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

Abstract

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.