7.3 Conclusion
To
mitigate hydraulic damage, many plant species adhere to a strict
coordination between regulation of ΨL and vulnerability
to embolism. However, we found that the ΨL behavior ofQ. alba was not buffered by embolism resistant tissues to the
same extent as co-occurring L. tulipifera and A. saccharumacross ten eastern US forests sites. These results highlight that
important and abundant eastern US forest species have drought-response
traits that are coordinated in a fundamentally different way than
popular modeling frameworks (Naudts et al. , 2015; Sperry & Love,
2015; Kennedy et al., 2019; Mirfenderesgi et al ., 2019).
Moreover, we found that Q. alba sustains gas exchange at the cost
of operating with damaging water potential gradients and low
Ψsafety such that Quercus dominated forests may
be vulnerable to shifting drought regimes (Ficklin & Novick, 2017).
Ultimately, our understanding of plant-water relations may be improved
by further investigation into physiological mechanisms which allow
plants to tolerate or recover from xylem dysfunction. Such mechanisms
may be particularly important in temperate regions, where generally
moisture-abundant conditions may facilitate embolism repair through
regrowth following drought.