Changes In The Dry Weights Of Germinating Seeds

Question 1

What unit of measurement is used when weighing plant material?

Answer 1

Dry weight (mass)

Question 2

What is dry weight also called?

Answer 2

Mass

Question 3

What is dry weight?

Answer 3

This is the weight without water

Question 4

How is dry weight measured?

Answer 4

By placing the plant in an oven at 100 degrees Celsius until the weight remains constant

Question 5

How is accuracy ensured when measuring dry weight?

2

Answer 5

Normally about 20 seeds are used and the average weight (or mass) is calculated

This allows for the different sizes of the seeds

Question 6

How does the dry weight of a seed change over a period of twelve days?
(2)

Answer 6

Days 0-9 the mass of the seed falls due to respiration

Days 9+ the mass of the seed increases due to photosynthesis taking place in the newly formed leaves

Question 7

What causes the dry weight of the seed to fall between days 0 and 9?

Answer 7

Respiration

Question 8

What causes the dry weight of the seed to increase from days 9 and onwards?

Answer 8

Photosynthesis taking place in the newly formed leaves

Question 9

What suggests that food is passing from the cotyledon to the embryo?

Answer 9

The fact that the loss of weight of the cotyledon is matched by a rise in the eight of the embryo