In:
Scientific Reports, Springer Science and Business Media LLC, Vol. 7, No. 1 ( 2017-03-23)
Abstract:
Understanding the mechanisms underlying variations in carbon isotope discrimination ( Δ ) in C4 plants is critical for predicting the C3/C4 ratio in C3/C4 mixed grassland. The value of Δ is determined by bundle sheath leakiness ( Ф ) and the ratio of intercellular to ambient CO 2 concentration ( C i / C a ). Leaf nitrogen concentration ( N leaf ) is considered a driver of Δ in C4 plants. However, little is known about how N leaf affects Ф and C i / C a , and subsequently Δ . Here leaf carbon isotope composition, N leaf , Ф , and leaf gas exchange were measured in Cleistogenes squarrosa , a dominant C4 species in the Inner Mongolia grassland. Δ remained relatively stable under variable N and water supply. Higher N supply and lower water supply increased N leaf , stimulated photosynthesis and further decreased C i / C a . High N supply increased Ф , which responded weakly to water supply. N leaf exerted similar effects on C i / C a and on Ф in the field and pot experiments. Pooling all the data, N leaf explained 73% of the variation in C i / C a . Overall, both Ф and C i / C a determined Δ ; however, the contribution of Ф was stronger. N leaf influenced Δ primarily though C i / C a , rather than Ф . Ф should be considered in estimating Δ of C4 endmember.
Type of Medium:
Online Resource
ISSN:
2045-2322
DOI:
10.1038/s41598-017-00498-w
Language:
English
Publisher:
Springer Science and Business Media LLC
Publication Date:
2017
detail.hit.zdb_id:
2615211-3
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