Morphological response of a cactus to cement dust pollution.

Cement dust from cement plants around the world has multiple negative effects on organisms and their environment. Cement's effects come from its strongly alkaline nature and high content of heavy metals. Previous studies on plants have documented that cement dust deposition can influence plant vegetative growth, the lipid and ionic composition of tissues, and foliar temperature. Here we evaluate the effects of cement dust coming from a plant in western Argentina on the morphology of the cactus Tephrocactus aoracanthus. In sites located at 0.15km, 2km and 6km from the cement plant, we recorded five morphological attributes of the cactus: length and number of spines, cladode (stem) diameter, and fresh and dry weight. We also transplanted plants in situ to evaluate the effect of distance from the cement plant. In addition, we set an experiment spreading cement dust weekly on the aerial and ground parts of the cactus. Results of our field observational and experimental studies indicate that cement dust deposition on aerial parts of the plant leads to increased spine length, number of spines, and wet and dry weights of cladodes.