Redefining Iso/Anisohydry: Key parameters and Implications in Pinaceae and Cupressaceae
Plants have different ways of managing water when conditions get dry, some close their pores early to conserve moisture, while others keep them open longer to continue photosynthesis. These strategies fall along a spectrum known as the iso/anisohydry continuum, and understanding where a species falls on that spectrum can help us predict how it will respond to drought and climate stress. In this study, I analyzed patterns across two major tree families to see how their water-use strategies vary, and whether factors like climate or evolutionary history play a role. What I found is that there’s no one-size-fits-all answer, in fact, trees within the same family can behave very differently, and the traits we use to measure water strategy don’t always agree. This highlights the need for more nuanced, trait-based approaches to studying plant water regulation. By digging deeper into these patterns, we can better understand forest resilience and improve predictions about how different species will fare in a changing climate.
The image below illustrates the continuum of plant water regulation strategies, from more isohydric to more anisohydric behavior, by comparing key physiological traits and their influence on drought response. This image reinforces the idea that isohydry and anisohydry are not fixed categories, but part of a dynamic spectrum shaped by both environmental and evolutionary factors.
Literature Cited:
- Rojas, J., *Carlsrud, K., Johnson, D. Redefining Iso/Anisohydry: Key parameters and Implications in Pinaceae and Cupressaceae (To be submit to Plant, Cell, and Environment)
- Hartmann H, Link RM, Schuldt B. A whole-plant perspective of isohydry: stem-level support for leaf-level plant water regulation. Tree Physiol. 2021 Jun 7;41(6):901-905. doi: 10.1093/treephys/tpab011. PMID: 33594416; PMCID: PMC8827077.
Justine Rojas 