Cold Resistance Physiology Of Viburnum Sargentii And Weigela Florida ‘variegata’

Taking Viburnum sargentii and Weigela florida ‘Variegata’ as experimental materials,this experiment first studied the effects of treatment of different reagents on the rooting of these two plants by means of hydroponic cutting and vermiculite cutting, and then, taking and one and two-year-old dormant branches of Viburnum sargentii and Weigela florida ‘Variegata’ as materials, studied how the relative conductivity, SOD, POD, MDA, the soluble protein and proline of the branches would change after low temperature treatment, and determined their lethal temperature(LT50) according to the Logistic equation, and finally got a comprehensive evaluation of the cold hardiness of the two plants combined with membership function method. The conclusions are listed as follows:1. Both NAA and IBA could induce rooting; NAA has a better effect on Viburnum sargentii than IBA, while IBA has a better effect on Weigela florida ‘Variegata’ than NAA; 50mg/L NAA treatment is the optimum concentration for hydroponic cuttings and vermiculite cuttings of Viburnum sargentii, while 200mg/L IBA treatment is the optimal concentration for vermiculite cuttings of Weigela florida ‘Variegata’, and 50mg/ L IBA is the best for the rooting of its hydroponic cuttings.2. As the temperature decreases, the relative conductivities of the dormant branches of both Viburnum sargentii and Weigela florida ‘Variegata’ show rising trends in various degrees. Based on the test data and combined with Logistic equation, the semi-lethal temperatures(LT50) of the four tested materials are determined:-16.36 ℃,-18.89 for 1 ℃and 2-year old branches of Viburnum sargentii respectively, and-19.22 ℃,-24.70 for 1 ℃and 2-year old branches of Weigela florida ‘Variegata’ respectively.3. In the process of low temperature stress, the SOD, POD activity of the four tested materials first rises and then drops as the temperature decreases; the SOD, POD activity of branches from plant with strong cold resistance has a stronger ability to adapt to the low temperature, and its change with temperature is relatively stable; plants with weak cold resistance has a poor ability to adapt to temperature changes.4. With the decrease of temperature stress, the proline contents of the four tested materials were all increased first and then decreased; and the contents of MDA and soluble protein increased gradually with decreasing temperature.5. During artificial low temperature processing, the changing trends of various physiological and biochemical indicators of Viburnum sargentii and Weigela florida ‘Variegata’ are basically consistent. The relative conductivity and MDA content were negatively correlated with their cold hardiness, while the protective enzyme activity and content of osmotic adjustment substance were positively correlated with their cold hardiness.6. Based on the comprehensive evaluation of 1 and 2-year old branches of Viburnum sargentii and Weigela florida ‘Variegata’, the cold hardiness of the four tested materials are listed in order: Weigela florida ‘Variegata’ 2 years old branches> Weigela florida ‘Variegata’ 1 year old branches> Viburnum sargentii 2 years old branches> Viburnum sargentii 1 year old branches.