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Aquatic Phytotherapy
Published in Namrita Lall, Medicinal Plants for Cosmetics, Health and Diseases, 2022
Muhali O. Jimoh, Learnmore Kambizi
Aquatic plants play a crucial role in environmental remediation as they mediate the uptake and release of nutrients (Lu et al., 2018). The process of phytoremediation is embedded in the ability of aquatic plants to photosynthetically produce, transform and mobilize molecules to rhizospheric organisms, resulting in oxidation, uptake of bio-nutrients and contaminants suspended in the rhizosphere in a species-specific manner (Jimoh and Jimoh, 2021; Stottmeister et al., 2003). Conventional waste stabilization and removal in water treatment involve different mechanisms, such as physical sedimentation and the use of a trickling filter and activated sludges. However, recent findings show that aquatic plants such as Myriophyllum spicatum L., Eichhornia crassipes Mart., Hydrilla verticillate (L.f.) Royle and Nelumbo nucifera Gaertn. are good candidates for regulating bacterial metabolism in water treatment systems (Kanabkaew and Puetpaiboon, 2004; Lu et al., 2018).
Environmental Factors Impacting Bioactive Metabolite Accumulation in Brazilian Medicinal Plants
Published in Luzia Valentina Modolo, Mary Ann Foglio, Brazilian Medicinal Plants, 2019
Camila Fernanda de Oliveira Junkes, Franciele Antonia Neis, Fernanda de Costa, Anna Carolina Alves Yendo, Arthur Germano Fett-Neto
The metabolic effects of nutritional imbalance are not entirely predictable. Although patterns can be recognized, it is not possible to establish a consensus on the classes of metabolites that will be benefited or impaired in each case (see Table 6.2). This is due to the complexity of the biochemical pathways and factors that are involved in mineral nutrition. Soil pH, for example, alters the availability of some nutrients, so that uptake by plants can be disrupted and their metabolism affected. Likewise, the presence of microorganisms in the rhizosphere may interfere with the absorption and availability of nutrients. The positive effect of mycorrhizal fungi on acquisition of phosphorus by the roots is well established. However, despite the recognized influence on plant development, few studies show relationships between pH or soil microorganisms in secondary metabolism. Furthermore, environmental factors do not seem to exert a homogeneous effect on the metabolism of different parts of the plant, which may respond differently to such external signals (Sampaio et al., 2016).
Organic Matter
Published in Michael J. Kennish, Ecology of Estuaries Physical and Chemical Aspects, 2019
The transformation of organic matter into inorganic compounds is considered to be the counterpart of photosynthesis.17 Aerobic mineralization takes place in the water column and, in general, in the top centimeter of sediment on the seafloor. Anaerobic mineralization occurs exclusively in oxygen-deficient habitats, such as in the deeper sediment layers of the seafloor, in salt marsh sediments, and in anoxic estuarine waters (e.g., bottom waters of fjord-type estuaries). Bacteria, fungi, protozoans, and microscopic metazoans are aerobic microorganisms inhabiting the top few millimeters of estuarine and salt marsh sediments, as well as microzones within the rhizosphere of living plant roots.296 It is in these aerobic zones where the degradation of organic matter proceeds most rapidly and a significant amount of nutrients is produced.
Rhizobacterial biofilm and plant growth promoting trait enhancement by organic acids and sugars
Published in Biofouling, 2020
Jishma Panichikkal, Radhakrishnan Edayileveetil Krishnankutty
Plant root exudates generally contain low molecular weight (amino acids, organic acids, sugars, phenolics, etc.) and high molecular weight (mucilage and proteins) compounds (Kumar et al. 2007; Liu et al. 2014). The factors determining the chemical complexity of root exudates are species or genotype specific and can also be influenced by the plant’s photosynthetic activity and size, and soil conditions (Sasse et al. 2018). The root exudates released by plants have also been reported to generate a nutrient gradient in the rhizosphere which can direct the movement of bacteria towards the plant root. Thus, the chemical composition of root exudates has been suggested to have a direct effect on shaping the rhizosphere microbiome to utilize its functioning for the growth and health of the plant (Schuch et al. 2013; Zhang et al. 2014; Mhlongo et al. 2018). In addition, the compounds present in the exudates including the organic acids and sugars can also be expected to play a key role in determining the functioning of bacteria at the rhizosphere.
Antimicrobial activities of Trichoderma atroviride against common bean seed-borne Macrophomina phaseolina and Rhizoctonia solani
Published in Egyptian Journal of Basic and Applied Sciences, 2020
Naglaa M. El-Benawy, Gamal M. Abdel-Fattah, Khalid M. Ghoneem, Yasser M. Shabana
Nearly 90% of researches on biological disease management had been done by using different strains of Trichoderma [11,15]. Trichoderma exists in all types of soils habitat and at high population density. It is a successful antagonist due to its ability to survive under different unfavorable conditions. It colonizes very quickly, compete for space and nutrients, and modify the rhizosphere. It is also an effective bio-fertilizer, aggressive against plant pathogenic fungi, plant growth promotor, and inducer of plant resistance [16,17]. T. koningii, T. pseudokoningii, T. viride, T. polysporum and T. atroviride have been reported as an antagonist against R. solani and M. phaseolina as [18]. Competition, mycoparasitism, antibiosis and induced systemic resistance are likely mechanisms involved in the antagonistic activities of Trichoderma spp [19]. Moreover, a recent report suggested the role of Trichoderma in production of secondary metabolites as studied on T. harzianum and T. koningii [20]. These volatiles and nonvolatile toxic metabolites prevent the pathogen colonization and cause its death [21,22].
Nanotoxicity of engineered nanomaterials (ENMs) to environmentally relevant beneficial soil bacteria – a critical review
Published in Nanotoxicology, 2019
Ricky W. Lewis, Paul M. Bertsch, David H. McNear
Microbes in the rhizosphere and in the environment at large, are rarely (if ever), found alone. Some work has examined the response of PGPR biofilms to ENMs, but much remains unknown, particularly with respect to root colonization. Future research should examine multi-species interactions of ENMs with microbes that are both motile and present as biofilms on abiotic (e.g. mineral) and biotic (e.g. plant root) surfaces. As researchers attempt to clarify the results of the past decade of pure-culture-based nanotoxicological research, it is essential that future efforts are focused on more environmentally relevant conditions (i.e. soils). Examination of the effects of ENMs on plant-microbe interactions in meso/microcosms, and ultimately, actual field sites, will provide a rich research topic for future researchers. Findings regarding ENM-induced changes in soil enzyme activities, nutrient cycling, and community interactions (reviewed by McKee and Filser 2016) should be examined with microbiome surveys, metagenomics, metametabolomics, metatranscriptomics, and metaproteomics to elucidate the biological mechanisms governing these crucial responses.