Bundle-sheath leakiness and intrinsic water use efficiency of a perennial C4 grass are increased at high vapour pressure deficit during growth.

ABSTRACT: Bundle-sheath leakiness (ϕ) is a key parameter of the CO₂-concentrating mechanism of C₄ photosynthesis and is related to leaf-level intrinsic water use efficiency (WUE_i). This work studied short-term dynamic responses of ϕ to alterations of atmospheric CO₂ concentration in Cleistogenes squarrosa, a perennial grass, grown at high (1.6 kPa) or low (0.6 kPa) vapour pressure deficit (VPD) combined with high or low N supply in controlled environment experiments. ϕ was determined by concurrent measurements of photosynthetic gas exchange and on-line carbon isotope discrimination, using a new protocol. Growth at high VPD led to an increase of ϕ by 0.13 and a concurrent increase of WUE_i by 14%, with similar effects at both N levels. ϕ responded

SUBMITTER: Gong XY 

PROVIDER: S-EPMC5853292 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature