The Chapter 31 and 32 homework is due on April 7 at 11:59 pm. (Chapter 32 only includes pages ) The Chapter 31 and 32 Test will be on April 8 th.

Chapter 31 Auxin

You Must Know The role of auxins in plants. (This is the only plant hormone you will be expected to remember.) How phototropism use changes in the environment to modify plant growth and behavior.

Cell 1 Cell 2 Basal end of cell 25  m Auxin Light Cell elongation

Figure 31.5a CELL WALL Cell wall-loosening enzymes cleave cross-linking polysaccharides. CYTOPLASM HH Plasma membrane ATP Acidity increases. Low pH activates expansins. Proton pump activity increases. 12 HH HH HH HH HH HH HH HH 34

Figure 31.5b Plasma membrane Cell wall H2OH2O Vacuole Sliding cellulose microfibrils allow cell to elongate. 5

Auxin also alters gene expression and stimulates a sustained growth response