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Leaf Mechanical Strength Corresponds To Tissue Water Relations In Twelve Species Of California Ferns, Breahna M. Gillespie, Stephen D. Davis, Jarmila Pitterman
Leaf Mechanical Strength Corresponds To Tissue Water Relations In Twelve Species Of California Ferns, Breahna M. Gillespie, Stephen D. Davis, Jarmila Pitterman
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The dominant vegetation types in southern California’s coastal foothills are chaparral and costal sage scrub. Chaparral shrubs have mechanically strong evergreen leaves whereas coastal sage scrubs bear mechanical weak, facultative deciduous leaves. What about the ferns that live in the understory of these vegetation types, especially considering their adaptations to a summer dry, Mediterranean-type climate? We tested the hypothesis that some fern leaves are stronger than others and mechanically strong leaves are associated with greater dehydration tolerance. Twelve fern species were examined. Tissue water relations were assessed via pressure volume curves using Scholander-Hammel pressure chambers. We estimated osmotic potential at …
Relationship Between Dehydration Tolerance Of California Ferns And The Mechanical Strength Of Their Stipes, Helen I. Holmlund, Jarmila Pitterman, Stephen D. Davis
Relationship Between Dehydration Tolerance Of California Ferns And The Mechanical Strength Of Their Stipes, Helen I. Holmlund, Jarmila Pitterman, Stephen D. Davis
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In vascular plants, water moves upwards through xylem vessels/tracheids due to negative pressures created by the evaporative pull of water. Under severe dehydrated, extreme negative pressures are known to cause xylem cavitation and embolism. In seed-bearing plants, the mechanical support of stem xylem has been shown to be a good predictor of cavitation resistance, presumably because sclerenchyma fibers buttress against micro-fracture or collapse of conduit walls. In spore-bearing plants, such as ferns, current anatomical theory indicates that mechanical support lies external to underlying xylem, in the outer hypodermal region, leaving the central xylem in ferns without any fiber support. In …