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This content will become publicly available on March 22, 2019

Title: Is desiccation tolerance and avoidance reflected in xylem and phloem anatomy of two co-existing arid-zone coniferous trees?: Xylem and Phloem Anatomy

Plants close their stomata during drought to avoid excessive water loss, but species differ in respect to the drought severity at which stomata close. The stomatal closure point is related to xylem anatomy and vulnerability to embolism, but it also has implications for phloem transport, and possibly phloem anatomy to allow sugar transport at low water potentials. Desiccation tolerant plants that close their stomata at severe drought should have smaller xylem conduits and/or fewer and smaller inter-conduit pits to reduce vulnerability to embolism, but more phloem tissue and larger phloem conduits compared to plants that avoid desiccation. These anatomical differences could be expected to increase in response to long-term reduction in precipitation. To test these hypotheses we used tridimensional synchroton X-ray microtomograph and light microscope imaging of combined xylem and phloem tissues of two coniferous species: one-seed juniper (Juniperus monosperma) and piñon pine (Pinus edulis) subjected to precipitation manipulation treatments. These species show different xylem vulnerability to embolism, contrasting desiccation tolerance, and stomatal closure points. Our results support the hypothesis that desiccation tolerant plants require higher phloem transport capacity than desiccation avoiding plants, but this can be gained through various anatomical adaptations in addition to changing conduit or tissue size.
ORCiD logo [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ; ORCiD logo [5] ;  [5]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Swiss Federal Lab. for Material Science and Technology (Empa), Duebendorf (Switzerland)
  3. Paul Scherrer Inst. (PSI), Villigen (Switzerland). Swiss Light Source
  4. Swiss Federal Lab. for Material Science and Technology (Empa), Duebendorf (Switzerland); Federal Inst. of Technology, Zurich (Switzerland)
  5. Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Biology
Publication Date:
Report Number(s):
Journal ID: ISSN 0140-7791
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Plant, Cell and Environment
Additional Journal Information:
Journal Name: Plant, Cell and Environment; Journal ID: ISSN 0140-7791
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); Paul Scherrer Institute; University of New Mexico
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES; Biological Science; Earth Sciences; plant anatomy; water transport; sugar transport; xylem; phloem; Inter-conduit pit; stomatal closure point; xylem vulnerability
OSTI Identifier: