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The ratio of 13 C to 12 C is slightly higher in plants employing C4 carbon fixation than in plants employing C3 carbon fixation. Because the different isotope ratios for the two kinds of plants propagate through the food chain, it is possible to determine if the principal diet of a human or other animal consists primarily of C3 plants or C4 ...
The δ 13 C of C3 plants depends on the relationship between stomatal conductance and photosynthetic rate, which is a good proxy of water use efficiency in the leaf. [19] C3 plants with high water-use efficiency tend to be less fractionated in 13 C (i.e., δ 13 C is relatively less negative) compared to C3 plants with low water-use efficiency. [19]
This material had an anomalously high 13 C: 12 C ratio (0.0112372 [4]), and was established as δ 13 C value of zero. Since the original PDB specimen is no longer available, its 13 C: 12 C ratio can be back-calculated from a widely measured carbonate standard NBS-19, which has a δ 13 C value of +1.95‰. [ 5 ]
C 4 and CAM plants have adaptations that allow them to survive in hot and dry areas, and they can therefore out-compete C 3 plants in these areas. The isotopic signature of C 3 plants shows higher degree of 13 C depletion than the C 4 plants, due to variation in fractionation of carbon isotopes in oxygenic photosynthesis across plant types.
In addition, there are two types of plants with different biochemical pathways; the C3 carbon fixation, where the isotope separation effect is more pronounced, C4 carbon fixation, where the heavier 13 C is less depleted, and Crassulacean Acid Metabolism (CAM) plants, where the effect is similar but less pronounced than with C 4 plants.
This is known as carbon isotope discrimination and results in carbon-12 to carbon-13 ratios in the plant that are higher than in the free air. Measurement of this isotopic ratio is important in the evaluation of water use efficiency in plants, [ 32 ] [ 33 ] [ 34 ] and also in assessing the possible or likely sources of carbon in global carbon ...
Carbon (6 C) has 14 known isotopes, from 8 C to 20 C as well as 22 C, of which 12 C and 13 C are stable.The longest-lived radioisotope is 14 C, with a half-life of 5.70(3) × 10 3 years. . This is also the only carbon radioisotope found in nature, as trace quantities are formed cosmogenically by the reactio
C 7 H 16: n-heptane: dipropyl methane; Gettysolve-C; heptyl hydride; Skellysolve C 8 18 24 C 8 H 18: n-octane: dibutyl; octyl hydride 9 35 55 C 9 H 20: n-nonane: nonyl hydride; Shellsol 140 10 75 136 C 10 H 22: n-decane: decyl hydride 11 159 345 C 11 H 24: n-undecane: hendecane 12 355 900 C 12 H 26: n-dodecane: adakane 12; bihexyl; dihexyl ...