The impacts of different Al(NO₃)₃ concentrations on the mitotic index of Allium sativum

Acid deposition, produced when NOx and SO₂ emissions react with water to produce HNO₃ and H₂SO₄, is regarded as a significant threat to biodiversity and agriculture. Soil pH conditioners have been developed to counteract this phenomenon; however, they sometimes fail to reverse nutrient imbalances caused by acid deposition. One of the problematic nutrient imbalances is the formation of aluminum nitrate, which dissociates to produce toxic Al³⁺ ions. In Basque country (Spain), a recent surge in metallurgical activities and the popularization of climate change denial threatens a drastic rise in NOx emissions. We explored whether returning to peak emissions of NOx, such as those in 1990, will increase Al(NO₃)₃ concentrations to a level where they significantly lower the mitotic index (the ratio of cells undergoing mitosis in a specific population of cells) of one of the most culturally significant vegetables of the region, Allium sativum. We grew cloves of A. sativum at different concentrations of Al(NO₃)₃. We processed tips of these cloves and placed them under a microscope to calculate their mitotic index. We hypothesized that a larger concentration of Al(NO₃)₃ would lower the mitotic index of A. sativum, since Al(NO₃)₃ dissociates in water to produce Al³⁺ ions, which are highly toxic as they inhibit cell division and elongation. Our results showed a negative exponential correlation between Al(NO₃₃ and the mitotic index of A. sativum, as the higher the Al(NO₃)₃ concentration, the lower the mitotic index.