Functions of Oligosaccharides in Improving Tomato Seeding Growth and Chilling Resistance

Abstract

Oligosaccharides help promote plant growth and resilience. In this study, chitosan oligosaccharide (CSOS), cello-oligosaccharide (COS), xylooligosaccharide (XOS), and oligomix (MixOS) (a mix of the three oligosaccharides (mass ratio 1:1:1)) were used to explore their possible regulatory abilities and mechanisms on tomatoes in normal conditions and chilling stress. In normal growth, the XOS had the greatest effect on increasing biomass (increased by 69.5%) in roots, and there was a significant increase (26.5%) of auxin (IAA) absorption. The COS increased main root length by 29.4%, but the content of methyl jasmonate (JA-ME) was 17% lower than other treatments. The MixOS was 2.7 times more effective in enhancing shoot biomass, and increased accumulation of IAA content by 30% above-ground. Under chilling stress, the plant photosynthetic activities and metabolic functions were less damaged with oligosaccharide treatments. In comparison to the control, COS, XOS, and CSOS effectively increased the content of soluble sugar and decreased the permeability of cell membrane, especially in the CSOS treatment in which soluble sugar increased by 37.8% and the permeability of cell membrane decreased by 35.4%. Similarly, the MixOS also possessed an effective resistance to chilling. These results suggested different oligosaccharides played different roles in plant growth, phenotype and resistance. The oligomix was the most effective in improving the plant growth and chilling tolerance. These novel results provide fundamental evidences for the development and application of oligosaccharide in sustainable agriculture.