Patterns of cytokinins and leaf gas exchange among canopy layers of a mature sugar maple (Acer saccharum) stand

Leaf cytokinins (CKs) were profiled within four locations throughout the inner and outer layers of a mature sugar maple (Acer saccharum) canopy. Leaf CK was associated with leaf gas exchange activity and some corresponding microclimate variables. Both inner and outer layers in the upper canopy had h...

Full description

Saved in:
Bibliographic Details
Published in:Trees (Berlin, West) West), 2007-03, Vol.21 (2), p.181-189
Main Authors: Reeves, Ian, Farrow, Scott C, Emery, R. J. Neil
Format: Article
Language:English
Subjects:
Acer saccharum
Canopy layers
cytokinins
Leaf gas exchange
microclimate
Photosynthesis
Regression analysis
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Leaf cytokinins (CKs) were profiled within four locations throughout the inner and outer layers of a mature sugar maple (Acer saccharum) canopy. Leaf CK was associated with leaf gas exchange activity and some corresponding microclimate variables. Both inner and outer layers in the upper canopy had higher concentrations of leaf CKs than the lower canopy layers and the difference was comprised primarily by riboside forms of CK. Transpiration (E) showed a similar pattern to leaf CK content, with significantly higher rates in the upper canopy. There was, however, no clear pattern discernable in stomatal conductance (gs), other than it tended to be higher in the outer canopy layers. The upper/outer canopy showed a significantly different environment than all other canopy positions with higher photosynthetically active radiation (PAR), ultra-violet light (UV-B) and leaf temperature. Simple linear regression analysis showed that the nucleotide CK group (including iPNT, cis- and trans-[9RMP]Z, [9RMP]DZ) was positively related to PAR. Exogenous applications of benzylaminopurine (BAP), showed that low concentrations of BAP reduced E and g s, and indicated that CK may help regulate stomatal aperture. The similar patterns in E and CK content suggest that CKs and leaf gas exchange are functionally connected.
ISSN:0931-1890
1432-2285
DOI:10.1007/s00468-006-0110-2