Effects of Foliar Spraying Chitosan on Relieving Low Temperature Stress on Loofah Seedlings

PurposeTo investigate the effects of exogenous chitosan on physiological characteristics of loofah seedlings under low temperature treatment, screening the optimal mass concentration of exogenous chitosan.

MethodsA pot experiment was conducted to study the effects of different mass concentrations of exogenous chitosan on photosynthetic pigment content, relative conductivity, malondialdehyde (MDA) content, osmotic adjust substance content, antioxidant enzyme activity and mineral element content in leaves of loofah seedlings under low temperature treatment (8 ℃).

ResultsUnder low temperature treatment, the contents of chlorophyll a, chlorophyll b, carotenoids, total chlorophyll, soluble protein, free proline, nitrogen and phosphorus in the leaves of loofah seedlings decreased or decreased significantly, and the activities of superoxide dismutase, peroxidase and catalase also decreased significantly, while the relative conductivity, MDA and potassium content increased significantly. After the application of exogenous chitosan, the contents of photosynthetic pigments, osmotic adjust substance and mineral elements in the leaves of loofah seedlings increased, the activities of three antioxidant enzymes increased, and the relative conductivity and MDA content decreased. When the mass concentration of exogenous chitosan was 25 mg/L, the mitigation effect on each index was the best.

ConclusionFoliar spraying 25 mg/L chitosan has the best effect on improving the cold tolerance of loofah seedlings, and it can promote the growth of loofah seedlings and the absorption of nitrogen, phosphorus and potassium.