Enzyme Activity - Indicator of Soil Biological Dynamics

Substrate utilization rate is a value of functional diversity specific for every ecosystem. The microbial groups are responsible for the exploitation of nutrient resources and conversion of organic matter, releasing into the soil the necessary enzymes for decomposition and mineralization processes. Monitoring the microbial enzymatic activity in the soil provides a number of useful indicators in determining the quality and equilibrium of soil. The enzymatic activity is concentrated in the rhizosphere of plants, the scale of the interpretation of the enzymatic processes ranging from a micro-level to a macro-(landscape) level. Enzymes provide good indications on biogeochemical cycles of elements, with a higher intensity of activity near to the soil surface. The study of soil enzymes provide effective analytical units for microbial processes, nutrient reserves and composition of microbial communities

Mycorrhiza – Benefits, Influence, Diagnostic Method

By studying mycorrhizal symbiosis, another important step is made in knowing the relationship between plants and soil microflora. Benefits that these symbiosis bring to plants and ecosystem are semnificative for the interpretation of physiological factors, like: extending the volume of soil accessible to plants, acquiring nutrient forms that would not normally be available to plants; for the ecosystem an important role is to soil structure and mechanical aggregation. In the pasture that we studied in the Apuseni Mountains we found as dominant species Carex hirta, percent in the floristic composition is 35-40%, and that is the primary reason for studying this plant. The study area is positioned at 2 meters far from the forest and the soil is caracterized by a big humidity – the subteran water is at a high level. To identify the influence of the forest, of the humidity and the relation with other plants in the pasture, first step was to find that plants of Carex hirta is colonized by mycorrhizal symbiosis. We harvest the plants with root from a 15 to 20 cm deep and we colored teh roots with a solution of ink with vinegar. The proposed method for diagnosis of mycorrhizal colonization on Carex hirta roots is specific for the area where the studies took place

Influence of Growth Period on Mycorrhizal Colonization in Roots of Trifolium Repens in a Green House Experiment

In natural plant communities are formed fungal-plant associations, associations with the increasing role of the feeding process of both partners, the fungus becoming an extension of the plant's root system, in exchange of carbohydrates synthesized by plants. Mycorrhizal associations are defined by three elements - plant root system, an intraradicular hyphal system and an extraradicular hyphal system. The study of mycorrhizal symbiosis in controlled environments provided by a green house allows the inplementation of a sampling system in different phase of growth and development of symbiotic fungi. Analisys on samples taken were used to explain the frequency and abundance of different structure in emerging or developed the extraroot by vesicular-arbusculare mushrooms Analizele efectuate asupra probelor recoltate au fost utilizate pentru explicarea frecvenţei şi abundenţei cu care apar diferitele structuri intra- sau extraradiculare dezvolatate de către ciupercile vezicular-arbusculare

Mycorrhizal Circuit In The Root Of Avena Sativa

Oats has the capacity to develop a strong radicular biomass in the soil, alongside a good adaptability to cold climats, characters which favor it over other cereals in the areas with lower temperatures and high humidity. The simultaneous evolution with the symbiotic fungi allowed the premisis for a stronger installation of mychorrizal fungi, stimulated by the radicular  exudate of the oats. The transfer of nutritive elements occurs between the fungi and plant, at the level of hyphal and arbuscular interfaces. The degree of mychorrization is greater in the senescent areas of the roots, while the transfer of nutritive elements thorugh the arbuscular circuit is higher in the freshly developed roots

INDUCED MODIFICATIONS ON SECONDARY METABOLISM OF AROMATIC AND MEDICINAL PLANTS – AN ENDOMYCORRHIZAL APPROACH

Researches demonstrated that arbuscular mycorrhizae can bring significant changes in the yield and composition of secondary metabolites of economic interest from aromatic and medicinal plants. Evidence shows that mechanisms responsible for changes in phytochemical content are related to the enhanced nutrition arbuscular mycorrhizae fungi can provide as well as to plant growth promoting rhizosphere bacteria and their synergistic relationship with arbuscular mycorrhizae. Plant response to inoculation can be modified by the AMF species and strains already present in the soil. It was identified a plant-fungus specificity that implies the need for the selection of appropriate inoculum for cost effectiveness in AM application for large scale field production of aromatic and medicinal plants

Inter-Radicular Connections of Festuca Rubra and Trifolium Repens

Simultaneous evolution of plants with useful rizospheric micro flora has allowed the appearance of symbiotic partnerships between the radicular systems and symbiotical fungi. Natural grasslands represents a stable complex of ecosystems, where the competition capacity of each species is given by the expansion of the root system and branching, in addition to the ability to associate with mycorrhizal fungi. Festuca rubra and Trifolium repens plants were grown in pots, the percentage of each species in the mixture increasing/decreasing by 10 up to 10%. The mycorrhizal circuit was assessed based on the colonization parameters in the root system. For plants with similar proportions in the mixture a strong development of young roots is detected while increasing the association with mycorrhizal fungi.  The colonization degree decrease is significant only for the high percentages of the specie in the experimental mixture

Evaluation Of The Absorption Ability Of Winter Wheat Based On Root System Clustering

Wheat is the crop with the highest global expansion, ensuring a balanced ratio between carbohydrates and protein substances. It requires a rational fertilization based on  the dynamics of growth and root branching, closely related to the mycorrhizal association potential for high values of nutrients export from soil. Modeling the associative system of root with mycorrhizas can provide solutions to obtain stable yields. The root system is separated into clusters based on the root’s architecture, the level of active and senescent mycorrhizal circuits being deteremined separately on each cluster. Root architecture provides a realistic picture of the momentary development of wheat plants. The level of mycorrhization indicates the function of absorption and transfer circuits. The evaluation of mycorrhization provides a number of parameters with high potential for the stability of mathematical models used for the installation and success of winter wheat cro

Assessing the Absorption Potential by Establishing the Hierarchy of Zea Mays Root System

Maize has good biological particularities to exploit a high variety of agricultural land in different climatic conditions, due to a complex root system. The exploration of soil by roots developed by maize is dependent on the mycorrhization level, that increases the absorption capacity of nutrients from soil solution. The current experiment assesses the differences of mycorrhization colonization in the maize roots, by levels of radicular architecture . The level’s division is performed based on the ramification point, by observing the hyphal network and arbuscular cirtcuit. The development of intraradicular hyphal networks is stronger in the aged areas of the root, while in the freshly formed segments the arbuscular impermanent structures are more visible.  In the segments with high colonization intensity high soil nutrient absorbtion phenomenon occurs, while in the areas with lots of arbusculs predominant is the intense transfer of minerals between the two partner