Introduction
In the environment, plants are critically affected by the composition of soil, as they acquire all nutrients from it. A nutrient must be soluble and must remain soluble long enough in order to travel into the roots of the plant (Kissel and Miller, 2008). Soil PH directly affects the life and growth of a plant, since it affects the availability of the nutrients needed for plant life. Most nutrients are in their most available state within a PH of 6.0 – 6.5 (Kissel and Miller, 2008). To germinate, seeds need favourable external conditions as well. In this lab the effect of acidic conditions on seed germination using lettuce seeds as the model has been observed. These properties were investigated using acidic solutions with various PH values. However, Lettuce seeds germinate best in soil with a PH of around 6.0 (Derek J. Bewley and David W. Fountain). Thus, the purpose of this study was to investigate seed germination for lettuce seeds under acidic conditions ranging from PH 4 to PH7 with a focus on acidity below PH6. The rate of germination was expected to decrease as the PH drops.
Methods & Materials
Lettuce seeds were placed in four culture tubes and allowed to germinate over the period of one week. The culture tubes each contained 8 ml of agar/test solution, along with 4 ml of acid and enclosed, five replicates (n=5) of lettuce seed, evenly dispersed. The acids that were used include: Sodium Acetate (ph4), Sodium Acetate (ph5), Sodium Phosphate (PH6) and Sodium Phosphate (PH7). Each acid was confined to its own culture tube. Room temperature and sunlight were kept constant in the room. The control group was lettuce seeds in PH 6 solution. The experimental group was lettuce seeds in PH 4, 5, and 7 solutions. Stem and root growth of the plant were measured in centimetres with the aid of a ruler.
A ttest was conducted using the computer program Sigma Plot to analyze the data