As a new type of plant immune inducer, chitosan oligosaccharide water is a broad-spectrum plant agent which can protect against cold and fruit. To investigate the effects of this drug on citrus antifreeze, fruit preservation, yield increase and fruit quality improvement, the effects of chitosan oligosaccharide soluble liquid on citrus stress resistance, quality and benefit were investigated.
There were eight treatments in the experiment, which were 200 times solution,500 times solution,650 times solution,800 times solution,950 times solution,1100 times solution and 1400 times solution of water spraying 5% chitosan oligosaccharide. Foliar spray was used 10 days before the onset of freezing injury, before the onset of freezing injury,2/3 of bud period,2/3 of flower Xie,2/3 of initial fruit stage and 2/2 physiological fruit setting respectively.
As a result, the percentage of lyophilized leaves treated with amino-oligosaccharides was lower than that of control. Using 800 times liquid spray, the rate of frozen leaves was the lowest (10.63%), the concentration was too high or too low, and the antifreeze effect was not ideal. the fruit setting rate of all treated with chitosan oligosaccharides was higher than that of the control. among them, the highest fruit setting rate of citrus was sprayed with 500 times solution (6.99%). It indicates that the citrus fruit setting rate can be significantly improved by spraying chitosan oligosaccharides in a certain concentration range. spraying chitosan oligosaccharides can significantly increase the single fruit weight of citrus fruit. Among them, the single fruit weight of citrus sprayed with 800 times solution was the highest at 140.55 g. the soluble solids content, total sugar content, and VC content were all treated with 800 times liquid as the highest,9.50%,14.29 g/100 ml,30.64 mg/100 g, respectively. The results showed that 5% chitosan oligosaccharide water had certain effect on preventing citrus freezing, increasing fruit setting rate and single fruit weight, improving fruit quality, among which 800 times liquid treatment had the best effect on freezing resistance, increasing fruit weight and improving nutrition quality of citrus.