New Zealand Journal of Botany abstract

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Differences in water-use efficiency between Agathis australis and Dacrycarpus dacrydioides are genetically, not environmentally, determined

DAVID W. STEPHENS
WARWICK B. SILVESTER^*

The University of Waikato
Department of Biological Sciences
Private Bag 3105
Hamilton, New Zealand

BRUCE R. BURNS

Landcare Research
Private Bag 3127
Hamilton, New Zealand

Abstract  Isotopic carbon ratios were measured in homogenised leaf litter and in sapwood of Agathis australis (kauri) and Dacrycarpus dacrydioides (kahikatea) trees growing together at ridge crest and valley sites in Northland, New Zealand. The discrimination ([[Delta]]) values for kauri were significantly less than for kahikatea, indicating a possibility of higher water-use efficiency of kauri. Discrimination did not vary significantly in different environments, with each species showing similar values at several valley and ridge sites even at distant locations. It is concluded that the differences in [[Delta]] between kauri and kahikatea are the result of fundamental physiological differences between the species rather than resulting from site preferences. For both species, wood is significantly less depleted than leaf material.

Keywords  carbon isotope discrimination; Agathis australis; Dacrycarpus dacrydioides; water-use efficiency

^*Author for correspondence
email: w.silvester@waikato.ac.nz
B98022
Received 15 April 1998; accepted 23 September 1998

PDF file of entire paper: medium quality (510K); (scanned from paper original: notes about this process)

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