由于学生已经练习过并巳初步掌握植物细胞有丝分裂的装片制作和观察方法,加上荠菜胚发育切片的价格也较高,模型又缺乏,而荠菜种子形成过程的实验材料的采集和保存又简单方便,因些,根据我校多年的实验情况,建议有条件的学校可以把“观察荠菜种子形成过程的切片”演示实验改为《荠菜种子形成过程的装片制作和观察》的分组实验.当 Because the students have practiced and have mastered the production and observation of the plant cell mitosis, the price of embryo-developing slices of shepherd’s purse is also high, and the model is lacking again, and the collection and preservation of the experimental materials of the shepherd’s-pursee seed formation process is simple Convenient, because of some, according to our school for many years of experimental conditions, it is recommended that schools can be conditional “observation Shepherd’s purse seed formation process of slicing ” demonstration experiment was changed to “shepherd’s purse seed formation process of loading production and observation” grouping experiment .when