HR: 0830h
AN: H51C-08    [Abstracts]
TI: Genetic Effect on Carbon-Isotope Composition of a Plant
AU: * Yeh, H
EM: hwyeh@earth.sinica.edu.tw
AF: Hsueh-Wen Yeh, Institute of Earth Sciences, Academia Sinica, P.O. Box 1-55, Nankang, Taipei, Taiwan
AB: Stable carbon isotopes of organic sediments are potential tools in investigating a wide spectrum of geological problems. These include paleoclimate, paleoecology, and the origin of life. The quality of the information the tools provides depends largely on our knowledge on the factors determining the isotopic composition of a plant. This is because most biogenic organic sediments are derived from plants. The factors can be grouped into internal and external. The internal factors are ultimately attributable to the genetic make-up of a plant. The most well known internal factor is the photosynthetic pathway. Others include structure of the leave tissue and metabolic characteristics of a plant. External factors are concentration and the isotopic composition of the source CO2 and the physical and chemical conditions of the plant's growth environments. This study addresses primarily the genetic effect, the internal factors. Based on the results of two suites of natural plant samples, it is concluded that the difference in photosynthetic pathway entails about 20.0 % of spread in terms of „13CPDB values. Genetic effect is also accountable for up to 7.0 to 8.0 % spread in „13CPDB values within a single category of photosynthetic pathway (i.e. the Calvin cycle). With constrains from the relevant known knowledge, it is concluded that the „13CPDB values of terrestrial plants are probably ranging from - 8.0 to equal or less than -44.9 %. This range of „13CPDB values may also be considered the bio-signature of organic sediments of great antiquity.
DE: 1040 Isotopic composition/chemistry
SC: Hydrology [H]
MN: 2005 Joint Assembly