The frost resistance of juvenile and adult forms of some heteroblastic New Zealand plants

Abstract

Many New Zea1and trees are heteroblastic, with juvenile forms that differ markedly from the fom Of the adu1t tree. Their phase change ‘Orresponds with the transition from cold air near the ground to warmer air above. Heteroblastic species, therefore, might be expected to have juvenile forms that are more frost resistant than their mature forms. Juveni1e forms of Streblus heteroPhYllus and so‐phora microphylla were more frost resistant than their mature forms and the juvenile and adult forms of the homoblastic Pittosporum eugenioides showed no consistent differences in their frost resistance. Juvenile forms of Carpodetus serratus, Hoheria angustifolia, P1agianthus regius, and Pseudopanax crassifolius were less frost resistant than their mature counte∼ms. We conc1ude that juvenile foms are not inherently more frost resistant than their equivalent mature forms and note that populations of the same species from different environments readily acquire the frost resistance appropriate to their habitat.

Keywords:

• climate
• frost resistance
• heteroblasty
• juvenile
• mature
• Pseudopanax crassifolius
• Streblus heterophyllus
• Pittosporum eugenioides
• Sophora microphvllu
• Carpodetus serratus
• Hoheria angustifolia
• Plagianthus regius
• New Zealand

Notes

Author for correspondence. Email: [email protected]