Tropic movement of plants

Tropic movement of plants

[principle]
When plants are subject to certain stimuli, if the intensity of the stimulus from all directions is not uniform, they will produce movement. The phototropism and geotropism of plants are the tropism that is easy to be observed. The direction of movement is related to the direction of stimulation. Movement towards the direction of stimulation is positive, and movement against the direction of stimulation is negative.
[Instruments and drugs]
Thermostat, tin foil, light box, dark room, petri dish, light
[Steps]
1. Phototropism
Take wheat seeds and sterilize them, sow them in wet sand in petri dishes, and cultivate them in a dark room. When the sprouts are as long as 1 paw and 2cm, and the leaves have not yet penetrated the sprouts, put foil sleeves on the sprouts of several seedlings. (Take a 1cm square of tin foil, wrap it on a matchstick and rub it by hand), then place the petri dish in a light box with a hole, and a light is added to the hole to let the light enter from the hole and shine on the seedlings. An incubator can also be used instead. Put the petri dish in the incubator, close the glass door, leave the outer box door open, add a light source outside the door, or face the door to the window and use natural light. After one day, observe whether the sprouts with and without tin foil have phototropic bending?
2. Terrestrial movement
Take the soybean seeds and sown them in the wet sand of the culture tank after disinfection. When the seedlings are 2 3 cm long, choose the radicles and hypocotyls that are not bent as the test materials. Choose different lengths and place them flat. Cover the wet sand in a culture tank with a thin layer of sand and keep it moist. Take out the seedlings after 1 paw and 2 days, paying attention to the direction of the seedlings’ bending.

Petri Dish 90 Mm,Sterile 90x 15 Petri Dish,Petri Dish Sterile