9.3: Growth in plants

Exercise 2: Read the relevant chapter in your textbook. Remember to make some notes as you read using the connect-extend-question routine.

A1: Micropropagation of plants using tissue from the shoot apex, nutrient agar gels and growth hormones.

A2: Use of micropropagation for rapid bulking up of new varieties, production of virus-free strains of existing varieties and propagation of orchids and other rare species.

Exercise 3: Create a powerpoint presentation about micropropagation of plants. Your presentation should cover the applications above. Please record your powerpoint presentation using screencasting software and submit on ManageBac. You may want to address the following questions:

• What is micropropagation?

• Why and when is it used?

• How is it carried out?

U1: Undifferentiated cells in the meristems of plants allow indeterminate growth.

U2: Mitosis and cell division in the shoot apex provide cells needed for extension of the stem and development of leaves.

Exercise 4: Use your notes from the pre-reading to create diagrams that explain understandings 1 & 2.

U3: Plant hormones control growth in the shoot apex.

U4: Plant shoots respond to the environment by tropisms.

U5: Auxin efflux pumps can set up concentration gradients of auxin in plant tissue.

U6: Auxin influences cell growth rates by changing the pattern of gene expression.

Exercise 5: Use your notes from the pre-reading to create diagrams that explain understandings 3-6.

Essential idea: Plants adapt their growth to environmental conditions.

NoS: Developments in scientific research follow improvements in analysis and deduction—improvements in analytical techniques allowing the detection of trace amounts of substances has led to advances in the understanding of plant hormones and their effect on gene expression. (1.8)

Guidance:

• Auxin is the only named hormone that is expected.