1a
4 marks
4 marks2,4-D is a synthetic plant auxin that is used as a weedkiller.
Researchers investigated the effectiveness of different treatments of 2,4-D on the control of the weed Conyza canadensis in fields of maize, Zea mays.
The results are shown in Table 1.
Table 1
treatment | time of treatment | mean dry mass of weeds / g per m2 | weed density / number of weeds per m2 | ||
Day 7 | Day 23 | Day 33 | |||
A | ✓ |
|
| 7.40 | 6.20 |
B |
| ✓ |
| 3.90 | 4.90 |
C |
|
| ✓ | 0.50 | 1.20 |
D | ✓ | ✓ |
| 0.66 | 1.90 |
E | ✓ |
| ✓ | 0.18 | 0.98 |
F |
| ✓ | ✓ | 0.07 | 0.29 |
G | ✓ | ✓ | ✓ | 0.08 | 0.51 |
Maize farmers that had been using treatment C were advised by the researchers to change to treatment F.
Discuss the advantages and disadvantages of changing to treatment F.
1b2 marks
2 marksAuxin causes the shoots of a plant to grow away from gravity.
State the name of this response.
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