Cell Transport in Plants

Cell Transport in Plants This activity can be found in your digital course. How does high salt concentrations in soil affect plant growth? Record Data and Observations Part 1 1. Why do some croplands suffer from excessive soil salinity? Croplands can suffer from excessive soil salinity when irrigation water contains dissolved salts. As the water evaporates, the salts remain and accumulate in the soil over time. Poor drainage and dry climates make this problem worse because the salts cannot be washed away naturally. Part 2 2. From the Notebook Complete the following table summarizing the effects of salinity on plant growth or paste a copy of the completed table from the notebook in the virtual activity. Electrical Conductivity of the Solution (dS/m) 0 4 8 12 Whole Plant Mass (g) 20 16 10 5 Number of Pods Mass of Beans (g) 12 15 11 9 6 2 4 1 3. Adding salt to water increases the ability of the saltwater solution to conduct electricity. dS/m is a measure of electrical conductivity. Does a 2 dS/m saltwater solution have more or less salt dissolved than a 10 dS/m saltwater solution? A 2 dS/m solution has less saltdissolved than a 10 dS/m solution. Higher electrical conductivity means more ions (salts) are present in the solution. Part 3 4. Summarize the differences between how the salt-sensitive plant cell and the salt-resistant plant cell behave in the 10% salt solution. Salt-sensitive plant cell:Loses water due to osmosis, causing the cell membrane to pull away from the cell wall (plasmolysis). The cell shrinks and can’t function properly. Salt-resistant plant cell:Maintains water balance by storing ions in vacuoles or producing solutes to counteract the salty environment, preventing severe water loss and plasmolysis. Cell Transport in Plants • Copyright © by Savvas Learning Company LLC. All Rights Reserved. Analyze and Conclude 5. From the Notebook One of the symptoms of high salt concentrations in soil is plants that appear dehydrated even when they are receiving adequate water. How can you explain this phenomena using what you observed in the root cells of the salt-sensitive plants? High salt concentrations cause water to move out of plant root cells into the soil (osmosis). Even though the soil has water, the high salt makes it unavailable to the plant, so the cells shrink and the plant looks wilted or dehydrated. 6. Apply Concepts Suppose a farmer has contacted you for advice on how to avoid and manage problems related to soil salinity. What advice would you provide to the farmer? Use freshwater or low-salt irrigation water. Improve drainageso salts can be washed away. Rotate cropswith salt-tolerant species. Leach saltsby occasionally flushing soil with extra freshwater. Add organic matterto improve soil structure and water retention. 7. Evaluate a Solution Most fields that are irrigated year after year will eventually build up salt in the soil as water regularly evaporates and leaves some salt behind. One way farmers minimize this salt build up is to flood their fields every few years before planting. This flood water leaches out the salt in the soil. What advantages and disadvantages do you see in this approach? Advantages Disadvantages Removes built-up salts from the soil (leaching effect) Wastes large amounts of water Improves soil conditions for crop growth Can cause soil erosion or nutrient loss Helps restore soil fertility May be expensive or impractical in dry areas Cell Transport in Plants • Copyright © by Savvas Learning Company LLC. All Rights Reserved.