10027/10417
Douglas J. Lynch
Douglas J.
Lynch
Francesca A. McInerney
Francesca A.
McInerney
Lenny L.R. Kouwenberg
Lenny L.R.
Kouwenberg
Miquel A. Gonzalez-Meler
Miquel A.
Gonzalez-Meler
Plasticity in Bundle Sheath Extensions of Heterobaric Leaves
University of Illinois at Chicago
2013
Acer saccharum
bulk delta C-13
bundle sheath extension
heterobaric
Liquidambar styraciflua
plasticity
water use efficiency
2013-11-07 00:00:00
Journal contribution
https://indigo.uic.edu/articles/journal_contribution/Plasticity_in_Bundle_Sheath_Extensions_of_Heterobaric_Leaves/10769954
Premise of the study: Leaf venation is linked to physiological performance, playing a critical role in ecosystem function. Despite the importance of leaf venation, associated bundle sheath extensions (BSEs) remain largely unstudied. Here, we quantify plasticity in the spacing of BSEs over irradiance and precipitation gradients. Because physiological function(s) of BSEs remain uncertain, we additionally explored a link between BSEs and water use efficiency (WUE).
Methods: We sampled leaves of heterobaric trees along intracrown irradiance gradients in natural environments and growth chambers and correlated BSE spacing to incident irradiance. Additionally, we sampled leaves along a precipitation gradient and correlated BSE spacing to precipitation and bulk delta C-13, a proxy for intrinsic WUE. BSE spacing was quantified using a novel semiautomatic method on fresh leaf tissue.
Key results: With increased irradiance or decreased precipitation, Liquidambar styraciflua decreased BSE spacing, while Acer saccharum showed little variation in BSE spacing. Two additional species, Quercus robur and Platanus occidentalis, decreased BSE spacing with increased irradiance in growth chambers. BSE spacing correlated with bulk delta C-13, a proxy for WUE in L. styraciflua, Q. robur, and P. occidentalis leaves but not in leaves of A. saccharum.
Conclusions: We demonstrated that BSE spacing is plastic with respect to irradiance or precipitation and independent from veins, indicating BSE involvement in leaf adaptation to a microenvironment. Plasticity in BSE spacing was correlated with WUE only in some species, not supporting a function in water relations. We discuss a possible link between BSE plasticity and life history, particularly canopy position.