初中生物(人教版)第一册(上)第六章第三节“茎的输导作用”中编排了“水分和无机盐通过导管向上运输”的演示实验,我在教学中将这个演示实验改为一组对比实验,效果很好。具体做法如下:剪取3段粗细相似的带有3～4片复叶的月季枝条分别作以下处理:甲枝条剥去树皮,保留木质部和髓; Junior high school biology (PEP) Volume I (on) Chapter VI, Section III, “the role of the stem” in the arrangement of the "moisture and inorganic salts up through the catheter transport experiments, I will teach this Demonstration experiment into a comparative experiment, the effect is very good. Specific practices are as follows: Cut three sections of similar thickness with three to four leaves of the rose branches were treated as follows: A branch stripped of bark, retain the xylem and pulp;