Within-leaf variation in embolism resistance is not a rule in compound-leaved angiosperms

Premise
Hydraulic segmentation, caused by the difference in embolism resistance across plant organs, provides a sacrificial layer of cheaper plant organs, like leaves, to protect more costly organs, such as stems, during drought. Within-leaf hydraulic segmentation has been observed in two compound-leaved tree species, with leaflets being more vulnerable than the rachis or petiole. Many herbaceous species have compound leaves, and some species have leaflets that are associated with pulvini at the base of the lamina, which could provide an anatomical means of preventing embolism from spreading within a leaf due to the high concentration of vessel-endings in the pulvinus.
Methods
We assessed embolism resistance across the leaf in three diverse palmately and pinnately compound-leaved herbaceous species, one of each with a pulvinus. We used the optical vulnerability method to simultaneously investigate whether hydraulic segmentation occurred across the leaves of six compound-leaved herbaceou..., Plants were cultivated in the Lilly Greenhouses at Purdue University (West Lafayette, Indiana, USA) in 5-L pots containing commercial potting mix and were maintained under greenhouse conditions for 4 to 7 months, except Eranthis hyemalis, which was gathered from Horticulture Park on the Purdue campus in February 2023. Plants in the greenhouse were watered daily and received weekly applications of liquid fertilizer (Miracle-Gro, Scotts Company LLC, OH, USA). Conditions in the glasshouse were maintained under a natural photoperiod and controlled day:night temperatures of 28:22°C.  Samples of Ailianthus altissima (“Tree of Heaven”), were collected in June of 2024 from Horticulture Park on the Purdue campus (n=3) and immediately bagged and brought back to the lab to rehydrate. Vulnerability curves of the rachis and lamina were conducted using the optical vulnerability method and subsequent image analysis outlined by (Brodribb et al., 2016). Three plants from each species were brought to the..., , # Within-leaf variation in embolism resistance is not a rule in compound-leaved angiosperms

[https://doi.org/10.5061/dryad.8pk0p2nxc](https://doi.org/10.5061/dryad.8pk0p2nxc)

Hydraulic segmentation, caused by the difference in embolism resistance across plant organs, provides a sacrificial layer of cheaper plant organs, like leaves, to protect more costly organs, such as stems, during drought. Within-leaf hydraulic segmentation has been observed in two compound-leaved tree species, with leaflets more vulnerable than the rachis or petiole. Many herbaceous species have compound leaves, and some species have leaflets associated with pulvini at the base of the lamina, which could provide an anatomical means of preventing embolism from spreading within a leaf. To determine if hydraulic segmentation is also a rule in herbaceous angiosperms, we assessed embolism resistance across the leaf in three diverse palmately and pinnately compound-leaved herbaceous species (n=3), one of each with a pu...