Pollen can be transferred from one plant to another by insects. List two features of insect-pollinated flowers.
Important Questions on Sexual Reproduction in flowering Plants
Wind can also transfer pollen from plant to plant. Explain how the following characteristics help wind-pollinated plants.
A large amount of pollen: Because most of the pollen does not _____
Wind can also transfer pollen from plant to plant. Explain how the following characteristics help wind-pollinated plants.
Anthers hang outside the flower: so _____ directly into the wind.
The sentences below describe what happens in fertilisation in a plant. The sentences are in the wrong order. Write the numbers 1-4 next to the sentences to show the correct order in which they happen. The first has been done for you.
The nucleus inside a pollen grain and the nucleus in an ovule join up
A pollen grain lands on the stigma 1
A pollen tube grows down to the ovary
The ovary develops into a fruit and each ovule becomes a seed containing an embryo
Chetan and Devi are investigating how sugar affects the growth of pollen tubes.
Chetan's plan:
A. Put some pollen into a concentrated sugar solution.
B. Put some pollen into a dilute sugar solution.
C. After one hour, estimate which solution has more pollen tubes.
Devi's plan:
A. Get four beakers:
• three contain different concentrations of sugar solution: 5%, 10% and 15%
• one contains pure water.
B. Add the same amount of pollen to each of the different sugar solutions.
C. After one hour, count how many pollen tubes can be seen.
Explain two reasons why Devi's plan is better than Chetan's.
Chetan and Devi are investigating how sugar affects the growth of pollen tubes.
Chetan's plan:
A. Put some pollen into a concentrated sugar solution.
B. Put some pollen into a dilute sugar solution.
C. After one hour, estimate which solution has more pollen tubes.
Devi's plan:
A. Get four beakers:
• three contain different concentrations of sugar solution: 5%, 10% and 15%
• one contains pure water.
B. Add the same amount of pollen to each of the different sugar solutions.
C. After one hour, count how many pollen tubes can be seen.
Name a piece of apparatus that you might use to observe the growth of the pollen tubes.
The table shows Devi's results:
| Sugar concentration (%) | 5 | 10 | 15 |
| Number of pollen cells with tube growth | 25 | 35 | 45 |
Devi concludes that 'increasing the sugar concentration increases the number of pollen tubes that can be seen:
Do Devi's results support his conclusion? Explain your answer using evidence from the table.
