Time series regression uncovers significant correlation between soil microbial DNA concentration and enzymatic glucose neo-generation
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Understanding how microbial DNA from root zone (rhizosphere) soil relates to key metabolic enzymes used by rhizosphere microbes was investigated using time series regression. We aimed to define the influence of these enzymes on DNA concentrations. This objective was achieved using phosphorescent measurement of both enzyme activities and DNA concentrations. Rhizosphere samples from three strains of canola genetically modified (GM) for herbicide resistance (HR) to atrazine, imidazolinone, and glyphosate respectively together with the isoline to the transgenic glyphosate-resistant variety were grown in a greenhouse in pH-neutral Vertisol soil. Analyses were carried out at days 7, 21, 42, and 56 growth representing germination, early growth, maturity, and seed formation-senescence. Enzymes represented key soil microbial metabolic processes and included leucine aminopeptidase (LAP), alkaline phosphatase (PHOS), cellobiose dehydrogenase (CELL), beta-glucosidase (BGL), and aryl sulphatase (SUL). The experiment employed a randomized complete block design with four blocks of eight pots, each pot containing two plants of identical genotype, and each cultivar randomly distributed within each block. Enzyme measurements were taken before substrate addition and again after incubating at 25 degrees Celsius for one hour. DNA concentrations were measured using the Pico Green technique. Mean increases in enzyme activities for each lifespan stage were correlated with DNA concentrations using time series regression. A highly significant relationship (p = 0.001) between DNA concentration and beta-glucosidase activity emerged. No other enzyme significantly influenced DNA. The implications of this finding are that during times in the plant lifecycle when microbial-root biochemical interaction are increased (flowering and seed formation), the soil must have adequate SOM available to the microorganisms. It is now known that commensal relationships exist between rhizosphere soil microorganisms and the roots within that soil. The importance of microorganisms in breaking down decaying organic material from plant residues is reflected in contemporary measurement of soil fertility which recognizes that a matrix of physical, chemical, and biological parameters together are required for an adequate assessment. This is because when organically-bound carbon biomass is subjected to transformation, other nutrients like Nitrogen (N), Phosphorus (P), and Sulphur (S) are released for mineralization by roots. The results reinforce the importance of soil organic matter (SOM) as a component of soil fertility and sustainable soil health.
22nd International Congress on Modelling and Simulation: Managing cumulative risks through model-based processes (MODSIM2017)
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Numerical and Computational Mathematics not elsewhere classified