|Age||≤22 years old||23–45 years old||>45 years old|
|Passed matriculation in biology||basic||expanded||Passed subject other then biology|
PLEASE RESPOND TO THE QUESTIONS STRICTLY IN ORDER OF APPEARANCE.
Are you acquainted with the term “plant movements”?
No, I have never heard of it
Yes, I have heard of it at an earlier stage of education
Yes, I learned about it through plant physiology class
How were you acquainted with the term “plant movements”? (You are able to choose more than one answer)
By performing an experiment*
Film or animation about plant tropism
Other (write an example)………………
* If you remember, please describe this experiment……………………………..
1. Q (Question): List the types of movements of plants known to you.
A (Answer): A full answer (The criteria for assessing the correctness of the answers contained in the questionnaire. The presented answers are model and ideal. Correct answers were those which were right substantially and included the answer to the posed question.) was one that contained the following elements: a. division of movements due to the mechanism of movement, i.e.: turgor movements, growth, and growth-turgor movements, and b. division of movements in terms of the cause of the movement (stimulus), namely: taxes, nastic movements, and tropisms.
2. Q: Are phototropism, photonasty, and phototaxis synonymous concepts? Justify.
A: Phototropism is a growth movement, the plant’s response to light, dependent on the direction of the stimulus; photonasty is the plant’s response to light, independent of the direction of the stimulus and its intensity; phototaxis is a locomotive movement caused by light, the direction of movement depends on the directional gradient of the stimulus.
3. Q: Define the concept tropisms.
A: Tropisms—these are a kind of growth movements caused by an external stimulus, whose direction of action depends on adapting the plant to the dynamic changes in the environment.
4. Q: Describe the stages of a shoot response to the directional effect of light (considering the place of the perception of the stimulus, the direction of the bend, and the role of hormones in the process).
A: A full answer was one that contained the following: the place of perception of the stimulus is the vertex/cone of growth, and reception of the stimulus is by the blue light receptor. The effect: as a result of unilateral illumination, electrical potential appears between the illuminated and shaded side of the shoot, where the illuminated side becomes electronegative, the change in the potential between the protoplasma and the external environment of the cell is a signal for the transport of auxins from the location of their synthesis (apex of the shoot) to the shaded side of the shoot. The accumulation of auxins on the shaded side of the shoot causes a loosening in the structures of the microfibrils of cell walls, with all the inherent consequences (acidic growth theory), which cause stronger expanding and elongating growth on that side of the shoot, and consequently directional bending toward the working stimulus.
5. Q: Describe the stages of a root response to the gravity (considering the place of the perception of the stimulus, the direction of the bend and the role of hormones in the process).
A: Places of perception of the stimulus is the root cap adjacent to the apex of growth, reception of the stimulus is through mechanoreceptors of the endoplasmic reticulum pressed by starch statoliths of amyloplasts, and efflux of calcium ion from cisternae of endoplasmic reticulum. The calcium signal is a signal for the transport of auxins from the place of their synthesis/apex of the shoot to the place in which the gravitropic reaction appears, to the elongation sphere of the root. In a root placed horizontally, a large accumulation of auxins occurs at its bottom side. This inhibits elongation growth, whereas a smaller concentration of auxins on the top side enables growth, and as a result, directional bending of the root toward the acting stimulus occurs.
6. Q: Underline the correct answers (you can select more than one correct answer).
The following react to a phototropic stimulus: A: a. leaf, b. shoot, c. root, d. I don’t know.
Q: The following react to gravitropic stimulus: A: a. leaf, b. shoot, c. root, d. I don’t know.
The full answer was: the following react to a phototropic stimulus: leaf, shoot, root; the following react to a gravitropic stimulus: shoot and root.
7. Q: Agar blocks were applied to one side of the shoot and root of a several-day-old seedling of a certain plant that contained the same concentration of auxins within the physiological range (the figure shows the location of the blocks), and then the seedlings were placed in the dark. The three consecutive drawings show the potential effect observed after 24 h, assuming a typical course of the experiment.
Mark the drawing that correctly demonstrates the direction of the bending of the shoot and root and for a justification of the choice, auxins from agar blocks accelerate: 1) elongating the cells of the shoot to which the block is attached, or 2) inhibition of elongation growth of the cells of the root to which the block is attached.
8. Q: Trees growing in a forest are taller, though less branched than the trees of the same species growing in a field (free space, e.g., a meadow). Explain the observed phenomenon in light of your knowledge of the movements of plants.
A: The full answer was considered to be that in a meadow, light determines phototropic reaction both of the main shoot and side shoots. In a thick forest, above all, the main shoot takes in the light stimulus (other parts of the plant can be shaded) indicating growth and movement reactions in its direction.
9. Q: Provide the physiological importance of gravitropism.
A: In the responses, above all, information was required stating that the gravitational field is essential for spatial orientation of plants and that this reaction is an important component of the physiological processes, e.g., germination.
Thank you very much for your attention