Effects of Chitosan Oligosaccharides with Different Molecular Weight on Growth and Physiological Characteristics of Maize Seedlings under Drought Stress
Under drought stress,50 mg/L chitosan oligosaccharides with different molecular weight(1 197,1 428,1 990 u)were sprayed to explore the effects of chitosan oligosaccharide with different molecular weight on the growth and physiological characteristics of maize seedlings,so as to provide a theoretical basis for the application of chitosan oligosaccharide with different molecular weight in production under drought stress.The results showed that under normal water condition,spraying chitosan oligosaccharide could promote the growth of maize seedlings.Under drought stress condition,spraying chitosan oligosaccharide could alleviate the impact of drought stress on the growth of maize seedlings.Among them,the plant height of treatments with chitosan oligosaccharides with small,medium and large molecular weight increased by 8.55%,9.37% and 5.80%,the stem diameter increased by 10.99%,5.23% and 1.31%,the dry weight of the aboveground part increased by 28.27%,38.82% and 19.83%,the dry weight of the underground part increased by 44.44%,39.58% and 29.17%,the leaf area increased by 43.45%,65.79% and 24.51%,the number of root branches increased by 114.57%,104.84% and 102.33%,the chlorophyll content increased by 43.07%,49.42% and 36.49%,the net photosynthetic rate(Pn)increased by 12.70%,22.49% and 6.80%,the content of superoxide anion decreased by 25.88%,35.74% and 21.83%,the activity of ascorbate peroxidase(APX)increased by 18.77%,29.92% and 11.43%,and the activity of glutathion peroxidase(GPX)increased by 23.30%,11.17% and 16.51%,respectively.Overall,under drought stress condition,spraying chitosan oligosaccharide with small molecular weight had the best effect on promoting the growth of the underground part,while spraying chitosan oligosaccharide with medium molecular weight had the best effect on promoting the growth of the aboveground part.The comprehensive evaluation results showed that the treatment with chitosan oligosaccharide with low molecular weight had the highest comprehensive score,followed by the treatment with chitosan oligosaccharide with medium molecular weight.
Chitosan oligosaccharideMolecular weightMaizeDrought stressGrowth and developmentPhysiological characteristics