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| In order to further confirm the connection between reactive oxygen species(ROS) and hyperhydricity, in this experiment, using garlic variety 'Ershuizao' as test material, the changes of hyperhydricity rate and the generation and localization of endogenous ROS of garlic plantlet in vitro were studied under exogenous hydrogen peroxide(H2O2), exogenous H2O2 + Ascorbic acid(AsA, a ROS scavenger) treatments with plantlet under normal culture as the control. The results showed that the hyperhydricity rate under exogenous H2O2 treatment was 30.66% on day 16 after treatment, significantly higher than that of the control(13.37%) and exogenous H2O2+AsA treatment(19.22%). Compared with the control, the O2.- generation rate and H2O2 level of garlic shoots treated by exogenous H2O2 on the 8th day increased significantly; whereas exogenous H2O2 + AsA treatment reduced the generation of O2.- and H2O2 significantly, accordingly, hyperhydricity rates decreased significantly. The histochemical localization of O2.- and H2O2 demonstrated that endogenous ROS accumulated mainly in leaves and pesudostems under different treatments with the H2O2 treatment exhibited the largest accumulation. Cytochemical staining showed that H2O2 accumulation was observed mostly in cell wall, intercellular space and chloroplast. The studies preliminarily confirmed that exogenous H2O2 stress enhanced the generation of endogenous O2.- , H2O2 and the occurrence of hyperhydricity of garlic plantlet in vitro effectively, and application of exogenous AsA significantly decreased the accumulation of ROS and hyperhydricity rate induced by H2O2 stress, indicating a close connection between ROS and hyperhydricity. |
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| Keywords:Garlic (Allium sativum L.); Plantlet in vitro; Hyperhydricity; Reactive oxygen species (ROS); Hydrogen peroxide (H2O2); Ascorbic acid (AsA) |
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