The Effect of Various pH Levels on the Root Growth of Arabidopsis thaliana Seedlings

Abstract

The detrimental effects of acid rain on plant growth are an environmental concern. We examined whether the pH of water affects the amount of root growth in Arabidopsis thaliana seedlings. We planted 192 A. thaliana seeds in Petri dishes and watered them at treatment levels of pH of 4.00, 5.50, 8.50, and a control at pH 7.13. We measured the root length, and on Day 14 recorded the mean root lengths at pH 4.00, 5.50, 7.13, and 8.50 to be 4.43 mm±0.39 mm, 7.07±0.33 mm, 9.82±0.39 mm, and 5.67±0.84 mm, respectively. Seedlings at pH 7.13 exhibited the greatest amount of growth and appeared healthier and more turgid on Day 14 than seedlings at all other treatments. Our results show a trend of decreasing root growth and health as pH diverges from a neutral pH of 7.13. Acidic water disrupts the Ca2+ processes, and basic water disassembles microfilaments, both of which inhibit cell growth (Hara et al. 2000, Guo et al. 2000). Results on Day 14 were statistically significant and indicate pH 7.13 as an optimal pH for seedling root growth. Thus, water at acidic and basic pH is detrimental to A. thaliana root growth.