Mitigative Effect Of Inositol And Its Derivatives On Chilling-Induced Injuries In Maize Seedlings

Low temperature stress is a common natural disaster in agricultural production, which would severely reduce the growth, development, and production of maize. Therefore, it’s urgent to find ways to improve the chilling tolerance of maize and figure out the possible mechanism. Inositol is a water-soluble vitamin which is required for the growth of human being, animals, and microorganisms. Among them, inositol is extremely important for plant growth, and is involved in phosphatidylinositol signaling pathway, auxin storage and transport, phytic acid biosynthesis, cell wall formation and plant response to stresses. Phytic acid and phytin are two derivates of inositol, but they are not commonly used in plant production.A maize cultivar "Suyu 24" was used in this study. The maize seedlings were foliar-sprayed with inositol solutions at certain concentrations, and then subjected to chilling treatment at 4℃. After that, the effect of inositol on the chilling responses and its physiological processes in maize seedlings was examined and analyzed. The results showed that 0.8 g/L inositol exhibited the strongest mitigating effect the low temperature-induced injuries in maize seedlings. Under chilling stress, the seedlings had the increased SOD, CAT, and POD activities, MDA, H2O2, superoxide anion and free proline contents, but the decreased chlorophyll content. Inositol application caused the significant decrease of MDA, H2O2 and superoxide anion contents, but the increase of SOD, CAT and POD activities, chlorophyll and free proline content. In conclusion, exogenous 0.8 g/L inositol were capable of reducing the accumulation of reactive oxygen species, enhancing the activities of antioxidant enzyme system, protecting the structure and function of membrane, reducing the membrane lipid peroxidation, thus mitigating the chilling injuries in maize seedlings.The actions of the two derivates of inositol were also examined. The maize seedlings were incubated at 4℃ after foliage spraying of different concentrations of phytic acid and phytin, and their effects on mitigating the chilling-induced injuries in maize seedlings was explored. Moreover, the actions of phytic acid and phytin on physiological processes involved in chilling responses were analyzed. The results showed that exogenous phytic acid can mitigate the low temperature-induced injuries in maize seedlings, and the best concentration is 1.6 g/L. SOD, CAT, and POD activities increased for both control and treatment at 4℃; MDA content of treatment were significantly lower than control, while SOD, CAT, and POD activities, chlorophyll and free proline content were significantly higher. Above results suggest that exogenous phytic acid is able to reduce the membrane lipid peroxidation, decrease the accumulation of reactive oxygen species, enhance the activities of antioxidant enzyme system, and protect the structure and function of membrane in maize seedlings under chilling stress.