元宝枫栓皮栎苗木水力结构特征的对比研究

元宝枫 (Acertruncatum)是散孔材树种 ,栓皮栎 (Quercusvariabilis)是环孔材树种 ,为了解二者在水分运输和耐旱机理方面的特点 ,该文应用水力结构的基本理论 ,在正常水分条件下 ,用改良的冲洗法测定 4年生元宝枫、栓皮栎苗木各部位的水力结构参数 .实验和模拟的结果表明 ,元宝枫和栓皮栎苗木都存在限速区 ;在非限速区 ,二者各部分木质部的导水率、比导率、叶比导率和胡伯尔值都随功能木质部直径的增加而增大 ,但表现出不同的变化趋势 ,这些变化较好地说明元宝枫和栓皮栎苗木耐旱的生态策略 .在功能木质部直径相同的情况下 ,栓皮栎苗木的各水力结构参数均较元宝枫苗木大 .

Comparative study on hydraulic architecture characteristics of Acer truncatum and Quercus variabilis seedlings.

The xylem of Acer truncatum is diffuse porous, and that of Quercus variabilis is ring porous. In the paper,the basic theory of hydraulic architecture is used,and the hydraulic architecture parameters of Acer truncatum and Quercus variabilis seedlings(4 years old) are measured by improved flushing method under the condition of normal water supply in order to understand the water transportation and drought tolerance mechanism of them. The results of experiment and simulation show that both Acer truncatum and Quercus variabilis seedlings have constriction areas. In non constriction area, the hydraulic conductivity, specific conductivity, leaf specific conductivity and Huber value of Acer truncatum and Quercus variabilis seedlings all escalate with the increase of functional xylem. But the increases manifest different variation trends, which can better explain the drought tolerance ecology strategy of Acer truncatum and Quercus variabilis seedlings. The hydraulic architecture parameters of Acer truncatum seedlings are all smaller than those of Quercus variabilis ones.