|
|
Evergreen trees lose their leaves _____. (Activity 39A)
|
| in the spring |
| in the summer |
| steadily all year |
| every fall |
| every winter |
|
|
|
Click on the diagram to start the animation.
The abscission layer is indicated by the letter _____. (Activity 39A)
|
| A |
| B |
| C |
| D |
| E |
|
|
|
The breakdown of chlorophyll reveals the _____ pigments of a leaf. (Activity 39A)
|
| carotenoid |
| xanthophylls |
| anthocyanin |
| melanin |
| phycoerythrin |
|
|
|
The
formation of the abscission layer cuts off transport of substances to and
from the leaf. As the concentration of sugar trapped within a leaf increases,
_____ pigments are produced. (Activity 39A)
|
| carotenoid |
| xanthophyll |
| anthocyanin |
| melanin |
| phycoerythrin |
|
|
|
The protective layer that forms between the abscission layer and the stem consists of _____. (Activity 39A)
|
| a layer of green palisade cells |
| weak, colorless, thin-walled cells |
| mycorrhizae |
| irregularly shaped cells with very thick, lignified secondary walls |
| densely colored cells filled with a waxy layer |
|
|
|
After leaf abscission, growth will resume from the _____. (Activity 39A)
|
| petiole |
| protective layer |
| palisade layer |
| axillary bud |
| abscission layer |
|
|
|
_____ trees lose their leaves in preparation for winter. (Activity 39A)
|
| Fir |
| Spruce |
| Deciduous |
| Conifer |
| Pine |
|
|
|
For a short-day plant, the _____ is critical in determining if flowering will occur. (Activity 39B)
|
| maximum number of hours of light |
| minimum number of hours of darkness |
| minimum number of hour of light |
| maximum number of hours of darkness |
| None of these is correct, since short-day plants are also known as day-neutral plants. |
|
|
|
For a long-day plant, the _____ is critical in determining if flowering will occur. (Activity 39B)
|
| maximum number of hours of light |
| minimum number of hours of darkness |
| minimum number of hours of light |
| maximum number of hours of darkness |
| None of these is correct, since short-day plants are also known as day-neutral plants. |
|
|
|
Day-neutral plants flower regardless of _____. (Activity 39B)
|
| night length |
| day length |
| photoperiod |
| day length or night length |
| day length, night length, or photoperiod |
|
|
|
Which of these would inhibit flowering in a short-day plant with a critical night length of 12 hours? (Activity 39B)
|
| 12
hours of light, 6 hours of dark, a flash of red light, a flash of far-red
light, a flash of red light, a flash of far-red light, 6 hours of dark |
| 12 hours of light, 6 hours of dark, a flash of red light, a flash of far-red light, 6 hours of dark |
| 12 hours of light followed by 12 hours of dark |
| 12 hours of light, 6 hours of dark, a flash of red light, 6 hours of dark |
| All of these regimens would inhibit flowering in a short-day plant with a critical night length of 12 hours. |
|
|
|
Which of these would stimulate flowering in a long-day plant with a critical night length of 12 hours? (Activity 39B)
|
| 12
hours of light, 6 hours of dark, a flash of red light, a flash of far-red
light, a flash of red light, a flash of far-red light, 6 hours of dark |
| 12 hours of light, 6 hours of dark, a flash of red light, a flash of far-red light, 6 hours of dark |
| 12 hours of light followed by 12 hours of dark |
| 12 hours of light, 6 hours of dark, a flash of red light, 6 hours of dark |
| 8 hours of light and 16 hours of dark |
