Agar oligosaccharide is an oligosaccharide molecule with low polymerization degree obtained by further degradation of agar. Biological activity studies have shown that agar oligosaccharides have antibacterial, anti-oxidant, anti-inflammatory and anti-tumor effects, and have elicitor activity on plants. Sun Minxiu and others explored the effect of agar oligosaccharides as elicitors on cucumber resistance and acetamiprid residues.
In the experiment, Cucumber No. 18 of Bicui was used as the material, and agar oligosaccharides with a degree of polymerization of 2-10 were selected. During the growth of cucumber, 3 agar oligosaccharides of 0 (CK), 100, and 200 ug/mL were sprayed. Fixed spraying once a week, 30 plants for each treatment, 3 repetitions. The cucumber growth indicators, resistance-related enzyme activity and gene expression, and pesticide acetamiprid residues were determined.
The test results show that spraying agar oligosaccharides can significantly promote the growth of cucumber plants and increase fruit yield (see Table 1 and Figure 1); increase the superoxide dismutase, peroxidase, polyphenol oxidase, and peroxidase of cucumber leaves Hydrogenase activity, reduce the content of malondialdehyde (see Figure 2); and up-regulate the expression of chitinase and disease-related protein 1 gene, the highest expression levels were 10.4 times and 14.5 times that of the control group (see Figure 3). In addition, spraying agar oligosaccharides effectively reduced the half-life of acetamiprid on cucumbers and accelerated its degradation (see Figure 4). Fruit soaking test results also show that agar oligosaccharides can significantly reduce pesticide residues, and 100 ug/mL agar oligosaccharide solution can reduce pesticide residues by 68.29% (see Figure 5). Therefore, agar oligosaccharides have the effects of promoting cucumber plant growth, improving resistance and reducing fruit pesticide residues, and have good development value in agricultural production.