Divergence in leaf and cambium phenologies among three temperate tree
species of different wood types with special reference to xylem
hydraulics
Abstract
Temperate tree species with non-porous, diffuse-porous and ring-porous
woods diverge substantially in the strategy of coping with
freezing-induced hydraulic dysfunction, which can be closely associated
with the timing of both leaf phenology and xylogenesis. Nevertheless, we
still know little about their potential differences in the intra-annual
process of xylogenesis as well as the association of this process with
leaf phenology. Here, we monitored leaf phenology and xylogenesis in a
non-porous ( Pinus), a diffuse-porous ( Populus), and a
ring-porous ( Ulmus) temperate tree species in a common garden.
The results showed clear divergences in leaf and cambium phenologies and
their chronological orders. The two angiosperm tree species exhibited
earlier bud burst and leaf unfolding than the conifer. The cambial
activity of the ring-porous species began earlier than the
diffuse-porous species, although the leaf phenology of the
diffuse-porous species was earlier. The conifer species showed the
latest leaf phenology but the initiation of cambium activity was as
early as the ring-porous species. The results revealed that leaf and
cambium phenologies are closely interconnected due to the coordination
between xylem water transport and leaf water demand. These findings
contribute to a better understanding of the divergent adaptive
strategies of temperate trees with different wood types.