compost applied with different concentrations to Vertisol and Black Chernozem did not appear to stimulate the microbial degradation of glyphosate. In Gleysol and Phaeozem with lower humus content, the mineralization curve of 14C indicate the increase degradation capacity, expressed as accumulated 14CO2 as % total 14C, with the increase of compost concentration.