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1.一种实验材料做4个实验——巧用洋葱在实验教学中,我们用洋葱连续完成高中《生物》的4个必做实验,效果较好。具体做法如下:买回的洋葱鳞茎埋在水槽的砂里进行“栽培”,注意经常浇水和晒太阳。首先,当洋葱根长到1～2cm时,切取根尖做实验一——观察植物细胞的有丝分裂。其次,当学完“水分代谢”后,取洋葱鳞茎的表皮做实验二——观察植物细胞的质壁分离和复原。第三,当洋葱的根长到5cm左右时,切取根做实验三——观察根对矿
1. An experimental material to do four experiments - clever use of onion in the experimental teaching, we use onion to complete high school “biology” of the four must be done experiment, the effect is better. Specific practices are as follows: bought the bulb of onion buried in the sink in the sand for “cultivation”, pay attention to regular watering and sunbathing. First of all, when the onion root length to 1 ~ 2cm, root tips were cut for experiment 1 - observed plant cell mitosis. Second, after studying “Water Metabolism”, take the epidermis of the onion bulb for Experiment 2 - observe the separation and recovery of the plasmalemma of plant cells. Third, when the onion root length to about 5cm, cut the root to do the experiment three - observe the root of the mine