Heteroblasty, crowding and shade avoidance
Acacia implexa shows leaf heteroblasty, developing compound, transitional and modified leaves (phyllodes), and previous experiments have shown that shade can alter the ontogeny. Forster et al. further demonstrate that high seedling density can also alter heteroblasty, with a higher number of nodes expressing compound leaves as the result of crowding. Compound leaves have a relatively larger photosynthetic capture area and less biomass per unit area, so a delay in the shift to transitional leaves has ecological significance.
