Abstract:

In the same or semblable planting sites, in the seasons of summer and autumn, the parameters of hydraulic architecture of four young Pinus tabulaeformis were measured in improved flushing method. The parameters were hydraulic conductivity (K_h, gm·Mpa^-1min^-1, the weight of oxalic acid solution through the xylem per minute and per pressure gradient),leaf specific conductivity(LSC, gm·Mpa^-1min^-1g^-1, hydraulic conductivity per dry weight of supplied leaves),specific conductivity(K_s, gm·Mpa^-1min^-1cm^-2, hydraulic conductivity per transverse sapwood area),and Huber value(HV, cm²·g^-1, transverse sapwood area per dry weight of supplied leaves). The study indicated hydraulic conductivity was influenced not only by the stem diameter, but also by the location of stem.The hydraulic conductivity of restriction area (namely in the base of the fork) was evidently lower than that of non-restriction area. Meanwhile, every parameter of hydraulic architecture was influenced in a way by the relative ramification rate, crown layer and ramification direction. To some extent, these characters expounded the biological trait of Pinus tabulaeformis, and determined its ecology strategy of drought resistance.

Key words: Pinus tabulaeformis, Hydraulic conductivity, Leaf specific conductivity, Specific conductivity, Huber values, Relative ramification rate, Ecology strategy