For the past few weeks my group and I have been working on growng rye grass! The experiment consisted of putting rye grass seeds in a compost-sand mix and watering it every week with either warm water, cold water, salt water and sugar water, then drawing the results out on a poster. We expected the sugar-watered seeds to grow better than normal, the salt-watered seeds to not grow at all or to ever-so-slowly grow, the cold water to grow normally, and the warm water to absolutely kill the seeds and all possible growth. 

       At the end of the two week experiment, the results were something we never expected! The salt water AND sugar water had both caused no growth, whereas the plants watered with warm and cold water had plenty of growth! My group and I figured out that the salt water had destroyed the plants because when salt dissolves in water, it separates into sodium and bicarbonate. When the salt water was given to the plant, the sodium took away the nutrients in the soil, while the bicarbonate messed with the plant's ability to photosynthesize and absorb nutrients from the soil. We had also figured out why sugar water negatively affected the rye grass! In a normal plant-soil relationship, the osmotic pressure of the soil is higher than the plant's inner osmotic pressure, so when water is absorbed into the soil, the plant draws it up. However, sugar lowers the osmotic potential of the soil, so when sugar is regularly put into the soil, the osmotic pressure is lowered significantly to the point where the soil's pressure is so low that no matter how much you water it, the plant will still not be able to draw water from the soil, no matter how much you water it!