(1) The plants selected in the experiment have been subjected to photosynthesis before, and they are rich in organic matter. If it is not removed, the experimental results will be affected. Therefore, before the experiment, plants should be kept in the dark for a day and night, so that the starch stored in the morning glory branches can be transported away by respiration.
(2) Students treated this morning glory with illumination, leaf decoloration, washing and dropping iodine solution.
A, the part of green leaves not covered by aluminum film is subjected to photosynthesis, and starch is generated. Dropping iodine solution will turn blue, indicating that light is the condition of plant photosynthesis, and starch is the product of plant photosynthesis.
B, the part of the green leaves covered by aluminum film has no light, and the plants have no photosynthesis and cannot make starch, so the iodine drops will not turn blue;
Because the carbon dioxide in the bottle is absorbed by sodium hydroxide, the leaves of C and B can't carry out photosynthesis, can't make starch, and won't turn blue when dropping iodine solution, which shows that carbon dioxide is the raw material of plant photosynthesis.
The green leaves of D and C leaves have chloroplasts, which can be used for photosynthesis and starch production. Dropping iodine solution will turn blue, indicating that chloroplast is the place of plant photosynthesis.
There is no chloroplast in the white spot of E.C. leaves, so photosynthesis and starch production cannot be carried out, and the iodine solution will not turn blue when dripped. Therefore, the external factors of plant photosynthesis are light and carbon dioxide.
F, Ye Ding has the conditions of photosynthesis, can carry out photosynthesis, produce starch, dripping iodine solution will turn blue.
(3) There are three groups of control experiments in this experiment, namely, the shading part and shading part of nail leaves, the silver edge and green part of C leaves, and the presence or absence of ethyl butyl carbon dioxide. The comparison of C leaves shows that chloroplast is the place of photosynthesis.
So the answer is: (1) waterproof.
(2)ADF
(3) carbon dioxide; Photosynthesis requires light and chloroplasts.