The following experiment shows the effect of auxins on growth of young shoot tips.
Auxins are produced at the tip of shoots.
Auxins are most effective at concentrations of 1 mg/l.
Question 2
Auxin solutions may induce elongation of shoot tips.
A high concentration of auxins inhibits elongation of shoots.
The diagram below shows the position of the lateral shoot and the apical bud in a plant.
Question 3
graph X represents the group that had their apical buds removed.
roots produce a substance that stimulates lateral shoot growth.
graph Y represents the group that had their buds removed.
lateral shoots produce a substance that stimulates apical bud growth.
The conclusion drawn from the above results would not be valid if ...
Question 4
apical buds were not removed from all 40 plants.
a large sample was used.
the plants used were identical to each other.
the measurement of growth of the lateral buds was done in millimetres instead of centimetres.
The plant hormone abscisic acid ...
Question 5
inhibits cell division in roots and stems.
inhibits cell division in stems only.
has no effect on the opening and closing of stomata.
plays no role in making buds dormant in winter.
Which one of the following statements about plant hormones is incorrect?
Question 6
Plant hormones are produced in one area and bring about a response in another area of a plant.
Tropic movements in plants are caused by auxin only.
Low auxin concentration in root tissue promotes cell division and cell elongation.
High auxin concentration in shoot tissue promotes cell division and cell elongation.
Which plant hormone promotes seed dormancy?
Question 7
Abscisic acid.
Growth hormone.
Auxin.
Gibberellin.
The plant hormone that retards growth is ...
Question 8
abscisic acid.
auxin.
gibberellius.
indole Acetic Acid (IAA).
A unilateral light source will cause ...
Question 9
auxin to move towards the darker side of the stem.
a stem to grow away from the light.
auxin to move toward the light.
all plants hormones to move away from the light.
Growth movement of part of a plant in response to light as an external stimulus is known as
Question 10
phototropism
tropism
hydrotropism
geotropism
Thirty straight root tips, each 10 mm long, were identified from oat seedlings. These were divided into six groups of 5 each. Each group was incubated in darkness at 25°C. One group was placed in water and each of the other five groups placed in varying concentrations of auxins.
After 24 hours the pieces were removed. The average length of each group is shown alongside:
Which one of the following conclusions cannnot be drawn from the experiment?
A learner investigated the growth of lateral shoots in bean plants. Two groups of 20 plants were used. One group had their apical buds removed and the other group was left unchanged. Every two days the total length of the lateral shoots was measured and the average lateral shoot length calculated for each group.
Graph showing results
From the data you may reasonably conclude that ...
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You must scroll to the top and examine your incorrect choices, with the view to improving your understanding of this topic. Refer to the Study Guide if necessary.
