Effects Of Exogenous Aluminum On Growth And Physiological Characteristics Of Hydrangea

Hydrangea macrophylla L.is an aluminum-tolerant plant with large,brightly colored flowers,and the flower color can be artificially adjusted to blue.In order to solve this problem,this experiment was conducted in a potted experiment with six varieties of Hydrangea macrophylla as the test material,and six gradients of aluminum sulfate concentrations of 5 g/L,10 g/L,15 g/L,20 g/L,25 g/L and 30 g/L were set up to investigate the growth and physiological indicators of the six varieties of Hydrangea macrophylla under different aluminum treatments at the seedling and flowering stages,and to investigate the growth and physiological characteristics of the six varieties of Hydrangea macrophylla under different concentrations of aluminum stress.The aim was to compare the aluminum tolerance of the six varieties and to screen the optimal aluminum sulfate concentration for healthy plant growth,with the aim of providing a theoretical basis for the application of aluminum color adjustment technology and a practical guide for the breeding of new aluminum-tolerant varieties of Hydrangea macrophylla in the future.The main research results were as follows:(1)All six Hydrangea macrophylla varieties could grow normally under low concentration of aluminum treatment(5 g/L and 10 g/L),and their growth was better compared with the control.Low concentration of aluminum stress had no toxic effect on Hydrangea macrophylla and also promoted plant growth;they could grow normally at aluminum sulfate concentrations of 15 g/L and 20 g/L but their growth was weakened compared with the control,and when the aluminum sulfate concentration was greater than 20 g/L,plant growth was inhibited and In severe cases,the leaves dried up and even the plants died.The optimum concentration of aluminum sulfate solution for the growth of Hydrangea macrophylla was 10 g/L.The tolerance of six varieties of Hydrangea macrophylla to aluminum sulfate solution in the growth response was as follows:’White Lemon’>’Little Sea Orchid’>’Flying Saucer Purple’.’Flying saucer series purple’>’Pink art’>’Double pride pink’>’Pink passion’.(2)As the concentration of aluminum sulfate increased,the chlorophyll content of the six varieties of Hydrangea macrophylla showed a general trend of first increasing and then decreasing.Low concentration of aluminum stress was beneficial to better photosynthesis of Hydrangea macrophylla and promoted its ability to adapt to adversity,while chlorophyll synthesis was inhibited when the concentration was too high.The antioxidant enzyme system could offset the oxidative damage caused by the stress to a certain extent,but under severe stress,the protective effect on the membrane system was limited.The analysis of physiological indexes showed that the optimum aluminum sulfate concentration of all the six species of Bacopa monniera was 10 g/L,and their tolerance to aluminum sulfate solution was in the following order:’Little Sea Orchid’>’Flying Saucer Series Purple’>’White Lemon ’>’Pink Art’>’Double Pride Pink’>’Pink Passion’.In conclusion,low concentration of aluminum treatment(5 g/L and 10 g/L)is beneficial to the growth of Hydrangea macrophylla,while high concentration of aluminum treatment(≥20 g/L)inhibits the growth of the plant,and in severe cases the plant dies.The optimal concentration of aluminum sulfate solution for the growth of Hydrangea macrophylla is 10 g/L.This study provides theoretical basis and technical guidance for the color control technology of Hydrangea macrophylla and the breeding of new aluminum-tolerant varieties.