Abstract Detail

Development and Structure

Suissa, Jacob [1], Friedman, William [1].

From cells to stems: the hydraulic implications of primary vascular construction in ferns.

Hundreds of studies over the last 200 years have elucidated the diversity of primary vascular construction in fern stems. However, the functional implications of this diversity are poorly understood. Here, we examine xylem structure-function relationships to begin to link this observed diversity to modern whole-plant ecophysiology and to understand the consequences of variation in primary vascular construction. In five fern species with diverse vascular construction, we used the optical vulnerability method to measure resistance to drought-induced embolism in the rhizome and vulnerability segmentation between stems and leaves. Using light and electron microscopy, we quantified anatomical traits at three levels of vascular construction: cellular, histological, and architectural. While interactions exist between these levels of construction, independently, cellular level traits were most predictive of vulnerable to embolism at P₁₂, P₅₀, and P₈₈. Leaves fully embolize before stems reach P₅₀, suggesting that lower percent embolism may be more informative of drought stress in mesic fern species. This is the first study to report vulnerability segmentation in ferns and to explore the hydraulics of primary vascular construction in the rhizome. Vulnerability segmentation suggests that leaves may hydraulically disconnect before significant embolism occurs in the stem, providing the first line of defense in protecting the perennial rhizome against hydraulic failure.

1 - Harvard University, Department of Organismic and Evolutionary Biology, 26 Oxford St, Cambridge, Massachusetts, 02138, United States

Keywords:
cavitation
fern
optical vulnerability
primary vasculature
rhizome
stele
vulnerability segmentation
xylem.

Presentation Type: Oral Paper
Session: DS3, Development and Structure III
Location: /
Date: Thursday, July 22nd, 2021
Time: 12:45 PM(EDT)
Number: DS3011
Abstract ID:42
Candidate for Awards:Katherine Esau Award,Developmental and Structural Section Graduate Student Registration Award