Homework Sourse1 In the summer of 1998 after extrely hot dry weather the Ge
1) In the summer of 1998, after extrely hot, dry weather, the Georgia corn harvest was expected to be reduced by at least 25%. Using your knowledge of the dual functions of guard cells relative to water retention and gasexchange, explain the reduction in photosynthetic productivity.
2) Plant cells have cell walls and animal cells do not. How does this difference relate to differences in plant andanimal function?
3) Table 20.2 – Structure and Function of Plant Cells
| Cell Type | Structure | Function | Plant |
|---|---|---|---|
| Epidermis | |||
| Guard Cells | |||
| Parenchyma | |||
| Collenchyma | |||
| Sclerenchyma | |||
| Tracheids | |||
| Vessels | |||
| Sieve Tubes | |||
| Endodermis | |||
| Primary Meristems | |||
| Vascular Cambium | |||
| Pericycle | |||
| Periderm | |||
| Ray Parenchyma |
Solution
1). Plants draw water through roots, Cuticle is the outer covering o plants, which is a waxy substance and it prevents the entry of water to and from stem and leaves. Cuticle contains specialized pores called stomata, which allow the passage of o2 and co2 through it. The Stomata contain two guard cells, they swell and shrink when water moves into and out of them and this controls the loss of water from the leaf while allowing the passage of gases.
During summer, the guard cells remain closed for most of the time to avoid water loss at an expense of reduced gaseous exchange. Means, less carbon dioxide (CO2) is available for photosynthesis, which reduces the rate of photosynthesis in summer in corn plants.
