Abstract Detail

Development and Structure

Morris, Hugh [1], Plavcová, Lenka [2], Jansen, Steven [3].

New insights into the functional anatomy of wood parenchyma.

Parenchyma represents an important interconnected three-dimensional living tissue in secondary xylem of woody seed plants, with functions ranging from transport and storage to defence and biomechanics, along with less understood functions, such as in long-distance water transport. We lack a large-scale analysis of ecological traits associated with ray parenchyma (RP) and axial parenchyma (AP). Here, we explore global trends in the AP and RP fraction per cross-sectional wood area based on literature data, including 1,727 entries from three major biomes (temperate, subtropical and tropical). We found a 29-fold variation in RAP fraction, where temperature was found to be the biggest driver of RAP (RP+AP) levels, followed by precipitation, with the latter showing a significant but negative relationship with RAP, demonstrating an increase in RAP towards drier sites. RAP fractions were higher in tropical than temperate angiosperm trees (21.1 vs 36.2 %), respectively, where AP was found to be the most versatile parenchyma type resulting in the sharp rise of RAP in the tropics, while RP remained relatively constant. Succulents (including pachycauls) and lianas were found to have higher RAP fractions than non-succulent angiosperm trees and conifers, with the latter having the lowest RAP fractions, as expected. The observed trends were interpreted with respect to the various functions of RAP in plants. Some of the functions explored include: capacitance, embolism repair, pathogen defence, non-structural carbohydrates (NSCs), and reponse to disturbance. We tested one of the hypotheses arising from the global analysis, and found RAP and/or living fibre levels in the juvenile stems and roots of a range of temperate species, to be the uppermost limit for NSC storage. This demonstrated that temperate species with higher RAP and/or living fibre fractions could have a greater capacity for carbon storage. The same trend was not found for lowland rainforest species. Also, starch accumulation was equally distributed across both RP and AP (including contact cells) in most of the temperate species analysed at the onset of winter. In summary, our results form a strong basis in which to better understand the functional implications of the great anatomical variability in wood parenchyma.

1 - Ulm University , Institute for systematic ecology and botany, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
2 - Charles University, Faculty of Science, Department of Experimental Plant Biology, Vinicná 5, Prague, 128 44, Czech Republic
3 - Ulm University , Institute for systematic ecology and botany, Albert-Einstein-Allee 11, Ulm, Germany

Keywords:
xylem
axial parenchyma
radial parenchyma
Plant-climate interactions
nonstructural carbohydrates.

Presentation Type: Oral Paper
Session: 29, Development and Structure I
Location: 202/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 3:45 PM
Number: 29009
Abstract ID:160
Candidate for Awards:None