Effects of charring on the carbon isotopic composition of grass (Poaceae) epidermis
Effects of charring on the carbon isotopic composition of grass (Poaceae) epidermis
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DOI：
10.1016/s0031-0182(01)00358-3
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发表时间：
2002-01-05
影响因子：
3
通讯作者：
Scott, JE
中科院分区：
文献类型：
--
作者：
Beuning, KRM;Scott, JE
烧焦的现代草表皮保留了亲本植物光合途径的碳同位素组成。在乌干达西部的低地采集了59种现代禾本科植物和莎草。所有来自C-4禾本科植物或莎草科植物的烧焦表皮样品的碳同位素值都在C-4植物的典型范围内（-17至-10ppm），而来自C-3植物的烧焦表皮碎片的碳同位素值在-30至-26ppm之间。炭化过程导致碳同位素略微富集（平均炭化值为-11.9ppm，而平均未改变的草组织值为-12.8ppm）。同一植物的重复样品的δ（13）C测量值在千分之1- 20之间变化，但同一植物的所有值都在植物光合作用途径的预期值之内。对取自乌干达西部低地三个湖泊表层沉积物样品的> 180 μ m烧焦草表皮碎片进行δ（13）C测量，证实了主要的低地C-4草输入（δ（13）C = -16至-19ppm）。这些结果表明，利用碳同位素分析的烧焦草表皮重建C-3与C-4草地组合的景观，此外，这种downcore三角洲（13）C剖面可以用来突出的关键地带C-3与C-4草变化的化石草表皮的分类分析，可以提供更详细的信息，草地群落组成。(C)2002 Elsevier Science B. V.保留所有权利。
Charred modern grass epidermis preserves the carbon isotopic composition of the parent plant photosynthetic pathway. Fifty-nine modern grasses and sedges were collected in lowland western Uganda. All charred epidermal samples from C-4 grasses or sedges preserve a carbon isotopic value within the range typical for C-4 plants (-17 to -10parts per thousand), and charred epidermal fragments from C-3 plants have carbon isotopic values between -30 and -26 parts per thousand. The process of charring results in a slightly enriched carbon isotopic signature (-11.9parts per thousand mean charred value as compared to -12.8parts per thousand mean unaltered grass tissue value). delta(13)C measurements of replicate samples from the same plant vary within 1-2parts per thousand, yet all values for the same plant stay within the expected values for the photosynthetic pathway of the plant. delta(13)C measurements on > 180-mum charred grass epidermal fragments extracted from surface sediment samples from three lakes on the lowland western Ugandan landscape confirm the predominant lowland C-4 grass input (delta(13)C = -16 to -19parts per thousand). These results demonstrate the utility of using carbon isotopic analysis of charred grass epidermis to reconstruct C-3 VS. C-4 grassland assemblages on the landscape, Furthermore, such downcore delta(13)C profiles can be used to highlight key zones Of C-3 VS. C-4 grass change for which taxonomic analysis of fossil grass epidermis could provide more detailed information regarding grassland community composition. (C) 2002 Elsevier Science B.V. All rights reserved.