Journal of Experimental Botany, Vol. 52, No. 364, pp. 2135-2142,
November 1, 2001
© 2001 Oxford University Press
Original Papers |
Stem diameter variations and cold hardiness in walnut trees
1 UMR PIAF (INRA, Université Blaise Pascal), Site INRA de Crouelle, 234 av. du Brezet, F-63039 Clermont-Ferrand Cedex 2, France
2 Department of Plant Biology, Michigan State University, East Lansing, MI 48824-1312, USA
The effect of freezing temperatures on stem diameter was measured in the field and in climatic chambers using linear variable differential transformers (LVDT sensors). In acclimated stems, there was reversible stem shrinkage associated with freezethaw cycles. The maximum shrinkage correlated with stem diameter (thickness of the bark). The wood was responsible for only 15% of the shrinkage associated with a freeze event, and experiments with isolated bark showed that connection with the wood was not necessary for most of the freeze-induced shrinkage to occur. Considering the amount of stem shrinkage associated with summer drought in walnut, the amount of contraction of the bark with freezing was actually much less than might be predicted by water relations theory. Reversible stem shrinkage occurred in living tissues, but not in autoclaved tissues. For the latter, swelling was observed with freezing and this swelling could be explained by the bark alone. Similar swelling was observed during September and October for non-acclimated plants. Water was lost with each freezethaw cycle starting with the first, and freezing injury of the bark, with discoloration of tissues, was also observed in non-acclimated plants. Given that the diameter fluctuation patterns were dramatically different for acclimated versus non-acclimated plants, and for living versus autoclaved tissues, LVDT sensors could represent a novel, non-invasive approach to testing cold hardiness.
Key words: Cold hardiness, frost hardiness, freezing avoidance, diameter variation, walnut.
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
S. Mayr, H. Cochard, T. Ameglio, and S. B. Kikuta Embolism Formation during Freezing in the Wood of Picea abies Plant Physiology, January 1, 2007; 143(1): 60 - 67. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Maurel, S. Sakr, F. Gerbe, A. Guilliot, M. Bonhomme, R. Rageau, and G. Petel Sorbitol uptake is regulated by glucose through the hexokinase pathway in vegetative peach-tree buds J. Exp. Bot., April 1, 2004; 55(398): 879 - 888. [Abstract] [Full Text] [PDF] |
||||

