Effect Of Paclobutrazol On Plant Architecture And Physiological Characteristics Of Caragana Korshinskii

In order to study the migration of paclobutrazol in the sand and the effects of paclobutrazol with different concentrations on the plant architecture characteristics of Caragana korshinskii,this paper analyzed the distribution of pesticides in sand by the simulation experiment on soil column under different application times(before and after preciptation,30 mm rainfall)and the migration of paclobutrazol with three types(pesticide A,B and C,respectively represent Chinese paclobutrazol mass fraction of 17.5%,Chinese paclobutrazol with mass fraction of 17.5% added the adhesive and American paclobutrazol with mass fraction of 22.3%)and three concentrations(200 mg/L?400 mg/L?600 mg/L)by intermittent leaching(each 20 mm,once every six days,ten times),proposing the suitable application of paclobutrazol in sandy soil preliminarity;and the paclobutrazol with three types and six concentrations(0?200 mg/L?300 mg/L?400 mg/L?500 mg/L?600 mg/L)was applied on annual Caragana korshinskii,monitoring the changing process of growth and physiological indexes of the plant,concluding that the optimal concentration range of different treatments in various indexes;this study aims to actively research artificial regulation measures to improve the effects of desert shrub on wind prevention and sand fixation,so as to provide a technical support for vegetation construction and management in semi-arid and arid region.The main results of this thesis:(1)The application effect of paclobutrazol before precipitation was better than that after precipitation.The residual amount of paclobutrazol in each layer of soil(0-10 cm?10-20 cm?20-40 cm?40-60 cm)before rainfall was higher than that after precipitation whether the initial value or the termination value of the residue in the soil,especially in the 20-60 cm.It showed that the effect of applying paclobutrazol before precipitation was better than that after precipitation.and the pesticide spread more easily in the 20-60 cm soil layer,which is beneficial for plants to absorb and utilize.(2)Under the condition of simulating rainfall leaching intermittently,the migrations of paclobutrazol with three types were different.The residual concentration of paclobutrazol decreased with the increase of leaching times no matter what concentration,and finally remained stabilization;in the surface soil,the residual concentration of paclobutrazol decreased gradually,while the residual concentration in deep soil increased gradually.The higher the concentration is,the more obvious the effect is.At the beginning of rainfall leaching,pesticide C could infiltrate into the deep soil with water,and it could maintain a good residual concentration in the 20-60 cm soil layer for plants to absorb and utilize,the adhesive in the pesticide B increased the ability to adhere the soil.The sequence of migration effect is pesticide C > pesticideB > pesticide A.(3)Paclobutrazol can significantly affect the plant architecture characteristics of Caragana korshinskii,and the optimum ranges of concentration were different.With the increasement of treatment concentration,the variation of the plant height and stem were all enhanced,and the reduced amount of the leaf area and increment of the leaf thickness also showed a rising trend,the numbers with 600 mg/L was the highest;the variable quantity of branching numbers and angle increased firstly and then decreased with the improvement of the concentration,when the concentrations of the three kinds of pesticide(A: China-paclobutrazol with the mass fraction of 17.5%;B: China-paclobutrazol with the mass fraction of 17.5% added the adhesive;C: America-paclobutrazol with the mass fraction of 22.5%)were in the range of 300~400 mg/L,the number of branching number was the most,and the branching angle was the largest;the root surface area reached the maximum under 400 mg/L concentration,A with 400 mg/L,B and C with 500 mg/L increased the number of all levels of the root.The results showed that paclobutrazol can regulate the architecture,dwarf the plant,thicken the ground diameter,and extend the area of cover and root,promoting root tillering.The optimum concentration was different under different treatments,balancing growth indexes,the optimal treatment concentration range is 300 mg/L~400 mg/L when applying A pesticide,and the optimal treatment concentration range is 400 mg/L~500 mg/L when applying B pesticide and C.(4)Paclobutrazol can significantly affect the plant physiological indexes,the paclobutrazol with suitable concentration increased the contents of chlorophyll,leaf water content and water holding capacity,which showed that PP333 enhanced the drought resistance of plants.When the treatment concentration is 300~400 mg/L with pesticide A and C,the chlorophyll content,leaf water content,succulent index were high and water saturation deficit and tissue density were low,and chlorophyll content remained high values after the growth period;when the concentration of pesticide B was 500 mg/L,the chlorophyll content in leaves was the highest,and when the concentration was 300 mg/L,the leaf water content and water holding capacity were the best.(5)Paclobutrazol can affect its adaptation to the environment by affecting the biochemical indexes of the plant,the paclobutrazol of suitable concentration increased the content of soluble sugar and free proline,reducing the damage of MDA to plant and improving the ability of drought resistance of Caragana korshinskii.When applying pesticide A,in the aspect of influencing MDA and soluble sugar,the optimal treatment concentration is 500~600 mg/L,in the aspect of influencing free proline,the optimal treatment concentration is 200 mg/L;when applying pesticide B,the optimal concentration of reducing MDA was 500 mg/L,the optimal concentration of increasing soluble sugar and free prolinewas 400 mg/L and 200 mg/L;when the concentration of pesticide C was 500 mg/L,MDA content was lowest,soluble sugar and free proline content were higher.