title: [Response of structural plasticity of Tilia amurensis sapling crowns to different light conditions].
abstract: This paper studied the crown structure of Tilia amurensis saplings, e.g. the shape of crown, and the distribution of branch and leaf. It is shown that the crown structure of the saplings was modified plastically in response to different light conditions. The differentiation of the first order branches was promoted by strong radiation, due to the bole growth being inhibited under high light condition, whereas the bifurcation density of the first order branches whose growth was inhibited by shading was promoted in under-canopy environment. The quantitative leaf densities of the saplings obviously decreased with the decrease of light level, while their leaves tented to distribute in upper crown. The interception of the saplings was enhanced by the distribution pattern of branches and leaves in crown. Under adequate shade condition, the saplings had the strategy of shade-avoidance of pioneer species in upward growth, and had the strategy of light-forage of moderate shade tolerance in horizontal branch growth. The saplings expressed typically shade-tolerant under weak light condition. Such a change of crown structure was an advantageous adaptation for enhancing light interception.
authors.affiliation: Forest Resources and Environment Faculty, Northeast Forestry University, Harbin 150040.
authors.forename: C
authors.initials: C
authors.lastname: Xu
mesh_terms: D000704:Analysis of Variance; D004548:Elasticity; D008027:Light; D019660:Malvaceae / Q000502:physiology*