New Zealand Journal of Botany abstracts
B00028Received 31 July 2000; accepted 19 October 2000
Variation in response to cold damage by populations of Cordyline
australis and of some other species of Cordyline (Lomandraceae)
WARWICK HARRIS*
Landcare Research
P.O. Box 69
Lincoln 8152, New Zealand
ROSS E. BEEVER
Landcare Research
Private Bag 92710
Auckland, New Zealand
BRUCE SMALLFIELD
New Zealand Institute for Crop & Food Research Limited
Invermay Agricultural Centre
Private Bag 50034
Mosgiel, New Zealand
*Present address: Lincoln Botanical, 27A Edward Street,
Lincoln 8152, New Zealand.
Abstract Winter cold damage in 1996 and 1997 was recorded for
28 populations of Cordyline australis from a wide latitudinal range in
New Zealand and single populations of C. banksii and C. indivisa
grown in field experiments at Lincoln and Invermay, New Zealand. Damage to a
single plant of C. obtecta grown at Lincoln was also recorded.
Cordyline banksii and C. obtecta were damaged the most by
freezing. Levels of cold damage to C. australis were closely related to
latitude of origin; populations from northern North Island suffered severe
damage whereas those from inland southern South Island showed little damage.
These relationships were clearest when the populations were exposed to the
lowest grass minimum temperature of -9.7[[ring]]C that occurred at Invermay in
winter 1996. Retardation of the height growth of the populations most severely
damaged in winter 1996 kept them in the frost layer in winter 1997, increasing
their exposure to further damage. Variation in cold damage that related to
altitude and topography of the sites of origin was also indicated. Damage to
shoot apices by freezing temperatures at Invermay in 1996 induced plants of
northern populations to form multiple shoots. The results suggest that there
has been strong natural selection matching the cold tolerance of seedlings of
C. australis populations to minimum temperature regimes at their sites
of origin. The results are relevant to the sourcing of plants for restoration
of native vegetation and to horticultural use of C. australis.
Keywords Cordyline australis; C. banksii; C.
indivisa; C. obtecta; population variation; freezing
tolerance; plant height; shoot multiplication; New Zealand flora
New Zealand Journal of Botany, 2001, Vol. 39: 147-160
0028-825X/00/3901-0147 $7.00 (c) The Royal Society of New Zealand 2001
PDF file of entire paper: medium quality (7319K); (scanned from paper original: notes about this process)
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