| In this paper,Camellia osmantha,which has just entered the fruiting stage for 5 years,was taken as the research object.On the basis of defining the flower bud differentiation by leaf-picking method.Treatments of Camellia osmantha were taken by spraying the different concentration gibberellin at 200,400,800,1600,3200,6400 mg/L and irrigating 2L Paclobutrazol at different concentrations of 500,1000,2000,3000,4000,5000 mg/L.The effects of plant growth regulators on flower bud differentiation and spring shoot growth of Camellia osmantha were studied by investigating the number and growth of spring shoot flower buds,and the related physiological indexes were determined by regular sampling.In order to provide theoretical basis and data support for flower bud regulation of Camellia osmantha,The mechanism of physiological changes of plants treated with plant growth regulators during flower induction period was analyzed so as to understand the physiological response mechanism of Camellia osmantha to plant growth regulators.The main results are as follows:1.According to the formation of flower buds of spring shoots after leaf-picking at different stages,it was judged that the induction period of Camellia osmantha was from March 26 to April 19.There was no flower bud formation in spring shoots of leaf-picking on March 14,and the chlorophyll content in leaves of spring shoots was significantly lower than that in flower induction period.The results showed that the leaves had not yet synthesized and transduced flower bud differentiation signals,and the Camellia osmantha had not entered the flower induction stage.2.It could effectively promote the elongation and growth of spring shoots by spraying gibberellin at 1600 mg/L concentration from March 14 to April 19.There were significant effects on spring shoot diameter and internode length by spraying Gibberellin on March 14.There were inhibitory effects in the spring shoots of elongation growth and shortened the length of intemodes,but it can significantly increased the diameters of spring.The higher the concentration of paclobutrazol,the earlier the treatment time,the more obvious the effect.There were not significant effects on axillary bud formation by four sprays of gibberellin and three irrigation of Paclobutrazol during the whole treatment period.It could significantly promote flower bud differentiation of Camellia osmantha by spraying 800 and 1600 mg/L of gibberellin and watering 2 L of Paclobutrazol at the concentration of 2000 mg/L at the early stage of flower bud induction on March 14 during flower induction period spring shoot,and the earlier the treatment time,the better the effect.3.The peak time of total soluble sugar,soluble protein and free amino acid was approximately the same after spraying Gibberellin on March 14 before the induction period and irrigating Paclobutrazol on March 26 during the induction period of Camellia osmantha.The peak of total free amino acids appeared earlier than that of soluble protein.The increase of sugar content in Camellia osmantha leaves treated with 200-1600 mg/L concentration of gibberellin and 500-3000 mg/L concentration of Paclobutrazol increased with the increase of concentration.It had the highest accumulation of soluble protein by spraying 1600 mg/L gibberellin treatment while it had been shown to inhibit protein content by irrigating 5000 mg/L Paclobutrazol.It had always been the best promoters of amino acids of 1600 mg/L gibberellin and 1000-3000 mg/L Paclobutrazol treatments.According to the results of correlation analysis,it showed that there was no significant correlation between total soluble sugar,soluble protein and free amino acid.4.The content of MDA in 200-1600 mg/L gibberellin treatment was lower than or close to the control,while that in 3200-6400 mg/L treatment was higher than that in the control.The application of Paclobutrazol at the initial stage of flower induction would make the content of MDA in the cells of Camellia osmantha leaf increase rapidly.On March 26,2000 mg/L Paclobutrazol treatment was the most suitable time and concentration for improving SOD activity of Camellia osmantha leaves,and 1600 mg/L gibberellin treatment had the best effect for improving SOD activity of Camellia osmantha leaves in a short time.The activity of CAT increased with the florescence,and the decreasing degree of GA3 activity decreased with the increase of concentration.The effect of 2000 mg/L application on CAT activity on 7 April was the best.On March 26,the POD activity was significantly increased after treatment with 2000 and 3000 mg/L paclobutrazol,and on April 7,1000 and 2000 mg/L Paclobutrazol significantly increased POD activity.The concentration of gibberellin at 800?1600 mg/L was the ideal concentration to increase the POD activity in Camellia osmantha.. |
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