Efficacy and application potential of purified hydrocolloid coatings sprayed onto maize seeds subjected to anti-aging

The use of purified hydrocolloids extracted from waste-activated sludge has significant potential for preventing seed deterioration caused by aging. In this study, we compared the advantages and disadvantages of 3 types of purified hydrocolloid seed coatings from different waste sludges and one commercial seed coating at different spraying times (2, 4, 6, and 8). Compared with coated maize seeds, uncoated maize seeds underwent significant functional changes during the aging process according to the infrared spectroscopy results. Subsequent pot experiments were conducted at 4 days after aging. The average germination rate of the coated maize seeds was greater than that of the uncoated seeds at all spraying times. In terms of antioxidant enzyme activities, seeds treated with different coatings presented an increasing trend with increasing spraying time, indicating a difference between different spraying times. Principal component analysis revealed that the optimum number of sprays to achieve the results of carboxymethyl cellulose seed coating was 8 for the Xiaohongmen Wastewater Treatment Plant, 6 for the Dongba Wastewater Treatment Plant, and 4 for the Nanyang Wastewater Treatment Plant. The number of sprays applied in practice is an important determining factor during seed storage.