PT  - JOURNAL ARTICLE
AU  - Johnson, Kate M.
AU  - Scherer, Muriel
AU  - Gerber, Dominic
AU  - Style, Robert W.
AU  - Dufresne, Eric R.
AU  - Brodersen, Craig R.
TI  - Ice and air: Visualisation of freeze-thaw embolism and freezing spread in young <em>L. tulipifera</em> leaves
AID  - 10.1101/2024.10.26.620221
DP  - 2024 Jan 01
TA  - bioRxiv
PG  - 2024.10.26.620221
4099  - http://biorxiv.org/content/early/2024/10/29/2024.10.26.620221.short
4100  - http://biorxiv.org/content/early/2024/10/29/2024.10.26.620221.full
AB  - – Spring freezing is an unforgiving stress for young leaves, often leading to death, with consequences for tree productivity and survival. While both the plant water transport system and living tissues are vulnerable to freezing, we do not know whether damage to one or both of these systems causes death in young leaves exposed to unseasonal freezing.– Whole saplings of Liriodendron tulipifera were exposed to freezing and thawing trajectories designed to mimic spring freezes in nature. We visualised freezing damage to the water transport system (xylem embolism) and living tissues (mesophyll freezing, decline in chlorophyll fluorescence).– We 1.) provide the first visualisation of freeze-thaw embolism in leaves, 2.) reveal a predictable progression of ice formation within the mesophyll which is strongly influenced by leaf vein architecture, notably the presence or absence of bundle sheath extensions, and 3.) show that freeze-thaw embolism occurs only in the largest vein orders where mean vessel diameter exceeds 30µm.– With evidence of both freeze-thaw embolism and damage to photosynthetic tissue, we conclude that this dual-mode lethality may be common among other wide-vesseled angiosperm-leaves, potentially playing a role in limiting distributions, and show that bundle sheath extensions may stall or even prevent freezing spread.Competing Interest StatementThe authors have declared no competing interest.