Biology 2483A Lecture 21: 21-Nutrient Supply and Cycling.docx
2 Jan 2015
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Carbon: carbon (c) is the main component of structural compounds in plants; nitrogen (n) is largely tied up in enzymes, c:n ratios reflect biochemistry: animals have lower c:n ratios (6 for humans); plants have c:n ratios of. 10 40: herbivores must consume more food than carnivores to get enough nutrients such as n. Plant nutrient requirements: all plants require a set of essential nutrients, some species have specific requirements. Some c4 and cam plants require sodium. (all animals require it. : some plants that host n-fixing bacteria require cobalt, some plants in selenium-rich soil require it, but it is toxic to most plants. Acquiring nutrients: plants and microorganisms take up nutrients in simple, soluble forms from the environment, animals mostly get nutrients in food as large, complex molecules. Rocks are collections of different minerals. minerals by weathering. Soil is a mix of mineral: particles, organic matter (mostly decomposing plant matter), water, and organisms.
