Macronutrient elements

Macronutrients Elements or compounds (like nitrate, phosphate, and silicate) that are necessary to sustaiin life and that are typically present in larger amounts than the micronutrients. 

We focus on temperate shelf seas because these are not only best studied, but also most subject to anthropogenic influence. Most of our examples are taken from studies in northwest European waters, because it is these that we know best. The aim of this chapter is to review recent improvements in knowledge of the sources and sinks of nutrients in the shelf seas of northwest Europe, and to consider, especially, the influence of ratios of nutrient elements on the floristic composition of the phytoplankton in these seas. We deal mainly with the macronutrient elements nitrogen, phosphorus and silicon, and to some extent with iron. The acronym DAIN (Dissolved Available /norganic Mtrogen) is a convenient way to refer to nitrate, nitrite and ammonium, excluding di-nitrogen which is not available to most phytoplankters. 

In plant nutritional science it is usual to regard also N, C, H, and O as essential elements, and to characterize the entire group as macronutrient elements (see Table 2.2). N, Ca, K, Mg, P, and S represent in this context the subgroup mineral macronutrient elements. Additionally, in plants the degree of essentiality (Table 2.1) is a more precisely considered criterion than in animals and humans (see below). This facilitates consideration of the major metabolic differences between many species. 

The energetic coupling process outlined is also necessary for the biosynthesis of proteins, many of which are enzymes or parts thereof Besides C, H, and O, proteins also contain the macronutrient elements N and... 

Macronutrients Elements that plants require significant quantities of to thrive, including nitrogen, phosphorus, sulfur, potassium, calcium, and magnesium. 

Phytin content of whole seeds and protein bodies varies with species and cultivar. Examples of the chemical composition of the aleurone grains of rice and protein bodies (and isolated globoids) of cotton seed are shown in Table 2.7. Note, in particular, the higher phosphorus but lower protein content of the cereal aleurone grain in comparison with the dicot protein body. The concentration of the associated macronutrient elements can also be seen to differ. Qualitative as well as quantitative differences occur between the macronutrient compositions of different seeds, e.g. in C. maxima the globoid is rich in phosphate, potassium... 

Sample preparation also requires careful fixation to avoid redistribution of the inorganic macronutrient elements including Potassium, Calcium, and Magnesium (these exist in their ionized states). 

Electron Microscopy (TEM) studies, this approach is not extensively used in SIMS. This stems from the fact that such preparation procedures tend to result in modification of the chemical composition, particularly for inorganic macronutrient elements, on or within the respective tissue sections. This approach can, however, be applied when nondiffusible ions or elements bound to large molecules are of interest. 

Macronutrient An element required in large proportion by plants and other life forms for survival and growth. Macronutrients include Nitrogen (N), Potassium (K), and Phosphorous (P). 

O Parenteral nutrition (PN), also called total parenteral nutrition (TPN), is the intravenous administration of fluids, macronutrients, electrolytes, vitamins, and trace elements for the purpose of weight maintenance or gain, to preserve or replete lean body mass and visceral proteins, and to support anabolism and nitrogen balance when the oral/enteral route is not feasible or adequate. 

PN should provide a balanced nutritional intake, including macronutrients, micronutrients, and fluid. Macronutrients, including amino acids, dextrose, and intravenous lipid emulsions, are important sources of structural and energy-yielding substrates. A balanced PN formulation includes 10% to 20% of total daily calories from amino acids, 50% to 60% of total daily calories from dextrose, and 20% to 30% of total daily calories from intravenous lipid emulsion. Micronutrients, including electrolytes, vitamins, and trace elements, are required to support essential biochemical reactions. Parenteral... 

Historically, EN formulations were created to provide essential nutrients including macronutrients (e.g., carbohydrates, fats, and proteins) and micronutrients (e.g., electrolytes, trace elements, vitamins, and water). 

Both macronutrients (i.e., water, protein, dextrose, and IV fat emulsion [IVFE]) and micronutrients (i.e., vitamins, trace elements, and electrolytes) are necessary to maintain normal metabolism. 

Plant nutrients are interesting not only in connection with the yields and the fertilisation, but also with regard to environmental effects of energy conversion processes. Thus, they are regulated in various standards. Nitrogen (N), phosphorous (P) and potassium (K), as well as sulphur (S) and chlorine (Cl) are the most important environmentally relevant macronutrient and micronutrient elements. 

The second characteristic feature of Forest Ecosystem soils is the accumulation of macronutrients in the litter with sharp decreasing to the download horizon. However, the trace elements show the opposite trend and the concentration of micronutrients is gradually increasing up to the soil-forming rocks. 

Carbohydrates are literally hydrates of carbon, containing only the elements carbon, oxygen, and hydrogen. In the human diet, they are considered macronutrients, along with proteins and fats (triacylglycerols). The three types of carbohydrates are monosaccharides, disaccharides, and polysaccharides. 

Micronutrients Elements or compounds (like iron, other trace metals, and vitamins) that are necessary to sustain life and that are present in smaller amounts than the macronutrients (see above). 

As rocks are transformed to soil so a proportion of each element is usually converted to a form which plant roots can absorb. Consequently, most of the elements in the Periodic Table would probably be detected in any plant sample if sufficiently sensitive analytical methods were used. Uptake of an element is no evidence that it plays any role in the development of the plant since a root has no power to reject any soluble element entirely. One must therefore differentiate between those elements which are needed, the essential nutrients, and the rest. The conventional criteria by which the presence of an element is regarded as essential rather than adventitious are these the plant cannot complete its life cycle in the absence of the element the action of the element must be specific in that no other element can wholly substitute for it nor is the element simply involved in beneficially altering the plants root environment the element must be shown to be a constituent of an essential metabolite, or required for the proper functioning of an essential enzyme system or be uniquely involved in maintaining the overall ionic composition of tissue. Table 1-2 lists the elements which are generally accepted as being essential for plants. Major or macronutrients are separated from micronutrients, the latter being present in tissue concentration < 0.1 %. 

Table 1-2. The essential plant nutrients. The major or macronutrients are divided into (a) the major structural elements and (b) the other macronutrients.

Plant micronutrients are those required in plant tissue at concentrations which are equal to or less than 100 mg kg-1 dry weight. Macronutrients or major elements are those which are needed in concentrations of 1000 mg kg-1 or more in dry weight of the plant. Typical concentrations of elements in plants are given by Bowen (1966), Kabata-Pendias and Pendias (1984) and Markert (1992) Angelone and Bini (1992) have detailed elemental concentrations for plants and soils of western Europe. 

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