Bio Ap Plant

The Effects of Salinity on Plants



Background:

We know that salinity can affect the growth of plants. When the salt in   the solution and the plant's roots is made equal, plants cannot use osmosis to transfer nutrients. From Science 10, we already know that plants move water down the concentration gradient when dealing with low and high concentrations of salt. However when they absorb the large amounts of sodium and chloride, that’s when the adverse effects start showing on the plant. Also when the surrounding solution is hypertonic to the roots of the plant,turgor pressure will be directly affected and photosynthesis will occur less often due to the stomata being closed. We must find out why sodium chloride is dangerous to plants. We have found most of our information on science websites and in the Campbell Reece Biology AP textbook.

Objective/ Problem:

In our experiment we were trying to understand the effects of salinity on the growth and health of a plant. The question we were asking is “ How plant growth is affected by salinity levels”, and we were also trying to determine the effects that salt has on the plants ability to take in water.

Hypothesis:

We predict that when salt is added to the water solution in a large enough concentration, plant growth will be stunted since the water potential of the surrounding solution would be lower than that of the potential within the plant and would thus prevent diffusion from occurring and would decrease the plants water intake. We predict that as the salt concentration increases the plants will take in less and less water and , the plants themselves will become shorter.

Materials:
Transparent plastic pot (3)             Ruler
Fertilizer spikes (3)                       Thermometer
Water                                         Plants seeds (3)
Salt

Experimental design: All of our plants were placed in the same room with the same amount of light, nutrients and water. We put our plants in a...