[Effects of Silicon-zinc Interaction on Growth and Physiological Parameters of Maize Under Cadmium Stress].

Abstract

To evaluate the effects of exogenous Si and Zn on the root architecture and physiological effects of maize under Cd stress, a hydroponic experiment was conducted to investigate the effects of 1 mmol·L^-1 Si and 100 μmol·L^-1 Zn on the growth, photosynthetic system, Cd concentration, absorption kinetics, malondialdehyde （MDA） content, and antioxidant of maize seedlings （Zhengdan 958） under 50 μmol·L^-1 Cd stress, which were evaluated using principal component analysis. The results showed that Cd stress significantly inhibited the growth of maize seedlings. The main root length, plant height, and biomass decreased significantly； root development and photosynthetic system were inhibited； and MDA and antioxidant content increased significantly. Under Cd stress, the application of exogenous Si and Zn could effectively reduce the maximum absorption rate of Cd in seedlings and reduce oxidative stress by improving the AsA-GSH cycle, decreasing MDA content, and enhancing photosynthesis, which effectively improved the growth status of maize seedlings. The main root length and plant height were increased by 9.19%-40.88% and 14.35%-18.92%, respectively. The dry weight of the root and shoot were increased by 51.76%-151.76% and 53.11%-84.31%, respectively, and the alleviation effect of Si-Zn interaction on Cd toxicity was slightly better than that of Si or Zn alone. Among them, Si played an important role in inhibiting Cd uptake by maize. The Cd concentration in the underground and aboveground parts was significantly reduced by 43.55% and 80.43%, respectively. The results showed that exogenous application of Si and Zn could alleviate Cd-induced oxidative stress by regulating the content of antioxidant, enhancing photosynthesis, promoting the growth of maize seedlings, and effectively improving the tolerance of maize seedlings to Cd toxicity, which was conducive to the rational utilization of heavy metal-contaminated farmland and food security production.