Oligosaccharides as the effective components of Ascophyllum nodosum extract on plant growth and plant resistance against chilling stress in soybean (Glycine max) seedlings

Abstract

Ascophyllum nodosum extract (ANE) is a biostimulant that is derived from brown algae and has been reported to promote plant growth and resistance against biotic and abiotic stresses. The major dry components of Ascophyllum nodosum are polysaccharides that are found in both algae and fungal cell walls. When Ascophyllum nodosum is exposed to alkaline extraction, these major polysaccharides are degraded to their corresponding oligo-forms including oligo-alginate, oligo-chitin and oligo-chitosan. In the present study, the effects of ANE and these oligosaccharides on the plant growth and resistance were compared with each other on soybean (Glycine max) seedlings under chilling stress. ANE, oligo-alginate and oligo-chitosan treatments induced plant tolerance to chilling stress by decreasing the electrolyte leakage and increasing the recovery rate of the soybean leaves. Oligo-chitosan treatment enhanced plant growth by increasing the chlorophyll content under chilling stress. These results suggest that oligosaccharides might be the effective components of ANE