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经过我们多次实验,认为塑料袋完全可以代替玻璃罩、三角瓶等仪器来做“叶的功能”一节教学中的几个实验。 (一) 光合作用需要二氧化碳的实验每组取两盆“饥饿”二天的天竹葵,在甲乙盆内分别放一杯清水和一杯氢氧化钠溶液。取两个体积大于盆栽植物的不漏气、透明度好的塑料袋,分别套在二盆实验材料上,并把袋口扎紧在花盆上。在袋口与花盆的交接处涂凡士林密封。放在阳光下照射几小时后,取叶片脱去叶绿素、滴上碘酒,即可看到变蓝和对照的结果。 (二) 蒸腾作用散失水分的实验
After our many experiments, that plastic bags can replace the glass cover, flask and other equipment to do “leaf function” teaching a few experiments. (A) photosynthesis experiments that require carbon dioxide Each group to take two basins “hungry” two days of bamboo, respectively, in a basin cup A cup of water and a cup of sodium hydroxide solution. Take two airtight, transparent plastic bags larger than the potted plants, set in the second basin of experimental materials, and tied the bag to the flowerpot. Vaseline sealed at the junction of the pocket and the flowerpot. A few hours after exposure to sunlight, take the leaves off chlorophyll, iodine drops, you can see the results of the blue and the control. (B) the experiment of water loss by transpiration