Impact of Zinc Stress on Biochemical and Biophysical Parameters in Coffea Arabica Seedlings

Zinc is an essential micronutrient for the healthy development of plants, since its insufficient and supraoptimal doses can disrupt the metabolism and biomass production. We aimed to investigate the physiological responses of coffee seedlings to Zn deficiency and excess. Six-month-old seedlings were transferred to plastic pots containing a nutrient solution. The treatments were control (0.03 ppm), zinc deficiency (0.00 ppm), and zinc excess (0.12 ppm). The evaluations were performed in leaves and roots at the beginning of the treatments and after 30 and 60 d of treatments. Zn deficiency and excess increased the production of hydrogen peroxide, antioxidant enzymes activity, ascorbate, and lipid peroxidation contents. The imbalance in zinc nutrition reduced total chlorophyll content and increased carotenoids content throughout the experimental period. Lower biomass and proline accumulation were observed only for deficient seedlings at the end of the experiment. The characteristics analyzed showed that zinc deficiency caused greater damage to the Coffea arabica plants of (Catuai cultivar) than zinc excess.