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Oxygen isotopes in carbon(3) and car...

Helliker, Brent R.

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Oxygen isotopes in carbon(3) and carbon(4) grasses .

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Oxygen isotopes in carbon(3) and carbon(4) grasses ./
Author:	Helliker, Brent R.
Description:	154 p.
Notes:	Adviser: James R. Ehleringer.
Contained By:	Dissertation Abstracts International62-09B.
Subject:	Biogeochemistry. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3026456
ISBN:	0493386564

Oxygen isotopes in carbon(3) and carbon(4) grasses .
Helliker, Brent R.

Oxygen isotopes in carbon(3) and carbon(4) grasses . - 154 p.

Adviser: James R. Ehleringer.

Thesis (Ph.D.)--The University of Utah, 2001.

Stable oxygen isotopes offer a unique tool that elucidates physiological plant processes from the chloroplastic to global scales. The range of potential applications include paleoclimatic reconstruction to leaf-level physiological comparisons to assessment of global productivity. Central to all these applications is the oxygen isotope ratio of leaf-water and the transfer of this signal to CO2, O2 and plant organic material. Grasses are the dominant plant form in one quarter of the earth's vegetation and the majority of the world's grain crop species and have largely been ignored in previous oxygen isotope studies. This dissertation examines oxygen isotopes in the leaf-water, leaf-cellulose and the effects of leaf-water on atmospheric CO 2 in C3 and C4 grasses.

ISBN: 0493386564Subjects--Topical Terms:

545717
Biogeochemistry.

Oxygen isotopes in carbon(3) and carbon(4) grasses .
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005 20110427
008 110427s2001 eng d
020 $a 0493386564
035 $a (UnM)AAI3026456
035 $a AAI3026456
040 $a UnM $c UnM
100 1 $a Helliker, Brent R. $3 1252842
245 1 0 $a Oxygen isotopes in carbon(3) and carbon(4) grasses .
300 $a 154 p.
500 $a Adviser: James R. Ehleringer.
500 $a Source: Dissertation Abstracts International, Volume: 62-09, Section: B, page: 3931.
502 $a Thesis (Ph.D.)--The University of Utah, 2001.
520 $a Stable oxygen isotopes offer a unique tool that elucidates physiological plant processes from the chloroplastic to global scales. The range of potential applications include paleoclimatic reconstruction to leaf-level physiological comparisons to assessment of global productivity. Central to all these applications is the oxygen isotope ratio of leaf-water and the transfer of this signal to CO2, O2 and plant organic material. Grasses are the dominant plant form in one quarter of the earth's vegetation and the majority of the world's grain crop species and have largely been ignored in previous oxygen isotope studies. This dissertation examines oxygen isotopes in the leaf-water, leaf-cellulose and the effects of leaf-water on atmospheric CO 2 in C3 and C4 grasses.
520 $a Evaporative enrichment of heavy oxygen isotopes in the leaf-water of grass species can be significantly greater than predicted by the Craig-Gordon model, with C4 grasses considerably more enriched than C3 grasses. Heavy isotope leaf-water enrichment in grasses is attributable to the progressive evaporative enrichment along parallel veins (a function of both leaf length and interveinal distance), a pattern that does not occur in Dicotyledonous species.
520 $a The oxygen isotope ratio of leaf-water between C3 and C 4 grasses becomes less distinct as relative humidity increases and the leaf-water differences translated directly to the oxygen isotope ratio of leaf cellulose. A conceptual model is presented that was based on grass blade growth characteristics and observed patterns of progressive heavy oxygen isotope enrichment in grasses. Additionally, environmentally induced changes in the oxygen isotope ratio of leaf water were recorded in grass blade cellulose during leaf-blade expansion. This suggests that, analogously to tree-rings, grass blades represent a season-long record of local climate.
520 $a Leaf water enrichment of heavy isotopes in the C4 grass <italic> Andropogon gerardii</italic> was shown to have a consistently small effect on atmospheric CO2 due to low carbonic anhydrase activity. There was no significant difference between the oxygen isotope ratio of CO 2 evolving from base and tip leaf segments where the mean oxygen isotopes of leaf water differed by more than 24&permil;. The consistent effect of leaf-water oxygen isotopes on atmospheric CO2 in C 4 grasses should result in a distinct oxygen isotope signature from C4 grasslands.
590 $a School code: 0240.
650 4 $a Biogeochemistry. $3 545717
650 4 $a Biology, Ecology. $3 1017726
650 4 $a Biology, Plant Physiology. $3 1017865
690 $a 0329
690 $a 0425
690 $a 0817
710 2 0 $a The University of Utah. $3 1017410
773 0 $t Dissertation Abstracts International $g 62-09B.
790 $a 0240
790 1 0 $a Ehleringer, James R., $e advisor
791 $a Ph.D.
792 $a 2001
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3026456