Physiological responses of soybean plants to pretreatment and foliar spraying with Ellagic acid and Seaweed extract under accelerated aging

Abstract

Loss of quality, viability and irreversible seed vigor over time due to seed aging is one of the main causes of reduction of quality and quantity of agricultural production. A wide range of secondary metabolites such as vitamins, growth regulators and antioxidant compounds were used to reduce the harmful effects of a variety of environmental stresses such as seed aging. These can be applied as seed pretreatment or foliar spraying of plants. To investigate the effect of seaweed extract (Ascophyllum nodosum) and ellagic acid on quality improvement of soybean, an experiment was designed and implemented in the field during 2019 and 2020. A factorial experiment was conducted based on a randomized complete block design (RCBD) with three replications. Two sets of seeds (un-aged and aged seeds), seed pretreatments and foliar spray treatments with ellagic acid and the seaweed extract to plants produced from aged seeds were conducted at three levels (control (zero), 50 mg/L of ellagic acid and 0.3% seaweed extract). The foliar spraying is done to improve the vigor of plants produced from aged seeds. Seed aging reduced the final emergence percentage under the field conditions. Seed pretreatments with the seaweed extract and ellagic acid increased the emergence. The amount of malondialdehyde, the activity of lipoxygenase, flavonoids and anthocyanins content also increased in the leaves of plants grown from the aged seeds in the field conditions. Seed aging reduced glutathione content, protein yield and seed yield. However, seed pretreatments with ellagic acid and the seaweed extract increased protein yield by 27.2% and 53.4%, respectively. Seed yield in plants grown from seeds treated with ellagic acid increased by 28.2%. Seed yield increased by 53.6% with application of seaweed extract as seed pretreatment. Foliar spray of ellagic acid and the seaweed extract to plants increased protein yield by 20.6% and 21.5%, respectively. Thus seed pretreatments and foliar spray of ellagic acid and the seaweed extract countered the effects of accelerated aging of soybean seed.