(University of Hawaii Press, 1980-04) Friend, Douglas J.
Seedlings of Metrosideros were capable of net accumulation of
dry matter at photon flux densities as low as 13 umol m-2 s-1 PAR (about
0.6 percent sunlight), when grown under a 12-hour day1ength at 20° or 25°C
for over 4 months. Seedlings became adapted to shade at low levels of PAR
by an increased leafiness of the plant (expressed as the leaf area ratio). This
increased leafiness was brought about by a marked reduction in leaf thickness
rather than by an increase in the proportion of assimilates distributed to
leaves.