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| Titel |
Responses of carbon isotope discrimination in C4 plant to variable N and water supply |
| VerfasserIn |
Hao Yang, Shenggong Li |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250127661
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| Publikation (Nr.) |
 EGU/EGU2016-7561.pdf |
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| Zusammenfassung |
| Understanding variations and underlying mechanisms of carbon isotope discrimination
(Δ) in C4 species is critical for predicting the effects of change in C3/C4 ratio
of plant community on ecosystem processes and functionning. However, little is
known about the effects of soil resource gradients on Δ of C4 plants. To address Δ
responses to drought and nitrogen supply, the leaf carbon isotope composition, bundle
sheath leakiness (BLS), and leaf gas exchange (A, gs, Ci/Ca) were measured on
Cleistogenes squarrosa, a dominant C4 species in the Inner Mongolia grassland. C.
squarrosa were grown in controlled-environment pots from seed under a combination of
water and N supply. High N availability and drought stimulated photosynthetic rate
(A) and further decreased the ratio of internal and ambient CO2 concentrations
(Ci/Ca) through increasing leaf N content. BLS was higher under high N supply
and was unchanged by drought. There was significant interaction between N and
water supply to affect BLS and Ci/Ca. Δ was negatively related to Ci/Ca and was
positively related to BLS. Tradeoff between the responses of BLS and Ci/Ca to
changing environmental conditions kept leaf Δ relatively stable, which was also
supported by a field N addition experiment. Our results suggested leaf Δ of C4
plant was unchanged under variable water and N environment conditions although
the operating efficiency of C4 pathway and CO2 concentration in photosynthesis
were changed. Our findings have implications for predicting the change of C3/C4
ratio of plant community and understanding ecosystem processes and functionning. |
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