Elaeocarpus hookerianus Raoul, a canopy tree native to New Zealand, has a divaricating juvenile stage. The juvenile produces short shoots on both vertical and horizontal axes in the spring ; long shoots are formed and expand most in summer months. Axes have regions of long internodes interspersed with regions of short internodes. Long internodes are associated with production of sinuate, linear-lanceolate leaves, the outgrowth of many lateral branches, and a wide angle of divergence between terminal and lateral axes. Regions with short internodes bear smaller, obovate leaves, and lateral outgrowth is suppressed. Periodicity in internode length is synchronous for first-and second-order horizontal axes at comparable distances along a branch. Vertical axes elongate more extensively, bear more linear lanceolate leaves, and branch more prolifically than horizontal axes. Topological growth, as determined by monthly estimates of mean order and of partition asymmetry, is similar for vertical and horizontal axes ; both become more symmetrical towards the end of the season. Most leaves fall, and growth halts over winter months. The characteristic habit of juvenile E. hookerianus results from weak apical control of lateral shoot outgrowth, and periodic growth that provides for efficiency in light capture and expenditure for structural support. Vertical axes are considered to ' explore ' the environment peripheral to the plant's canopy, whereas horizontal axes ' exploit ' the canopy volume already captured.
Summary. While many woody plant cuttings respond to
propagation conditions in similar ways, results presented here indicate that
some responses are species specific. Propagation of
Boronia megastigma and
Hypocalymma angustifolium cuttings was successful except
when cuttings were struck without auxin treatment in a pinebark-based
propagation medium. More stem H. angustifolium cuttings
(100%) produced roots than terminal (shoot tip) cuttings
(45.2%). Benzyladenine and gibberellic acid treatment of stock plants
decreased endogenous starch concentration and propagation success of both
species. Boronia megastigma cuttings propagated poorly
when taken in winter when flowers were developing on stock plants. Conversely,
adventitious rooting of H. angustifolium had greatest
success when cuttings were taken in winter during flower development. Seasonal
variation in propagation success may be mediated through changes in the
endogenous plant growth regulator or carbohydrate concentrations.
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