Plant Growth and Development quiz

Which of the following is a natural auxin?

Bakanae disease of rice is caused by:

Cytokinins were discovered as kinetin from autoclaved:

Which gaseous hormone promotes fruit ripening?

Which hormone causes closure of stomata during water stress?

2,4-D is used as a:

Bolting in cabbage is caused by:

The hormone that delays leaf senescence is:

In the sigmoid growth curve, the phase of rapid growth is the:

Who isolated auxin from the tips of oat coleoptiles?

What are the three phases of growth? (2 marks)

Distinguish between absolute and relative growth rate. (2 marks)

Why is oxygen essential for growth? (2 marks)

How do auxins promote parthenocarpy? (2 marks)

What is the role of gibberellins in malting? (2 marks)

How do cytokinins overcome apical dominance? (2 marks)

What is the role of ethylene in deep-water rice? (2 marks)

What is ethephon? Give one use. (2 marks)

How does ABA act as an antagonist to gibberellins? (2 marks)

What is meant by differentiation in plants? (2 marks)

A plant has a mass of 10 g and grows geometrically according to W1 = W0 x e^(rt). If e^(rt) = 3 after 5 days, calculate W1. (3 marks)

A bean seedling grows from 4 cm to 16 cm in 6 days, linearly. Calculate the growth rate per day and its height after 10 days. (3 marks)

A watermelon cell can increase in size up to 3,50,000 times. If the initial volume is 2 x 10^-6 cubic mm, calculate its final volume. (3 marks)

A population of 500 cells doubles every 3 hours. How many cells are there after 15 hours? (3 marks)

A leaf area increases from 20 to 26 square cm in a week. Calculate the relative growth rate as a percentage. (3 marks)

Read the passage and answer the questions. Charles Darwin and his son Francis Darwin observed that the coleoptiles of canary grass responded to unilateral illumination by growing towards the light source. After a series of experiments, it was concluded that the tip of the coleoptile was the site of the transmittable influence that caused the bending of the entire coleoptile. (i) Name the hormone responsible. (ii) Who isolated it? (iii) Why does the coleoptile bend towards light? (5 marks)

Read the passage and answer the questions. E. Kurosawa reported the appearance of symptoms of a disease in uninfected rice seedlings when they were treated with sterile filtrates of a fungus. The infected rice seedlings grew abnormally tall and were weak. (i) Name the disease and the fungus. (ii) Which hormone was discovered from this? (iii) Give two uses of this hormone in agriculture. (5 marks)

Read the passage and answer the questions. A gardener wanted to make a hedge of plants grow thicker. He cut off the tips of the shoots. A few weeks later, many side branches had developed. (i) What phenomenon was removed by cutting? (ii) Which hormone causes this phenomenon? (iii) Which hormone could be applied to get the same result without cutting? (5 marks)

Read the passage and answer the questions. Ethylene is a simple gaseous PGR. It is synthesised in large amounts by tissues undergoing senescence and ripening fruits. It promotes senescence and abscission of plant organs, especially of leaves and flowers. It is highly effective in fruit ripening and enhances the respiration rate during ripening. (i) What is the climacteric rise? (ii) Name a compound used as a source of ethylene. (iii) Give two other effects of ethylene. (5 marks)

Read the passage and answer the questions. A farmer noticed that her plants growing in a dry season had closed stomata and their seeds stayed dormant. She learnt that a plant hormone helped them survive. (i) Name the hormone. (ii) How does it help during drought? (iii) Why is it important for seed dormancy? (5 marks)

Explain the concept of growth in plants. Describe the phases of growth and the measurement of growth with examples. (6 marks)

Explain arithmetic and geometric growth with equations and graphs. Describe the sigmoid growth curve. (6 marks)

Describe the discovery and physiological effects of auxins and gibberellins. (6 marks)

Describe the discovery and physiological effects of cytokinins, ethylene and abscisic acid. (6 marks)

Explain differentiation, dedifferentiation and redifferentiation. Discuss the role of plasticity and growth regulators in development. (6 marks)