Unit 4-Final Exam Study Guide

Question 1

What is etoliation?

Answer 1

exaggerated growth of the stem caused by low light levels.

Question 2

Epinasty

Answer 2

It’s the downward bending of petioles, wilting, and death due to oxygen deficiency. Epinasty occurs when soil oxygen levels that are less than 10% - 12%.

Question 3

Identify at what colors of wavelengths a chlorophyll molecule absorbs lights.

Answer 3

390 – 750 nm, Blue, yellow, orange, red

Question 4

Short day plants

Answer 4

flower only when dark period is greater than critical length

Question 5

Long day plants

Answer 5

flower only when dark period is shorter than critical length

Question 6

What does ozone do to plants?

Answer 6

causes the stomates to close, thereby limiting gas exchange. It also causes stippling and bronzing of the leaves.

Question 7

What does sulfur dioxide do to plants?

Answer 7

causes plant cells to shrink and collapse, interveinal chlorosis on broad-leaf plants, and brown tips on conifers.

Question 8

Saturation

Answer 8

soil pores are full of water and gravitational water drains freely due to gravity

Question 9

Field capacity

Answer 9

After all gravitational water has drained out of the large pore spaces leaving only the small pore spaces containing water, the soil is at field moisture capacity.

Question 10

Wilting point

Answer 10

occurs when no more water is available for the plant due to evapotranspiration.

Question 11

How can the color of plastic or mulch affect soil temperature?

Answer 11

Light-colored plastic or mulch reflects sunlight and lowers soil temperature; dark-colored plastic or mulch absorbs light and warms the soil.

Question 12

Describe the symptoms of excess salt levels.

Answer 12

wilting, reduced plant growth, and, in some cases, the appearance of a green to bluish-green color.